JP6894751B2 - Non-aqueous electrolyte for batteries, additives for batteries, and lithium secondary batteries - Google Patents

Description

The present disclosure relates to non-aqueous electrolytes for batteries, additives for batteries, and lithium secondary batteries.

In recent years, lithium secondary batteries have been widely used as power sources for electronic devices such as mobile phones and notebook computers, electric vehicles, and power storage. In particular, recently, there has been a rapid increase in demand for batteries with high capacity, high output, and high energy density that can be installed in hybrid vehicles and electric vehicles.
The lithium secondary battery is mainly composed of a positive electrode and a negative electrode containing a material capable of occluding and releasing lithium, and a non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent.
As the positive electrode active material used for the positive electrode, for example, lithium metal oxides such as _{LiCoO 2} , LiMnO ₂ , LiNiO ₂ , and LiFePO _{4 are used.}
As the non-aqueous electrolyte solution, LiPF ₆ , LiBF ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiPF 6, LiBF 4, LiN (SO 2 CF 3) 2, LiPF 6, LiBF 4, LiN (SO 2 CF 3) 2, etc. A solution mixed with a Li electrolyte such as LiN (SO ₂ CF ₂ CF ₃ ) _{2 is used.}
On the other hand, as active materials for negative electrodes used for negative electrodes, metallic lithium, metal compounds capable of occluding and releasing lithium (single metal, oxides, alloys with lithium, etc.) and carbon materials are known, and in particular, lithium is used. Lithium secondary batteries using coke, artificial graphite, and natural graphite that can be occluded and released have been put into practical use.

Among the battery performances, especially for lithium secondary batteries for automobiles, high output is required, so it is desired to reduce the resistance of the batteries over various conditions.
As one of the factors that increase the resistance of the battery, a film formed on the surface of the negative electrode by a decomposition product of a solvent or an inorganic salt is known. Generally, it is known that a reduction decomposition reaction of an electrolytic solution occurs on the surface of a negative electrode because lithium metal is present in the active material of the negative electrode under charging conditions. If such reduction decomposition occurs continuously, the resistance of the battery increases, the charge / discharge efficiency decreases, and the energy density of the battery decreases. Attempts have been made to add various compounds to the electrolytic solution in order to overcome these problems.
As an attempt to reduce the battery resistance by containing various sulfonic acid ester compounds (see, for example, Patent Documents 1 to 4).

Japanese Unexamined Patent Publication No. 2000-3724 Japanese Unexamined Patent Publication No. 2000-133304 International Publication No. 2005/05/7713 Japanese Unexamined Patent Publication No. 2009-054287

However, there are cases where it is required to suppress an increase in battery resistance with time as compared with the prior art (for example, the techniques described in Patent Documents 1 to 4).
Here, in the concept of "suppressing the increase in battery resistance with time", the battery resistance increases with time, but when the degree of the increase is reduced, the battery resistance is maintained without increasing with time. This includes all cases where the battery resistance does not increase but rather decreases over time.
The increase in battery resistance with time is evaluated, for example, by determining the ratio of battery resistance after aging to battery resistance before aging (hereinafter, also referred to as "battery resistance ratio [after aging / before aging]"). The smaller the battery resistance ratio [after aging / before aging], the more the increase in battery resistance over time is suppressed.

An object of the present disclosure is to provide a non-aqueous electrolyte solution for a battery and an additive for a battery capable of suppressing an increase in battery resistance with time, and a lithium secondary battery in which an increase in battery resistance with time is suppressed. is there.

Means for solving the above problems include the following aspects.
<1> A non-aqueous electrolytic solution for a battery containing a compound represented by the following formula (I).

[In the formula (I), R ^{1 to} R ¹⁰ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl halide group having 1 to 3 carbon atoms. However, ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.
In the formula (I), X represents an alkylene group having 1 to 6 carbon atoms, an alkaneylene group having 2 to 6 carbon atoms, or a carbonyl group. ]

<2> The non-aqueous electrolytic solution for a battery according to <1>, wherein X is a methylene group, an ethylene group, a vinylene group, or a carbonyl group.
<3> The non-aqueous electrolytic solution for a battery according to <1> or <2>, which further contains a compound that releases a fluorine atom when reduced.
<4> The non-aqueous electrolytic solution for a battery according to <3>, wherein the compound that releases a fluorine atom when reduced is a compound represented by the following formula (II) or the following formula (III).

[In formula (II), R ^{21 to} R ²³ independently represent a fluorine atom, a −OLi group, or an alkoxy group having 1 to 3 carbon atoms. However, ^{at least one of R 21 to} R ²³ is a fluorine atom.
In formula (III), R ^{31 to} R ³⁴ independently represent a hydrogen atom or a fluorine atom. However, ^{at least one of R 31 to} R ³⁴ is a fluorine atom. ]
<5> The non-aqueous electrolytic solution for a battery according to any one of <1> to <4>, which further contains a compound represented by the following formula (C).

[In formula (C), Y ¹ and Y ² each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group. ]

<6> An additive for a battery containing a compound represented by the following formula (I).

[In the formula (I), R ^{1 to} R ¹⁰ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl halide group having 1 to 3 carbon atoms. However, ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.
In the formula (I), X represents an alkylene group having 1 to 6 carbon atoms, an alkaneylene group having 2 to 6 carbon atoms, or a carbonyl group. ]

<7> Positive electrode and
Metallic lithium, lithium-containing alloys, metals or alloys that can be alloyed with lithium, oxides that can be doped and dedoped with lithium ions, transition metal nitrogen compounds that can be doped and dedoped with lithium ions, and lithium. A negative electrode containing at least one selected from the group consisting of carbon materials capable of doping and dedoping ions as a negative electrode active material, and a negative electrode.
The non-aqueous electrolyte solution for batteries according to any one of <1> to <5>.
Lithium secondary battery including.
<8> A lithium secondary battery obtained by charging / discharging the lithium secondary battery according to <7>.

According to the present disclosure, a non-aqueous electrolyte solution for a battery and an additive for a battery capable of suppressing an increase in battery resistance with time, and a lithium secondary battery in which an increase in battery resistance with time is suppressed are provided.

It is a schematic perspective view which shows an example of the laminated type battery which is an example of the lithium secondary battery of this disclosure. It is schematic cross-sectional view in the thickness direction of the laminated type electrode body housed in the laminated type battery shown in FIG. It is the schematic cross-sectional view which shows the example of the coin type battery which is another example of the lithium secondary battery of this disclosure.

In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.
In the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means.

