CN100559648C - Non-aqueous electrolytic solution and lithium secondary battery using the same - Google Patents

Abstract

The present invention provides a nonaqueous electrolytic solution that is excellent in battery characteristics such as electric capacity, cycle characteristics, and storage characteristics and can maintain battery performance for a long time, and a lithium secondary battery using the same. The invention discloses a non-aqueous electrolytic solution for a lithium secondary battery and a lithium secondary battery using the non-aqueous electrolytic solution. The non-aqueous electrolytic solution is an electrolyte salt dissolved in a non-aqueous solvent. It is characterized in that the non-aqueous electrolytic solution , containing 0.1 to 10% by weight of an ethylene carbonate derivative represented by the following general formula (1) and 0.01 to 10% by weight of (A) a compound containing a triple bond and/or (B) represented by the following general formula A pentafluorophenoxy compound represented by (X). Wherein, in the general formula (I), R ¹ to R ³ represent a hydrogen atom, a halogen atom, an alkenyl group, an alkynyl group or an aryl group. It does not include ethylene carbonate. In formula (X), R ¹⁵ represents an alkylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group or an alkanesulfonyl group.

Description

Non-aqueous electrolytic solution and lithium secondary battery using the same

technical field

The present invention relates to a nonaqueous electrolytic solution capable of forming a lithium secondary battery excellent in battery characteristics such as electric capacity, cycle characteristics, and storage characteristics, and a lithium secondary battery using the same.

Background technique

In recent years, lithium secondary batteries have been widely used as power sources for driving small electronic devices and the like. A lithium secondary battery is mainly composed of a positive electrode containing a lithium composite oxide, a negative electrode containing a carbon material or lithium metal, and a nonaqueous electrolytic solution. As the non-aqueous electrolytic solution, carbonates such as ethylene carbonate (EC) and propylene carbonate (PC) can be used.

In lithium secondary batteries using LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , etc. as positive electrodes, the solvent in the non-aqueous electrolyte will be partially oxidized and decomposed during charging, and the decomposed products will hinder the battery's desired performance. The electrochemical reaction of the battery decreases, which is considered to be caused by the electrochemical oxidation of the solvent at the interface of the positive electrode material and the nonaqueous electrolyte.

In addition, in a lithium secondary battery using a highly crystalline carbon material such as natural graphite or artificial graphite as a negative electrode, the solvent in the non-aqueous electrolyte will be reductively decomposed on the surface of the negative electrode during charging, even if it is commonly used as a non-aqueous electrolyte The EC of the solvent will also be partially reduced and decomposed during repeated charging and discharging, causing the performance of the battery to decrease.

As a method of improving the battery characteristics of this lithium secondary battery, for example, Patent Documents 1 to 9 have been proposed.

In Patent Document 1, a non-aqueous solvent containing a cyclic carbonate having a non-conjugated unsaturated bond such as vinyl ethylene carbonate (VEC) in an amount of 0.1 to 20% by weight relative to the entire non-aqueous solvent and The non-aqueous electrolytic solution for a secondary battery composed of an electrolyte teaches that cycle life can be improved by this feature. However, a battery to which VEC has been added has a problem in that, compared with a battery to which no VEC has been added, more gas is generated due to decomposition of the electrolytic solution on the negative electrode, resulting in lower battery performance.

Patent Document 2 discloses a lithium secondary battery in which a mixture of an ethylene carbonate derivative such as VEC or monofluoroethylene carbonate and triphenyl phosphate is added. However, the cycle characteristics obtained from such electrolytic solutions are insufficient. In addition, when the end-of-charge voltage of the battery is higher than conventional (4.3V or higher), sufficient initial capacity, cycle characteristics, etc. cannot be obtained.

In addition, Patent Documents 3 to 6 disclose non-aqueous electrolytic solutions for lithium secondary batteries containing an alkyne derivative in the electrolytic solution.

In Patent Document 7, a lithium secondary battery is disclosed in which a pentafluorobenzene compound having an electron-donating group such as pentafluoroanisole is added, but the 200-cycle capacity retention rate of the button battery is about 80%, and the cycle performance insufficient.

Patent Document 8 describes that pentafluoroanisole can be used as a redox reagent as a chemical overcharge protection method for a nonaqueous electrolyte secondary battery, but there is no description about cycle characteristics. In addition, Patent Document 9 discloses a nonaqueous electrolyte solution for lithium secondary batteries containing a pentafluorophenoxy compound in the electrolyte solution.

Although these nonaqueous electrolytic solutions have improved cycle characteristics and the like to some extent, further improvement in performance has been demanded.

Patent Document 1: JP-A-2000-40526

Patent Document 2: Specification of US Patent Application Publication No. 2003/157413

Patent Document 3: JP-A-2000-195545

Patent Document 4: JP-A-2001-313072

Patent Document 5: JP-A-2002-100399

Patent Document 6: JP-A-2002-124297

Patent Document 7: Specification of US Patent Application Publication No. 2002/110735

Patent Document 8: JP-A-7-302614

Patent Document 9: JP-A-2003-272700

Contents of the invention

An object of the present invention is to provide a non-aqueous electrolytic solution that is excellent in battery characteristics such as electric capacity, cycle characteristics, and storage characteristics and can maintain battery performance for a long period of time, and a lithium secondary battery using the same.

The present inventors have found that gas generation can be reduced by using a specific ethylene carbonate derivative and (A) a compound containing a triple bond and/or (B) a pentafluorophenoxy compound in a specific amount in a non-aqueous electrolytic solution. , long-term maintenance of battery performance such as cycle characteristics, thereby completing the present invention.

That is, the present invention provides the following (1) and (2).

(1) A non-aqueous electrolytic solution for a lithium secondary battery, which is a non-aqueous electrolytic solution in which an electrolyte salt has been dissolved in a non-aqueous solvent, characterized in that, the non-aqueous electrolytic solution contains: 0.1 to 10% by weight The ethylene carbonate derivative represented by the following general formula (1) and 0.01 to 10% by weight of (A) a compound containing a triple bond and/or (B) the pentafluoro compound represented by the following general formula (X) Phenoxy compounds.

(In formula (I), R ¹ to R ³ each independently represent a hydrogen atom, a halogen atom, an alkenyl group with 2 to 12 carbon atoms, an alkynyl group with 2 to 12 carbon atoms, or an alkynyl group with 2 to 12 carbon atoms or Aryl groups of 6 to 18. Ethylene carbonate is not included.)

(In formula (X), R ¹⁵ represents an alkylcarbonyl group with 2 to 12 carbon atoms, an alkoxycarbonyl group with 2 to 12 carbon atoms, an aryloxycarbonyl group with 7 to 18 carbon atoms, or a carbon an alkanesulfonyl group having 1 to 12 atoms. Among them, at least ^one of the hydrogen atoms possessed by R may be substituted by a halogen atom or an aryl group having 6 to 18 carbon atoms.)

(2) A lithium secondary battery comprising a positive pole, a negative pole and a nonaqueous electrolytic solution obtained by dissolving an electrolyte salt in a nonaqueous solvent, characterized in that the nonaqueous electrolytic solution contains: 0.1 to 10% by weight The ethylene carbonate derivative represented by the above-mentioned general formula (1), and 0.01 to 10% by weight of (A) a compound containing a triple bond and/or (B) the pentafluorobenzene represented by the above-mentioned general formula (X) Oxygen compounds.

Since the non-aqueous electrolytic solution of the present invention does not generate gas and dry up in the non-aqueous electrolytic solution, battery characteristics such as electric capacity, cycle characteristics, and storage characteristics of the lithium secondary battery are improved, and battery performance can be maintained for a long time.

The lithium secondary battery using the nonaqueous electrolytic solution of the present invention is excellent in battery characteristics such as electric capacity, cycle characteristics, and storage characteristics, and can exhibit excellent battery performance for a long period of time.

Detailed ways

The non-aqueous electrolytic solution for lithium secondary batteries of the present invention is a non-aqueous electrolytic solution in which an electrolyte salt is dissolved in a non-aqueous solvent, and is characterized in that, in the non-aqueous electrolytic solution, 0.1 to 10% by weight of The ethylene carbonate derivative represented by (1) (hereinafter simply referred to as "ethylene carbonate derivative"), and 0.01 to 10% by weight of (A) a triple bond-containing compound and/or (B) derived from the above general A pentafluorophenoxy compound represented by formula (X) (hereinafter simply referred to as "pentafluorophenoxy compound").

It can be considered that by using ethylene carbonate derivatives in combination with (A) a compound containing a triple bond and/or (B) a pentafluorophenoxy compound, a strong coating film can be formed on the negative electrode, and the decomposition of the solvent can be suppressed, so it can be suppressed. Gas generation improves battery characteristics such as capacity, cycle characteristics, and storage characteristics.

The ethylene carbonate derivative used in the present invention is represented by the following general formula (I).

In formula (I), R ¹ to R ³ each independently represent a hydrogen atom, a halogen atom, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, or an alkynyl group having 6 carbon atoms. ~18 Aryl. It does not include ethylene carbonate.

Examples of the halogen atom include fluorine, chlorine, bromine, and iodine, preferably a fluorine or chlorine atom, particularly preferably a fluorine atom.

Examples of the alkenyl group having 2 to 12 carbon atoms include vinyl, allyl, crotyl and the like, preferably an alkenyl group having 2 to 5 carbon atoms, particularly preferably a vinyl group.

The alkynyl group having 2 to 12 carbon atoms is preferably an ethynyl group having 2 to 5 carbon atoms, 2-propynyl group, 3-butynyl group, 1-methyl-2-propynyl group and the like.

Examples of the aryl group having 6 to 18 carbon atoms include phenyl, tolyl, xylyl, naphthyl and the like.

Specific examples of ethylene carbonate derivatives include fluoroethylene carbonate (FEC), vinyl ethylene carbonate (VEC), 4,5-divinyl-1,3-dioxolane -2-one, 4-methyl-5-vinyl-1,3-dioxolan-2-one, 4-ethyl-5-vinyl-1,3-dioxolan-2-one , 4-propyl-5-vinyl-1,3-dioxolane-2-one, 4-butyl-5-vinyl-1,3-dioxolane-2-one, 4-pentane Base-5-vinyl-1,3-dioxolane-2-one, 4-hexyl-5-vinyl-1,3-dioxolane-2-one, 4-phenyl-5-ethene Base-1,3-dioxolane-2-one, 4,4-difluoro-1,3-dioxolane-2-one, 4,5-difluoro-1,3-dioxolane -2-one etc.

In addition, in this specification, when a compound exists an isomer, it means an independent isomer and these mixtures. The following is also the same.

Among these substances, preferably selected from FEC, VEC, 4,5-divinyl-1,3-dioxolane-2-one, 4,5-difluoro-1,3-dioxolane- One or more of the 2-ketones preferably contain FEC and/or VEC in terms of charge and discharge characteristics and suppression of gas generation.

