JP2012064572A - Nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery improved in durability characteristics, such as a cycle and a storage characteristic, and a load characteristic.SOLUTION: The nonaqueous electrolyte battery includes: nonaqueous electrolyte comprising lithium salt and nonaqueous solvent in which the lithium salt is dissolved; and a negative electrode capable of absorbing/desorbing lithium ions, and a positive electrode. The positive electrode contains a lithium transition metal compound powder, and the electrolyte contains a specific compound.

Description

  The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte battery containing a specific cyclic compound having a triple bond as an electrolyte.

  Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are widely used as power sources for so-called portable electronic devices such as mobile phones and notebook computers, to in-vehicle power sources for automobiles and large power sources for stationary applications. It is being put into practical use. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, high temperature storage characteristics, cycle characteristics, and the like.

The electrolyte used for the non-aqueous electrolyte lithium secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.
In addition, various nonaqueous solvents, electrolytes, auxiliaries, and the like have been proposed in order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low temperature characteristics of batteries using these nonaqueous electrolyte solutions. .
For example, in a non-aqueous electrolyte using a carbon material for the negative electrode, by using vinylene carbonate and its dielectric or vinyl ethylene carbonate derivative, the cyclic carbonate having a double bond reacts preferentially with the negative electrode surface. Patent Documents 1 and 2 disclose that a high-quality film is formed on the battery, thereby improving the storage characteristics and cycle characteristics of the battery.
Patent Document 3 describes that LiNi _0.5 Mn _1.5 O ₄ has a high energy density as a positive electrode material. However, since this positive electrode active material has an operating voltage as high as 4.5 V or more, there is a problem that side reactions with the electrolytic solution easily occur and gas generation is large.

JP-A-8-45545 JP-A-4-87156 JP-A-2005-322480

  As described above, the demand for higher performance of the secondary battery in recent years is increasing, and thus the improvement of the characteristics of the lithium secondary battery, that is, the improvement of the capacity, the high temperature storage characteristic, the cycle characteristic and the like is required. In such a background, in the nonaqueous electrolyte battery using the electrolyte solution described in Patent Documents 1 and 2, if the charged battery is left at a high temperature or a continuous charge / discharge cycle is performed, However, there is a problem that the unsaturated cyclic carbonate or a derivative thereof oxidizes and decomposes to generate carbon dioxide gas. If carbon dioxide gas is generated in such a use environment, the battery itself may become unusable due to, for example, activation of a battery safety valve or expansion of the battery.

Further, the oxidative decomposition of unsaturated cyclic carbonate on the positive electrode also causes a problem of generating a solid decomposition product in addition to the generation of carbon dioxide gas. The generation of such a solid decomposition product may cause clogging of the electrode layer or separator to inhibit the movement of lithium ions, or may remain on the surface of the electrode active material to inhibit the lithium ion insertion / release reaction. is there. Under such conditions, for example, the charge / discharge capacity gradually decreases during a continuous charge / discharge cycle, the charge / discharge capacity decreases after the high temperature storage or the continuous charge / discharge cycle, or the load characteristics deteriorate. There is a case.

  Also, the oxidative decomposition of unsaturated cyclic carbonate on these positive electrodes becomes a particularly serious problem under the design of high performance secondary batteries in recent years. That is, this oxidative decomposition tends to become more prominent when the potential at which the positive electrode active material inserts and desorbs lithium increases the redox potential of lithium. For example, when the battery voltage at the time of full charge that is currently on the market is operated at a higher voltage than a battery of 4.2 V, these oxidation reactions are particularly prominent.

  In addition, as an alternative method for increasing the capacity of a non-aqueous electrolyte battery, it has been studied to pack as many active materials as possible in a limited battery volume. In batteries designed to increase the density or reduce the volume other than the active material in the battery as much as possible, the voids inside the battery are reduced, and the internal pressure of the battery increases significantly even when a small amount of gas is generated by oxidative decomposition. The battery itself may become unusable due to the operation of the safety valve or the expansion of the battery.

  Therefore, the present invention solves the above-mentioned various problems that are manifested in the required performance of secondary batteries in recent years, and in particular, a non-aqueous electrolyte battery having improved durability characteristics such as cycle and storage and load characteristics. It is to provide a non-aqueous electrolyte suitable for the non-aqueous electrolyte battery.

As a result of intensive studies to solve the above-mentioned problems, the inventors have used a positive electrode containing the following positive electrode active material (A) in a non-aqueous electrolyte solution used for a non-aqueous electrolyte battery, It has been found that a non-aqueous electrolyte battery with improved durability and load characteristics such as cycle and storage can be realized by containing at least one or more compounds selected from the group consisting of compounds represented by the following general formula (1). The present invention has been completed.
That is, the gist of the present invention is as follows.
(1) A non-aqueous electrolyte battery comprising a non-aqueous electrolyte solution comprising a lithium salt and a non-aqueous solvent for dissolving the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a positive electrode, A non-aqueous electrolyte battery comprising the following positive electrode active material (A), wherein the electrolyte contains a compound represented by the following general formula (1).
(A) A lithium transition metal-based compound powder that includes a crystal structure belonging to a spinel structure, has a BET specific surface area of 0.3 m ² / g or more, and has a composition represented by the following composition formula (A).
Li [Li _a M _x Mn _2−x−a ] O _{4 + d} (i)
(In formula (a), 0 ≦ a ≦ 0.3, 0.4 ≦ x ≦ 0.6, −0.5 <δ <0.5 is satisfied, and M is Ni, Cr, Fe, Co and Cu. Represents at least one of transition metals selected from

(In the formula (1), X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ^{1 and} are the same. However, Y may be different, and Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . , R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, and R ² represents a functional group. .R ³ is also a hydrocarbon group having from good 1 to 20 carbon atoms having the, Li, ^NR _{4 4,} or a hydrocarbon group having carbon atoms 1 may have a functional group 20 .R ⁴ Is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, n and m each represents an integer of 0 or more, and in the adjacent ring Carbon may form a further bond with each other, and the R of the carbon may be reduced by one each. W represents the above R.)
(2) The non-aqueous electrolyte battery according to (1), wherein 0 <a ≦ 0.3 in the formula (A) of the lithium transition metal-based compound powder.
(3) The non-aqueous electrolyte solution according to (1) or (2), wherein the compound represented by the general formula (1) is a compound represented by the formula (2).

(Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ^3, and R ² may have a functional group. And a hydrocarbon group having 1 to 20. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and R ⁴ has a functional group. And may be the same or different from each other.
(4) The amount of the compound represented by the general formula (1) is 0.001% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. 3) The nonaqueous electrolyte battery according to any one of the above.
(5) The non-aqueous electrolyte contains at least one or more selected from the group consisting of a cyclic carbonate having a double bond and a cyclic carbonate having a fluorine atom. (1) to (4) The non-aqueous electrolyte battery according to any one of the above.
(6) The non-aqueous electrolyte battery according to any one of (1) to (5), wherein the median diameter of the lithium transition metal compound is 2 μm or more and 60 μm or less.
(7) The non-aqueous electrolyte battery according to any one of (1) to (6), wherein an electrode plate density of the positive electrode is 2 g / cm ³ or more.
(8) A non-aqueous electrolyte used in the non-aqueous electrolyte battery according to any one of (1) to (7).

One feature of the present invention is that a compound in which a triple bond is bonded to a ring structure by a single bond without using any other functional group or heteroelement is used in a non-aqueous electrolyte battery. Usually, as typified by Patent Documents 1 and 2, many of the materials that protect the electrode surface and improve battery durability such as storage characteristics and cycle characteristics are compounds of a cyclic structure, and further have multiple bonding sites. Have. The present inventors paid attention to this point, and examined in detail the bonding sites of functional groups and heteroelements in the ring structure, the sites where multiple bonds are bonded to the ring structure, and the hybrid state of the electron orbits of the multiple bonds. As a result, for example, a compound in which a double bond is bonded to a ring structure is more stable with a positive electrode than a compound in which a part of the ring skeleton constituting the cyclic compound is a double bond, In addition, when the triple bond substituent is bonded to the ring structure, an effect superior in durability characteristics to the double bond can be obtained, and the knowledge that the above problems can be solved has been obtained. In addition, the present inventors have found that the effect of the present invention is more effective when combined with battery components such as a negative electrode, a positive electrode, and a separator. As an example, it is configured to include a crystal structure belonging to the spinel structure as in the present invention, and the effect is further manifested in combination with a lithium transition metal compound powder represented by the following composition formula (I). I also found out.

<Reason why the present invention is effective>
The reason why the nonaqueous electrolyte battery of the present invention is effective is not yet clear, but is presumed as follows.
That is, the triple bond site of the compound represented by the general formula (1) contained in the electrolytic solution defined in the present invention is a dangling bond on the surface of the lithium transition metal compound represented by the composition formula (I). It is presumed that the high-temperature storage characteristics are improved in order to bind to the active sites of these compounds to lose activity and suppress side reactions with the electrolyte.

  That is, by using the present invention as described above, the non-aqueous electrolyte solution has improved battery load characteristics, durability characteristics such as cycle and storage, especially in the design of lithium secondary batteries with higher voltages and higher capacities. A battery and a non-aqueous electrolyte used for the non-aqueous electrolyte are provided.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.
1. Non-aqueous electrolyte 1-1. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, inorganic lithium salts LiTaF 6, LiWF ₇ and the like;
Lithium fluorophosphates such as LiPO ₃ F and LiPO ₂ F ₂ ;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ Sulfonic acid lithium salts such as CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium imide salts such as lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) ;
Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiBF 3 C 3} F 7, LiBF 2 (CF 3) 2, LiBF 2 (C 2 F 5) 2, LiBF 2 (CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2 Fluorine-containing organic lithium salts such as;

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiPO ₂ F ₂ , FSO ₃ Li, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN ( CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , Li PF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) _{3 and the} like are particularly preferable because they have an effect of improving output characteristics, high-rate charge / discharge characteristics, high-temperature storage characteristics, cycle characteristics, and the like.

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using two or more kinds in combination is a combination of LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li, LiPF ₆ and LiPO ₂ F _2, etc., and has an effect of improving load characteristics and cycle characteristics. . Among these, the combined use of LiPF ₆ and FSO ₃ Li, and the combination of LiPF ₆ and LiPO ₂ F ₂ is preferable because the effect is remarkable. Among them, the combined use of LiPF ₆ and LiPO ₂ F _{2 has} a remarkable effect with a small amount of addition. Is particularly preferred because

When LiPF ₆ and LiBF ₄ , LiPF ₆ and FSO ₃ Li are used in combination, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by weight of the entire non-aqueous electrolyte is not limited, and the effects of the present invention are not significantly impaired. As long as it is optional, it is usually 0.01% by weight or more, preferably 0.1% by weight or more, based on the non-aqueous electrolyte of the present invention, while its upper limit is usually 30% by weight or less, preferably 20%. % By weight or less. On the other hand, even when LiPF ₆ and LiPO ₂ F ₂ are used in combination, the concentration of LiPO ₂ F ₂ with respect to 100% by weight of the total amount of the non-aqueous electrolyte is not limited as long as the effect of the present invention is not significantly impaired. However, with respect to the non-aqueous electrolyte of the present invention, it is usually 0.001% by weight or more, preferably 0.01% by weight or more, while the upper limit is usually 10% by weight or less, preferably 5% by weight or less. is there. Within this range, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature characteristics are improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. may be reduced.

Here, the preparation of the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, Ya separately active material method and later be added to the electrolytic solution containing LiPF ₆ and LiPO ₂ F ₂ synthesized by a known method A method of generating LiPO ₂ F ₂ in the system when water is allowed to coexist in a battery component such as an electrode plate and assembling a battery using an electrolyte containing LiPF ₆ is used. This method may be used.

The method for measuring the content of LiPO ₂ F ₂ in the non-aqueous electrolyte and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. Examples include ion chromatography and F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR).
Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As the organic lithium salt, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , Lithium bisoxalatoborate, Lithium difluorooxalatoborate, Lithium tetrafluorooxalatophosphate, Lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ LiPF ₃ (C ₂ F ₅ ) ₃ or the like is preferable. In this case, the ratio of the organic lithium salt to 100% by weight of the whole non-aqueous electrolyte is preferably 0.1% by weight or more, particularly preferably 0.5% by weight or more, preferably 30% by weight or less, particularly preferably. 20% by weight or less.

  The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired, but the electric conductivity of the electrolyte solution is in a good range, and good battery performance is ensured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and further preferably 0.5 mol / L or more. Preferably it is 3 mol / L or less, More preferably, it is 2.5 mol / L or less, More preferably, it is 2.0 mol / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

1-2. Solvent As the non-aqueous solvent, a saturated cyclic carbonate, a cyclic carbonate having a fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, a sulfone compound, and the like can be used.