[Non-aqueous electrolyte for batteries]
The non-aqueous electrolytic solution for batteries of the present disclosure (hereinafter, also simply referred to as “non-aqueous electrolytic solution”) contains a compound represented by the formula (I) described later.
According to the non-aqueous electrolyte solution of the present disclosure, an increase in battery resistance over time can be suppressed. In other words, according to the non-aqueous electrolytic solution of the present disclosure, the battery resistivity ratio [after aging / before aging] can be reduced as compared with the conventional non-aqueous electrolytic solution.
The details of the reason why such an effect is exerted are not clear, but it is presumed as follows.
The compound represented by the formula (I) is considered to emit fluorine atoms on the surface of the negative electrode during charging. The released fluorine atom has the property of binding to Li in the non-aqueous electrolytic solution. Therefore, the negative electrode surface film formed by the compound represented by the formula (I) contains Li. In this way, the compound represented by the formula (I) is considered to form a low-resistance surface film that does not interfere with the removal and insertion of Li from the negative electrode. This low-resistance surface film is considered to be a stable film over time. It is considered that the action of this low resistance surface film suppresses the increase in battery resistance over time.

According to the non-aqueous electrolytic solution of the present disclosure, an increase in battery resistance with time can be suppressed, so that the output of the battery can be increased.

<Compound represented by formula (I)>
The compound represented by the formula (I) is as follows.
The non-aqueous electrolytic solution of the present disclosure may contain only one type of the compound represented by the formula (I), or may contain two or more types of the compound.

In the formula (I), R ^{1 to} R ¹⁰ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl halide group having 1 to 3 carbon atoms. However, ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.
In the formula (I), X represents an alkylene group having 1 to 6 carbon atoms, an alkaneylene group having 2 to 6 carbon atoms, or a carbonyl group.

In the formula (I), ^{as the halogen atom represented by R 1 to} R ¹⁰ , a fluorine atom, a chlorine atom, a bromine atom or an iodine atom is preferable, a fluorine atom, a chlorine atom or a bromine atom is more preferable, and a fluorine atom or a chlorine atom is preferable. Atoms are more preferred, and fluorine atoms are particularly preferred.

In the formula (I), ^{examples of the alkyl group having 1 to 3 carbon atoms represented by R 1 to} R ¹⁰ include a methyl group, an ethyl group, a propyl group (that is, a normal propyl group), and an isopropyl group, and methyl. A group or an ethyl group is preferable, and a methyl group is particularly preferable.

In the formula (I), ^{as the alkyl halide group having 1 to 3 carbon atoms represented by R 1 to} R ¹⁰ , at least one of the hydrogen atoms contained in the alkyl group having 1 to 3 carbon atoms is halogenated. It means a group replaced with an atom.
As the halogen atom in this alkyl halide group, a fluorine atom, a chlorine atom, a bromine atom or an iodine atom is preferable, a fluorine atom, a chlorine atom or a bromine atom is more preferable, a fluorine atom or a chlorine atom is further preferable, and a fluorine atom is particularly preferable. preferable.
In the formula (I), ^{as the alkyl halide group having 1 to 3 carbon atoms represented by R 1 to} R ¹⁰ , all the hydrogen atoms contained in the alkyl group having 1 to 3 carbon atoms were replaced with halogen atoms. It is preferably a group.

In the formula (I), the ^{alkyl halide group having 1 to 3 carbon atoms represented by R 1 to} R ¹⁰ includes a methyl halide group (preferably a trifluoromethyl group) or an ethyl halide group (preferably pentafluoro). Ethyl group) is preferable, and methyl halide group (preferably trifluoromethyl group) is particularly preferable.

In formula (I), ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.

In formula (I),
It is preferable that at least one of R ¹ , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom, and ^{two or more of R 1 to} R ^{10 are fluorine atoms.}
It is more preferable that at least one of R ¹ and R ⁵ and at least one of R ⁶ and R ^{10 are fluorine atoms.}

It ^{is also preferable that at least one of R 1 to} R ¹⁰ (excluding the fluorine atom) is a methyl group.

In the formula (I), X represents an alkylene group having 1 to 6 carbon atoms, an alkaneylene group having 2 to 6 carbon atoms, or a carbonyl group.

The carbon number of the alkylene group having 1 to 6 carbon atoms represented by X is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.
The carbon number of the alkenylene group having 2 to 6 carbon atoms represented by X is preferably 2 or 3, and particularly preferably 2.

In formula (I), X is a methylene group (that is, -CH _2- group), an ethylene group (that is, -CH ₂ CH _2- group), a vinylene group (that is, -CH = CH- group), or A carbonyl group (ie, a -C (= O) -group) is preferred.
Needless to say, the methylene group is an alkylene group having 1 carbon atom, the ethylene group is an alkylene group having 2 carbon atoms, and the vinylene group is an alkaneylene group having 2 carbon atoms.

In the compound represented by the formula (I), isomers having sterically different relative arrangements may exist depending on the combination of ^{R 1 to} R ^10.
In this case, the non-aqueous electrolytic solution may contain only one of them, or may contain both of them.

Hereinafter, exemplary compounds of the compound represented by the formula (I) will be shown, but the compound represented by the formula (I) is not limited to the following exemplified compounds.

Examples of the method for synthesizing the compound represented by the formula (I) include a method for dimerizing 2-fluorobenzyl chloride, 2-fluorobenzyl bromide, and the like.
Further, as a method for synthesizing the compound represented by the formula (I), publicly known documents such as International Publication No. 2014/114964 may be referred to.
Further, as the compound represented by the formula (I), a commercially available product may be used.
Commercially available products include 2-fluorodiphenylmethane (Hiroshima Wako, 577-59071), 2,4-difluorobenzophenone (Tokyo Kasei, D1796), 2-fluoro-3- (trifluoromethyl) benzophenone (APPOLO, PC4374E) and the like. Can be mentioned.

The non-aqueous electrolytic solution of the present disclosure may contain only one type of the compound represented by the formula (I), or may contain two or more types of the compound.
The content of the compound represented by the formula (I) in the non-aqueous electrolytic solution of the present disclosure (total content when two or more kinds; the same applies hereinafter) is preferably based on the total amount of the non-aqueous electrolytic solution. It is 0.001% by mass to 15% by mass, more preferably 0.01% by mass to 10% by mass, still more preferably 0.1% by mass to 10% by mass, still more preferably 0.5% by mass. It is 10% by mass.

<Compound that releases fluorine atoms when reduced>
The non-aqueous electrolytic solution of the present disclosure preferably further contains a compound that releases fluorine atoms when reduced (hereinafter, also referred to as “fluorine releasing compound”). As a result, the increase in battery resistance over time can be suppressed more effectively.
In this case, the non-aqueous electrolytic solution of the present disclosure may contain only one type of fluorine-releasing compound, or may contain two or more types of fluorine-releasing compounds.