If the content of the ethylene carbonate derivative contained in the non-aqueous electrolytic solution is too small, desired and sufficient battery performance cannot be obtained, and if it is too large, the battery performance may decrease. The content thereof is 0.1 to 10% by weight, preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight, based on the weight of the nonaqueous electrolytic solution.

As the triple bond-containing compound used in the present invention, one or more alkyne derivatives represented by the following general formulas (II) to (VII) are preferably used.

In formulas (II) to (V), R ⁴ to R ¹⁰ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, preferably 1 to 5 carbon atoms, and an alkyl group having 3 to 5 carbon atoms. 6 cycloalkyl group or aryl group with 6 to 12 carbon atoms; R ⁵ and R ⁶ , R ⁷ and R ⁸ can also be combined with each other to form a cycloalkyl group with 3 to 6 carbon atoms; Y ¹ and Y ² represent -COOR ¹⁰ , -COR ¹⁰ or SO ₂ R ¹⁰ , which may be the same or different; x represents an integer of 1 or 2.

In formula (VI), R ¹¹ to R ¹³ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 5 carbon atoms, a cycloalkane having 3 to 6 carbon atoms group, an aryl group with 6 to 12 carbon atoms, or an aralkyl group with 7 to 12 carbon atoms, R ¹² and R ¹³ can also be combined with each other to form a cycloalkyl group with 3 to 6 carbon atoms. W represents a sulfoxide group, a sulfo group or an oxalyl group; ^Y represents an alkyl group with 1 to 12 carbon atoms, an alkenyl group, an alkynyl group, a cycloalkyl group with a carbon number of 3 to 6, and a carbon number with 6 An aryl group with ∼12 carbon atoms or an aralkyl group with 7-12 carbon atoms. x is the same as defined above.

In formula (VII), R ⁴ is the same as defined above, and R ¹⁴ represents an alkyl group with 1 to 12 carbon atoms, preferably an alkyl group with 1 to 5 carbon atoms, a cycloalkyl group with 3 to 6 carbon atoms, or An aryl group having 6 to 12 carbon atoms. p represents an integer of 1 or 2.

Specific examples of the alkynyl derivatives represented ^by the general formula (II) include 2-propynyl methyl carbonate ^[ R ⁴ to R ⁶ = H, R ¹⁰ =methyl], 1-methyl-2-propynyl methyl carbonate [R ⁴ =R ⁶ =H, R ⁵ =R ¹⁰ =methyl], 2-propynyl ethyl carbonate Esters [R ⁴ ~ R ⁶ = H, R ¹⁰ = ethyl], 2-propynyl propyl carbonate [R ⁴ ~ R ⁶ = H, R ¹⁰ = propyl], 2-propynyl butyl carbonate Ester [R ⁴ ~R ⁶ =H, R ¹⁰ =butyl], 2-propynyl phenyl carbonate [R ⁴ ~R ⁶ =H, R ¹⁰ =phenyl], 2-propynyl cyclohexyl carbonate Esters [R ⁴ ～R ⁶ =H, R ¹⁰ =cyclohexyl], 2-butynyl methyl carbonate [R ⁴ =R ¹⁰ =methyl, R ⁵ =R ⁶ =H], 2-pentynyl Methyl carbonate [R ⁴ = ethyl, R ⁵ = R ⁶ = H, R ¹⁰ = methyl], 1-methyl-2-butynyl methyl carbonate [R ⁴ = R ⁵ = methyl, R ⁶ =H, R ¹⁰ =methyl], 1,1-dimethyl-2-propynyl methyl carbonate [R ⁴ =H, R ⁵ =R ⁶ =R ¹⁰ =methyl], 1, 1-diethyl-2-propynyl methyl carbonate [R ⁴ =H, R ⁵ =R ⁶ =ethyl, R ¹⁰ =methyl], 1-ethyl-1-methyl-2-prop Alkynyl methyl carbonate [R ⁴ =H, R ⁵ =ethyl, R ⁶ =R ¹⁰ =methyl], 1-isobutyl-1-methyl-2-propynyl methyl carbonate [R ⁴ = H, R ⁵ = isobutyl, R ⁶ = R ¹⁰ = methyl], 1,1-dimethyl-2-butynyl methyl carbonate [R ⁴ ~ R ⁶ = R ¹⁰ = methyl ], 1-ethynylcyclohexylmethyl carbonate [R ⁴ = H, R ⁵ combined with R ⁶ = pentylene, R ¹⁰ = methyl], 1-phenyl-1-methyl-2-propyne 1,1-diphenyl-2-propynyl methyl carbonate [R ⁴ =H, R ⁵ =phenyl, R ⁶ =R ¹⁰ =methyl], 1,1-diphenyl-2-propynyl methyl carbonate [R ⁴ =H, R ⁵ =R ⁶ =phenyl, R ¹⁰ =methyl], 1,1-dimethyl-2-propynylethyl carbonate [R ⁴ =H, R ⁵ =R ⁶ =methyl, R ¹⁰ = ethyl] etc.

In the case of Y1 = -COR ¹⁰ and x = 1, examples include 2-propynyl formate [R ⁴ to R ⁶ =R ¹⁰ =H], 2-propynyl acetate [R ⁴ to R ⁶ =H , R ¹⁰ =methyl], 1-methyl-2-propynyl formate [R ⁴ =H, R ⁵ =methyl, R ⁶ =R ¹⁰ =H], 1-methyl-2-propynyl acetate Esters [R ⁴ =R ⁶ =H, R ⁵ =R ¹⁰ =methyl], 2-propynyl propionate [R ⁴ to R ⁶ =H, R ¹⁰ =ethyl], 2-propynyl butyrate [R ⁴ to R ⁶ =H, R ¹⁰ =propyl], 2-propynyl benzoate [R ⁴ to R ⁶ =H, R ¹⁰ =phenyl], 2-propynyl cyclohexanecarboxylate [ R ⁴ ～R ⁶ ＝H, R ¹⁰ ＝cyclohexyl], 2-butynyl formate [R ⁴ ＝methyl, R ⁵ ＝R ⁶ ＝R ¹⁰ ＝H], 3-butynyl formate [R ⁴ ～ R ⁶ =R ¹⁰ =H], 2-pentynyl formate [R ⁴ =ethyl, R ⁵ =R ⁶ =R ¹⁰ =H], 1-methyl-2-butynyl formate [R ⁴ = R ⁵ =R ¹⁰ =methyl, R ⁶ =H], 1,1-dimethyl-2-propynyl formate [R ⁴ =R ¹⁰ =H, R ⁵ =R ⁶ =methyl], formic acid -1,1-diethyl-2-propynyl ester [R ⁴ =R ¹⁰ =H, R ⁵ =R ⁶ =ethyl], formic acid-1-ethyl-1-methyl-2-propynyl ester [R ⁴ =R ¹⁰ =H, R ⁵ =ethyl, R ⁶ =methyl], formic acid-1-isobutyl-1-methyl-2-propynyl ester [R ⁴ =R ¹⁰ =H, R ⁵ = isobutyl, R ⁶ = methyl], formic acid-1,1-dimethyl-2-butynyl ester [R ⁴ ~ R ⁶ = methyl, R ¹⁰ = H], formic acid 1-ethynyl ring Hexyl ester [R ⁴ =R ¹⁰ =H, R ⁵ combined with R ⁶ =pentylene], 1-phenyl-1-methyl-2-propynyl formate [R ⁴ =R ¹⁰ =H, R ⁵ =phenyl, R ⁶ =methyl], 1,1-diphenyl-2-propynyl formate [R ⁴ =R ¹⁰ =H, R ⁵ =R ⁶ =phenyl], 2-butyne acetate Esters [R ³ =R ¹⁰ =methyl, R ⁴ =R ⁵ =H], 2-pentynyl acetate [R ⁴ =ethyl, R ⁵ =R ⁶ =H, R ¹⁰ =methyl], acetic acid 1-methyl-2-butynyl ester [R ⁴ =R ⁵ =R ¹⁰ =methyl, R ⁶ =H], 1,1-dimethyl-2-propynyl acetate [R ⁴ =H, R ⁵ =R ⁶ =R ¹⁰ =methyl], 1,1-diethyl-2-propynyl acetate [R ⁴ =H, R ⁵ =R ⁶ =ethyl, R ¹⁰ =methyl], Acetic acid-1-ethyl-1- Methyl-2-propynyl ester [R ⁴ =H, R ⁵ =ethyl, R ⁶ =R ¹⁰ =methyl], 1-isobutyl-1-methyl-2-propynyl acetate [R ⁴ = H, R ⁵ = isobutyl, R ⁶ = R ¹⁰ = methyl], 1,1-dimethyl-2-butynyl acetate [R ⁴ ~ R ⁶ = methyl, R ¹⁰ = methyl base], 1-ethynylcyclohexyl acetate [R ⁴ = H, R ⁵ combined with R ⁶ = pentylene, R ¹⁰ = methyl], 1-phenyl-1-methyl-2-propyne acetate Ester [R ⁴ =H, R ⁵ =phenyl, R ⁶ =R ¹⁰ =methyl], 1,1-diphenyl-2-propynyl acetate [R ⁴ =H, R ⁵ =R ⁶ = Phenyl, R ¹⁰ =methyl], 1,1-dimethyl-2-propynyl propionate [R ⁴ =H, R ⁵ =R ⁶ =methyl, R ¹⁰ =ethyl] and the like.