<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms.
Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.
A saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

  The blending amount of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the blending amount when one kind is used alone is 5% in 100% by volume of the non-aqueous solvent. Volume% or more, more preferably 10 volume% or more. By setting this range, the decrease in electrical conductivity resulting from the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, negative electrode stability, and cycle characteristics of the non-aqueous electrolyte secondary battery are good. It becomes easy to be in a range. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

Moreover, one of the preferable combinations when using 2 or more types of saturated cyclic carbonates by arbitrary combinations is a combination to ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is 99: 1 to 40:
60 is preferable, and 95: 5 to 50:50 is particularly preferable. Furthermore, the amount of propylene carbonate in the whole non-aqueous solvent is 0.1% by volume or more, preferably 1% by volume or more, more preferably 2% by volume or more, and the upper limit is usually 20% by volume or less, preferably 8% by volume. % Or less, more preferably 5% by volume or less. When propylene carbonate is contained within this range, it is preferable because the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

<Cyclic carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated cyclic carbonate”) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is more preferable in terms of imparting properties and suitably forming an interface protective film.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. The blending amount of the fluorinated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired, but in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, more preferably 0.8%. It is 1 volume% or more, More preferably, it is 0.2 volume% or more, Preferably it is 95 volume% or less, More preferably, it is 90 volume% or less. Within this range, the non-aqueous electrolyte secondary battery tends to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in the amount of gas generated. Cheap.

  In addition, the cyclic carbonate which has a fluorine atom expresses an effective function not only as a solvent but also as an auxiliary agent described in the following 1-3. There is no clear boundary in the blending amount when used as a cyclic carbonate solvent / auxiliary having a fluorine atom, and the blending amount described in [0034] can be followed as it is.

<Chain carbonate>
As a chain carbonate, a C3-C7 thing is preferable.
Specifically, as the chain carbonate having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-
Propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t- Examples include butyl ethyl carbonate.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.
Further, chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated chain carbonate”) can also be suitably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily set to a favorable range. Become. Further, the chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte and to make the large current discharge characteristics of the non-aqueous electrolyte secondary battery in a favorable range. .

The battery performance can be remarkably improved by combining ethylene carbonate at a specific blending amount with respect to the specific chain carbonate.
For example, when dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is selected as the specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 80% by volume or less, dimethyl carbonate, ethyl methyl carbonate, or diethyl It is preferable that the blending amount of carbonate is 20% by volume or more and 90% by volume or less. By selecting such a blending amount, the low-temperature deposition temperature of the electrolyte is lowered, the viscosity of the nonaqueous electrolytic solution is also lowered to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

  It is also preferable to use two or more types of specific chain carbonates in combination. When dimethyl carbonate and ethyl methyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume or less. Particularly preferred are those in which the amount of ethyl methyl carbonate is 10% by volume or more and 80% by volume or less. When a specific chain carbonate is used in combination with dimethyl carbonate and diethyl carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume. Hereinafter, it is particularly preferable that the amount of diethyl carbonate is 10% by volume or more and 70% by volume or less. Further, when ethyl methyl carbonate and diethyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, the blending amount of ethyl methyl carbonate is 10% by volume or more, 80% Those having a volume% or less and a blending amount of diethyl carbonate of 10 vol% or more and 70 vol% or less are particularly preferable.

<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula.
Specific examples include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

  The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this manner, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula.
Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate.

Among them, methyl acetate, ethyl acetate, acetate-n-propyl acetate-n-butyl acetate, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.
The compounding amount of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. The amount of the chain carboxylic acid ester is preferably 60% by volume or less, more preferably 50% by volume or less in 100% by volume of the non-aqueous solvent. By setting the upper limit in this manner, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms in which part of hydrogen may be substituted with fluorine is preferable.
As the chain ether having 3 to 10 carbon atoms,
Diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2, 2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2-trifluoroethyl) ether, (2-fluoroethyl) ) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, ethyl-n-propyl ether, ethyl (3-Fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) ether, ethyl (2,2,3,3-teto Fluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propylether, (2-fluoroethyl) (3-fluoro- n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) Ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl-n-propyl ether, (2,2,2- (Trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2, , 2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3,3-pentafluoro- n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3-fluoro-n-propyl) ether, (1, 1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3-tetrafluoro -N-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-propyl ether, (n- Propyl) (3-fluoro (Ro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3,3-tetrafluoro-n-propyl) Ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, (3-fluoro-n-propyl) (3 , 3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) ether ) (2, 2, 3, 3- Trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3) , 3-Tetrafluoro-n-propyl) ether, (2,2,
3,3-tetrafluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether Ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) ) Methane, diethoxymethane, ethoxy (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2- Fluoroethoxy) methane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2-fluoroeth Ii) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetra Fluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ethane, methoxy (2,2,2-trifluoroethoxy) ethane , Methoxy (1,1,2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1, 2,2-tetrafluoroethoxy) ethane, di (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2, -Trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2,2-trifluoroethoxy) ethane, (2,2,2-tri Fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether And diethylene glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, di (1,1,2,2-tetrafluoroethoxy) methane, ( 1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether Is preferable from the viewpoint of high solvating ability to lithium ions and improving ion dissociation property, and particularly preferable is dimethoxymethane, diethoxymethane, and ethoxymethoxymethane because of low viscosity and high ion conductivity. is there.

  The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall, and when a negative electrode active material is a carbonaceous material, a chain ether with lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter sometimes abbreviated as “sulfolane” including sulfolane). As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable.
Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane , 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output.

  As the chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, BR monocrymethyl sulfone, ethyl difluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl tri Fluoromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di (trifluoroethyl) sulfone, perfluorodiethylsulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone Trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, Pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyls Hong, pentafluoroethyl -n- butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is preferred because a higher high output ionic conductivity.

  The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 0.5% by volume or more, and further preferably 1% by volume or more in 100% by volume of the nonaqueous solvent. Is 40% by volume or less, more preferably 35% by volume or less, and still more preferably 30% by volume or less. Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte secondary battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.

1-3. The compound represented by the general formula (1) The present invention is characterized in that the non-aqueous electrolyte contains at least one or more compounds selected from the group consisting of the compound represented by the following general formula (1).

(Wherein X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ¹ , which may be the same or different. Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ where R is And R ¹ is hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different, and R ² has a functional group. .R ³ is also a hydrocarbon group having from good 1 to 20 carbon atoms and is, Li, ^NR _{4 4,} or, .R ⁴ is a hydrocarbon group having a functional group from 1 carbon atoms which may 20 It is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, n and m each represents an integer of 0 or more, and in an adjacent ring The carbon A further bond may be formed, and each R of the carbon may be decreased by one. W represents the above R.)

<Compound represented by the general formula (1)>
Wherein, X and Z have the general formula (1) are not particularly limited as long as the scope of the described, _{^{preferably, CR 1 2, O, S}} , N-R are more preferred. Y is not particularly limited as long as it is within the range described in the general formula (1), but preferably C═O, S═O, S (═O) ₂ , P (═O) —R ² , P ( ═O) —OR ³ is more preferred. R and R ¹ are not particularly limited as long as they are within the range described in the general formula (1), but preferably have hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, or a substituent. And an unsaturated aliphatic hydrocarbon group which may be substituted and an aromatic hydrocarbon group which may have a substituent.

R ² and R ⁴ are not particularly limited as long as they are within the range described in the general formula (1), but are preferably a saturated aliphatic hydrocarbon group that may have a substituent or a substituent. Examples thereof include unsaturated aliphatic hydrocarbons and aromatic hydrocarbons and aromatic heterocycles which may have a substituent.
R ³ is not particularly limited as long as it is in the range described in the general formula (1), but preferably Li,
Examples thereof include a saturated aliphatic hydrocarbon which may have a substituent, an unsaturated aliphatic hydrocarbon which may have a substituent, and an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.

  Saturated aliphatic hydrocarbons that may have substituents, unsaturated aliphatic hydrocarbons that may have substituents, substituents of aromatic hydrocarbons and aromatic heterocycles that may have substituents Is not particularly limited, but preferably has a saturated aliphatic hydrocarbon group, which may have a substituent such as halogen, carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, phosphorous acid, etc. And an unsaturated aliphatic hydrocarbon group, an ester of an aromatic hydrocarbon group which may have a substituent, and the like, more preferably halogen, and most preferably fluorine.

  Preferable saturated aliphatic hydrocarbons include, specifically, methyl group, ethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl. Group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group A phenyl group, a cyclopentyl group, and a cyclohexyl group are preferred.

Specific preferred unsaturated aliphatic hydrocarbons include ethenyl, 1-fluoroethenyl, 2-fluoroethenyl, 1-methylethenyl, 2-propenyl, and 2-fluoro-2-propenyl. 3-fluoro-2-propenyl group, ethynyl group, 2-fluoroethynyl group, 2-propynyl group, and 3-fluoro-2propynyl group are preferable.
Preferred aromatic hydrocarbons include phenyl, 2-fluorophenyl, 3-fluorophenyl, 2,4-difluorophenyl, 2,6-difluorophenyl, 3,5-difluorophenyl, 2,4 , 6-trifluorophenyl group is preferred.

Preferred aromatic heterocycles are 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-methyl-2-pyrrolyl group, and 1-methyl-3-pyrrolyl group.
Among these, a methyl group, an ethyl group, a fluoromethyl group, a trifluoromethyl group, a 2-fluoroethyl group, a 2,2,2-trifluoroethyl group, an ethenyl group, an ethynyl group, and a phenyl group are preferable.

More preferably, a methyl group, an ethyl group, and an ethynyl group are preferable.
n and m are not particularly limited as long as they are within the range described in the general formula (1), but are preferably 0 or 1, and more preferably n = m = 1 or n = 1 and m = 0.
The molecular weight is preferably 50 or more. Moreover, Preferably, it is 500 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. Specific examples of these preferable compounds include

And so on.
Among these, it is preferable that R is hydrogen, a fluorine, or an ethynyl group from both the reactivity and the stability. In the case of other substituents, the reactivity is lowered, and the expected properties may be lowered. Moreover, when it is halogen other than fluorine, there is a possibility that the reactivity is too high and the side reaction increases.

The number of fluorine or ethynyl groups in R is preferably within 2 in total. If the number is too large, the compatibility with the electrolytic solution may be deteriorated, and the reactivity may be too high to increase the side reaction.
Among these, n = 1 and m = 0 are preferable. When both are 0, stability deteriorates from the distortion of the ring, the reactivity becomes too high, and there is a possibility that side reactions increase. Further, even if n = 2 or more, or n = 1, when m = 1 or more, there is a possibility that the chain is more stable than the ring and the initial characteristics may not be exhibited.

Furthermore, wherein, X and Z are, ^CR _{1 2} or O are more preferred. In cases other than these, the reactivity may be too high and side reactions may increase.
The molecular weight is more preferably 100 or more, and more preferably 200 or less. If it is this range, it will be easy to ensure further the solubility of General formula (1) with respect to a non-aqueous electrolyte solution, and the effect of this invention will be further fully expressed easily.
Specific examples of these more preferable compounds include

Is given.
More preferably, R is all hydrogen. In this case, the side reaction is most likely to be suppressed while maintaining the expected characteristics. Further, when Y is C═O or S═O, one of X and Z is O, indicating that Y is S (═O) ₂ , P (═O) −R ² , P (=
In the case of O) —OR ³ , it is preferred that both X and Z are O or CH ₂ , or one of X and Z is O and the other is CH ₂ . When Y is C═O or S═O, if both X and Z are CH ₂ , the reactivity may be too high and side reactions may increase.
Specifically as these compounds

Is given.
On the other hand, the compound represented by the general formula (2) is preferable from the viewpoint of ease of industrial production.

(Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ^3, and R ² may have a functional group. And a hydrocarbon group having 1 to 20. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and R ⁴ has a functional group. And may be the same or different from each other.
As these compounds having preferable conditions, specifically,

Is given.
The compound represented by General formula (1) may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios. Moreover, the compounding quantity of the compound represented by General formula (1) is not restrict | limited especially, unless the effect of this invention is impaired remarkably. The compounding amount of the compound represented by the general formula (1) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass in 100% by mass of the non-aqueous electrolyte solution. % Or more, preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid. On the other hand, if the amount is too small, the effects of the present invention may not be sufficiently exerted. If the amount is too large, the resistance may increase and the output and load characteristics may decrease.