The fluorine-releasing compound releases fluorine atoms on the surface of the negative electrode during charging. Since the released fluorine atoms have the property of binding to Li in the electrolyte, the negative electrode surface film formed by such a compound contains Li, which hinders the removal and insertion of Li from the negative electrode. It is thought that it forms a surface film with no low resistance.
Since the compound represented by the above-mentioned formula (I) has the same effect, the battery resistance increases with time by using the compound represented by the formula (I) and the fluorine-releasing compound in combination. Is thought to be able to be suppressed more effectively.

As described above, the compound represented by the formula (I) also has a property of releasing a fluorine atom when reduced.
The "fluorine-releasing compound" (that is, a compound that releases a fluorine atom when reduced) in the present specification is a compound that releases a fluorine atom when reduced and is other than the compound represented by the formula (I). Means the compound of.

As the fluorine-releasing compound, a compound represented by the formula (II) or the formula (III) is preferable.
The non-aqueous electrolytic solution of the present disclosure may contain only one of at least one compound represented by the formula (II) and at least one compound represented by the formula (III) as the fluorine-releasing compound. However, both may be contained.

In formula (II), R ^{21 to} R ²³ independently represent a fluorine atom, a −OLi group, or an alkoxy group having 1 to 3 carbon atoms. However, ^{at least one of R 21 to} R ²³ is a fluorine atom.
In formula (III), R ^{31 to} R ³⁴ independently represent a hydrogen atom or a fluorine atom. However, ^{at least one of R 31 to} R ³⁴ is a fluorine atom.

Examples of the compound represented by the formula (II) include dimethyl fluorophosphate, lithium monofluorophosphate, methyl difluorophosphate, lithium difluorophosphate, and trifluorophosphoric acid. Of these, lithium difluorophosphate is particularly preferable.

Examples of the compound represented by the formula (III) include fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and trifluoroethylene carbonate. Of these, fluoroethylene carbonate is particularly preferable.

When the non-aqueous electrolytic solution of the present invention contains a fluorine-releasing compound (for example, a compound represented by the formula (II) or the formula (III)), the content of the fluorine-releasing compound in the non-aqueous electrolytic solution of the present invention (for example, When two or more kinds are used, the total content; the same applies hereinafter) can be appropriately selected depending on the intended purpose, but is preferably 0.001% by mass to 15% by mass, and more preferably 0.01% by mass to. It is 10% by mass, more preferably 0.1% by mass to 10% by mass, still more preferably 0.5% by mass to 10% by mass.

<Cyclic carbonate with unsaturated bond>
The non-aqueous electrolyte solution of the present disclosure may contain a cyclic carbonate having an unsaturated bond. In this case, the non-aqueous electrolytic solution of the present disclosure may contain only one type of cyclic carbonate having an unsaturated bond, or may contain two or more types.
In general, in a battery using a non-aqueous electrolytic solution containing a cyclic carbonate having an unsaturated bond, the battery resistance may increase significantly with time.
However, the non-aqueous electrolytic solution of the present disclosure contains a compound represented by the formula (I), which has an effect of suppressing an increase in battery resistance with time. Therefore, the non-aqueous electrolytic solution of the present disclosure can further suppress an increase in battery resistance with time even when it contains a cyclic carbonate having an unsaturated bond.
Therefore, when the non-aqueous electrolytic solution of the present disclosure contains a cyclic carbonate having an unsaturated bond, the effect of containing the compound represented by the formula (I) (that is, the increase in battery resistance with time) is increased. The effect of suppressing) is more effectively exhibited.

As the cyclic carbonate having an unsaturated bond, a compound represented by the following formula (C) is preferable.

In formula (C), Y ¹ and Y ² each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group.
Examples of the compound represented by the formula (C) include vinylene carbonate, methylvinylene carbonate, ethylvinylene carbonate, bropyrvinylene carbonate, dimethylvinylene carbonate, diethylvinylene carbonate, dipropylvinylene carbonate and the like. Of these, vinylene carbonate is particularly preferable.

When the non-aqueous electrolyte solution of the present disclosure contains a cyclic carbonate having an unsaturated bond, the content of the cyclic carbonate having an unsaturated bond is 0.001% by mass to 10% by mass with respect to the total amount of the non-aqueous electrolyte solution. % Is preferable, 0.001% by mass to 5% by mass is more preferable, 0.001% by mass to 3% by mass is further preferable, 0.01% by mass to 3% by mass is further preferable, and 0. It is more preferably 1 to 3% by mass, further preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1% by mass.

<Other additives>
The non-aqueous electrolytic solution of the present disclosure may contain the above-mentioned compound represented by the formula (I), a fluorine-releasing compound, and other additives other than the cyclic carbonate having an unsaturated bond.
Examples of other additives include sulfone compounds, sultone compounds, sulfate ester compounds, oxalate compounds and the like.

Next, other components of the non-aqueous electrolyte solution will be described. The non-aqueous electrolyte solution generally contains an electrolyte and a non-aqueous solvent.

<Non-aqueous solvent>
The non-aqueous electrolyte solution generally contains a non-aqueous solvent.
As the non-aqueous solvent, various known ones can be appropriately selected, but it is preferable to use at least one selected from a cyclic aprotic solvent and a chain aprotic solvent.

When aiming to improve the flash point of the solvent in order to improve the safety of the battery, it is preferable to use a cyclic aprotic solvent as the non-aqueous solvent.

(Cyclic aprotic solvent)
As the cyclic aprotic solvent, cyclic carbonate, cyclic carboxylic acid ester, cyclic sulfone, and cyclic ether can be used.

The cyclic aprotic solvent may be used alone or in combination of two or more.
The mixing ratio of the cyclic aprotic solvent in the non-aqueous solvent is 10% by mass to 100% by mass, more preferably 20% by mass to 90% by mass, and particularly preferably 30% by mass to 80% by mass. By setting such a ratio, the conductivity of the electrolytic solution related to the charge / discharge characteristics of the battery can be increased.

Specific examples of the cyclic carbonate include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, and 2,3-pentylene carbonate. Of these, ethylene carbonate and propylene carbonate having a high dielectric constant are preferably used. In the case of a battery using graphite as the negative electrode active material, ethylene carbonate is more preferable. Moreover, you may use these cyclic carbonates in mixture of 2 or more types.