In the case of Y1=-SO ₂ R ¹⁰ and x=1, examples include 2-propynyl methanesulfonate [R ⁴ to R ⁶ =H, R ¹⁰ =methyl], 1-methyl methanesulfonate 2-propynyl ester [R ⁴ =R ⁶ =H, R ⁵ =R ¹⁰ =methyl], 2-propynyl ethanesulfonate [R ⁴ to R ⁶ =H, R ¹⁰ =ethyl], 2-propynyl propanesulfonate [R ⁴ ~R ⁶ =H, R ¹⁰ =propyl], 2-propynyl p-toluenesulfonate [R ⁴ ~R ⁶ =H, R ¹⁰ =p-tolyl], 2-propynyl cyclohexanesulfonate [R ⁴ ～R ⁶ =H, R ¹⁰ =cyclohexyl], 2-butynyl methanesulfonate [R ⁴ =R ¹⁰ =methyl, R ⁵ =R ⁶ = H], 2-pentynyl methanesulfonate [R ⁴ = ethyl, R ⁵ = R ⁶ = H, R ¹⁰ = methyl], 1-methyl-2-butynyl methanesulfonate [R ⁴ =R ⁵ =R ¹⁰ =methyl, R ⁶ =H], 1,1-dimethyl-2-propynyl methanesulfonate [R ⁴ =H, R ⁵ =R ⁶ =R ¹⁰ =methyl ], 1,1-diethyl-2-propynyl methanesulfonate [R ⁴ =H, R ⁵ =R ⁶ =ethyl, R ¹⁰ =methyl], 1-ethyl-methanesulfonate 1-methyl-2-propynyl ester [R ⁴ =H, R ⁵ =ethyl, R ⁶ =R ¹⁰ =methyl], methanesulfonic acid-1-isobutyl-1-methyl-2-propane Alkyne esters [R ⁴ =H, R ⁵ =isobutyl, R ⁶ =R ¹⁰ =methyl], 1,1-dimethyl-2-butynyl methanesulfonate [R ⁴ to R ⁶ =R ¹⁰ = methyl], 1-ethynylcyclohexyl methanesulfonate [R ⁴ = H, R ⁵ combined with R ⁶ = pentylene, R ¹⁰ = methyl], 1-phenyl-1-methanesulfonate Methyl-2-propynyl ester [R ⁴ =H, R ⁵ =phenyl, R ⁶ =R ¹⁰ =methyl], 1,1-diphenyl-2-propynyl methanesulfonate [R ⁴ =H, R ⁵ =R ⁶ =phenyl, R ¹⁰ =methyl], ethanesulfonic acid-1,1-dimethyl-2-propynyl ester [R ⁴ =H, R ⁵ =R ⁶ =methyl , R ¹⁰ =ethyl] and the like.

Examples of alkyne derivatives represented by the general formula (II) with x=2 include 3-butynyl methyl carbonate [R ⁴ to R ⁶ =H, Y ¹ =-COOCH ₃ ], acetic acid 3- Butynyl ester [R ⁴ to R ⁶ =H, Y ¹ =-COCH ₃ ], 3-butynyl methanesulfonate [R ⁴ to R ⁶ =H, Y ¹ =-SO ₂ CH ₃ ], etc.

Among these substances, preferably selected from the group consisting of 2-propynyl methyl carbonate, 2-propynyl ethyl carbonate, 2-propynyl propyl carbonate, 2-propynyl formate, 2-butyl formate One or more of alkyne esters, 2-propynyl acetate, 2-propynyl methanesulfonate, and 1-methyl-2-propynyl methanesulfonate, particularly preferably selected from 2-propynylmethyl One or more of carbonate, 2-propynyl formate and 2-propynyl methanesulfonate.

Specific examples of alkyne derivatives represented by the general formula (III) include 2-butyne-1,4-diol diol in the case of Y ¹ =Y ² =-COOR ¹⁰ and x = 1. Methyl dicarbonate [R ⁵ ~R ⁸ =H, R ¹⁰ =methyl], 2-butyne-1,4-diol diethyl dicarbonate [R ⁵ ~R ⁸ =H, R ¹⁰ = ethyl], 3-hexyne-2,5-diol dimethyl dicarbonate [R ⁵ =R ⁷ =R ¹⁰ =methyl, R ⁶ =R ⁸ =H], 3-hexyne-2, 5-diol diethyl dicarbonate [R ⁵ =R ⁷ =methyl, R ⁶ =R ⁸ =H, R ¹⁰ =ethyl], 2,5-dimethyl-3-hexyne-2, 5-diol dimethyl dicarbonate [R ⁵ ～R ⁸ =R ¹⁰ =methyl], 2,5-dimethyl-3-hexyne-2,5-diol diethyl dicarbonate [ R ⁵ to R ⁸ = methyl group, R ¹⁰ = ethyl group] and the like.

When Y ¹ =Y ² =-COR ¹⁰ and x = 1, examples include 2-butyne-1,4-diol dicarboxylate [R ⁵ to R ⁸ =R ¹⁰ =H], 2 -Butyne-1,4-diol diacetate [R ⁵ ~R ⁸ =H, R ¹⁰ =methyl], 2-butyne-1,4-diol dipropionate [R ⁵ ~R ⁸ = H, R ¹⁰ = ethyl], 3-hexyne-2,5-diol dicarboxylate [R ⁵ = R ⁷ = methyl, R ⁶ = R ⁸ = R ¹⁰ = H], 3- Hexyne-2,5-diol diacetate [R ⁵ =R ⁷ =R ¹⁰ =methyl, R ⁶ =R ⁸ =H], 3-hexyne-2,5-diol dipropionate [R ⁵ =R ⁷ =methyl, R ⁶ =R ⁸ =H, R ¹⁰ =ethyl], 2,5-dimethyl-3-hexyne-2,5-diol dicarboxylate [R ⁵ ~ R ⁸ = methyl, R ¹⁰ = H], 2,5-dimethyl-3-hexyne-2,5-diol diacetate [R ⁵ ~ R ⁸ = R ¹⁰ = methyl] , 2,5-dimethyl-3-hexyne-2,5-diol dipropionate [R ⁵ to R ⁸ = methyl group, R ¹⁰ = ethyl group] and the like.

In the case of Y ¹ =Y ² =-SO ₂ R ¹⁰ and x = 1, examples include 2-butyne-1,4-diol dimethanesulfonate [R ⁵ to R ⁸ =H, R ¹⁰ =methyl], 2-butyne-1,4-diol diethanesulfonate [R ⁵ ~R ⁸ =H, R ¹⁰ =ethyl], 3-hexyne-2,5-diol dimethyl Sulfonate [R ⁵ =R ⁷ =R ¹⁰ =methyl, R ⁶ =R ⁸ =H], 3-hexyne-2,5-diol diethanesulfonate [R ⁵ =R ⁷ =methyl , R ⁶ =R ⁸ =H, R ¹⁰ =ethyl], 2,5-dimethyl-3-hexyne-2,5-diol dimethanesulfonate [R ⁵ ~ R ⁸ =R ¹⁰ = methyl], 2,5-dimethyl-3-hexyne-2,5-diol diethanesulfonate [R ⁵ to R ⁸ =methyl, R ¹⁰ =ethyl], etc.

Among the alkyne derivatives represented by the general formula (III), it is preferably selected from 2-butyne-1,4-diol dimethyl carbonate, 2-butyne-1,4-diol diethyl Carbonate, 3-hexyne-2,5-diol dimethyl dicarboxylate, 2,5-dimethyl-3-hexyne-2,5-diol dimethyl dicarbonate, 2- Butyne-1,4-diol diacetate, 2-butyne-1,4-diol dicarboxylate, 3-hexyne-2,5-diol dicarboxylate, 2,5- Dimethyl-3-hexyne-2,5-diol dicarboxylate, 2-butyne-1,4-diol dimesylate, 3-hexyne-2,5-diol dimethyl One or more of sulfonate and 2,5-dimethyl-3-hexyne-2,5-diol dimethanesulfonate.

Particularly preferred is a compound selected from the group consisting of 2-butyne-1,4-diol dimethyl carbonate, 2-butyne-1,4-diol dicarboxylate and 2-butyne-1,4-diol One or more kinds of dimesylate.

Specific examples of alkyne derivatives represented by the general formula (IV) include 2,4 ^{- hexadiyne -} 1,6- Diol dimethyl dicarbonate [R ⁵ ~R ⁸ =H, R ¹⁰ =methyl], 2,4-hexadiyn-1,6-diol diethyl dicarbonate [R ⁵ ~R ⁸ =H, R ¹⁰ =ethyl], 2,7-dimethyl-3,5-octadiyn-2,7-diol dimethyl dicarbonate [R ⁵ ~ R ⁸ =R ¹⁰ =methyl ], 2,7-dimethyl-3,5-octadiyn-2,7-diol diethyl dicarbonate [R ⁵ to R ⁸ =methyl, R ¹⁰ =ethyl] and the like.

In the case of Y ¹ =Y ² =-COR ¹⁰ and x = 1, examples include 2,4-hexadiyn-1,6-diol diacetate [R ⁵ to R ⁸ =H, R ¹⁰ =methyl], 2,4-hexadiyn-1,6-diol dipropionate [R ⁵ ~R ⁸ =H, R ¹⁰ =ethyl], 2,7-dimethyl-3,5 - Octadiyne-2,7-diol diacetate [R ⁵ ~ R ⁸ =methyl, R ¹⁰ =methyl], 2,7-dimethyl-3,5-octadiyne-2, 7-diol dipropionate [R ⁵ to R ⁸ = methyl group, R ¹⁰ = ethyl group] and the like.

In the case of Y ¹ =Y ² =-SO ₂ R ¹⁰ and x = 1, examples include 2,4-hexadiyn-1,6-diol dimethanesulfonate [R ⁵ to R ⁸ =H , R ¹⁰ =methyl], 2,4-hexadiyn-1,6-diol diethanesulfonate [R ⁵ to R ⁸ =H, R ¹⁰ =ethyl], 2,7-dimethyl -3,5-octadiyne-2,7-diol dimesylate [R ⁵ ～R ⁸ =R ¹⁰ =methyl], 2,7-dimethyl-3,5-octadiyne- 2,7-diol diethanesulfonate [R ⁵ to R ⁸ = methyl group, R ¹⁰ = ethyl group] and the like.

Among these substances, preferred are those selected from the group consisting of 2,4-hexadiyn-1,6-diol dimethyl dicarbonate, 2,4-hexadiyn-1,6-diol diacetate and 2 , and one or more of 4-hexadiyn-1,6-diol dimesylate.

Specific examples of alkyne derivatives represented by the general formula (V) include, for example, dipropargyl carbonate [R ⁵ to R ¹⁰ =H], bis(1-methyl base-2-propynyl)carbonate [[R ⁵ =R ⁷ =methyl, R ⁶ =R ⁸ ~R ¹⁰ =H], bis(2-butynyl)carbonate [R ⁵ ~R ⁸ = H, R ⁹ =R ¹⁰ =methyl], bis(2-pentynyl) carbonate [R ⁵ to R ⁸ =H, R ⁹ =R ¹⁰ =ethyl], bis(1-methyl-2- butynyl) carbonate [[R ⁵ =R ⁶ =R ⁹ =R ¹⁰ =methyl, R ⁷ =R ⁸ =H], 2-propynyl-2-butynyl carbonate [R ⁵ ~R ⁹ = H, R ¹⁰ = methyl], bis(1,1-dimethyl-2-propynyl) carbonate [R ⁵ ~ R ⁸ = methyl, R ⁹ = R ¹⁰ = H], bis( 1,1-diethyl-2-propynyl) carbonate [R ⁵ ~ R ⁸ = ethyl, R ⁹ = R ¹⁰ = H], bis (1-ethyl-1-methyl-2-prop Alkynyl) carbonate [R ⁵ =R ⁷ =ethyl, R ⁶ =R ⁸ =methyl, R ⁹ =R ¹⁰ =H], bis(1-isobutyl-1-methyl-2-propyne base) carbonate [R ⁵ =R ⁷ =isobutyl, R ⁶ =R ⁸ =methyl, R ⁹ =R ¹⁰ =H], bis(1,1-dimethyl-2-butynyl)carbonic acid Ester [R ⁵ ~ R ¹⁰ = methyl], bis(1-ethynylcyclohexyl) carbonate [R ⁵ combined with R ⁶ = pentylene, R ⁷ combined with R ⁸ = pentylene, R ⁹ = R ¹⁰ =H] and the like.