1-4. Auxiliary agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used according to the purpose in addition to the compound of the general formula (1). Examples of the auxiliary agent include cyclic carbonates having an unsaturated bond shown below, cyclic carbonates having fluorine atoms, unsaturated cyclic carbonates having fluorine atoms, overcharge inhibitors, and other auxiliary agents.

(C) Carbonate having at least one of carbon-carbon unsaturated bond or fluorine atom The nonaqueous electrolytic solution of the present invention includes a compound represented by the general formula (1) and a carbon-carbon unsaturated bond or fluorine atom. It contains a carbonate having at least one (hereinafter also referred to as a compound of (C)). The compound (C) is not particularly limited as long as it is a carbonate having a carbon-carbon unsaturated bond or a fluorine atom, and may be a chain or a ring. However, the compound represented by the general formula (1) is not included in this.

<Unsaturated cyclic carbonate>
The cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated cyclic carbonate) has vinylene carbonates having an unsaturated bond in the skeleton of the cyclic carbonate, or has an aromatic ring or a carbon-carbon unsaturated bond. Examples thereof include ethylene carbonates substituted with a substituent, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates and the like.

  As vinylene carbonates, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4 , 5-diallyl vinylene carbonate.

  Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene Examples thereof include carbonate and 4-methyl-5-allylethylene carbonate.

Examples of the unsaturated cyclic carbonate include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate Vinylene carbonate and vinyl ethylene carbonate are particularly preferred. Since these form a stable interface protective film, they are more preferably used.
Moreover, an unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<Unsaturated linear carbonate>
The chain carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated chain carbonate) is a chain carbonate having a carbon-carbon unsaturated bond or a chain substituted with a substituent having an aromatic ring. And carbonated carbonates.

  Examples of the chain carbonate having a chain hydrocarbon having a carbon-carbon unsaturated bond include methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, methyl-1-propenyl carbonate, ethyl-1-propenyl carbonate, di-1- Propenyl carbonate, methyl (1-methylvinyl) carbonate, ethyl (1-methylvinyl) carbonate, di (1-methylvinyl) carbonate, methyl-2-propenyl carbonate, ethyl-2-propenyl carbonate, di (2-propenyl) Carbonate, 1-butenyl methyl carbonate, 1-butenyl ethyl carbonate, di (1-butenyl) carbonate, methyl (1-methyl-1-propenyl) carbonate, ethyl (1-methyl-1-propenyl) carbonate Di (1-methyl-1-propenyl) carbonate, methyl-1-ethyl vinyl carbonate, ethyl-1-ethyl vinyl carbonate, di-1-ethyl vinyl carbonate, methyl (2-methyl-1-propenyl) carbonate, Ethyl (2-methyl-1-propenyl) carbonate, di (2-methyl-1-propenyl) carbonate, 2-butenylmethyl carbonate, 2-butenylethyl carbonate, di-2-butenyl carbonate, methyl (1- Methyl-2-propenyl) carbonate, ethyl (1-methyl-2-propenyl) carbonate, di (1-methyl-2-propenyl) carbonate, methyl (2-methyl-2-propenyl) carbonate, ethyl (2-methyl- 2-propenyl) carbonate, di (2-methyl-2) Propenyl) carbonate, methyl (1,2-dimethyl-1-propenyl) carbonate, ethyl (1,2-dimethyl-1-propenyl) carbonate, di (1,2-dimethyl-1-propenyl) carbonate, ethynylmethyl carbonate, Ethyl ethynyl carbonate, diethynyl carbonate, methyl-1-propynyl carbonate, ethyl-1-propynyl carbonate, di-1-propynyl carbonate, methyl-2-propynyl carbonate, ethyl-2-propynyl carbonate, di-2-propynyl carbonate, 1-butynylmethyl carbonate, 1-butynylethyl carbonate, di-1-butynyl carbonate, 2-butynylmethyl carbonate, 2-butynylethyl carbonate, di-2-butynyl carbonate, Methyl (1-methyl-2-propynyl) carbonate, ethyl (1-methyl-2-propynyl) carbonate, di (1-methyl-2-propynyl) carbonate, 3-butynylmethyl carbonate, 3-butynylethyl carbonate, Di-3-butynyl carbonate, methyl (1,1-dimethyl-2-propynyl) carbonate, ethyl (1,1-dimethyl-2-propynyl) carbonate, dityl (1,1-dimethyl-2-propynyl) carbonate, Methyl (1,3-dimethyl-2-propynyl) carbonate, ethyl (1,3-dimethyl-2-propynyl) carbonate, dityl (1,3-dimethyl-2-propynyl) carbonate, methyl (1,2,3- Trimethyl-2-propynyl) carbonate, ethyl (1,2,3-trimethyl) 2-propynyl) carbonate, Jichiru (1,2,3-trimethyl-2-propynyl) carbonate, and the like.

Examples of the chain carbonates substituted with a substituent having an aromatic ring include methyl phenyl carbonate, ethyl phenyl carbonate, phenyl vinyl carbonate, allyl phenyl carbonate, enethyl phenyl carbonate, 2-propenyl phenyl carbonate, diphenyl carbonate, methyl (2 -Methylphenyl) carbonate, ethyl (2-methylphenyl) carbonate, (2-methylphenyl) vinyl carbonate, allyl (2-methylphenyl) carbonate, enethyl (2-methylphenyl) carbonate, 2-propenyl (2-methylphenyl) ) Carbonate, di (2-methylphenyl) carbonate, methyl (3-methylphenyl) carbonate, ethyl (3-methylphenyl) carbonate, (3-methylphenyl) Vinyl carbonate, allyl (3-methylphenyl) carbonate, enethyl (3-methylphenyl) carbonate, 2-propenyl (3-methylphenyl) carbonate, di (3-methylphenyl) carbonate, methyl (4-methylphenyl) carbonate, Ethyl (4-methylphenyl) carbonate, (4-methylphenyl) vinyl carbonate, allyl (4-methylphenyl) carbonate, enethyl (4-methylphenyl) carbonate, 2-propenyl (4-methylphenyl) carbonate, di (4 -Methylphenyl) carbonate, benzyl methyl carbonate, benzyl ethyl carbonate, benzyl phenyl carbonate, benzyl vinyl carbonate, benzyl-2-propenyl carbonate, benzyl ethynyl carbonate Bonate, benzyl-2-propynyl carbonate, dibenzyl carbonate, methyl (2-cyclohexylphenyl) carbonate, methyl (3-cyclohexylphenyl) carbonate, methyl (4-cyclohexylphenyl) carbonate, ethyl (2-cyclohexylphenyl) carbonate, di (2-cyclohexylphenyl) carbonate, and the like.

Among the above unsaturated chain carbonates, methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 2-propynyl ethyl carbonate, 1-methyl- 2-propynylmethyl carbonate, 1-methyl-2-propynylethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, dipropynyl carbonate, 2-butynylmethyl carbonate, 1-methyl-2-butynylmethyl carbonate, 1,1-dimethyl-2-butynylmethyl carbonate, dibutynyl carbonate, methylphenyl carbonate, ethylphenyl carbonate, phenyl vinyl carbonate, Ryl phenyl carbonate, diphenyl carbonate, benzyl methyl carbonate, benzyl ethyl carbonate, benzyl phenyl carbonate, allyl benzyl carbonate, dibenzyl carbonate, 2-propynyl phenyl carbonate, 2-butynyl phenyl carbonate are preferred, methyl vinyl carbonate, ethyl vinyl carbonate, Divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 1-methyl-2-propynyl methyl carbonate, 1,1-dimethyl-2-propynyl methyl carbonate, dipropynyl carbonate, 2-butynyl Methyl carbonate, 1-methyl-2-butynyl methyl carbonate, 1,1-dimethyl 2-butynyl methyl carbonate, dibutyl alkenyl carbonate, methyl phenyl carbonate, ethyl phenyl carbonate, diphenyl carbonate is particularly preferred. Since these form a stable interface protective film, they are more preferably used.
Moreover, an unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<Fluorinated saturated carbonate>
As saturated carbonates having fluorine atoms, either saturated chain carbonates having fluorine atoms (hereinafter also referred to as fluorinated saturated chain carbonates) or saturated cyclic carbonates having fluorine atoms (hereinafter also referred to as fluorinated saturated cyclic carbonates). Can also be used.

The number of fluorine atoms in the fluorinated saturated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated saturated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated saturated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, and fluorinated diethyl carbonate derivatives.

  Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.

  Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

As the fluorinated saturated chain carbonate, 2,2,2-trifluoroethyl methyl carbonate and bis (2,2,2-trifluoroethyl) carbonate are particularly preferable.
Moreover, a fluorinated saturated chain carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

  Examples of the fluorinated saturated cyclic carbonate include derivatives of saturated cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Examples of the fluorinated saturated cyclic carbonate include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,
Particularly preferred is at least one selected from the group consisting of 5-difluoro-4,5-dimethylethylene carbonate. These provide high ionic conductivity and preferably form an interface protective coating.
Moreover, a fluorinated saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<Fluorinated unsaturated cyclic carbonate>
The cyclic carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as a fluorinated unsaturated cyclic carbonate) is a fluorinated vinylene carbonate derivative, an aromatic ring or a substituent having a carbon-carbon unsaturated bond. Examples thereof include substituted fluorinated ethylene carbonate derivatives.

  Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- Examples include vinyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, and the like.

  Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5. -Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate , 4,5-Diff Oro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4- Examples thereof include phenylethylene carbonate.

Examples of the fluorinated unsaturated cyclic carbonate include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4 , 4-Difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro -4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate are preferred. . Since these form a stable interface protective film, they are more preferably used.
Moreover, a fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

<Fluorinated unsaturated chain carbonate>
Examples of the chain carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as fluorinated unsaturated chain carbonate) include 1-fluorovinyl methyl carbonate, 2-fluorovinyl methyl carbonate, 1,2- Difluorovinylmethyl carbonate, ethyl-1-fluorovinyl carbonate, ethyl-2-fluorovinyl carbonate, ethyl-1,2-difluorovinyl carbonate, bis (1-fluorovinyl) carbonate, bis (2-fluorovinyl) carbonate, bis (1,2-difluorovinyl) carbonate, 1-fluoro-1-propenylmethyl carbonate, 2-fluoro-1-propenylmethyl carbonate, 3-fluoro-1-propenylmethyl carbonate, 1,2-difluoro-1-pro Nylmethyl carbonate, 1,3-difluoro-1-propenylmethyl carbonate, 2,3-difluoro-1-propenylmethyl carbonate, 3,3-difluoro-1-propenylmethyl carbonate, 1-fluoro-2-propenylmethyl carbonate, 2-fluoro-2-propenylmethyl carbonate, 3-fluoro-2-propenylmethyl carbonate, 1,1-difluoro-2-propenylmethyl carbonate, 1,2-difluoro-2-propenylmethyl carbonate, 1,3-difluoro- 2-propenylmethyl carbonate, 2,3-difluoro-2-propenylmethyl carbonate, fluoroethynylmethyl carbonate, 3-fluoro-1-propynylmethyl carbonate, 1-fluoro-2-propynylmethyl Boneto, 3-fluoro-2-propynyl methyl carbonate, and the like.
Moreover, a fluorinated unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.

  The molecular weight of the compound (C) is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired, but is preferably 50 or more and 250 or less. In the case of unsaturated cyclic carbonates, more preferably 80 or more and 150 or less, and in the case of fluorinated unsaturated cyclic carbonates, more preferably 100 or more and 200 or less. If it is this range, the solubility of the cyclic carbonate which has a carbon-carbon unsaturated bond with respect to a non-aqueous electrolyte solution will be easy to be ensured, and the effect of this invention will fully be expressed easily.

As the compound (C), one type may be used alone, or two or more types may be used in any combination and ratio.
The blending amount in the case of carbonate having at least one carbon-carbon unsaturated bond is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and still more preferably in 100% by mass of the non-aqueous solvent. Is 0.1% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.
The blending amount in the case of using a carbonate having at least one fluorine atom is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.1% by mass in 100% by mass of the nonaqueous electrolytic solution. It is 2% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and still more preferably 80% by mass or less.

  In particular, when carbonate having at least one fluorine atom plays a role as a solvent, the blending amount thereof is 100% by mass of the non-aqueous electrolyte solution, preferably 5% by mass or more, more preferably 7% by mass or more, Preferably it is 10 mass% or more, Preferably it is 90 mass% or less, More preferably, it is 70 mass% or less, More preferably, it is 50 mass% or less. Within this range, when the battery is operated at a high voltage, the secondary decomposition reaction of the non-aqueous electrolyte can be suppressed, the battery durability can be improved, and the electrical conductivity of the non-aqueous electrolyte is extremely reduced. Can be prevented. When used as a solvent, a fluorinated saturated carbonate is preferable among carbonates having at least one fluorine atom.