Specific examples of the cyclic carboxylic acid ester include γ-butyrolactone, δ-valerolactone, and alkyl substituents such as methyl γ-butyrolactone, ethyl γ-butyrolactone, and ethyl δ-valerolactone.
The cyclic carboxylic acid ester has a low vapor pressure, a low viscosity, and a high dielectric constant, and can reduce the viscosity of the electrolytic solution without lowering the flash point of the electrolytic solution and the degree of dissociation of the electrolyte. Therefore, it has a feature that the conductivity of the electrolytic solution, which is an index related to the discharge characteristics of the battery, can be increased without increasing the flammability of the electrolytic solution. It is preferable to use a cyclic carboxylic acid ester as the cyclic aprotic solvent. γ-Butyrolactone is most preferred.

Further, the cyclic carboxylic acid ester is preferably used by mixing with another cyclic aprotic solvent. For example, a mixture of a cyclic carboxylic acid ester and a cyclic carbonate and / or a chain carbonate can be mentioned.

Specific examples of combinations of cyclic carboxylic acid ester and cyclic carbonate and / or chain carbonate include γ-butyrolactone and ethylene carbonate, γ-butyrolactone and ethylene carbonate and dimethyl carbonate, γ-butyrolactone and ethylene carbonate and methyl ethyl. Carbonate, γ-butyrolactone and ethylene carbonate and diethyl carbonate, γ-butyrolactone and propylene carbonate, γ-butyrolactone and propylene carbonate and dimethyl carbonate, γ-butyrolactone and propylene carbonate and methyl ethyl carbonate, γ-butyrolactone and propylene carbonate and diethyl carbonate, γ-Butyrolactone, ethylene carbonate and propylene carbonate, γ-butyrolactone, ethylene carbonate, propylene carbonate and dimethyl carbonate, γ-butyrolactone, ethylene carbonate, propylene carbonate and methyl ethyl carbonate, γ-butyrolactone, ethylene carbonate, propylene carbonate and diethyl carbonate, γ-Butyrolactone, ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate, γ-butyrolactone, ethylene carbonate, dimethyl carbonate and diethyl carbonate, γ-butyrolactone, ethylene carbonate, methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone, ethylene carbonate and dimethyl carbonate And methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone and ethylene carbonate and propylene carbonate and dimethyl carbonate and methyl ethyl carbonate, γ-butyrolactone and ethylene carbonate and propylene carbonate and dimethyl carbonate and diethyl carbonate, γ-butyrolactone and ethylene carbonate and propylene carbonate. And methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone and ethylene carbonate and propylene carbonate and dimethyl carbonate and methyl ethyl carbonate and diethyl carbonate, γ-butyrolactone and sulfolane, γ-butyrolactone and ethylene carbonate and sulfolane, γ-butyrolactone and propylene carbonate Sulfolane, γ-butyrolactone, ethylene carbonate, propylene carbonate, sulfolane, γ-bu Examples thereof include tyrolactone, sulfolane and dimethyl carbonate.

Examples of cyclic sulfone include sulfolane, 2-methylsulfolane, 3-methylsulfolane, dimethylsulfone, diethylsulfone, dipropylsulfone, methylethylsulfone, methylpropylsulfone and the like.
Dioxolane can be mentioned as an example of the cyclic ether.

(Chain aprotic solvent)
As the chain aprotic solvent, a chain carbonate, a chain carboxylic acid ester, a chain ether, a chain phosphate ester and the like can be used.

The mixing ratio of the chain aprotic solvent in the non-aqueous solvent is 10% by mass to 100% by mass, more preferably 20% by mass to 90% by mass, and particularly preferably 30% by mass to 80% by mass.

Specifically, as the chain carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate, dipropyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, dibutyl carbonate, methyl pentyl carbonate, Examples thereof include ethylpentyl carbonate, dipentyl carbonate, methylheptyl carbonate, ethylheptyl carbonate, diheptyl carbonate, methylhexyl carbonate, ethylhexyl carbonate, dihexyl carbonate, methyloctyl carbonate, ethyloctyl carbonate, dioctyl carbonate, methyltrifluoroethyl carbonate and the like. Two or more kinds of these chain carbonates may be mixed and used.

Specific examples of the chain carboxylic acid ester include methyl pivalate.
Specific examples of the chain ether include dimethoxyethane and the like.
Specific examples of the chain phosphate ester include trimethyl phosphate and the like.

(Solvent combination)
The non-aqueous solvent contained in the non-aqueous electrolytic solution of the present disclosure may be only one type or two or more types.
Further, only one or more kinds of cyclic aprotic solvents may be used, one or more kinds of chain aprotic solvents may be used, or cyclic aprotic solvents and chain protics. Solvents may be mixed and used. When it is particularly intended to improve the load characteristics and low temperature characteristics of the battery, it is preferable to use a combination of a cyclic aprotic solvent and a chain aprotic solvent as the aprotic solvent.

Further, from the viewpoint of the electrochemical stability of the electrolytic solution, it is most preferable to apply cyclic carbonate to the cyclic aprotic solvent and to apply chain carbonate to the chain aprotic solvent. Further, the conductivity of the electrolytic solution related to the charge / discharge characteristics of the battery can also be enhanced by the combination of the cyclic carboxylic acid ester and the cyclic carbonate and / or the chain carbonate.

Specific combinations of cyclic carbonate and chain carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and methyl ethyl carbonate, and propylene carbonate. Diethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and methyl ethyl carbonate and diethyl carbonate. , Ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, methyl ethyl carbonate and diethyl Examples thereof include carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate.

The mixing ratio of the cyclic carbonate and the chain carbonate is expressed by mass ratio, and the cyclic carbonate: chain carbonate is 5:95 to 80:20, more preferably 10:90 to 70:30, and particularly preferably 15:85. ~ 55:45. By setting such a ratio, it is possible to suppress an increase in the viscosity of the electrolytic solution and increase the degree of dissociation of the electrolyte, so that the conductivity of the electrolytic solution related to the charge / discharge characteristics of the battery can be increased. Moreover, the solubility of the electrolyte can be further increased. Therefore, since the electrolytic solution having excellent electrical conductivity at room temperature or low temperature can be obtained, the load characteristics of the battery at room temperature to low temperature can be improved.

(Other solvents)
Examples of the non-aqueous solvent include other solvents other than the above.
Specific examples of other solvents include amides such as dimethylformamide, chain carbamates such as methyl-N and N-dimethylcarbamate, cyclic amides such as N-methylpyrrolidone, and N, N-dimethylimidazolidinone. Examples thereof include boron compounds such as cyclic urea, trimethyl borate, triethyl borate, tributyl borate, trioctyl borate, and trimethylsilyl borate, and polyethylene glycol derivatives represented by the following general formulas.
HO (CH ₂ CH ₂ O) _a H
HO [CH ₂ CH (CH ₃ ) O] _b H
CH ₃ O (CH ₂ CH ₂ O) _c H
CH ₃ O [CH ₂ CH (CH ₃ ) O] _d H
CH ₃ O (CH ₂ CH ₂ O) _e CH ₃
CH ₃ O [CH ₂ CH (CH ₃ ) O] _f CH ₃
C ₉ H ₁₉ PHO (CH ₂ CH ₂ O) _g [CH (CH ₃ ) O] _h CH ₃
(Ph is a phenyl group)
CH ₃ O [CH ₂ CH (CH ₃ ) O] _i CO [OCH (CH ₃ ) CH ₂ ] _j OCH ₃
In the above formula, a to f are integers of 5 to 250, g to j are integers of 2 to 249, 5 ≦ g + h ≦ 250, and 5 ≦ i + j ≦ 250.