Moreover, when x=2, bis(3-butynyl) carbonate [ ^R5 - ^R10 =H] is mentioned, for example.

Among the alkyne derivatives represented by the general formula (V), those selected from dipropargyl carbonate, bis(1-methyl-2-propynyl) carbonate and bis(2-butynyl) One or more types of carbonates.

Among the alkyne derivatives represented by the general formula (VI), bis(2-propynyl)sulfite [R ¹¹ ~R ¹³ =H, Y ³ =2-propynyl], bis(1-methyl-2-propynyl)sulfite [R ¹¹ =H, R ¹² =methyl, R ¹³ =H, Y ³ = 1-methyl-2-propynyl], bis(2-butynyl) sulfite [R ¹¹ = methyl, R ¹² = R ¹³ = H, Y ³ = 2-butynyl], Bis(2-pentynyl)sulfite [R ¹¹ =ethyl, R ¹² =R ¹³ =H, Y ³ =2-pentynyl], bis(1-methyl-2-butynyl)sulfite Sulfate [R ¹¹ =R ¹² =methyl, R ¹³ =H, Y ³ =1-methyl-2-butynyl], di(1,1-dimethyl-2-propynyl)sulfurous acid Esters [R ¹¹ =H, R ¹² =R ¹³ =methyl, Y ³ =1,1-dimethyl-2-propynyl], bis(1,1-diethyl-2-propynyl) Sulfite [R ¹¹ =H, R ¹² =R ¹³ =ethyl, Y ³ =1,1-diethyl-2-propynyl], bis(1-ethyl-1-methyl-2- propynyl)sulfite [R ¹¹ =H, R ¹² =ethyl, R ¹³ =methyl, Y ³ =1-ethyl-1-methyl-2-propynyl], bis(1-iso Butyl-1-methyl-2-propynyl)sulfite [R ¹¹ =H, R ¹² =isobutyl, R ¹³ =methyl, Y ³ =1-isobutyl-1-methyl- 2-propynyl], bis(1,1-dimethyl-2-butynyl)sulfite [R ¹¹ =R ¹² =R ¹³ =methyl, Y ³ =1,1-dimethyl- 2-butynyl], bis(1-ethynylcyclohexyl) sulfite [R ¹¹ = H, R ¹² combined with R ¹³ = pentylene, Y ³ = 1-ethynylcyclohexyl], bis(1 -Methyl-1-phenyl-2-propynyl)sulfite [R ¹¹ =H, R ¹² =phenyl, R ¹³ =methyl, Y ³ =1-methyl-1-phenyl-2 -propynyl], bis(1,1-diphenyl-2-propynyl)sulfite [R ¹¹ =H, R ¹² =R ¹³ =phenyl, Y ³ =1,1-diphenyl -2-propynyl], methyl 2-propynyl sulfite [R ¹¹ ~ R ¹³ = H, Y ³ = methyl], methyl 1-methyl-2-propynyl sulfite [ R ¹¹ =H, R ¹² =methyl, R ¹³ =H, Y ³ =methyl], ethyl 2-propynyl sulfite [R ¹¹ to R ¹³ =H, Y ³ =ethyl], benzene 2-propynyl sulfite [R ¹¹ ～R ¹³ =H, Y ³ =phenyl], cyclohexyl 2-propynyl sulfite [R ¹¹ ～R ¹³ = H, Y ³ = cyclohexyl] and the like.

In addition, when W is a sulfoxide group and x=2, bis(3-butynyl)sulfite [R ¹¹ to R ¹³ =H, Y ³ =3-butynyl] and the like can be mentioned.

Among these substances, preferably selected from bis(2-propynyl)sulfite, bis(1-methyl-2-propynyl)sulfite, bis(2-butynyl)sulfite, One or more of methyl 2-propynyl sulfite, methyl 1-methyl-2-propynyl sulfite and ethyl-2-propynyl sulfite, particularly preferably containing One or more kinds of bis(2-propynyl)sulfite, methyl-2-propynylsulfite, and ethyl-2-propynylsulfite.

In the general formula (VI), specific examples in the case where W is a sulfo group and x=1 include bis(2-propynyl)sulfate [R ¹¹ to R ¹³ =H, Y ³ = 2-propynyl], bis(1-methyl-2-propynyl) sulfate [R ¹¹ =R ¹³ =H, R ¹² =methyl, Y ³ =1-methyl-2-propynyl ], bis(2-butynyl)sulfate [R ¹¹ =methyl, R ¹² =R ¹³ =H, Y ³ =2-butynyl], bis(2-pentynyl)sulfate [R ¹¹ =ethyl, R ¹² =R ¹³ =H, Y ³ =2-pentynyl], bis(1-methyl-2-butynyl)sulfate [R ¹¹ =R ¹² =methyl, R ¹³ = H, Y ³ =1-methyl-2-butynyl], bis(1,1-dimethyl-2-propynyl)sulfate [R ¹¹ =H, R ¹² =R ¹³ =methyl, Y ³ =1,1-dimethyl-2-propynyl], bis(1,1-diethyl-2-propynyl)sulfate [R ¹¹ =H, R ¹² =R ¹³ =ethyl , Y ³ =1,1-diethyl-2-propynyl], bis(1-ethyl-1-methyl-2-propynyl)sulfate [R ¹¹ =H, R ¹² =ethyl , R ¹³ =methyl, Y ³ =1-ethyl-1-methyl-2-propynyl], bis(1-isobutyl-1-methyl-2-propynyl)sulfate [R ¹¹ = H, R ¹² = isobutyl, R ¹³ = methyl, Y ³ = 1-isobutyl-1-methyl-2-propynyl], bis(1,1-dimethyl-2- butynyl)sulfate [R ¹¹ ～R ¹³ =methyl, Y ³ =1,1-dimethyl-2-butynyl], bis(1-ethynylcyclohexyl)sulfate [R ¹¹ =H , R ¹² combined with R ¹³ = pentylene, Y ³ = 1-ethynylcyclohexyl], bis(1-methyl-1-phenyl-2-propynyl) sulfate [R ¹¹ = H, R ¹² = phenyl, R ¹³ = methyl, Y ³ = 1-methyl-1-phenyl-2-propynyl], bis(1,1-diphenyl-2-propynyl)sulfate [ R ¹¹ =H, R ¹² =R ¹³ =phenyl, Y ³ =1,1-diphenyl-2-propynyl], methyl 2-propynyl sulfate [R ¹¹ to R ¹³ =H, Y ³ =methyl], methyl 1-methyl-2-propynyl sulfate [R ¹¹ =R ¹³ =H, R ¹² =methyl, Y ³ =methyl], ethyl 2-propynyl Sulfate [R ¹¹ ~ R ¹³ = H, Y ³ = ethyl], phenyl 2-propynyl sulfate [R ¹¹ ~ R ¹³ = H, Y ³ = phenyl], cyclohexyl 2-propynyl Sulfate [R ¹¹ to R ¹³ =H, Y ³ =cyclohexyl] and the like.

In addition, when W is a sulfo group and x=2, bis(3-butynyl)sulfate [R ¹¹ to R ¹³ =H, Y ³ =3-butynyl] and the like can be mentioned.

Among these substances, preferably selected from bis(2-propynyl)sulfate, bis(1-methyl-2-propynyl)sulfate, methyl 2-propynylsulfate and ethyl 2- One or more kinds of propynyl sulfate esters.

In the general formula (VI), as specific examples in the case where W is oxalyl and x=1, bis(2-propynyl) oxalate [R ¹¹ to R ¹³ =H, Y ³ = 2-propynyl], bis(1-methyl-2-propynyl) oxalate [R ¹¹ =R ¹³ =H, R ¹² =methyl, Y ³ =1-methyl-2-propyne base], bis(2-butynyl) oxalate [R ¹¹ =methyl, R ¹² =R ¹³ =H, Y ³ =2-butynyl], bis(2-pentynyl) oxalate [R ¹¹ = ethyl, R ¹² = R ¹³ = H, Y ³ = 2-pentynyl], bis(1-methyl-2-butynyl) oxalate [R ¹¹ = R ¹² = methyl , R ¹³ =H, Y ³ =1-methyl-2-butynyl], bis(1,1-dimethyl-2-propynyl) oxalate [R ¹¹ =H, R ¹² =R ¹³ = methyl, Y ³ = 1,1-dimethyl-2-propynyl], bis(1,1-diethyl-2-propynyl) oxalate [R ¹¹ =H, R ¹² =R ¹³ =ethyl, Y ³ =1,1-diethyl-2-propynyl], bis(1-ethyl-1-methyl-2-propynyl) oxalate [R ¹¹ = H, R ¹² = ethyl, R ¹³ = methyl, Y ³ = 1-ethyl-1-methyl-2-propynyl], bis(1-isobutyl-1-methyl-2-prop Alkynyl)oxalate [R ¹¹ =H, R ¹² =isobutyl, R ¹³ =methyl, Y ³ =1-isobutyl-1-methyl-2-propynyl], bis(1, 1-Dimethyl-2-butynyl) oxalate [R ¹¹ ~ R ¹³ = methyl, Y ³ = 1,1-dimethyl-2-butynyl], bis(1-ethynyl ring Hexyl) oxalate [R ¹¹ = H, combination of R ¹² and R ¹³ = pentylene, Y ³ = 1-ethynylcyclohexyl], bis(1-methyl-1-phenyl-2-propynyl ) oxalate [R ¹¹ =H, R ¹² =phenyl, R ¹³ =methyl, Y ³ =1-methyl-1-phenyl-2-propynyl], bis(1,1-diphenyl base-2-propynyl) oxalate [R ¹¹ = H, R ¹² = R ¹³ = phenyl, Y ³ = 1,1-diphenyl-2-propynyl], methyl 2-propynyl oxalate [R ¹¹ ～R ¹³ =H, Y ³ =methyl], methyl 1-methyl-2-propynyl oxalate [R ¹¹ =H, R ¹² =methyl, R ¹³ = H, Y ³ = methyl], ethyl 2-propynyl oxalate [R ¹¹ ~ R ¹³ R ¹³ = H, Y ³ = ethyl], ethyl 1-methyl-2-propynyl oxalate ester [R ¹¹ =R ¹³ =H, R ¹² =methyl, Y ³ =ethyl], phenyl 2-propynyl oxalate [R ¹¹ to R ¹³ =H, Y ³ =phenyl], Cyclohexyl 2-propynyl oxalate [R ¹¹ to R ¹³ =H, Y ³ =cyclohexyl], etc.