On the other hand, when the carbonate having at least one fluorine atom plays a role as an auxiliary, the blending amount thereof is 100% by mass in the non-aqueous electrolyte solution, preferably 0.01% by mass or more, more preferably It is 0.1 mass% or more, More preferably, it is 0.2 mass% or more, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the durability can be improved without excessively increasing the charge transfer resistance, so that the charge / discharge durability at a high current density can be improved. When used as an auxiliary agent, as the carbonate having at least one fluorine atom, any of fluorinated saturated carbonate, fluorinated unsaturated cyclic carbonate, and fluorinated unsaturated chain carbonate can be used.

Further, even when two or more carbonates having at least one fluorine atom are used in combination, it is preferable to adjust within the above range.
Although the role of the carbonate having at least one fluorine atom as a solvent and auxiliary agent has been described above, there is no clear boundary line in the solvent or auxiliary agent when actually used, and the nonaqueous electrolyte solution is in an arbitrary ratio. Can be prepared.

The proportion of the compound represented by the general formula (1) and the compound (C) is not particularly limited. However, when the compound (C) is a carbonate having an unsaturated bond, the compound has an unsaturated bond. When the total content of carbonate is [M _u ] and the total content of the compound represented by the general formula (1) is [M ₍₁₎ ], usually [M ₍₁₎ ] / [M _u ] Is 100 to 0.01, more preferably 20 to 0.05, and still more preferably 10 to 0.1.

<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively suppress battery explosion / ignition when the non-aqueous electrolyte secondary battery is in an overcharged state or the like. .
As an overcharge inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, Partially fluorinated products of the above aromatic compounds such as o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And a fluorine-containing anisole compound. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

  The amount of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the battery characteristics, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1-fluoro-1,3- Propane sultone, 2-fluoro-1,3-propane sultone, 3-ph Oro-1,3-propane sultone, 1-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro -1-propene-1,3-sultone, 1,4-butanesultone, 1-butene-1,4-sultone, 3-butene-1,4-sultone, methyl fluorosulfonate, ethyl fluorosulfonate, methanesulfonic acid Sulfur-containing compounds such as methyl, ethyl methanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2 -Piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-me Nitrogen-containing compounds such as Rusukushin'imido; heptane, octane, nonane, decane, hydrocarbon compounds cycloheptane, etc., fluorobenzene, difluorobenzene, hexafluorobenzene, fluorinated aromatic compounds such as benzotrifluoride, and the like. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

  The blending amount of other auxiliary agents is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate. The blending amount of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

2. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte secondary battery of the present invention can adopt a known structure, and typically includes a negative electrode capable of inserting and extracting ions (for example, lithium ions), a positive electrode described later, and the above-described present invention. A non-aqueous electrolyte solution.

2-1. Cathode <Lithium transition metal compound>
The lithium transition metal compound powder used in the present invention is a lithium transition metal compound mainly composed of a lithium transition metal compound represented by the following general formula (I).

Li [Li _a M _x Mn _2−x−a ] O _{4 + d} (I)
(In the formula, 0 ≦ a ≦ 0.3, 0.4 ≦ x ≦ 0.6, −0.5 <δ <0.5 is satisfied, and M is selected from Ni, Cr, Fe, Co, and Cu. Represents at least one of transition metals.)
<Composition>
More specifically, the lithium transition metal-based compound of the present invention includes a lithium transition metal-based compound represented by the following general formula (I) as a main component.

Li [Li _a M _x Mn _2−x−a ] O _{4 + d} (I)
However, M is an element composed of at least one of transition metals selected from Ni, Cr, Fe, Co and Cu. Among these, M is most preferable from the viewpoint of charge / discharge capacity at a high potential. Ni.
The value of x is usually 0.4 or more, preferably 0.425 or more, more preferably 0.45 or more,
More preferably 0.475 or more, most preferably 0.49 or more, usually 0.6 or less, preferably 0.575 or less, more preferably 0.55 or less, still more preferably 0.525 or less, and most preferably 0.00. 51 or less.

If the value of x is in this range, the energy density per unit weight in the lithium transition metal compound is high, which is preferable.
The value of a is usually 0 or more, preferably 0.01 or more, more preferably 0.02 or more, further preferably 0.03 or more, most preferably 0.04 or more, usually 0.3 or less, preferably 0. .2 or less, more preferably 0.15 or less, still more preferably 0.1 or less, and most preferably 0.075 or less.

If the value of a is within this range, it is preferable because the energy density per unit weight in the lithium transition metal compound is not significantly impaired and good load characteristics can be obtained.
Furthermore, the value of d is usually in the range of ± 0.5, preferably in the range of ± 0.4, more preferably ±
The range is 0.2, more preferably ± 0.1, and particularly preferably ± 0.05.

If the value of δ is within this range, the stability as a crystal structure is high, and the cycle characteristics and high-temperature storage of a battery having an electrode produced using this lithium transition metal compound are favorable.
Here, the chemical meaning of the lithium composition in the lithium nickel manganese composite oxide, which is the composition of the lithium transition metal compound of the present invention, will be described in more detail below.

In order to obtain a and x in the composition formula of the lithium transition metal compound, each transition metal and lithium are analyzed by an inductively coupled plasma emission spectrometer (ICP-AES) to obtain a ratio of Li / Ni / Mn. It is calculated by the thing.
From a structural point of view, it is considered that lithium related to a is substituted for the same transition metal site. Here, due to the lithium according to a, the average valence of M and manganese becomes larger than 3.5 due to the principle of charge neutrality.

<Additives>
When the lithium transition metal-based compound of the present invention is produced by a production method comprising simultaneously pulverizing main component raw materials in a liquid medium and spray-drying and firing a slurry in which these are uniformly dispersed, As a result of forming secondary particles having a large void and a large amount of voids, the bulk density is decreased and the specific surface area is increased, and the energy density improvement effect as the positive electrode active material may be reduced. Further, when the firing temperature is increased for the purpose of improving the bulk density or reducing the specific surface area, load characteristics such as rate characteristics may be impaired. However, by adding the additive of the present invention and firing, active material particles such as sintering between primary particles or secondary particles of a lithium transition metal compound are promoted without raising the firing temperature. As the growth and the high crystallization progress, there is an effect of obtaining a high-density powder property without impairing the load characteristics, and such a lithium transition metal compound may be used.

  Further, the element contained in the additive of the present invention is incorporated in the crystal structure of the lithium transition metal compound, or is not incorporated in the crystal structure of the lithium transition metal compound, and the particle surface or grain boundary Present as a simple substance or a compound, etc., has the effect of facilitating insertion / extraction of lithium during charge / discharge reactions and improving load characteristics such as output characteristics and rate characteristics. This is because the elements contained in the additive of the present invention are incorporated into the crystal structure of the lithium transition metal compound and change the lattice constant, etc., thereby increasing the diffusibility of lithium in the lithium transition metal compound, It is considered that it exists as a simple substance or compound having high lithium conductivity on the surface or grain boundary and facilitates lithium insertion / extraction and diffusion at the particle surface or grain boundary.

  Further, since the additive of the present invention is effective even in a very small amount, even when incorporated in the crystal structure of the lithium transition metal compound, the average valence of the transition metal in the lithium transition metal compound is large. Has no effect. For this reason, there is no adverse effect such as a decrease in charge / discharge capacity. Furthermore, even if it is not incorporated into the crystal structure of the lithium transition metal compound and exists as a simple substance or compound on the particle surface or crystal grain boundary, it acts as a layer that traps eluting manganese or causes electrolyte elution By acting as a barrier layer for the derived compound, the amount of manganese elution is reduced, and cycle characteristics and storage characteristics are improved.

That is, by adding the additive of the present invention, it is possible not only to achieve both the energy density and load characteristics of the lithium transition metal compound, but also to achieve effects such as reduction of manganese elution amount and improvement of cycle characteristics. In addition, battery durability when used as a positive electrode active material for a lithium secondary battery is also improved.
As an example of an additive having a sintering promoting action on the lithium transition metal compound of the present invention, a compound having at least one element selected from the group consisting of B, P, V, Sb, Pb, Bi, and the like. Can be mentioned. These elements are characterized by the fact that they melt when the lithium transition metal compound of the present invention is fired to form a liquid phase around the solid particles and express the effect of promoting grain growth and sintering. Sometimes acts as an additive of the present invention. Among these, an oxide having a melting point of 1000 ° C. or lower is preferable from the viewpoint of being easily melted when the lithium transition metal compound is fired, an oxide of 950 ° C. or lower is more preferable, and an oxide of 900 ° C. or lower is particularly preferable. B, P, V and Bi are preferred because they form an oxide having a melting point of 900 ° C. or lower, are relatively inexpensive and easily available as industrial raw materials, and have low toxicity.

In the present invention, the type of the compound added as the additive of the present invention is not particularly limited as long as the effect of the present invention is exhibited. Exemplary compounds for the additive include BO, B ₂ O ₂ , B ₂ O ₃ , B ₄ O ₅ , B ₆ O, B ₇ O, B ₁₃ O ₂ , LiBO ₂ , LiB ₅ O ₈ , Li ₂ B _4. O ₇ , HBO ₂ , H ₃ BO ₃ , B (OH) ₃ , B (OH) ₄ , P ₄ O ₁₀ , P ₂ O ₅ , P ₄ O ₈ , P ₄ O ₆ , PH ₃ , H ₃ PO ₄ , VO, V ₂ O ₃ , VO ₂ , V ₂ O ₅ , V ₆ O ₁₃ , V (C ₂ O ₄ ) O, V (OH) _x , VH _x , VC, VN, VB, VB ₂ , LiVO ₃ , Sb ₂ O ₃ , Sb ₂ O ₅ , SbH ₃ , PbO, PbO ₂ , Pb ₃ O ₄ , Pb (N ₃ ) ₂ , Pb (OCOCH ₃ ) ₂ , Pb (OCOCH ₃ ) ₄ , (C ₂ H ₅ ) ₄ Pb, BiBO ₃ , B
i ₂ O ₃ , Bi ₂ O ₅ , Bi (OH) _{3, and the} like. Among these, the melting point is 900 ° C. or less, it is relatively inexpensive and easily available as an industrial raw material, and has low toxicity. Preferably, B ₂ O ₃ , H ₃ BO ₃ , P ₂ O ₅ , V ₂ O ₃ , Bi ₂ O _{3 and the} like are mentioned. These additives may be used alone or in combination of two or more.

  The range of the additive amount of the present invention is usually 0.001 mol% or more, preferably 0.01 mol% or more, more preferably based on the total amount of main components calculated from the raw materials charged. It is 0.1 mol% or more, particularly preferably 0.5 mol% or more, and usually 10 mol% or less, preferably 8 mol% or less, more preferably 5 mol% or less, and particularly preferably 3 mol% or less. If the lower limit is not reached, the above effects may not be obtained. If the upper limit is exceeded, battery performance may be reduced.

<Surface concentration of elements contained in the additive of the present invention>
The lithium transition metal-based compound of the present invention has, on its secondary particle surface portion, an element derived from the additive of the present invention, that is, at least one element selected from the group consisting of B, P, V, Sb, Pb and Bi. More preferably, is concentrated. Specifically, the total molar ratio of the additive elements present on the surface portion of the secondary particles is preferably at least 1 time the atomic ratio of the whole particle as a lower limit with respect to the charged composition ratio. It is more preferably 2 times or more, further preferably 3 times or more, particularly preferably 4 times or more, and most preferably 5 times or more.

As an upper limit, it is usually preferably 300 times or less of the whole particle, more preferably 200 times or less, still more preferably 100 times or less, and particularly preferably 80 times or less. The ratio is most preferably 50 times or less.
If the concentration ratio is the above, it is preferable because Li insertion / desorption and diffusion in the active material are facilitated and load characteristics are excellent.

  The composition of the surface portion of the primary particles of the lithium transition metal compound was analyzed by X-ray photoelectron spectroscopy (XPS) using a monochromatic light AlKα as an X-ray source, an analysis area of 0.8 mm diameter, and an extraction angle of 65 °. To do. Although the range (depth) that can be analyzed varies depending on the composition of the primary particles, it is usually 0.1 nm to 50 nm, particularly 1 nm to 10 nm for a positive electrode active material. Therefore, in the present invention, the surface portion of the primary particles of the lithium transition metal compound indicates a measurable range under these conditions.