<Electrolyte>
As the non-aqueous electrolyte solution of the present disclosure, various known electrolytes can be used, and any one that is usually used as an electrolyte for a non-aqueous electrolyte solution can be used.

Specific examples of the electrolyte include (C ₂ H ₅ ) ₄ NPF ₆ , (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NAsF ₆ , (C _2). H ₅ ) ₄ N ₂ SiF ₆ , (C ₂ H ₅ ) ₄ NOSO ₂ C _k F _{(2 k + 1)} (integer of k = 1 to 8), (C ₂ H ₅ ) ₄ NPF _n [C _k F _{(2 k + 1) ] (6-n) (n} = 1~5, k = 1~8 integer) tetraalkylammonium salts, such _{as, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, Li 2 SiF 6, LiOSO 2 C k F _{(2k + 1) (k =} 1~8 _integer) include lithium salts such as _{LiPF n [C k F (2k} + 1)] (6-n) (n = 1~5, k = 1~8 integer) .. Further, a lithium salt represented by the following general formula can also be used.

LiC (SO ₂ R ⁷ ) (SO ₂ R ⁸ ) (SO ₂ R ⁹ ), LiN (SO ₂ OR ¹⁰ ) (SO ₂ OR ¹¹ ), LiN (SO ₂ R ¹² ) (SO ₂ R ¹³ ) (here R ^{7 to} R ¹³ may be the same or different from each other and are perfluoroalkyl groups having 1 to 8 carbon atoms). These electrolytes may be used alone or in combination of two or more.
Of these, a lithium salt is preferable, and _{further, LiPF 6, LiBF 4, LiOSO} 2 C k F (2k + 1) (k = 1~8 _{integer), LiClO 4, LiAsF 6,} LiNSO 2 [C k F ( _{2k + 1)] 2 (k} = 1~8 _{integer), LiPF n [C k F} (2k + 1)] (6-n) (n = 1~5, k = 1~8 integer) are preferred.

The electrolyte is usually preferably contained in a non-aqueous electrolytic solution at a concentration of 0.1 mol / L to 3 mol / L, preferably 0.5 mol / L to 2 mol / L.

In the non-aqueous electrolytic solution of the present disclosure, when a cyclic carboxylic acid ester such as γ-butyrolactone is used in combination as the non-aqueous solvent, it is particularly desirable to contain _{LiPF 6.} Since LiPF ₆ has a high degree of dissociation, it can increase the conductivity of the electrolytic solution, and further has an effect of suppressing the reduction decomposition reaction of the electrolytic solution on the negative electrode. LiPF ₆ may be used alone, or LiPF ₆ and other electrolytes may be used. As the other electrolyte, any one that is usually used as an electrolyte for a non-aqueous electrolyte solution can be used, but among the above-mentioned specific examples of lithium salts, lithium salts other than _{LiPF 6 are preferable.} ..
Specific examples include LiPF ₆ and LiBF ₄ , LiPF ₆ and LiN [SO ₂ C _k F _{(2 k + 1)} ] ₂ (integer of k = 1 to 8), LiPF ₆ and LiBF ₄ and LiN [SO ₂ C _k F _{(SO 2 C k F). 2k + 1)} ] (an integer of k = 1 to 8) and the like are exemplified.

_{The ratio of LiPF 6} to the lithium salt is preferably 1% by mass to 100% by mass, more preferably 10% by mass to 100% by mass, and further preferably 50% by mass to 100% by mass. Such an electrolyte is preferably contained in the non-aqueous electrolyte solution at a concentration of 0.1 mol / L to 3 mol / L, preferably 0.5 mol / L to 2 mol / L.

The non-aqueous electrolyte solution of the present disclosure is not only suitable as a non-aqueous electrolyte solution for a lithium secondary battery, but also a non-aqueous electrolyte solution for a primary battery, a non-aqueous electrolyte solution for an electrochemical capacitor, and an electric double layer capacitor. It can also be used as an electrolytic solution for aluminum electrolytic capacitors.

[Battery additives]
The battery additive of the present disclosure contains the compound represented by the above-mentioned formula (I).
Therefore, according to the battery additive of the present disclosure, the same effect as that of the non-aqueous electrolytic solution of the present disclosure can be obtained.
The battery additive of the present disclosure is preferably an additive for a non-aqueous electrolyte solution of a battery (preferably a lithium secondary battery).

[Lithium secondary battery]
The lithium secondary battery of the present disclosure includes a positive electrode, a negative electrode, and a non-aqueous electrolytic solution of the present disclosure.

(Negative electrode)
The negative electrode may include a negative electrode active material and a negative electrode current collector.
Examples of the negative electrode active material in the negative electrode include metallic lithium, lithium-containing alloys, metals or alloys that can be alloyed with lithium, oxides that can be doped / dedoped with lithium ions, and lithium ions that can be doped / dedoped. At least one selected from the group consisting of transition metal nitridants and carbon materials capable of doping and dedoping lithium ions (may be used alone, or a mixture containing two or more of these may be used. Good) can be used.
Examples of the metal or alloy that can be alloyed with lithium (or lithium ion) include silicon, a silicon alloy, tin, and a tin alloy. Further, lithium titanate may be used.
Among these, a carbon material capable of doping and dedoping lithium ions is preferable. Examples of such carbon materials include carbon black, activated carbon, graphite materials (artificial graphite, natural graphite), amorphous carbon materials, and the like. The form of the carbon material may be fibrous, spherical, potato-like, or flake-like.

Specific examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500 ° C. or lower, and mesophase pitch carbon fiber (MCF).
Examples of the graphite material include natural graphite and artificial graphite. As the artificial graphite, graphitized MCMB, graphitized MCF and the like are used. Further, as the graphite material, a material containing boron or the like can also be used. Further, as the graphite material, a material coated with a metal such as gold, platinum, silver, copper or tin, a material coated with amorphous carbon, or a mixture of amorphous carbon and graphite can also be used.