In addition, as specific examples in the case where W is oxalyl and x=2, bis(3-butynyl)oxalate [R ¹¹ to R ¹³ =H, Y ³ =3-butynyl ]wait.

Among these substances, preferably selected from bis(2-propynyl) oxalate, bis(1-methyl-2-propynyl) oxalate, methyl 2-propynyl oxalate, ethyl One or more of base 2-propynyl oxalate, methyl 1-methyl-2-propynyl oxalate and 1-methyl-2-propynyl oxalate, especially preferably containing selected One or more selected from di(2-propynyl) oxalate, methyl-2-propynyl oxalate, and ethyl-2-propynyl oxalate.

As specific examples of alkyne derivatives represented by the general formula (VII), when p=1, 2-pentyne [R ⁴ =methyl, R ¹⁴ =ethyl], 1-hexyne [R ⁴ =butyl, R ¹⁴ =H], 2-hexyne [R ⁴ =propyl, R ¹⁴ =methyl], 3-hexyne [R ⁴ =R ¹⁴ =ethyl], 1-heptyne [R ⁴ =pentyl, R ¹⁴ =H], 1-octyne [R ⁴ =hexyl, R ¹⁴ =H], 2-octyne [R ⁴ =methyl, R ¹⁴ =pentyl], 4-octyne alkyne [R ⁴ =R ¹⁴ =propyl], 1-decyne [R ⁴ =octyl, R ¹⁴ =H], 1-dodecyne [R ⁴ =decyl, R ¹⁴ =H], phenylacetylene [R ⁴ =phenyl, R ¹⁴ =H], 1-phenyl-1-propyne [R ⁴ =phenyl, R ¹⁴ =methyl], 1-phenyl-1-butyne [R ⁴ =benzene group, R ¹⁴ = ethyl], 1-phenyl-1-pentyne [R ⁴ = phenyl, R ¹⁴ = propyl], 1-phenyl-1-hexyne [R ⁴ = phenyl, R ¹⁴ =butyl], diphenylacetylene [R ⁴ =R ¹⁴ =phenyl], 4-ethynyltoluene [R ⁴ =p-tolyl, R ¹⁴ =methyl], 4-tert-butylphenylacetylene [R ⁴ = 4-tert-butylphenyl, R ¹⁴ = H], 1-ethynyl-4 fluorobenzene [R ⁴ = p-fluorophenyl, R ¹⁴ = H], 1,4-diethynylbenzene [R ⁴ =p-ethynylphenyl, R ¹⁴ =H], dicyclohexylacetylene [R ⁴ =R ¹⁴ =cyclohexyl] and the like.

In addition, when p=2, for example, 1,4-diphenylbutadiene [R ⁴ =R ¹⁴ =phenyl] and the like can be mentioned.

Among these substances, preferably selected from the group consisting of phenylacetylene, 1-phenyl-1-propyne, 1-phenyl-1-butyne, diphenylacetylene, 4-ethynyl toluene, 1-ethynyl-4 fluoro One or more of benzene and 1,4-diethynylbenzene, particularly preferably contains phenylacetylene and/or 1-phenyl-1-propyne.

Among the above-mentioned alkyne derivatives, the most preferred compound is selected from 2-propynyl methyl carbonate represented by general formula (II), 2-propynyl methanesulfonate, 2-propynyl methanesulfonate represented by general formula (III) -butyne-1,4-diol dimethyl carbonate, 2-butyne-1,4-diol dicarboxylate, 2-butyne-1,4-diol dimethanesulfonate and Bis(2-propynyl) sulfite represented by general formula (VI), methyl 2-propynyl sulfite, ethyl 2-propynyl sulfite, bis(2-propynyl) sulfite One or more compounds selected from esters, methyl 2-propynyl oxalate, and ethyl 2-propynyl oxalate. By using these compounds in combination with an ethylene carbonate derivative, battery characteristics such as improvement of charge and discharge characteristics, suppression of gas generation, and the like can be most effectively improved.

If the content of one or more alkyne derivatives represented by the general formulas (II) to (VII) contained in the nonaqueous electrolyte solution is too small, a sufficient coating film cannot be formed and desired battery characteristics cannot be obtained, If too much, the electrical conductivity of electrolyte solution etc. will change, and battery performance may fall. The content thereof is 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, based on the weight of the nonaqueous electrolytic solution.

The mixing ratio (weight ratio) of the ethylene carbonate derivative: the above alkyne derivative is 96:4 to 25:75, preferably 90:10 to 40:60, more preferably 80:20 to 50:50.

The pentafluorophenoxy compound used in the present invention is represented by the following general formula (X).

In formula (X), R ¹⁵ represents an alkylcarbonyl group with 2 to 12 carbon atoms, preferably 2 to 5 carbon atoms, and an alkylcarbonyl group with 2 to 12 carbon atoms, preferably 2 to 5 carbon atoms. An alkoxycarbonyl group, an aryloxycarbonyl group having 7 to 18 carbon atoms, or an alkanesulfonyl group having 1 to 12 carbon atoms, preferably 2 to 5 carbon atoms. However, at least one of the hydrogen atoms contained in R ¹⁵ may be substituted with a halogen atom or an aryl group having 6 to 18 carbon atoms.

Examples of the alkylcarbonyl group having 2 to 12 carbon atoms include methylcarbonyl, ethylcarbonyl, propylcarbonyl, butylcarbonyl, pentylcarbonyl, hexylcarbonyl, heptylcarbonyl, octylcarbonyl, and nonylcarbonyl. , decylcarbonyl, dodecylcarbonyl and other straight-chain substituents, isopropylcarbonyl, tert-butylcarbonyl, 2-ethylhexylcarbonyl and other branched-chain alkylcarbonyl groups, and the like.

Specific examples of compounds in which at least one of the hydrogen atoms in the alkylcarbonyl group is substituted by a halogen atom or an aryl group having 6 to 18 carbon atoms include trifluoromethylcarbonyl, 1,2-bis Chloroethylcarbonyl, pentafluoroethylcarbonyl, heptafluoropropylcarbonyl, benzylcarbonyl and the like. In addition, an alkylcarbonyl group substituted with an alkyl group having an unsaturated bond such as a methylene group (CH ₂ =) or an allyl group (CH ₂ =CH-CH ₂ -) can be mentioned. Specific examples thereof include vinylcarbonyl, 1-methylvinylcarbonyl and the like.

Specific examples of the pentafluorophenoxy compound include pentafluorophenyl acetate, pentafluorophenyl propionate, pentafluorophenyl butyrate, pentafluorophenyl trifluoroacetate, and pentafluorophenyl pentafluoropropionate. ester, pentafluorophenyl acrylate, pentafluorophenyl methacrylate, etc. Among these substances, pentafluorophenyl acetate, pentafluorophenyl trifluoroacetate, and the like are particularly preferable.

Examples of the alkoxycarbonyl group having 2 to 12 carbon atoms include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentyloxycarbonyl, hexyloxycarbonyl, heptyloxy Straight-chain substituents such as carbonyl, octyloxycarbonyl, nonyloxycarbonyl, decyloxycarbonyl, dodecyloxycarbonyl, isopropoxycarbonyl, tert-butoxycarbonyl, 2-ethylhexyloxycarbonyl, etc. Branched chain alkoxycarbonyl, etc.

Specific examples of compounds in which at least one of the hydrogen atoms in the alkoxycarbonyl group is substituted by a halogen atom or an aryl group having 6 to 18 carbon atoms include 1-chloroethoxycarbonyl, 2- Chloroethoxycarbonyl, 2,2,2-trifluoroethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, benzyloxycarbonyl and the like.

Specific examples of the pentafluorophenoxy compound include methyl pentafluorophenyl carbonate, ethyl pentafluorophenyl carbonate, tert-butyl pentafluorophenyl carbonate, 9-fluorenylmethyl pentafluorophenyl Phenyl carbonate, 2,2,2-trifluoroethylpentafluorophenyl carbonate, and the like. Among these substances, preferred are methyl pentafluorophenyl carbonate, ethyl pentafluorophenyl carbonate, tert-butyl pentafluorophenyl carbonate, 2,2,2-trifluoroethyl pentafluorophenyl carbonate Esters, particularly preferably methyl pentafluorophenyl carbonate and the like.

Examples of the aryloxycarbonyl group having 7 to 18 carbon atoms include phenyloxycarbonyl, o-, m-, or p-tolyloxycarbonyl and the like.

Specific examples of pentafluorophenoxy compounds having these substituents include phenyl pentafluorophenyl carbonate, bis(pentafluorophenyl) carbonate, and the like.

Examples of the alkanesulfonyl group having 1 to 12 carbon atoms include methanesulfonyl, ethylsulfonyl, propanesulfonyl, butanesulfonyl, pentylsulfonyl, hexylsulfonyl, heptylsulfonyl, octanesulfonyl, nonylsulfonyl, Straight-chain substituents such as sulfonyl, decanesulfonyl, and dodecanesulfonyl; branched-chain alkanesulfonyl such as 2-propanesulfonyl, etc.

Specific examples of the compound in which at least one of the hydrogen atoms of the alkanesulfonyl group is replaced by a halogen atom include trifluoromethanesulfonyl group, 2,2,2-trifluoroethanesulfonyl group and the like.

Specific examples of the pentafluorophenoxy compound include pentafluorophenylmethanesulfonate, pentafluorophenylethanesulfonate, pentafluorophenylpropanesulfonate, pentafluorophenyltrifluoromethanesulfonate ester, pentafluorophenyl-2,2,2-trifluoroethanesulfonate, etc. Among these substances, preferred are pentafluorophenyl mesylate, pentafluorophenylethanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl-2,2,2-trifluoroethane The sulfonate is particularly preferably pentafluorophenylmethanesulfonate or pentafluorophenyl triflate.

If the content of the pentafluorophenoxy compound contained in the non-aqueous electrolyte solution is too small, the expected battery characteristics cannot be obtained because a sufficient coating film cannot be formed, and if it is too large, the conductivity of the electrolyte solution, etc. will change, Sometimes battery performance degrades. The content thereof is 0.01 to 10% by weight, preferably 0.05 to 5% by weight, more preferably 0.1 to 3% by weight, based on the weight of the nonaqueous electrolytic solution.

The mixing ratio (weight ratio) of pentafluorophenoxy compound: ethylene carbonate derivative is 2:98-95:5, preferably 20:80-75:25, more preferably 30:70-50:50.

[Non-aqueous solvent]

As the non-aqueous solvent used in the present invention, cyclic carbonates, chain carbonates, esters, sulfuric acid ester compounds (sulfuric acid estel), ethers, amides, phosphoric acid esters, sulfones, Lactones, nitriles, etc.