<Pore characteristics by mercury intrusion method>
The lithium transition metal compound for a lithium secondary battery positive electrode material of the present invention preferably satisfies a specific condition in measurement by mercury porosimetry.
The mercury intrusion method employed in the evaluation of the lithium transition metal compound of the present invention will be described below.

The mercury intrusion method is a method for obtaining information such as specific surface area and pore size distribution from the relationship between pressure and the amount of mercury intruded into a pore of a sample such as porous particles while applying pressure. It is.
Specifically, first, the container containing the sample is evacuated and filled with mercury. Mercury has a high surface tension, and as it is, mercury does not penetrate into the pores on the sample surface, but when pressure is applied to the mercury and the pressure is gradually increased, the pores increase in size from the smallest to the smallest. Gradually mercury enters the pores. If a change in the mercury liquid level (that is, the amount of mercury intruded into the pores) is detected while the pressure is continuously increased, a mercury intrusion curve representing the relationship between the pressure applied to the mercury and the amount of mercury intruded can be obtained. .

Here, assuming that the shape of the pore is cylindrical, the radius is r, the surface tension of mercury is δ, and the contact angle is θ, the size in the direction of extruding mercury from the pore is −2πrδ (cos θ). (If θ> 90 °, this value is positive). Moreover, since the magnitude of the force in the direction of pushing mercury into the pores under the pressure P is represented by πr ² P, the following formulas (1) and (2) are derived from the balance of these forces. It will be.

-2πrδ (cosθ) = πr ² P (1)
Pr = -2δ (cos θ) (2)
In the case of mercury, values of surface tension δ = 480 dyn / cm and contact angle θ = 140 ° are generally used. When these values are used, the radius of the pore into which mercury is injected under the pressure P is expressed by the following formula (3).

  That is, since there is a correlation between the pressure P applied to mercury and the radius r of the pore into which mercury enters, the size of the pore radius of the sample and its volume are calculated based on the obtained mercury intrusion curve. A pore distribution curve representing the relationship can be obtained. For example, when the pressure P is changed from 0.1 MPa to 100 MPa, the pores in the range from about 7500 nm to about 7.5 nm can be measured.

Note that the approximate measurement limit of the pore radius by the mercury intrusion method is that the lower limit is about 2 nm or more and the upper limit is about 200 μm or less, and the pores in a relatively large range compared to the nitrogen adsorption method described later. It can be said that it is suitable for analysis of distribution.
Measurement by the mercury intrusion method can be performed using an apparatus such as a mercury porosimeter. Specific examples of the mercury porosimeter include an autopore manufactured by Micromeritics, a pore master manufactured by Quantachrome, and the like.

  In the lithium transition metal compound of the present invention, when a pore distribution curve is measured by the above mercury intrusion method, a specific main peak described below usually appears. In the present specification, the “pore distribution curve” refers to the total pore volume per unit weight (usually 1 g) of pores having a radius equal to or larger than the radius of the pores on the horizontal axis, The value obtained by differentiating the logarithm of the pore radius is plotted on the vertical axis, and is usually expressed as a graph connecting the plotted points. In particular, the pore distribution curve obtained by measuring the lithium transition metal-based compound of the present invention by mercury porosimetry is referred to as “the pore distribution curve according to the present invention” as appropriate in the following description.

In this specification, “main peak” refers to the largest peak among the peaks of the pore distribution curve, and “sub peak” refers to a peak other than the main peak of the pore distribution curve.
In the present specification, “peak top” refers to the point at which the coordinate value of the vertical axis takes the largest value in each peak of the pore distribution curve.

<Main peak>
The main peak of the pore distribution curve according to the present invention has a peak top whose pore radius is usually 800 nm or more, more preferably 900 nm or more, most preferably 1000 nm or more, and usually 6000 nm or less, preferably 5600 nm or less, More preferably, it exists in 5400 nm or less, More preferably, it is 5200 nm or less, Most preferably, it exists in the range of 5000 nm or less. When the upper limit of this range is exceeded, when a battery is produced using the lithium transition metal compound of the present invention as the positive electrode material, lithium diffusion in the positive electrode material is inhibited, or the conductive path is insufficient, resulting in a decrease in load characteristics. there's a possibility that. On the other hand, below the lower limit of this range, when a positive electrode is produced using the lithium transition metal compound of the present invention, the required amount of conductive material and binder increases, and the positive electrode plate (positive electrode current collector). There is a possibility that the filling rate of the active material into the battery is restricted and the battery capacity is restricted. In addition, with the fine particles, the mechanical properties of the coating film become hard or brittle,
There is a possibility that peeling of the coating film is likely to occur in the winding process at the time of battery assembly.

Further, the pore volume of the peak having a peak top at a pore radius of 800 nm or more and 6000 nm or less, which the pore distribution curve according to the present invention has, is preferably usually 0.1 cm ³ / g or more, preferably 0. .15cm ³ / g or more, more preferably 0.2 cm ³ / g or more, most preferably 0.25 cm ³ / g or more and usually 0.5 cm ³ / g or less, preferably 0.45 cm ³ / g or less, more preferably 0.4 cm ³ / g or less, and most preferably not more than 0.35 cm ³ / g. When the upper limit of this range is exceeded, the voids become excessive, and when the lithium transition metal compound powder of the present invention is used as the positive electrode material, the filling rate of the positive electrode active material into the positive electrode plate becomes low, and the battery capacity is limited. There is a possibility of being. On the other hand, if the lower limit of this range is not reached, voids between the particles become too small, so that when a battery is produced using the lithium transition metal compound of the present invention as a positive electrode material, lithium diffusion between secondary particles is inhibited. As a result, the load characteristics may deteriorate.

<Sub peak>
The pore distribution curve according to the present invention may have a plurality of sub-peaks in addition to the main peak described above, and in particular, a sub-peak in which a peak top exists within a pore radius range of 80 nm or more and 800 nm or less. It is characterized by having.
The pore volume of the sub-peak where the peak top exists in the pore radius of 80 nm or more and 800 nm or less of the pore distribution curve according to the present invention is suitably usually 0.01 cm ³ / g or more, preferably 0.02 cm ^3. / g or more, more preferably 0.03 cm ³ / g or more, most preferably 0.04 cm ³ / g or more and usually 0.2 cm ³ / g or less, preferably 0.15 cm ³ / g, more preferably 0.1 cm ³ / g or less, and most preferably not more than 0.08 cm ³ / g. If the upper limit of this range is exceeded, voids between secondary particles become excessive, and when the lithium transition metal-based compound powder of the present invention is used as a positive electrode material, the filling rate of the positive electrode active material into the positive electrode plate becomes low. The battery capacity may be limited. On the other hand, if the lower limit of this range is not reached, voids between secondary particles become excessively small. Therefore, when a battery is produced using the lithium transition metal-based compound powder of the present invention as a positive electrode material, between secondary particles. Lithium diffusion may be hindered and load characteristics may be reduced.

  In the present invention, the pore distribution curve by the mercury intrusion method has at least one main peak having a peak top at a pore radius of 800 nm or more and 4000 nm or less, and a pore radius of 80 nm or more and 800 nm or less. A lithium transition metal compound for a lithium secondary battery positive electrode material having a sub-peak in which a peak top is present is preferable.

<Median diameter and 90% integrated diameter ( _D90 )>
The median diameter of the lithium transition metal compound of the present invention is usually 2 μm or more, preferably 2.5 μm or more, more preferably 3 μm or more, still more preferably 3.5 μm or more, most preferably 4 μm or more, and usually 60 μm or less, preferably It is 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less, and most preferably 20 μm or less. When the median diameter is less than this lower limit, there is a possibility that a problem occurs in the coating property at the time of forming the positive electrode active material layer, and when the upper limit is exceeded, battery performance may be deteriorated.

The 90% cumulative diameter (D ₉₀ ) of the secondary particles of the lithium transition metal-based compound of the present invention is usually 30 μm or less, preferably 25 μm or less, more preferably 22 μm or less, most preferably 20 μm or less, and usually 3 μm or more. Preferably it is 4 micrometers or more, More preferably, it is 5 micrometers or more, Most preferably, it is 6 micrometers or more. If the 90% cumulative diameter (D ₉₀ ) exceeds the above upper limit, the battery performance may be deteriorated, and if it is less than the lower limit, there is a possibility of causing a problem in the coating property when forming the positive electrode active material layer.
In the present invention, the median diameter and the 90% cumulative diameter (D ₉₀ ) as the average particle diameter are set to a refractive index of 1.60 by a known laser diffraction / scattering particle size distribution measuring device, and the particle diameter standard is determined. Measured as a volume reference. In this invention, it measured using 0.1 weight% sodium hexametaphosphate aqueous solution as a dispersion medium used in the case of a measurement.

<Average primary particle size>
The average diameter (average primary particle diameter) of the lithium transition metal compound of the present invention is not particularly limited, but the lower limit is preferably 0.1 μm or more, more preferably 0.2 μm or more, and most preferably 0.3 μm. The upper limit is preferably 3 μm or less, more preferably 2 μm or less, still more preferably 1.5 μm or less, and most preferably 1.2 μm or less. If the average primary particle size exceeds the above upper limit, it may adversely affect the powder filling property or the specific surface area will decrease, which may increase the possibility that the battery performance such as rate characteristics and output characteristics will decrease. There is sex. If the lower limit is not reached, there is a possibility that problems such as inferior reversibility of charge / discharge due to the undeveloped crystals.
In addition, the average primary particle diameter in this invention is an average diameter observed with the scanning electron microscope (SEM), and the average of the particle diameter of about 10-30 primary particles using a 10,000 times SEM image. It can be obtained as a value.

<BET specific surface area>
The lithium transition metal compound of the present invention also has a BET specific surface area of usually 0.3 m ² / g or more, preferably 0.35 m ² / g or more, most preferably 0.4 m ² / g or more, and usually 3 m ^2. / G or less, preferably 2.5 m ² / g or less, more preferably 2 m ² / g or less, and most preferably 1.5 m ² / g or less. If the BET specific surface area is smaller than this range, the battery performance tends to be lowered. If the BET specific surface area is larger, the bulk density is difficult to increase, and the energy density as the positive electrode active material may not be improved.

  The BET specific surface area can be measured by a known BET type powder specific surface area measuring device. In the present invention, an OMS Riken: AMS8000 type automatic powder specific surface area measuring device was used, nitrogen was used as an adsorption gas, and helium was used as a carrier gas. Specifically, the powder sample was heated and deaerated with a mixed gas at a temperature of 150 ° C., then cooled to liquid nitrogen temperature to adsorb the mixed gas, and then heated to room temperature with water to be adsorbed. Nitrogen gas was desorbed, the amount was detected by a heat conduction detector, and the specific surface area of the sample was calculated therefrom.

<Bulk density>
The lower limit of the bulk density of the lithium transition metal compound of the present invention is usually 0.8 g / cm ³ or more, preferably 0.9 g / cm ³ or more, more preferably 1 g / cm ³ or more, and most preferably 1.1 g / cm ^3. cm ³ or more.
The upper limit is usually 5 g / cm ³ or more, preferably 4 g / cm ³ or more, more preferably 3.5 g / cm ³ or more, and most preferably 3.2 g / cm ³ or more. If the bulk density exceeds this upper limit, it is preferable for improving powder filling properties and electrode density, but the specific surface area may be too low, and battery performance may be reduced. If the bulk density is below this lower limit, there is a possibility of adversely affecting the powder filling property and electrode preparation. In the present invention, the bulk density is measured by putting 5 to 10 g of a lithium transition metal compound into a 10 ml glass graduated cylinder and measuring the bulk density by tapping at least 100 times with a stroke of about 30 mm, and thereafter every 200 taps. The bulk density is measured and determined as the powder packing density (bulk density) g / cm ³ when tapped until the amount of change in the bulk density by tapping 200 times is 0.1 g / cm ³ or less.

<Crystal structure>
The lithium transition metal-based compound of the present invention is preferably composed mainly of a lithium nickel manganese composite oxide having a spinel structure.
Here, the spinel structure will be described in more detail. As a typical crystal system having a spinel structure, there is a crystal system belonging to the MgAl ₂ O ₄ type such as LiMn ₂ O ₄ , which is a cubic system, and because of its symmetry, the space group

(Hereinafter sometimes referred to as “spinel-type Fd (−3) m structure”).
However, the spinel type LiMeO ₄ is not limited to the spinel type Fd (−3) m structure. In addition, spinel type LiMeO ₄ belonging to a different space group (P4 ₃ 32) also exists.

<Additional elements>
In the present invention, in addition to the compound having at least one element selected from the group consisting of B, Ca, Mg, Al, V and Bi (the additive of the present invention), Mo, It is preferable to use at least one selected from W, Nb, Ta and Re. Among these additional elements 1, the additional element 1 is preferably Mo or W, and most preferably W, because the effect is great.