These carbon materials may be used alone or in admixture of two or more.
As the carbon material, a carbon material having a surface spacing d (002) of the (002) plane measured by X-ray analysis of 0.340 nm or less is particularly preferable. Further, as the carbon material, graphite having a true density of 1.70 g / cm ³ or more or a highly crystalline carbon material having a property close to that of graphite is also preferable. When the carbon material as described above is used, the energy density of the battery can be further increased.

The material of the negative electrode current collector in the negative electrode is not particularly limited, and any known material can be used.
Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, and nickel-plated steel. Of these, copper is particularly preferable from the viewpoint of ease of processing.

(Positive electrode)
The positive electrode may include a positive electrode active material and a positive electrode current collector.
Examples of the positive electrode active material in the positive electrode include transition metal oxides or transition metal sulfides such _{as MoS 2} , TiS ₂ , MnO ₂ , and V ₂ O _{5 , LiCoO 2} , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , and LiNi _X Co. _(1-X) O ₂ [0 <X <1], _{Li 1 + α} Me _1-α O _{2 having an α-NaFeO type 2} crystal structure (Me is a transition metal element containing Mn, Ni and Co, 1.0. ≦ (1 + α) / ( 1-α) ≦ 1.6), LiNi x Co y Mn z O 2 [x + y + z = 1,0 < x <1,0 <y <1,0 <z <1 ] (e.g., LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ etc.), LiFePO ₄ , LiMnPO ₄ and other composite oxides consisting of lithium and transition metals, Examples thereof include conductive polymer materials such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiaizole, and polyaniline complex. Among these, a composite oxide composed of lithium and a transition metal is particularly preferable. When the negative electrode is a lithium metal or a lithium alloy, a carbon material can also be used as the positive electrode. Further, as the positive electrode, a mixture of a composite oxide of lithium and a transition metal and a carbon material can also be used.
The positive electrode active material may be used alone or in combination of two or more. When the positive electrode active material has insufficient conductivity, it can be used together with a conductive auxiliary agent to form a positive electrode. Examples of the conductive auxiliary agent include carbon materials such as carbon black, amorphous whiskers, and graphite.

The material of the positive electrode current collector in the positive electrode is not particularly limited, and any known material can be used.
Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloy, stainless steel, nickel, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper; and the like.

(Separator)
The lithium secondary battery of the present disclosure preferably contains a separator between the negative electrode and the positive electrode.
The separator is a membrane that electrically insulates the positive electrode and the negative electrode and allows lithium ions to pass through, and examples thereof include a porous membrane and a polymer electrolyte.
As the porous film, a microporous polymer film is preferably used, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, polyester and the like.
In particular, porous polyolefin is preferable, and specifically, a porous polyethylene film, a porous polypropylene film, or a multilayer film of a porous polyethylene film and a polypropylene film can be exemplified. The porous polyolefin film may be coated with another resin having excellent thermal stability.
Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved, a polymer inflated with an electrolytic solution, and the like.
The non-aqueous electrolyte solution of the present disclosure may be used for the purpose of swelling a polymer to obtain a polymer electrolyte.

(Battery configuration)
The lithium secondary battery of the present disclosure can take various known shapes, and can be formed into a cylindrical type, a coin type, a square type, a laminated type, a film type, or any other shape. However, the basic structure of the battery is the same regardless of the shape, and the design can be changed according to the purpose.

An example of the lithium secondary battery (non-aqueous electrolyte secondary battery) of the present disclosure is a laminated battery.
FIG. 1 is a schematic perspective view showing an example of a laminated battery which is an example of the lithium secondary battery of the present disclosure, and FIG. 2 is a thickness of a laminated electrode body housed in the laminated battery shown in FIG. It is a schematic cross-sectional view of a direction.
The laminated battery shown in FIG. 1 contains a non-aqueous electrolytic solution (not shown in FIG. 1) and a laminated electrode body (not shown in FIG. 1), and the peripheral edge thereof is sealed. A laminated exterior body 1 whose inside is hermetically sealed is provided. As the laminated exterior body 1, for example, a laminated exterior body made of aluminum is used.
As shown in FIG. 2, the laminated electrode body housed in the laminated exterior body 1 is a laminated body in which a positive electrode plate 5 and a negative electrode plate 6 are alternately laminated via a separator 7, and a laminated body of the laminated body. A separator 8 that surrounds the periphery is provided. The positive electrode plate 5, the negative electrode plate 6, the separator 7, and the separator 8 are impregnated with the non-aqueous electrolytic solution of the present disclosure.
The plurality of positive electrode plates 5 in the laminated electrode body are all electrically connected to the positive electrode terminal 2 via the positive electrode tab (not shown), and a part of the positive electrode terminal 2 is the laminated exterior body 1. It protrudes outward from the peripheral end (Fig. 1). A portion of the peripheral end of the laminated exterior body 1 on which the positive electrode terminal 2 protrudes is sealed with an insulating seal 4.
Similarly, the plurality of negative electrode plates 6 in the laminated electrode body are all electrically connected to the negative electrode terminal 3 via the negative electrode tab (not shown), and a part of the negative electrode terminal 3 is the laminated exterior. It protrudes outward from the peripheral end of the body 1 (FIG. 1). A portion of the peripheral end of the laminated exterior body 1 from which the negative electrode terminal 3 protrudes is sealed with an insulating seal 4.
In the laminated battery according to the above example, the number of positive electrode plates 5 is 5 and the number of negative electrode plates 6 is 6, and the positive electrode plate 5 and the negative electrode plate 6 are located on both sides of the battery via the separator 7. The outer layers are all laminated so as to be the negative electrode plate 6. However, it goes without saying that the number of positive electrode plates, the number of negative electrode plates, and the arrangement of the laminated battery are not limited to this example, and various changes may be made.

Another example of the lithium secondary battery of the present disclosure is a coin-type battery.
FIG. 3 is a schematic perspective view showing an example of a coin-type battery, which is another example of the lithium secondary battery of the present disclosure.
In the coin-type battery shown in FIG. 3, a disk-shaped negative electrode 12, a separator 15 injected with a non-aqueous electrolyte solution, a disk-shaped positive electrode 11, and, if necessary, spacer plates 17 and 18 made of stainless steel or aluminum are arranged in this order. In a laminated state, it is stored between the positive electrode can 13 (hereinafter, also referred to as “battery can”) and the sealing plate 14 (hereinafter, also referred to as “battery can lid”). The positive electrode can 13 and the sealing plate 14 are caulked and sealed via the gasket 16.
In this example, the non-aqueous electrolytic solution of the present disclosure is used as the non-aqueous electrolytic solution to be injected into the separator 15.