Examples of cyclic carbonates include EC, PC, butylene carbonate and the like, among which EC having a high dielectric constant is most preferably included.

As chain carbonates, asymmetric chain carbonates such as methyl ethyl carbonate (MEC), methyl propyl carbonate, methyl butyl carbonate, ethylene propyl carbonate, etc.; dimethyl carbonate (DMC), dicarbonate Ethyl ester (DEC) and other symmetrical chain carbonates. In particular, asymmetric chain carbonates are preferable because they have a low melting point and are effective in low-temperature characteristics of batteries. Among them, MEC is most preferable.

Examples of esters include methyl propionate, methyl pivalate, butyl pivalate, hexyl pivalate, octyl pivalate, etc., and examples of sulfuric acid ester compounds include 1,3-propanesulfone Lactone, 1,4-butanediol dimesylate, ethylene glycol sulfite, propylene glycol sulfite, ethylene glycol sulfate, propylene glycol sulfate, etc.

In addition, examples of ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2 - Dibutoxyethane, etc. Examples of amides include dimethylformamide, etc., examples of phosphates include trimethyl phosphate, trioctyl phosphate, etc., examples of sulfones include di Vinyl sulfone and the like, examples of lactones include γ-butyrolactone and the like, and examples of nitriles include acetonitrile, adiponitrile and the like.

Among the above-mentioned non-aqueous solvents, cyclic carbonates, chain carbonates, esters, and sulfate ester compounds are preferable, and these may be used alone or in combination of two or more of them. Among them, it is more preferable to contain cyclic carbonates and/or chain carbonates.

More specifically, combinations of cyclic carbonates such as EC and PC and chain carbonates such as MEC and DEC are particularly preferable.

The capacity ratio of cyclic carbonates:chain carbonates is 10:90 to 40:60, preferably 20:80 to 40:60, more preferably 25:75 to 45:55.

In addition, among cyclic carbonates and chain carbonates, it is preferable to use a sulfuric acid ester compound and/or divinyl sulfone in combination. In particular, the combination of at least one sulfuric acid ester compound selected from 1,3-propane sultone, ethylene glycol sulfite, and 1,4-butanediol dimesylate and divinyl sulfone for charging and discharging The characteristic aspect is most preferred.

[electrolyte salt]

Examples of the electrolyte salt used in the present invention include LiPF ₆ , LiBF ₄ , LiClO ₄ , LiN(SO ₂ CF ₃ ) ₂ , LiN(SO ₂ C ₂ F ₅ ) ₂ , LiC(SO ₂ CF ₃ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (iso-C ₃ F ₇ ) ₃ , LiPF ₅ (iso-C ₃ F ₇ ), etc. . Among these substances, LiPF ₆ , LiBF ₄ , and LiN(SO ₂ CF ₃ ) ₂ are preferable, and LiPF ₆ is most preferable. These electrolyte salts may be used alone or in combination of two or more.

Preferable combinations include LiPF ₆ and LiBF ₄ , LiPF ₆ and LiN(SO ₂ CF ₃ ) ₂ , LiBF ₄ and LiN(SO ₂ CF ₃ ) ₂ , and the like, and a combination of LiPF ₆ and LiBF ₄ is particularly preferable.

Electrolyte salts can be mixed in any proportion, and when used in combination with LiPF ₆ , the ratio (mol ratio) of other electrolyte salts to the total electrolyte salts is preferably 0.01 to 45%, more preferably 0.03 to 20%, and even more preferably 0.05-10%, most preferably 0.05-5%.

In addition, all electrolyte salts are dissolved in the above-mentioned non-aqueous solvent at a concentration of usually 0.1 to 3M, preferably 0.5 to 2.5M, more preferably 0.7 to 2.0M, most preferably 0.8 to 1.4M, and used.

As a preferable combination of the above-mentioned non-aqueous solvent and electrolyte salt, there may be listed LiPF ₆ and/or LiBF ₄ as electrolyte salt in a mixed solvent of (i) EC and/or PC, and (ii) MEC and/or DEC of electrolyte.

More specifically, it is preferred that the capacity ratio of [(i) EC and/or PC, (ii) MEC and/or DEC] be preferably 15:85 to 45:55, more preferably 20:80 to 40:60, Particularly preferably, a mixed solvent of 25:75 to 35:65 is combined with LiPF ₆ as an electrolyte salt. Furthermore, it is also preferable to use a combination of LiPF ₆ and LiBF ₄ or a combination of LiPF ₆ and LiN(SO ₂ CF ₃ ) ₂ as the electrolyte salt for the mixed solvent described above.

[Manufacture of non-aqueous electrolyte]

The electrolytic solution of the present invention can be prepared by, for example, mixing non-aqueous solvents such as EC, PC, and MEC, dissolving electrolyte salt therein, dissolving ethylene carbonate derivatives, (A) 1 represented by the above general formulas (II) to (VII) A compound containing a triple bond such as more than one alkyne derivative and/or (B) a pentafluorophenoxy compound can be obtained.

At this time, the non-aqueous solvent, ethylene carbonate derivative, (A) triple bond-containing compound and/or (B) pentafluorophenoxy compound, and other additives used are within a range that does not significantly reduce productivity, It is preferable to use a material that has been purified in advance and has very few impurities.

In addition, by including, for example, air or carbon dioxide in the non-aqueous electrolytic solution of the present invention, the gas generated due to the decomposition of the electrolytic solution can be suppressed, and battery performance such as cycle characteristics and storage characteristics can be improved.

In the present invention, as a method of containing (dissolving) carbon dioxide or air in the nonaqueous electrolytic solution, (1) before the nonaqueous electrolytic solution is injected into the battery, it is previously contacted with a gas containing air or carbon dioxide. method, (2) a method of enclosing a gas containing air or carbon dioxide in the battery after injecting the liquid and before or after the battery is sealed. The gas containing air or carbon dioxide preferably does not contain moisture, more preferably has a dew point of -40°C or lower, especially -50°C or lower.

In the electrolytic solution of the present invention, by further containing an aromatic compound, the safety of the battery during overcharge can be ensured.

As this aromatic compound, the following (a)-(c) are mentioned, for example.

(a) Cyclohexylbenzene, fluorocyclohexylbenzene compounds (1-fluoro-2-cyclohexylbenzene, 1-fluoro-3-cyclohexylbenzene, 1-fluoro-4-cyclohexylbenzene), biphenyl.

(b) tert-butylbenzene, 1-fluoro-4-tert-butylbenzene, tert-aminobenzene, 4-tert-butylbiphenyl, 4-tert-aminobiphenyl.

(c) Terphenyl (o-, m-, p-body), diphenyl ether, 2-fluorodiphenyl ether, 4-diphenyl ether, fluorobenzene, difluorobenzene (o-, m-, p-body), 2-fluorobiphenyl, 4-fluorobiphenyl, 2,4-difluoroanisole, partial hydrogenation of terphenyl (1,2-dicyclohexylbenzene, 2-phenylbicyclohexane, 1,2 - diphenylcyclohexane, o-cyclohexylbiphenyl).

Among these substances, (a) and (b) are preferred, and most preferably selected from cyclohexylbenzene, fluorocyclohexylbenzene compounds (1-fluoro-4-cyclohexylbenzene, etc.), tert-butylbenzene, tertiary amino One or more kinds of benzene.

As a combination when using 2 or more types of said aromatic compounds, the following (d)-(f) are mentioned, for example.

(d) Biphenyl and tert-butylbenzene, biphenyl and tertiary aminobenzene, cyclohexylbenzene and tertiary aminobenzene, cyclohexylbenzene and 1-fluoro-4-tert-butylbenzene, tertiary aminobenzene and 1-fluoro-4 - Combinations of tert-butylbenzene.

(e) Combinations of biphenyl and cyclohexylbenzene, cyclohexylbenzene and tert-butylbenzene.

(f) Biphenyl and fluorobenzene, cyclohexylbenzene and fluorobenzene, 2,4-difluoroanisole and cyclohexylbenzene, cyclohexylbenzene and fluorocyclohexylbenzene compound, fluorocyclohexylbenzene compound and fluorobenzene A combination of 2,4-difluoroanisole and a fluorocyclohexylbenzene compound.

Among these combinations, a combination of (d) and (e) is preferable, a combination of (d) is more preferable, and a combination containing a fluorine-containing compound in (d) is particularly preferable. The mixing ratio (weight ratio) of fluorine-free aromatic compound: fluorine-containing aromatic compound is preferably 50:50 to 10:90, more preferably 50:50 to 20:80, most preferably 50:50 to 25: 75.

The total content of the above-mentioned aromatic compounds is preferably 0.1 to 5% by weight based on the weight of the non-aqueous electrolytic solution.

[Lithium secondary battery]

The lithium secondary battery of the present invention is composed of a positive electrode, a negative electrode, and a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent. There are no particular limitations on components such as the positive electrode and the negative electrode other than the non-aqueous electrolytic solution, and various known components can be used.

For example, a composite metal oxide with lithium containing cobalt, manganese, and nickel can be used as the positive electrode active material. These positive electrode active materials may be used alone or in combination of two or more.

Examples of such composite metal oxides include LiCoO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiCo _1-x Ni _x O ₂ (0.01<x<1), LiCo _1/3 Ni _1/3 Mn _{1/3 3} O ₂ , LiNi _1/2 Mn _3/2 O ₄ etc. In addition, LiCoO ₂ and LiMn ₂ O ₄ , LiCoO ₂ and LiNiO ₂ , and LiMn ₂ O ₄ and LiNiO ₂ can be used in combination. Among these substances, lithium composite metal oxides such as LiCoO ₂ , LiMn ₂ O ₄ , and LiNiO ₂ , which can be used in a fully charged state with a charge potential of the positive electrode of 4.3 V or higher based on Li, are preferable, and LiCo ₁ is more preferable. Lithium composite oxides such as _/3 Ni _1/3 Mn _1/3 O ₂ and LiNi _1/2 Mn _3/2 O ₄ that can be used at 4.4 V or higher. In addition, a part of the lithium composite oxide may be substituted by other elements, for example, a part of Co in _LiCoO2 may be substituted by Sn, Mg, Fe, Ti, Al, Zr, Cr, V, Ga, Zn, Cu, etc.

In addition, an olivine-type phosphate containing lithium can also be used as the positive electrode active material. Specific examples thereof include LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO ₄ , LiFe _1-x M _x PO ₄ (M is at least one selected from Co, Ni, Mn, Cu, Zn, and Cd, x 0≤x≤0.5), etc. Among these materials, LiFePO ₄ or LiCoPO ₄ is preferably used as a positive electrode active material for high voltage.