The type of the compound (further additive 1) containing the additional element 1 is not particularly limited as long as the effect of the present invention is exhibited, but an oxide is usually used.
Further exemplary compounds of additive 1 include MoO, MoO ₂ , MoO ₃ , MoO _x , Mo ₂ O ₃ , Mo ₂ O ₅ , Li ₂ MoO ₄ , WO, WO ₂ , WO ₃ , WO _x , W _2. O ₃ , W ₂ O ₅ , W ₁₈ O ₄₉ , W ₂₀ O ₅₈ , W ₂₄ O ₇₀ , W ₂₅ O ₇₃ , W ₄₀ O ₁₁₈ , Li ₂ WO ₄ , NbO, NbO ₂ , Nb ₂ O ₃ , Nb ₂ O ₅ , Nb ₂ O ₅ .nH ₂ O, LiNbO ₃ , Ta ₂ O, Ta ₂ O ₅ , LiTaO ₃ , ReO ₂ , ReO ₃ , Re ₂ O ₃ , Re ₂ O _{7 and the} like are listed as industrial raw materials. MoO ₃ , Li ₂ MoO ₄ , WO ₃ , Li ₂ WO ₄ are preferable, and WO ₃ is particularly preferable because it is relatively easily available or includes lithium. These additional additives 1 may be used individually by 1 type, and 2 or more types may be mixed and used for them.

  The range of the total addition amount of the compound (additive of the present invention) having at least one element selected from the group consisting of B, Ca, Mg, Al, V and Bi and the additive 1 is as follows. The lower limit is usually 0.001 mol% or more, preferably 0.01 mol% or more, more preferably 0.1 mol% or more, and particularly preferably 1 mol%, relative to the total molar amount of the transition metal elements constituting. As described above, the upper limit is usually 10 mol% or less, preferably 5 mol% or less, more preferably 3 mol% or less, and particularly preferably 2 mol% or less. If the lower limit is not reached, the above effect may not be obtained. If the upper limit is exceeded, battery performance may be reduced.

<Contained carbon concentration C>
The carbon concentration C (wt%) value of the lithium transition metal compound of the present invention is usually 0.005 wt% or more, preferably 0.01 wt% or more, more preferably 0.015 wt% or more, most preferably 0.02% by weight or more, usually 0.25% by weight or less, preferably 0.2% by weight or less, more preferably 0.15% by weight or less, still more preferably 0.1% by weight or less, most preferably 0. 0.07% by weight or less. If the lower limit is not reached, battery performance may be reduced. If the upper limit is exceeded, swelling due to gas generation when the battery is produced may increase or battery performance may be reduced.

In the present invention, the carbon content C of the lithium transition metal compound is determined by measurement by combustion in an oxygen stream (high-frequency heating furnace type) infrared absorption method, as shown in the section of Examples described later. In addition, the carbon component contained in the lithium transition metal-based compound obtained by carbon analysis described later can be regarded as indicating information on the amount of carbonic acid compound, particularly lithium carbonate. This is due to the fact that the carbon amount determined by carbon analysis is assumed to be all derived from carbonate ions, and the carbonate ion concentration analyzed by ion chromatography generally agrees.
On the other hand, when a composite treatment with conductive carbon is performed as a method for increasing the electron conductivity, a C amount exceeding the specified range may be detected, but such a treatment was performed. The C value in the case is not limited to the specified range.

[Method for producing lithium transition metal compound for positive electrode material of lithium secondary battery]
The method for producing the lithium transition metal compound of the present invention is not limited to a specific production method, but the lithium compound and at least one or more transitions selected from Mn, Ni, Cr, Fe, Co and Cu are used. A slurry preparation step for obtaining a slurry in which a metal compound and the additive of the present invention are pulverized in a liquid medium to uniformly disperse them, and a spray drying step for spray drying the obtained slurry were obtained. It is preferably produced by the method for producing a lithium transition metal-based compound for a lithium secondary battery positive electrode material of the present invention, which includes a firing step of firing a spray-dried body.
Hereinafter, the method for producing a lithium transition metal compound of the present invention will be described in detail, taking as an example the method for producing a lithium nickel manganese composite oxide powder which is a preferred embodiment of the present invention.

<Slurry preparation process>
Among the raw material compounds used for the preparation of the slurry in producing a lithium transition metal compound by the method of the present invention, as the lithium compound, Li ₂ CO ₃ , LiNO ₃ , LiNO ₂ , LiOH, LiOH.H ₂ O, Examples include LiH, LiF, LiCl, LiBr, LiI, CH ₃ OOLi, Li ₂ O, Li ₂ SO ₄ , dicarboxylic acid Li, citric acid Li, fatty acid Li, and alkyl lithium. Among these lithium compounds, preferred is a lithium compound that does not contain nitrogen atoms, sulfur atoms, or halogen atoms in that no harmful substances such as SO _x and N · BR> N _x are generated during the firing treatment. Moreover, it is a compound that easily forms voids by generating decomposition gas in the secondary particles of the spray-dried powder, for example, by generating decomposition gas at the time of firing, and taking these points into consideration, Li ₂ CO ₃ , LiOH, and LiOH.H ₂ O are preferable, and Li ₂ CO ₃ is particularly preferable. These lithium compounds may be used individually by 1 type, and may use 2 or more types together.

Moreover, as a nickel compound, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC ₂ O ₄ .2H ₂ O, Ni (NO ₃ ) ₂ .6H ₂ O, NiSO ₄ , NiSO ₄ .6H ₂ O, nickel fatty acid, nickel halide and the like. Among these, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , 2NiCO ₃ .3Ni (OH) ₂ .4H ₂ O, NiC are used in that no harmful substances such as SO _X and NO _X are generated during the firing process. Nickel compounds such as ₂ O ₄ .2H ₂ O are preferred. Further, from the viewpoint that it can be obtained as an industrial raw material at a low cost and from the viewpoint of high reactivity, Ni (OH) ₂ , NiO, NiOOH, NiCO ₃ , and further, a decomposition gas is generated at the time of firing. Ni (OH) ₂ , NiOOH, and NiCO ₃ are particularly preferable from the viewpoint of easily forming voids in the secondary particles. These nickel compounds may be used individually by 1 type, and may use 2 or more types together.

In addition, as manganese compounds, manganese oxides such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , MnCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylate, manganese citrate, fatty acid manganese And manganese salts such as oxyhydroxide, manganese chloride and the like. Among these manganese compounds, MnO ₂ and Mn ₂ O ₃
, Mn ₃ O ₄ , and MnCO ₃ are preferable because they do not generate gas such as SO _X and NO _X during the firing process and can be obtained at low cost as industrial raw materials. These manganese compounds may be used individually by 1 type, and may use 2 or more types together.

  In addition to the above Li, Ni, and Mn raw material compounds, substitution of other elements is performed to introduce the above-mentioned foreign elements, or voids in secondary particles formed by spray drying described later can be efficiently formed. It is possible to use a group of compounds intended to do this. In addition, the addition stage of the compound used for the purpose of efficiently forming the voids of the secondary particles used here can be selected either before or after mixing the raw materials depending on the property. It is. In particular, it is preferable to add a compound that is easily decomposed due to mechanical shear stress applied by the mixing step after the mixing step.

The additive of the present invention is as described above.
The method for mixing the raw materials is not particularly limited, and may be wet or dry. For example, a method using an apparatus such as a ball mill, a vibration mill, or a bead mill can be used. Wet mixing in which the raw material compound is mixed in a liquid medium such as water or alcohol is preferable because more uniform mixing is possible and the reactivity of the mixture can be increased in the firing step.

The mixing time varies depending on the mixing method, but it is sufficient that the raw materials are uniformly mixed at the particle level. For example, in a ball mill (wet or dry type), usually about 1 to 2 days, and in a bead mill (wet continuous method), a residence time. Is usually about 0.1 to 6 hours.
In the raw material mixing stage, it is preferable that the raw material is pulverized in parallel. As the degree of pulverization, the particle diameter of the raw material particles after pulverization is an index, but the average particle diameter (median diameter) is usually 0.7 μm or less, preferably 0.6 μm or less, more preferably 0.55 μm or less, most preferably Preferably, it is 0.5 μm or less. If the average particle size of the pulverized raw material particles is too large, the reactivity in the firing process is lowered, and the composition is difficult to homogenize. However, making particles smaller than necessary leads to an increase in the cost of pulverization, so that the average particle size is usually 0.01 μm or more, preferably 0.02 μm or more, more preferably 0.05 μm or more. It ’s fine. A means for realizing such a degree of pulverization is not particularly limited, but a wet pulverization method is preferable. Specific examples include dyno mill.

  In the present invention, the median diameter of the pulverized particles in the slurry was measured with a known laser diffraction / scattering type particle size distribution measuring apparatus with a refractive index of 1.24 and a particle diameter standard set as a volume standard. Is. In the present invention, a 0.1 wt% sodium hexametaphosphate aqueous solution was used as a dispersion medium used in the measurement, and measurement was performed after 5 minutes of ultrasonic dispersion (output 30 W, frequency 22.5 kHz).

<Spray drying process>
After the wet mixing, it is then usually subjected to a drying process. The drying method is not particularly limited, but spray drying is preferable from the viewpoints of uniformity of the generated particulate matter, powder fluidity, powder handling performance, and efficient production of dry particles. In addition, the lithium transition metal compound fired after spray drying does not require a pulverization step, so the process can be simplified, and the addition of the present invention uniformly distributed over the entire particle or concentrated on the surface There is an advantage that the element contained in the agent is more likely to exhibit the effect.

(Spray-dried powder)
In the method for producing a lithium transition metal compound powder such as lithium nickel manganese complex oxide powder of the present invention, the slurry obtained by wet-grinding the raw material compound and the additive of the present invention is spray-dried. As a result, a powder obtained by agglomerating primary particles to form secondary particles is obtained. The spray-dried powder formed by agglomerating primary particles to form spherical secondary particles is a shape characteristic of the spray-dried powder of the present invention. Since the spray-dried body is spherical, it is possible to obtain a lithium transition metal compound having excellent filling properties. Examples of the method for confirming the shape of the spray-dried body include SEM observation and cross-sectional SEM observation.

  The median diameter of a powder obtained by spray drying which is also a firing precursor of a lithium transition metal compound powder such as the lithium nickel manganese composite oxide powder of the present invention (here, a value measured without applying ultrasonic dispersion) ) Is usually 25 μm or less, more preferably 20 μm or less, still more preferably 18 μm or less, and most preferably 16 μm or less. However, since it tends to be difficult to obtain a too small particle size, it is usually 3 μm or more, preferably 4 μm or more, more preferably 5 μm or more. In the case of producing a particulate material by the spray drying method, the particle size can be controlled by appropriately selecting the spray format, the pressurized gas flow supply rate, the slurry supply rate, the drying temperature, and the like.

  That is, for example, after a slurry in which a lithium compound, a nickel compound, and a manganese compound and the additive of the present invention are dispersed in a liquid medium is spray-dried, the obtained powder is fired to obtain a lithium nickel manganese composite oxide In producing the powder, when the slurry viscosity during spray drying is V (cP), the slurry supply amount is S (L / min), and the gas supply amount is G (L / min), the slurry viscosity V is 50 cP. Spray drying is performed under the condition that ≦ V ≦ 10000 cP and the gas-liquid ratio G / S is 500 ≦ G / S ≦ 10000.

  If the slurry viscosity V (cP) is too low, it may be difficult to obtain a powder obtained by agglomerating primary particles to form secondary particles. If the slurry viscosity V (cP) is too high, the supply pump may fail or the nozzle may be blocked. is there. Therefore, the slurry viscosity V (cP) is usually 50 cP or more as a lower limit, preferably 100 cP or more, more preferably 300 cP or more, most preferably 500 cP, and the upper limit is usually 10000 cp or less, preferably 7500 cp or less, more preferably Is 6500 cp or less, most preferably 6000 cp or less.

  Further, when the gas-liquid ratio G / S is lower than the lower limit, the secondary particle size is coarsened or the drying property is liable to be lowered. When the upper limit is exceeded, the productivity may be lowered. Therefore, the gas-liquid ratio G / S is usually 500 or more, preferably 800 or more, more preferably 1000 or more, most preferably 1500 or more as the lower limit, and usually 10,000 or less, preferably 9000 or less, as the upper limit. Preferably it is 8000 or less, most preferably 7500 or less. The slurry supply amount S and the gas supply amount G are appropriately set according to the viscosity of the slurry used for spray drying, the specifications of the spray drying apparatus used, and the like.