The lithium secondary battery of the present disclosure is obtained by charging / discharging a lithium secondary battery (lithium secondary battery before charging / discharging) containing a negative electrode, a positive electrode, and the non-aqueous electrolyte solution of the present disclosure. It may be a lithium secondary battery.
That is, as the lithium secondary battery of the present disclosure, first, a lithium secondary battery before charging / discharging containing a negative electrode, a positive electrode, and the non-aqueous electrolyte solution of the present disclosure is prepared, and then the lithium secondary battery before charging / discharging is prepared. It may be a lithium secondary battery (charged / discharged lithium secondary battery) manufactured by charging / discharging the lithium secondary battery one or more times.

The use of the lithium secondary battery of the present disclosure is not particularly limited, and it can be used for various known uses. For example, laptops, mobile computers, mobile phones, headphone stereos, video movies, LCD TVs, handy cleaners, electronic organizers, calculators, radios, backup power supplies, motors, automobiles, electric vehicles, bikes, electric bikes, bicycles, electric It can be widely used regardless of whether it is a small portable device or a large device such as a bicycle, a lighting device, a game machine, a clock, an electric tool, or a camera.

Hereinafter, examples of the present disclosure will be shown, but the present disclosure is not limited to the following examples.
In the following examples, the "addition amount" represents the content in the finally obtained non-aqueous electrolytic solution (that is, the amount with respect to the total amount of the finally obtained non-aqueous electrolytic solution).
Further, "wt%" means mass%.

[Example 1]
A coin-type lithium secondary battery (hereinafter, also referred to as “coin-type battery”) having the configuration shown in FIG. 3 was produced by the following procedure.

<Manufacturing of negative electrode>
97 parts by mass of natural graphite-based graphite, 1 part by mass of carboxymethyl cellulose and 2 parts by mass of SBR latex were kneaded with an aqueous solvent to prepare a paste-like negative electrode mixture slurry.
Next, this negative electrode mixture slurry is applied to a negative electrode current collector made of a strip-shaped copper foil having a thickness of 18 μm, dried, and then compressed by a roll press to form a sheet composed of the negative electrode current collector and the negative electrode active material layer. A negative electrode was obtained. At this time, the coating density of the negative electrode active material layer was 10 mg / cm ² , and the packing density was 1.5 g / ml.

<Preparation of positive electrode>
90 parts by mass of LiNi _0.5 Mn _0.3 Co _0.2 O ₂ and 5 parts by mass of acetylene black and 5 parts by mass of polyvinylidene fluoride are kneaded with N-methylpyrrolidinone as a solvent to form a paste-like positive electrode mixture slurry. Was prepared.
Next, this positive electrode mixture slurry is applied to a positive electrode current collector of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and then compressed by a roll press to obtain a sheet-shaped positive electrode composed of the positive electrode current collector and the positive electrode active material. Obtained. At this time, the coating density of the positive electrode active material layer was 30 mg / cm ² , and the packing density was 2.5 g / ml.

<Preparation of non-aqueous electrolyte solution>
As a non-aqueous solvent, ethylene carbonate (EC), dimethyl carbonate (DMC) and methyl ethyl carbonate (EMC) were mixed at a ratio of 34:33:33 (mass ratio) to obtain a mixed solvent.
In the obtained mixed solvent, LiPF ₆ , which is an electrolyte, was dissolved so that the electrolyte concentration in the finally prepared non-aqueous electrolyte solution was 1 mol / liter.
With respect to the obtained solution, the above-mentioned exemplified compound 1 as a compound represented by the formula (I) (hereinafter, also referred to as “compound of the formula (I)”) is finally prepared as an additive. The non-aqueous electrolytic solution was added so that the content was 1% by mass based on the total mass of the non-aqueous electrolytic solution (that is, the addition amount was 1% by mass) to obtain a non-aqueous electrolytic solution.

<Making coin-type batteries>
The above-mentioned negative electrode was punched in a disk shape with a diameter of 14 mm and the above-mentioned positive electrode was punched in a disk shape, respectively, to obtain a coin-shaped negative electrode and a coin-shaped positive electrode, respectively. Further, a microporous polyethylene film having a thickness of 20 μm was punched into a disk shape having a diameter of 17 mm to obtain a separator.
The obtained coin-shaped negative electrode, separator, and coin-shaped positive electrode were laminated in this order in a stainless steel battery can (2032 size), and then 20 μl of a non-aqueous electrolytic solution was injected into the battery can. It was impregnated in the separator, the positive electrode and the negative electrode.
Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery was sealed by crimping the battery can lid via a polypropylene gasket.
As described above, a coin-type battery (that is, a coin-type lithium secondary battery) having a diameter of 20 mm and a height of 3.2 mm and having the configuration shown in FIG. 3 was obtained.

<Evaluation>
The following evaluations were carried out on the obtained coin-type batteries.

(Initial capacity)
At 25 ° C., the coin cell battery was charged with a constant current of 0.4 mA and a constant voltage of 4.2 V, and then discharged to a constant current of 0.8 mA to 2.85 V. The discharge capacity at the time of this discharge was measured and used as the initial capacity.
Similarly, the initial capacity of the coin cell battery of Comparative Example 1 described later was measured.
Table 1 shows the initial capacity of Example 1 as a relative value when the initial capacity of Comparative Example 1 is 100.

(Battery resistivity [after aging / before aging])
The battery resistivity [after aging / before aging] was determined as follows.
The smaller the battery resistance ratio [after aging / before aging], the more the increase in battery resistance over time is suppressed.

The coin-type battery was charged and discharged three times at a constant voltage of 4.2 V, and then charged to a constant voltage of 3.9 V. The charged coin-type battery is kept at 25 ° C in a constant temperature bath, discharged at a constant current of 0.2 mA at 25 ° C, and the potential drop in 10 seconds from the start of discharge is measured to measure the potential drop of the coin-type battery at 25 ° C. DC resistance [Ω] was measured. The obtained value was taken as the battery resistance (25 ° C.) before aging.
The coin-type battery whose battery resistance (25 ° C.) before aging was measured was charged at a constant voltage of 4.2 V, and the charged coin-type battery was allowed to elapse for 2 days in a constant temperature bath at 80 ° C.
Set the coin-type battery after aging for the above two days to a constant voltage of 3.9 V, and measure the DC resistance [Ω] of the coin-type battery at 25 ° C by the same method as the battery resistance (25 ° C) before aging. did. The obtained value was taken as the battery resistance (25 ° C.) after aging.

Based on the battery resistance before aging (25 ° C.) and the battery resistance after aging (25 ° C.), the battery resistance ratio [after aging / before aging] was determined by the following formula.
Battery resistivity [after aging / before aging]
= (Battery resistance after aging (25 ° C) / Battery resistance before aging (25 ° C))

Similarly, for the coin-type battery of Comparative Example 1 described later, the ratio of battery resistance [after aging / before aging] was determined.