Lithium-containing olivine-type phosphate can also be mixed with other positive electrode active materials.

The conductive agent for the positive electrode is not particularly limited as long as it is a conductive material that does not cause a chemical reaction. Examples thereof include graphites such as natural graphite (flaky graphite, etc.), artificial graphite, and carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. In addition, graphites and carbon blacks may be appropriately mixed and used. The amount of the conductive agent added to the positive electrode mixture is preferably 1 to 10% by weight, particularly preferably 2 to 5% by weight.

The positive electrode can be produced as follows: the positive electrode active material and acetylene black, carbon black and other conductive agents and polytetrafluoroethylene, polyvinylidene fluoride, copolymers of styrene and butadiene, copolymers of acrylonitrile and butadiene, carboxyl After kneading binders such as methyl cellulose and ethylene propylene diene terpolymer to form a positive electrode mixture, the positive electrode material is rolled on an aluminum foil or stainless steel strip as a collector, and heated at 50°C The heat treatment under vacuum is performed at a temperature of about 250° C. for about 2 hours.

As the negative electrode (negative electrode active material), lithium metal or lithium alloy, and carbon materials capable of intercalating and deintercalating lithium [pyrolytic carbon, coke, graphite (artificial graphite, natural graphite, etc.), organic polymer compound Combustion body, carbon fiber], tin, tin compound, silicon, silicon compound, etc., are used alone or in combination of two or more. Battery capacity can be increased by substituting part or all of the carbon material with tin, tin compounds, silicon, or silicon compounds.

Among these substances, carbon materials are preferable, and carbon materials having a graphite-type crystal structure with a lattice plane (002) interplanar spacing (d ₀₀₂ ) of 0.340 nm or less, especially 0.335 to 0.340 nm are preferable.

The production of the negative electrode can be carried out by the same method using the same binder and high-boiling-point solvent as in the above-mentioned positive electrode production method.

The structure of the lithium secondary battery is not particularly limited, and a button-type battery, a cylindrical battery, a square battery, a stacked battery, etc. having a single-layer or multi-layer separator can be used.

As the battery separator, single-layer or laminated porous films, woven fabrics, non-woven fabrics, and the like of polyolefins such as polypropylene and polyethylene can be used.

The battery separator depends on the manufacturing conditions. If the air permeability is too low, the mechanical strength will decrease, and if the air permeability is too high, the conductivity of lithium ions will decrease, and the performance as a battery separator will be insufficient. Therefore, the air permeability is preferably 50 to 1000 seconds/100 cc, more preferably 100 to 800 seconds/100 cc, and most preferably 300 to 500 seconds/100 cc. From the viewpoint of improving battery capacity characteristics, the porosity thereof is preferably 30 to 60%, more preferably 35 to 55%, and most preferably 40 to 50%.

In addition, the thickness of the battery separator is preferably 5 to 50 μm, more preferably 10 to 40 μm, and most preferably 15 to 25 μm or less in terms of mechanical strength and energy density as it becomes thinner.

In the present invention, in order to increase the effect of adding the ethylene carbonate derivative, (A) triple bond-containing compound, and/or (B) pentafluorophenoxy compound, it is preferable to adjust the density of the electrode material layer. In particular, the density of the positive electrode mixture layer formed on aluminum foil or the like is preferably 3.2-4.0 g/cm ³ , more preferably 3.3-3.9 g/cm ³ , and most preferably 3.4-3.8 g/cm ³ . If the positive electrode mixture density exceeds 4.0 g/cm ³ and becomes large, it may be practically difficult to manufacture. On the other hand, the density of the negative electrode mixture layer formed on the copper foil is preferably 1.3-2.0 g/cm ³ , more preferably 1.4-1.9 g/cm ³ , and most preferably 1.5-1.8 g/cm ³ . If the density of the negative electrode mixture layer exceeds 2.0 g/cm ³ and becomes large, it may be practically difficult to manufacture.

In addition, if the thickness of the electrode layer is too thin, the amount of active material in the electrode material layer will decrease, so the battery capacity will decrease; if it is too thick, the cycle characteristics or rate characteristics will decrease. Therefore, the thickness of the positive electrode layer (per single-sided current collector) is usually 30 to 120 μm, preferably 50 to 100 μm, and the thickness of the negative electrode layer (per single-sided current collector) is usually 1 to 100 μm, preferably 3 to 100 μm. 70 μm.

The lithium secondary battery of the present invention can have excellent cycle characteristics for a long time even when the end-of-charge voltage is 4.2V or more, especially 4.3V or more, and also has good cycle characteristics at 4.4V. The end-of-discharge voltage may be greater than or equal to 2.5V, and further may be greater than or equal to 2.8V. There is no particular limitation on the current value, and it is usually used under a constant current discharge of 0.1 to 3C. In addition, the lithium secondary battery in the present invention can be charged and discharged at -40°C to 100°C, preferably at 0°C to 80°C.

In the present invention, as a countermeasure against the increase in internal pressure of the lithium secondary battery, a safety valve may be provided on the sealing plate, or a method of notching parts such as the battery can and the gasket may be used.

A plurality of lithium secondary batteries in the present invention may be connected in series and/or in parallel and housed in a battery case as needed. In the battery box, it is preferable to install a safety circuit (a circuit with the function of monitoring the voltage, temperature, current, etc. of each battery and/or battery pack as a whole, and cutting off the current) other than overcurrent prevention elements such as PTC elements, thermal fuses, and bimetals. ) etc. at least one or more.

Example

Examples and comparative examples of the cylindrical battery of the present invention will be described, but the present invention is not limited to the following examples, and the combination of solvents and the like are not limited either.

Example 1

[Preparation of non-aqueous electrolyte solution]

Prepare EC: MEC: DEC (capacity ratio) = 3: 4: 3 non-aqueous solvent, dissolve LiPF ₆ as electrolyte salt therein, make it reach 1M concentration, thus after preparing non-aqueous electrolytic solution, add relative non-aqueous The electrolytic solution was 2% by weight of fluoroethylene carbonate (FEC), and 2-propynyl methyl carbonate as an alkyne derivative was added so as to be 1% by weight relative to the nonaqueous electrolytic solution.

[Preparation of Lithium Secondary Battery and Measurement of Battery Characteristics]

Mix 94% by weight of LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ (positive electrode active material), 3% by weight of acetylene black (conductive agent), 3% by weight of polyvinylidene fluoride (binder), A 1-methyl-2-pyrrolidone solvent was added thereto, and the mixed material was coated on an aluminum foil, dried, press-molded, and heat-treated to prepare a positive electrode. In addition, 95% by weight of artificial graphite (negative electrode active material) and 5% by weight of polyvinylidene fluoride (binder) were mixed, 1-methyl-2-pyrrolidone solvent was added thereto, and the mixed material was coated on Copper foil, dried, press-molded, and heat-treated to prepare the negative electrode.

A separator (thickness 20 μm) of polyethylene microporous film was used to inject the above-mentioned non-aqueous electrolyte, and the battery contained air with a dew point of -60°C before the battery was sealed to prepare a 18650-size cylindrical battery (18 mm in diameter). , height 65mm). In the battery, a pressure release port and an internal current cutoff device (PTC element) are provided. The electrode density of the positive electrode was 3.5 g/cm ³ , and the electrode density of the negative electrode was 1.6 g/cm ³ . In addition, the thickness of the positive electrode layer (per single-side current collector) was 70 μm, and the thickness of the negative electrode layer (per single-side current collector) was 60 μm.

This 18650 battery was charged to 4.2V at a constant current of 2.2A (1C) at normal temperature (20°C), and then charged at a constant voltage of 4.2V as a cut-off voltage for a total of 3 hours. Thereafter, it was discharged to a cut-off voltage of 3.0V at a constant current of 2.2A (1C), and this charging and discharging was repeated. The initial charge and discharge capacity is the same as the case where no ethylene carbonate derivative and a triple bond-containing compound were added (Comparative Example 1), and the battery characteristics after 200 cycles were measured, and the discharge capacity retention rate when the initial discharge capacity was 100% was 82.8%, the results are shown in Table 1.

Embodiment 2-9

In Example 1, it carried out similarly to Example 1 except having used the alkyne derivative shown in Table 1 in the predetermined amount instead of 2-propynyl methyl carbonate. The results are shown in Table 1.

Example 10

After preparing the non-aqueous electrolytic solution in the same manner as in Example 1, add vinyl ethylene carbonate (VEC) that is 2% by weight relative to the non-aqueous electrolytic solution, and then add two (2-propynyl) sulfites to make It carried out similarly to Example 1 except that it was 0.5 weight% with respect to a nonaqueous electrolytic solution. The results are shown in Table 1.

Examples 11-12

Use the positive electrode shown in Table 1 instead of LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ as the positive electrode (positive electrode active material), and add 0.5% by weight relative to the non-aqueous electrolyte shown in Table 1 Alkyne derivatives, except that it was carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative example 1

After preparing a non-aqueous electrolytic solution in the same manner as in Example 1, it was carried out in the same manner as in Example 1 except that FEC and an alkyne derivative were not used. The results are shown in Table 1.

Comparative example 2-5

It carried out similarly to Example 1 except having set the conditions shown in Table 1 with respect to a nonaqueous electrolytic solution. The results are shown in Table 1.

Table 1

[Research on Additive Ratio]

Examples 13-16

After preparing the non-aqueous electrolytic solution in the same manner as in Example 1, add a predetermined amount of FEC shown in Table 2 relative to the non-aqueous electrolytic solution, and then add a predetermined amount of 2-butyne-1,4 as an alkyne derivative. - Glycol dicarboxylate was carried out in the same manner as in Example 1 except that. The results are shown in Table 2.

Table 2

[Study on Electrolyte Salt Ratio]

Examples 17-20

A non-aqueous solvent was prepared in the same manner as in Example 1, LiPF ₆ and LiBF ₄ were dissolved as electrolyte salts therein, so as to reach the specified concentrations shown in Table 3, and after the non-aqueous electrolyte was prepared, a relative non-aqueous electrolyte was added The same procedure as in Example 1 was performed except that the alkyne derivatives shown in Table 3 were further added to FEC at 2% by weight. The results are shown in Table 3.

Example 21

After dissolving LiPF ₆ and LiN(SO ₂ CF ₃ ) ₂ as electrolyte salts to concentrations of 0.9M and 0.1M, respectively, to prepare a non-aqueous electrolyte, use 1% by weight relative to the non-aqueous electrolyte as an alkyne 2-butyne-1,4-diol dicarboxylate of a hydrocarbon derivative was carried out in the same manner as in Example 17 except that. The results are shown in Table 3.

table 3

[Combined use of aromatic compounds]

Examples 22-26

Using 0.2% by weight bis(2-propynyl) oxalate as an alkyne derivative relative to the nonaqueous electrolytic solution, adding a prescribed amount of ethylene carbonate derivatives and aromatic compounds shown in Table 4, Except for this, it carried out similarly to Example 1. The results are shown in Table 4.