In the method of the present invention, the above-mentioned gas-liquid ratio G / S is satisfied by controlling the slurry supply amount and gas supply amount that meet the above-mentioned slurry viscosity V (cP) and that are suitable for the specifications of the spray drying apparatus to be used. Spray drying may be performed within a range, and other conditions are appropriately set according to the type of apparatus to be used, but it is preferable to select the following conditions.
That is, spray drying of the slurry is usually 50 ° C. or higher, preferably 70 ° C. or higher, more preferably 120 ° C. or higher, most preferably 140 ° C. or higher, usually 300 ° C. or lower, preferably 250 ° C. or lower, more preferably 200 ° C. It is preferable to carry out the reaction at a temperature of ℃ or less, most preferably 180 ℃ or less. If this temperature is too high, the resulting granulated particles may have a lot of hollow structures, which may reduce the packing density of the powder. On the other hand, if it is too low, problems such as powder sticking and blockage due to moisture condensation at the powder outlet may occur.

<Baking process>
The fired precursor thus obtained is then fired.
Here, in the present invention, the “firing precursor” means a precursor of a lithium transition metal compound such as a lithium nickel manganese composite oxide before firing obtained by treating a spray-dried powder. For example, the above spray-dried powder may contain a compound that generates or sublimates decomposition gas during the above-described firing to form voids in the secondary particles, and serves as a firing precursor.

  This firing condition depends on the composition and the lithium compound raw material used, but as a tendency, if the firing temperature is too high, primary particles grow excessively, sintering between the particles proceeds too much, and the specific surface area becomes small. Pass. On the other hand, if it is too low, heterogeneous phases are mixed, and the lattice distortion increases without developing the crystal structure. Moreover, the specific surface area becomes too large. The firing temperature is usually 700 ° C. or higher, preferably 750 ° C. or higher, more preferably 775 ° C. or higher, most preferably 800 ° C. or higher, usually 1000 ° C. or lower, preferably 950 ° C. or lower, more preferably 925 ° C. or lower, Most preferably, it is 900 degrees C or less.

  Also, starting from the start time of raising the temperature of the lithium transition metal-based compound from room temperature, after reaching the maximum temperature and holding that temperature, the time to cool down and return to room temperature is the firing time, The shorter the firing time, the more industrially advantageous. However, when the firing time is too short, the raw material does not sinter sufficiently, foreign phases are mixed, the crystal structure does not develop, and the lattice strain increases. The firing time is usually 24 hours or less, preferably 18 hours or less, more preferably 15 hours or less, most preferably 12 hours or less, usually 30 minutes or more, preferably 1 hour or more, more preferably 1.5 hours or more. Most preferably, it is 2 hours or more.

  For firing, for example, a box furnace, a tubular furnace, a tunnel furnace, a rotary kiln or the like can be used. The firing process is usually divided into three parts: temperature increase, maximum temperature retention, and temperature decrease. The second maximum temperature holding portion is not necessarily limited to one time, and may include two or more stages depending on the purpose, which means that aggregation is eliminated to the extent that secondary particles are not destroyed. The temperature raising, maximum temperature holding, and temperature lowering steps may be repeated twice or more with a crushing step or a crushing step meaning crushing to primary particles or even fine powder.

  In the temperature raising step leading to the maximum temperature holding step, the temperature in the furnace is usually raised at a temperature raising rate of 1 ° C./min to 15 ° C./min. Even if this rate of temperature rise is too slow, it takes time and is industrially disadvantageous. However, if it is too fast, the furnace temperature does not follow the set temperature depending on the furnace. The rate of temperature rise is preferably 2 ° C./min or more, more preferably 3 ° C./min or more, preferably 20 ° C./min or less, more preferably 18 ° C./min or less.

  Although the holding time in the maximum temperature holding step varies depending on the temperature, it is usually 15 minutes or longer, preferably 30 minutes or longer, more preferably 45 minutes or longer, most preferably 1 hour or longer within the above-mentioned temperature range. Time or less, preferably 12 hours or less, more preferably 9 hours or less, and most preferably 6 hours or less. If the firing time is too short, it becomes difficult to obtain a lithium transition metal-based compound powder with good crystallinity, and it is not practical to be too long. If the firing time is too long, subsequent crushing becomes difficult, which is disadvantageous.

  In the temperature lowering step, the temperature in the furnace is usually decreased at a temperature decreasing rate of 0.1 ° C./min to 15 ° C./min. If the temperature lowering rate is too slow, it takes time and is industrially disadvantageous, but if it is too fast, the uniformity of the target product tends to be lost or the deterioration of the container tends to be accelerated. The temperature lowering rate is preferably 1 ° C./min or more, more preferably 3 ° C./min or more, preferably 20 ° C./min or less, more preferably 15 ° C./min or less.

As the atmosphere during firing, there is an appropriate oxygen partial pressure region depending on the composition of the lithium transition metal compound to be obtained, and therefore various gas atmospheres appropriate to satisfy the oxygen partial pressure region are used. Examples of the gas atmosphere include oxygen, air, nitrogen, argon, hydrogen, carbon dioxide, and a mixed gas thereof. Further, in order to improve the filling property of the lithium transition metal compound of the present invention, it is fired in an oxygen-containing gas atmosphere such as air after being fired in an atmosphere having a low oxygen partial pressure, such as a nitrogen atmosphere. It is preferable that The oxygen concentration of the oxygen-containing gas is usually 1% by volume or higher, preferably 10% by volume or higher, more preferably 15% by volume or higher.

In such a production method, in order to produce the lithium transition metal compound of the present invention, for example, the lithium nickel manganese composite oxide powder having the specific composition, the lithium compound is obtained under the same production conditions. When preparing a slurry in which a nickel compound and a manganese compound and the additive of the present invention are dispersed in a liquid medium, by adjusting the mixing ratio of each compound, the desired molar ratio of Li / Ni / Mn Can be controlled.
According to the method for producing a lithium transition metal compound as described above, a lithium transition metal compound capable of realizing a lithium secondary battery having a high energy density and excellent load characteristics is provided in a simple and short process. The

[Positive electrode for lithium secondary battery]
The positive electrode for a lithium secondary battery of the present invention is obtained by forming a positive electrode active material layer containing a lithium transition metal compound powder for a lithium secondary battery positive electrode material of the present invention and a binder on a current collector. It is.
The positive electrode active material layer is usually formed by mixing a positive electrode material, a binder, and a conductive material and a thickener, which are used if necessary, in a dry form into a sheet shape, and then pressing the positive electrode current collector on the positive electrode current collector. Alternatively, these materials are dissolved or dispersed in a liquid medium to form a slurry, which is applied to the positive electrode current collector and dried.

  As the material for the positive electrode current collector, metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, and carbon materials such as carbon cloth and carbon paper are usually used. Of these, metal materials are preferable, and aluminum is particularly preferable. As for the shape, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder Etc. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape.

  When a thin film is used as the positive electrode current collector, its thickness is arbitrary, but it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 100 mm or less, preferably 1 mm or less, more preferably 50 μm or less. The range of is preferable. If it is thinner than the above range, the strength required for the current collector may be insufficient. On the other hand, if it is thicker than the above range, the handleability may be impaired.

The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that is stable with respect to the liquid medium used during electrode production may be used. Specific examples include polyethylene, Resin polymers such as polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene・ Rubber polymers such as propylene rubber, styrene / butadiene / styrene block copolymers and hydrogenated products thereof, EPDM (ethylene / propylene / diene terpolymers), styrene / ethylene / butadiene / ethylene copolymers, Styrene / isoprene styrene bromide Copolymer and its hydrogenated thermoplastic elastomeric polymer, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Fluorine polymers such as soft resinous polymers, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers, ion conductivity of alkali metal ions (especially lithium ions) And a polymer composition having the same. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and usually 20% by weight or less, preferably 15% by weight or less. Most preferably, it is 10 wt% or less. If the proportion of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. Battery capacity and conductivity may be reduced.

  The positive electrode active material layer usually contains a conductive material in order to increase conductivity. There are no particular restrictions on the type, but specific examples include metal materials such as copper and nickel, graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. And carbon materials. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. The proportion of the conductive material in the positive electrode active material layer is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 1% by weight or more, and usually 50% by weight or less, preferably 30%. % By weight or less, more preferably 20% by weight or less. If the proportion of the conductive material is too low, the conductivity may be insufficient, and conversely if it is too high, the battery capacity may be reduced.

  As a liquid medium for forming a slurry, it is possible to dissolve or disperse a lithium transition metal compound powder as a positive electrode material, a binder, and a conductive material and a thickener used as necessary. If it is a solvent, there is no restriction | limiting in particular in the kind, You may use either an aqueous solvent or an organic solvent. Examples of the aqueous solvent include water and alcohol. Examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. be able to. In particular, when an aqueous solvent is used, a dispersant is added together with the thickener, and a slurry such as SBR is slurried. In addition, these solvents may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The content of the lithium transition metal compound of the present invention as the positive electrode material in the positive electrode active material layer is usually 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more, and usually 99.9%. % By weight or less, preferably 99% by weight or less. If the proportion of the lithium transition metal compound powder in the positive electrode active material layer is too large, the strength of the positive electrode tends to be insufficient, and if it is too small, the capacity may be insufficient.

The thickness of the positive electrode active material layer is usually about 10 to 200 μm.
As the electrode plate density after pressing of the positive electrode, the lower limit is usually 2.2 g / cm ³ or more, preferably 2.4 g / cm ³ or more, particularly preferably 2.6 g / cm ³ or more, and the upper limit is Usually, 4.2 g / cm ³ or less, preferably 4.0 g / cm ³ or less, particularly preferably 3.8 g / cm ³ or less.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the positive electrode active material.
Thus, the positive electrode for a lithium secondary battery of the present invention can be prepared.

2-2. Negative electrode The negative electrode is usually formed by forming a negative electrode active material layer on a negative electrode current collector, as in the case of the positive electrode.
As a material of the negative electrode current collector, a metal material such as copper, nickel, stainless steel, nickel-plated steel, or a carbon material such as carbon cloth or carbon paper is used. Among these, in the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder, etc. are mentioned. Among these, metal thin films are preferable because they are currently used in industrialized products. In addition, you may form a thin film suitably in mesh shape. When a metal thin film is used as the negative electrode current collector, the preferred thickness range is the same as the range described above for the positive electrode current collector.

<Negative electrode active material>
The negative electrode active material layer includes a negative electrode active material. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions, but it can usually occlude and release lithium from the viewpoint of high safety. A carbon material is used.
Although there is no restriction | limiting in particular as a carbon material, Graphite (graphite), such as artificial graphite and natural graphite, and the thermal decomposition thing of organic substance on various thermal decomposition conditions are mentioned. Examples of pyrolysis products of organic matter include coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or carbide obtained by oxidizing these pitches, needle coke, pitch coke, phenol resin, crystalline cellulose, etc. And carbon materials obtained by partially graphitizing these, furnace black, acetylene black, pitch-based carbon fibers, and the like. Among them, graphite is preferable, and particularly preferable is artificial graphite, purified natural graphite, or graphite material containing pitch in these graphites, which is manufactured by subjecting easy-graphite pitch obtained from various raw materials to high-temperature heat treatment. Therefore, those subjected to various surface treatments are mainly used. One of these carbon materials may be used alone, or two or more thereof may be used in combination.

When a graphite material is used as the negative electrode active material, the d value (interlayer distance: d ₀₀₂ ) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method is usually 0.335 nm or more, and usually 0.34 nm. In the following, it is preferable that the thickness is 0.337 nm or less.
Further, the ash content of the graphite material is usually 1% by weight or less, particularly 0.5% by weight or less, and particularly preferably 0.1% by weight or less, based on the weight of the graphite material.

Further, the crystallite size (Lc) of the graphite material determined by X-ray diffraction by the Gakushin method is usually 30 nm or more, preferably 50 nm or more, and particularly preferably 100 nm or more.
The median diameter of the graphite material determined by the laser diffraction / scattering method is usually 1 μm or more, especially 3 μm or more, more preferably 5 μm or more, especially 7 μm or more, and usually 100 μm or less, especially 50 μm or less, more preferably 40 μm or less, especially 40 μm or less. It is preferable that it is 30 micrometers or less.