Table 1 shows the ratio of the battery resistance of Example 1 [after aging / before aging] as a relative value when the ratio of the battery resistance of Comparative Example 1 [after aging / before aging] is 100.

[Examples 2 to 8]
In the preparation of the non-aqueous electrolytic solution, the same operation as in Example 1 was carried out except that at least one of the type and amount of the compound of the formula (1) was changed as shown in Table 1.
The results are shown in Table 1.

[Comparative Example 1]
In the preparation of the non-aqueous electrolytic solution, the same operation as in Example 1 was carried out except that the compound of the formula (1) was not used.
The results are shown in Table 1.

As shown in Table 1, the coin cell batteries of Examples 1 to 8 using the non-aqueous electrolytic solution containing the compound of the formula (I) used the non-aqueous electrolytic solution not containing the compound of the formula (I). The battery resistance ratio [after aging / before aging] was smaller than that of the coin-type battery of Comparative Example 1. That is, the coin-type batteries of Examples 1 to 8 were suppressed from increasing in battery resistance with time as compared with the coin-type batteries of Comparative Example 1.
Further, in the coin-type batteries of Examples 1 to 8, the initial capacity at the same level as that of the coin-type batteries of Comparative Example 1 was maintained.

[Example 101]
The same operation as in Example 1 was performed except that the non-aqueous electrolytic solution used for producing the battery was changed to the non-aqueous electrolytic solution prepared as follows.
However, the initial capacity is shown as a relative value when the initial capacity of Comparative Example 101 is 100, and the battery resistivity ratio [after aging / before aging] is the battery resistivity ratio [after aging / before aging] of Comparative Example 101. It is shown as a relative value when it is set to 100.
The results are shown in Table 2.

<Preparation of non-aqueous electrolyte solution (Example 101)>
As a non-aqueous solvent, ethylene carbonate (EC), dimethyl carbonate (DMC) and methyl ethyl carbonate (EMC) were mixed at a ratio of 34:33:33 (mass ratio) to obtain a mixed solvent.
In the obtained mixed solvent, LiPF ₆ , which is an electrolyte, was dissolved so that the electrolyte concentration in the finally prepared non-aqueous electrolyte solution was 1 mol / liter.
As an additive to the obtained solution
The above-mentioned exemplified compound 1 (addition amount 1% by mass) as the compound of the formula (I),
Vinylene carbonate (hereinafter, also referred to as "VC") as a compound represented by the formula (C) (hereinafter, also referred to as "compound of formula (C)") (addition amount: 0.3% by mass), and reduced. Lithium difluorophosphate (hereinafter, also referred to as "LiDFP") as a compound that releases fluorine atoms (hereinafter, also referred to as "fluorine-releasing compound") (addition amount: 0.5% by mass)
Was added to obtain a non-aqueous electrolyte solution.

[Examples 102 to 104]
In the preparation of the non-aqueous electrolytic solution, the same operation as in Example 101 was carried out except that the type of the compound of the formula (1) was changed as shown in Table 2.
The results are shown in Table 2.

[Comparative Example 101]
In the preparation of the non-aqueous electrolytic solution, the same operation as in Example 101 was carried out except that the compound of the formula (1) was not used.
The results are shown in Table 2.

As shown in Table 2, the coin cell batteries of Examples 101 to 104 using the non-aqueous electrolytic solution containing the compound of the formula (I) used the non-aqueous electrolytic solution not containing the compound of the formula (I). The battery resistance ratio [after aging / before aging] was smaller than that of the coin-type battery of Comparative Example 101. That is, the coin-type batteries of Examples 101 to 104 were suppressed from increasing in battery resistance with time as compared with the coin-type batteries of Comparative Example 101.
Further, in the coin-type batteries of Examples 101 to 104, the initial capacity at the same level as that of the coin-type batteries of Comparative Example 101 was maintained.

1 Laminated exterior 2 Positive electrode terminal 3 Negative electrode terminal 4 Insulation seal 5 Positive electrode plate 6 Negative electrode plate 7, 8 Separator 11 Positive electrode 12 Negative electrode 13 Positive electrode can 14 Seal plate 15 Separator 16 Gasket 17, 18 Spacer plate

Claims (8)

A non-aqueous electrolytic solution for a battery containing a compound represented by the following formula (I).

[In the formula (I), R ^{1 to} R ¹⁰ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl halide group having 1 to 3 carbon atoms. However, ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.
In formula (I), X represents an alkylene group having 1 to 6 carbon atoms. ] The non-aqueous electrolytic solution for a battery according to claim 1, wherein X is a methylene group or an ethylene group. The non-aqueous electrolytic solution for a battery according to claim 1 or 2, further comprising a compound that releases a fluorine atom when reduced. The non-aqueous electrolytic solution for a battery according to claim 3, wherein the compound that releases a fluorine atom when reduced is a compound represented by the following formula (II) or the following formula (III).

[In formula (II), R ^{21 to} R ²³ independently represent a fluorine atom, a −OLi group, or an alkoxy group having 1 to 3 carbon atoms. However, ^{at least one of R 21 to} R ²³ is a fluorine atom.
In formula (III), R ^{31 to} R ³⁴ independently represent a hydrogen atom or a fluorine atom. However, ^{at least one of R 31 to} R ³⁴ is a fluorine atom. ] The non-aqueous electrolytic solution for a battery according to any one of claims 1 to 4, further comprising a compound represented by the following formula (C).

[In formula (C), Y ¹ and Y ² each independently represent a hydrogen atom, a methyl group, an ethyl group, or a propyl group. ] An additive for a battery containing a compound represented by the following formula (I).

[In the formula (I), R ^{1 to} R ¹⁰ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkyl halide group having 1 to 3 carbon atoms. However, ^{at least one of R 1} , R ⁵ , R ⁶ and R ¹⁰ is a fluorine atom.
In formula (I), X represents an alkylene group having 1 to 6 carbon atoms. ] With the positive electrode
Metallic lithium, lithium-containing alloys, metals or alloys that can be alloyed with lithium, oxides that can be doped and dedoped with lithium ions, transition metal nitrogen compounds that can be doped and dedoped with lithium ions, and lithium. A negative electrode containing at least one selected from the group consisting of carbon materials capable of doping and dedoping ions as a negative electrode active material, and a negative electrode.
The non-aqueous electrolyte solution for a battery according to any one of claims 1 to 5.
Lithium secondary battery including. A lithium secondary battery obtained by charging / discharging the lithium secondary battery according to claim 7.

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