In addition, in Table 4, TAB means tertiary aminobenzene, CHB means cyclohexylbenzene, BP means biphenyl, FCHB means 1-fluoro-4-cyclohexylbenzene, and TBB means tert-butylbenzene.

Table 4

[Evaluation of Gas Generation Amount]

Examples 27-31

After preparing a non-aqueous electrolytic solution in the same manner as in Example 1, a cylindrical battery with a size of 18650 was prepared in the same manner as in Example 1, except that the specified amounts of ethylene carbonate derivatives and alkyne derivatives shown in Table 5 were used. .

Using this 18650 battery, after charging to 4.2V at a constant current of 2.2A (1C) at 60°C, charging was performed at a constant voltage of 4.2V as a cut-off voltage for a total of 3 hours. Then, it was discharged to a cut-off voltage of 3.0 V at a constant current of 2.2 A (1 C), and the charge and discharge were repeated, and the amount of gas generated in the battery after 100 cycles was measured by the Archimedes method. The results are shown in Table 5.

Comparative Examples 6-8

Using the same non-aqueous electrolytic solution as Comparative Examples 1-3, it carried out similarly to Example 27. The results are shown in Table 5.

table 5

Example 32

[Preparation of non-aqueous electrolyte solution]

Prepare a non-aqueous solvent of EC: MEC: DEC (capacity ratio) = 3: 4: 3, dissolve LiPF ₆ as an electrolyte salt in it to a concentration of 1M, and after preparing a non-aqueous electrolyte, add a relative non-aqueous The electrolytic solution was 2% by weight of fluoroethylene carbonate (FEC), and pentafluorophenylmethanesulfonate was added to make it 1% by weight relative to the nonaqueous electrolytic solution.

[Preparation of Lithium Secondary Battery and Measurement of Battery Characteristics]

An 18650-size cylindrical secondary battery (18 mm in diameter, 65 mm in height) was produced in the same manner as in Example 1.

This 18650 battery was charged to 4.2V at a constant current of 2.2A (1C) at normal temperature (20° C.), and then charged at a constant voltage of 4.2V as a cut-off voltage for a total of 3 hours. Thereafter, it was discharged to a cut-off voltage of 3.0 V at a constant current of 2.2 A (1 C), and this charging and discharging was repeated. The initial charge-discharge capacity is basically the same as that of the case (Comparative Example 9) without adding ethylene carbonate derivatives and pentafluorophenoxy compounds, and the battery characteristics after 300 cycles are: discharge when the initial discharge capacity is set to 100%. The capacity maintenance rate was 79.1%. The results are shown in Table 6.

Examples 33-36

In Example 32, it carried out similarly to Example 32 except having used the positive electrode and pentafluorophenoxy compound shown in Table 6. The results are shown in Table 6.

Comparative Example 9

After preparing a non-aqueous electrolytic solution in the same manner as in Example 32, it was carried out in the same manner as in Example 32 except that FEC and the pentafluorophenoxy compound were not used. The results are shown in Table 6.

Comparative Examples 10-13

With respect to the non-aqueous electrolytic solution, it carried out similarly to Example 32 except having set the conditions shown in Table 6. The results are shown in Table 6.

Table 6

[Research on Additive Ratio]

Examples 37-40

After preparing the non-aqueous electrolytic solution in the same manner as in Example 32, except adding the specified amount of FEC shown in Table 7 relative to the non-aqueous electrolytic solution, and then adding a specified amount of pentafluorophenyl methanesulfonate, the same as in Example 3 32 in the same manner. The results are shown in Table 7.

Table 7

[Study on Electrolyte Salt Ratio]

Examples 41-44

A non-aqueous solvent was prepared in the same manner as in Example 32, and LiPF ₆ and LiBF ₄ as electrolyte salts were dissolved therein so as to reach the specified concentrations shown in Table 8, thereby preparing a non-aqueous electrolyte, and then adding It carried out in the same manner as in Example 32 except that the FEC was 2% by weight and 1% by weight of pentafluorophenylmethanesulfonate was used with respect to the non-aqueous electrolytic solution. The results are shown in Table 8.

Example 45

After dissolving LiPF ₆ and LiN(SO ₂ CF ₃ ) ₂ as electrolyte salts to concentrations of 0.9M and 0.1M, respectively, to prepare a non-aqueous electrolyte, 2% by weight of FEC was added to the non-aqueous electrolyte, Furthermore, it carried out similarly to Example 41 except having used 1 weight% of pentafluorophenylmethanesulfonate with respect to a nonaqueous electrolytic solution. The results are shown in Table 8.

Table 8

[combined use with aromatic compound]

Examples 46-50

Using 0.5% by weight of pentafluorophenylmethanesulfonate with respect to the nonaqueous electrolytic solution, and adding predetermined amounts of ethylene carbonate derivatives and aromatic compounds shown in Table 9, it was the same as in Example 32 proceed. The results are shown in Table 9.

In addition, in Table 9, TAB means tertiary aminobenzene, CHB means cyclohexylbenzene, BP means biphenyl, TBB means t-butylbenzene, and FCHB means 1-fluoro-4-cyclohexylbenzene.

Table 9

[Evaluation of Gas Generation Amount]

Examples 51-54

After preparing the non-aqueous electrolytic solution in the same manner as in Example 1, 18650 sized cylindrical battery.

Using this 18650 battery, after charging to 4.2V at a constant current of 2.2A (1C) at 60°C, charging was performed at a constant voltage of 4.2V as a cut-off voltage for a total of 3 hours. Thereafter, the battery was discharged to a cutoff voltage of 3.0 V at a constant current of 2.2 A (1 C), the charge and discharge were repeated, and the amount of gas generated in the battery after 300 cycles was measured by the Archimedes method. The results are shown in Table 10.

Comparative Examples 14-16

Using the same non-aqueous electrolytic solution as in Comparative Examples 9 to 11, it was carried out in the same manner as in Example 51. The results are shown in Table 10.

Table 10

By using the non-aqueous electrolytic solution of the present invention, it is possible to obtain a lithium secondary battery that is excellent in battery characteristics such as electric capacity, cycle characteristics, and storage characteristics, and that can exhibit excellent battery performance for a long period of time. In addition, the obtained lithium secondary battery can be suitably used as a cylindrical battery, a prismatic battery, a button battery, a laminated battery, and the like.

Claims (5)

1, a kind of secondary lithium batteries nonaqueous electrolytic solution, it is the nonaqueous electrolytic solution that has dissolved electrolytic salt in nonaqueous solvents, it is characterized in that, in this nonaqueous electrolytic solution, contain that: (A) by the ethylene carbonate derivative of following general formula (I) expression and 0.01～10 weight % of 0.1～10 weight % contains the compound of triple bond and/or (B) by the phenyl-pentafluoride oxo-compound of following general formula (X) expression;

In formula (I), R ¹～R ³Represent that independently of one another hydrogen atom, halogen atom, carbon number are that 2～12 alkenyl, carbon number are that 2～12 alkynyl or carbon number are 6～18 aryl; Wherein do not comprise ethylene carbonate;

In formula (X), R ¹⁵The expression carbon number is that 2～12 alkyl-carbonyl, carbon number are that 2～12 alkoxy carbonyl, carbon number are that 7～18 aryloxycarbonyl or carbon number are 1～12 alkanesulfonyl; Wherein, R ¹⁵In the hydrogen atom that has at least 1 is that 6～18 aryl replaces or is not substituted by halogen atom or carbon number;

Wherein, the compound that contains triple bond is the alkynes derivative more than a kind by following general formula (II)～(VII) expression;

In formula (II)～(V), R ⁴～R ¹⁰Represent hydrogen atom independently of one another, carbon number is 1～12 alkyl, and carbon number is that 3～6 cycloalkyl or carbon number are 6～12 aryl, perhaps, and R ⁵And R ⁶, with and/or R ⁷And R ⁸The formation carbon number that is bonded to each other is 3～6 cycloalkyl; Y ¹And Y ²Expression-COOR ¹⁰,-COR ¹⁰Or SO ₂R ¹⁰, identical or inequality; X represents 1 or 2 integer;

In formula (VI), R ¹¹～R ¹³Represent hydrogen atom independently of one another, carbon number is 1～12 alkyl, and carbon number is that 3～6 cycloalkyl, carbon number are that 6～12 aryl or carbon number are 7～12 aralkyl, perhaps R ¹²And R ¹³The formation carbon number that is bonded to each other is 3～6 cycloalkyl; W represents sulfoxide group, sulfo group or oxalyl group, Y ³The expression carbon number is that 1～12 alkyl, alkenyl, alkynyl, carbon number are that 3～6 cycloalkyl, carbon number are that 6～12 aryl or carbon number are 7～12 aralkyl; X is identical with the front definition;

In formula (VII), R ⁴Identical with the front definition, R ¹⁴The expression carbon number is that 1～12 alkyl, carbon number are that 3～6 cycloalkyl or carbon number are 6～12 aryl; P represents 1 or 2 integer.

2, secondary lithium batteries nonaqueous electrolytic solution according to claim 1, wherein, ethylene carbonate derivative is fluoroethylene carbonate and/or vinylethylene carbonate.

3, according to claim described 1 or 2 described secondary lithium batteries nonaqueous electrolytic solutions, wherein, the weight that also contains with respect to nonaqueous electrolytic solution is the aromatic compound of 0.1～5 weight %.

4, a kind of lithium secondary battery, it comprises: positive pole, negative pole and the nonaqueous electrolytic solution that is obtained by dissolving electrolytic salt in nonaqueous solvents, it is characterized in that, in nonaqueous electrolytic solution, contain that: (A) by the ethylene carbonate derivative of general formula (I) expression and 0.01～10 weight % of 0.1～10 weight % contains the compound of triple bond and/or (B) by the phenyl-pentafluoride oxo-compound of general formula (X) expression;

In formula (I), R ¹～R ³Represent that independently of one another hydrogen atom, halogen atom, carbon number are that 2～12 alkenyl, carbon number are that 2～12 alkynyl or carbon number are 6～18 aryl; Wherein do not comprise ethylene carbonate;

In formula (X), R ¹⁵The expression carbon number is that 2～12 alkyl-carbonyl, carbon number are that 2～12 alkoxy carbonyl, carbon number are that 7～18 aryloxycarbonyl or carbon number are 1～12 alkanesulfonyl; Wherein, R ¹⁵In the hydrogen atom that has at least 1 is that 6～18 aryl replaces or is not substituted by halogen atom or carbon number.

5, lithium secondary battery according to claim 4, wherein, positive pole is the material that comprises lithium composite xoide, negative pole is the material that comprises graphite.