Moreover, the BET specific surface area of the graphite material is usually 0.5 m ² / g or more, preferably 0.7 m ² / g or more, more preferably 1.0 m ² / g or more, and further preferably 1.5 m ² / g. or more, and usually 25.0 m ² / g or less, preferably 20.0 m ² / g, more preferably 15.0 m ² / g or less, still more preferably 10.0 m ² / g or less.
Further, when performing Raman spectroscopy using argon laser light for graphite material, and strength _{I A} of the peak _{P A} is detected in the range of 1580～1620Cm ^-1, it is detected in the range of 1350 ^-1 that intensity ratio _I a / _{I B} of the intensity _{I B} of a peak _{P B} is what is preferably 0 to 0.5. Further, the half width of the peak _{P A} is preferably 26cm ^-1 or less, 25 cm ^-1 or less is more preferable.

In addition to the above-mentioned various carbon materials, it can also be used as a negative electrode active material of other materials capable of inserting and extracting lithium. Specific examples of negative electrode active materials other than carbon materials include metal oxides such as tin oxide and silicon oxide, nitrides such as Li _2.6 Co _0.4 N, and lithium alloys such as lithium alone and lithium aluminum alloys. Can be mentioned. One of these materials other than the carbon material may be used alone, or two or more thereof may be used in combination. Moreover, you may use in combination with the above-mentioned carbon material.

  As in the case of the positive electrode active material layer, the negative electrode active material layer is usually prepared by slurrying the above-described negative electrode active material, a binder, and optionally a conductive material and a thickener in a liquid medium. It can manufacture by apply | coating to a negative electrode electrical power collector, and drying. As the liquid medium, the binder, the thickener, the conductive material, and the like that form the slurry, the same materials as those described above for the positive electrode active material layer can be used.

2-3. Separator Normally, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, a resin, glass fiber, inorganic material, etc. formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention is used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention properties is used. Is preferred.

  As materials for the resin and glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, glass filters and the like can be used. Of these, glass filters and polyolefins are preferred, and polyolefins are more preferred. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 8 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

  Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-mentioned independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

2-4. Battery design <Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less. .

  When the electrode group occupancy is below the above range, the battery capacity decreases. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Current collection structure>
The current collecting structure is not particularly limited, but in order to more effectively realize the high current density charge / discharge characteristics by the non-aqueous electrolyte solution of the present invention, a structure that reduces the resistance of the wiring part and the joint part is used. It is preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

  In the case where the electrode group has the above laminated structure, a structure formed by bundling the metal core portions of the electrode layers and welding them to the terminals is preferably used. When the area of one electrode increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the winding structure described above, the internal resistance can be lowered by providing a plurality of lead structures for the positive electrode and the negative electrode, respectively, and bundling the terminals.

<Exterior case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

  In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.

<Protective element>
Protection elements such as PTC (Positive Temperature Coefficient), thermal fuse, thermistor, which increases resistance when abnormal heat is generated or excessive current flows, shuts off current flowing through the circuit due to sudden increase in battery internal pressure or internal temperature during abnormal heat generation A valve (current cutoff valve) or the like can be used. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

<Exterior body>
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

  The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

<Charge potential of the positive electrode when fully charged>
In the following examples, the lithium secondary battery of the present invention proves its effectiveness with a battery designed so that the charging potential of the positive electrode in a fully charged state is about 4.9 V (vs. Li ^/ Li ⁺ ). is doing. However, even when the lithium transition metal-based composite oxide powder for a lithium secondary battery positive electrode material of the present invention is used for a lithium secondary battery designed to be charged at a higher charging potential, the effect of the present invention is also achieved. To effectively demonstrate.

  The general embodiment of the lithium secondary battery of the present invention has been described above. However, the lithium secondary battery of the present invention is not limited to the above-described embodiment, and various modifications are possible as long as the gist thereof is not exceeded. Can be implemented.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
[Production of negative electrode]
98 parts by mass of graphite as a carbonaceous material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of carboxymethylcellulose sodium) and an aqueous dispersion of styrene-butadiene rubber (as a thickener and a binder, respectively) 1 part by mass of styrene-butadiene rubber (concentration: 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 10 μm, dried, and rolled with a press. The active material layer was 30 mm wide, 40 mm long, 5 mm wide, and 9 mm long uncoated. It cut out into the shape which has a part, and it was set as the negative electrode used for Example 1 and Comparative Example 1, respectively.

[Production of positive electrode]
(Example 1 and Comparative Example 1)
Li ₂ CO ₃ , NiCO ₃ , and Mn ₃ O ₄ are used as raw materials for constituting the main component of the lithium transition metal compound, and a molar ratio of Li: Ni: Mn: = 1.05: 0.5: 1.5 Weighed to achieve a ratio. Pure water was added thereto to prepare a slurry. While stirring the slurry, the solid content in the slurry was pulverized to a median diameter of about 0.30 μm using a circulating medium agitation type wet pulverizer.

Next, this slurry (solid content 30 wt%, viscosity 1150 cP) was spray-dried using a two-fluid nozzle type spray dryer (Okawara Kako Co., Ltd .: LT-8 type). About 10 g of particulate powder obtained by spray drying with a spray drier is charged into an alumina crucible, and fired in an air atmosphere at a maximum temperature of 900 ° C. and a maximum temperature holding time of 6 hours (heating rate 6). 7 ° C./min.) And then crushed to obtain a lithium nickel manganese composite oxide powder (Li [Li _0.05 Ni _0.475 Mn _0.52 ] O having a spinel structure.
₄ ) was obtained. The powder properties are shown in Table 1.

85% by mass of the lithium nickel manganese composite oxide having the above spinel structure as a positive electrode active material, 10% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder, Were slurried by mixing in N-methylpyrrolidone solvent. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press. The active material layer was 30 mm in width, 40 mm in length, 5 mm in width, and 9 mm in length. It cut out in the shape which has a process part, and was set as the positive electrode used for Example 1 and Comparative Example 1. The electrode plate density was 2.4 g / cm ³ .

[Manufacture of electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a mixture (volume ratio 30:30:40) of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) was adjusted to a ratio of 1 mol / L. A basic electrolyte solution was prepared by dissolution. This basic electrolytic solution was used as the electrolytic solution used in Comparative Example 1, and an electrolytic solution obtained by mixing the basic electrolytic solution with a compound of the formula (2) in which Y is C═O at a ratio of 1 wt% is shown in Example 1. It was set as the electrolyte solution to be used.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and the above electrolytes were poured into the bags. Then, vacuum-sealing was performed to prepare a sheet-like battery, and the batteries used in Example 1 and Comparative Example 1 were obtained.

[Run-in operation]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes.
[Evaluation of high-temperature storage characteristics]
The battery after the break-in operation has been completed is charged to 4.9 V (VS Li / Li ⁺ ) at 25 ° C. with a low current of 0.2 C, left at 85 ° C. for 3 days, and then cooled to room temperature. The amount of gas was measured. The amount of gas generated after storage was calculated by comparing the buoyancy when the battery was submerged in an ethanol bath before and after high temperature storage. The evaluation results are shown in Table 2.

  As is clear from Table 2, the battery using the non-aqueous electrolyte solution according to the present invention (Example 1) is compared to the battery not using the non-aqueous electrolyte solution according to the present invention (Comparative Example 1). Low gas generation during storage at high temperatures.

<Examples 2 and 3 and Comparative Example 2>
[Production of positive electrode]
90% by mass of the lithium nickel manganese composite oxide having the above-mentioned spinel structure as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride as a binder are N- Mix in a methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to an aluminum foil having a thickness of 15 μm, dried, and rolled with a press. The active material layer was 30 mm in width, 40 mm in length, 5 mm in width, and 9 mm in length. It cut out in the shape which has a process part, and it was set as the positive electrode used for Examples 2, 3, and the comparative example 2. FIG.

[Manufacture of electrolyte]
Under a dry argon atmosphere, a mixture of trans-4,5-difluoroethylene carbonate and bis (2,2,2-trifluoroethyl) carbonate (volume ratio 50:50, Examples 2 and 3), and trans-4, A basic electrolyte solution was prepared by dissolving LiPF ₆ dried in a mixture of 5-difluoroethylene carbonate and diethyl carbonate (volume ratio 50:50, Comparative Example 20) to a ratio of 1 mol / L. The basic electrolyte solution was mixed with a compound shown in Table 9 to obtain an electrolyte solution used in Examples 2, 3 and Comparative Example 2.

[Manufacture of lithium secondary batteries]
A sheet-like battery was produced in the same manner as in Example 1 except that the positive electrode and the electrolytic solution were used.

[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned by a constant current corresponding to 0.3 C at 25 ° C. in a state where the lithium secondary battery was sandwiched between glass plates in order to enhance the adhesion between the electrodes. The battery that had been conditioned was charged at a constant current corresponding to 0.3 C at 25 ° C., and then discharged at a constant current corresponding to 0.3 C to determine the initial discharge capacity.

[Evaluation of high-temperature storage characteristics]
After confirming the capacity with a constant current corresponding to 0.3 C at 25 ° C. in a state where the lithium secondary battery is sandwiched between glass plates in order to enhance the adhesion between the electrodes, a constant current corresponding to 0.3 C is obtained. And stored at 60 ° C. for 72 hours. After cooling the battery to room temperature, discharge at a constant current equivalent to 0.3 C to obtain the discharge capacity, and maintain the capacity from the formula of (discharge capacity after storage) ÷ (discharge capacity before storage) × 100 The rate was determined.

  As is clear from Table 3, the batteries using the non-aqueous electrolyte solution according to the present invention (Examples 2 and 3) are batteries using the non-aqueous electrolyte solution not containing the compound represented by the general formula (1). Compared to (Comparative Example 2), the capacity retention rate after high-temperature storage is excellent. That is, it can be seen that by introducing the compound (C) together with the compound represented by the general formula (1), an effect of improving battery durability is exhibited. In addition, even when the battery voltage is high, the effect of the present invention is remarkably shown. From the above, it can be seen that when the non-aqueous electrolyte solution according to the present invention is used, the durability improving effect is exhibited regardless of the electrode design.

The non-aqueous electrolyte secondary battery of the present invention can improve high-temperature storage characteristics.
Therefore, the non-aqueous electrolyte secondary battery of the present invention can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Load Examples include leveling power sources and natural energy storage power sources.

Claims (8)

A non-aqueous electrolyte battery comprising a non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, a negative electrode capable of occluding and releasing lithium ions, and a positive electrode, the positive electrode comprising: A non-aqueous electrolyte battery comprising the positive electrode active material of (A), wherein the electrolyte contains a compound represented by the following general formula (1).
(A) A lithium transition metal-based compound powder that includes a crystal structure belonging to a spinel structure, has a BET specific surface area of 0.3 m ² / g or more, and has a composition represented by the following composition formula (A).
_{Li [Li a M x Mn 2} -x-a] O 4 + d ··· ( b)
(In formula (a), 0 ≦ a ≦ 0.3, 0.4 ≦ x ≦ 0.6, −0.5 <δ <0.5 is satisfied, and M is Ni, Cr, Fe, Co and Cu. Represents at least one of transition metals selected from

(In the formula (1), X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ^{1 and} are the same. However, Y may be different, and Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . , R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, and R ² represents a functional group. .R ³ is also a hydrocarbon group having from good 1 to 20 carbon atoms having the, Li, ^NR _{4 4,} or a hydrocarbon group having carbon atoms 1 may have a functional group 20 .R ⁴ Is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, n and m each represents an integer of 0 or more, and in the adjacent ring Carbon may form a further bond with each other, and the R of the carbon may be reduced by one each. W represents the above R.)   2. The non-aqueous electrolyte battery according to claim 1, wherein 0 <a ≦ 0.3 in the formula (A) of the lithium transition metal-based compound powder. The non-aqueous electrolyte solution according to claim 1 or 2, wherein the compound represented by the general formula (1) is a compound represented by the formula (2).

(Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ^3, and R ² may have a functional group. And a hydrocarbon group having 1 to 20. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and R ⁴ has a functional group. And may be the same or different from each other.   The amount of the compound represented by the general formula (1) is 0.001% by mass or more and 5% by mass or less in 100% by mass of the nonaqueous electrolytic solution. The non-aqueous electrolyte battery described in 1.   The said non-aqueous electrolyte solution contains at least 1 or more types from the group chosen from the cyclic carbonate which has a double bond, and the cyclic carbonate which has a fluorine atom, The Claim 1 thru | or 4 characterized by the above-mentioned. Non-aqueous electrolyte battery.   6. The nonaqueous electrolyte battery according to claim 1, wherein the median diameter of the lithium transition metal compound is 2 μm or more and 60 μm or less. The non-aqueous electrolyte battery according to claim 1, wherein an electrode plate density of the positive electrode is 2 g / cm ³ or more.   The non-aqueous electrolyte solution used for the non-aqueous electrolyte battery in any one of Claims 1 thru | or 7.