JP2019153541A - Nonaqueous electrolyte solution and nonaqueous electrolyte solution battery using the same - Google Patents

Abstract

To provide a nonaqueous electrolyte solution superior in the rate characteristic after an endurance test, and a nonaqueous electrolyte solution battery using the nonaqueous electrolyte solution.SOLUTION: A nonaqueous electrolyte solution comprises: an electrolyte; a nonaqueous solvent; an aromatic carboxylic acid ester represented by the formula (1); and adiponitrile. (In the formula (1), Ris a saturated carbon hydride group with 1-12 carbon atoms, which may have a substituent group; Rand Rindependently represent a fluorine atom or a carbon hydride group with 1-12 carbon atoms, which may have a substituent group, and which may be bonded to each other to form a ring; A represents a carbon hydride group with 1-12 carbon atoms, an alkoxy group with 1-12 carbon atoms, a fluorine atom or a substituent group including a fluorine atom; m is an integer of 1-5.)SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery using the same.

  Non-aqueous electrolyte batteries such as lithium secondary batteries are being put to practical use in a wide range of applications from so-called consumer power sources such as mobile phones and notebook computers to in-vehicle power sources for automobiles and the like. However, the demand for higher performance of non-aqueous electrolyte batteries in recent years has been increasing, and in particular, various battery characteristics such as high capacity, low temperature use characteristics, high temperature storage characteristics, cycle characteristics, and overcharge safety. Improvement is demanded.

  The electrolyte used for a non-aqueous electrolyte battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

In order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, etc. of these non-aqueous electrolyte batteries, and to improve battery safety during overcharge, various studies have been conducted on non-aqueous solvents, electrolytes, and additives. Has been made.
Patent Documents 1 and 2 propose a method of adding various aromatic compounds such as aromatic carboxylic acid esters to an electrolyte together with other additives, which solves the problem of safety improvement and durability during overcharge to some extent. It is disclosed.

International Publication No. 2015/111676 JP 2015-18667 A

According to the study by the present inventors, aromatic ester compounds such as those described in Patent Documents 1 and 2 have a lower oxidation potential than other electrolyte constituent materials, and therefore, within the normal battery operating range. It was found that the film was oxidized to form a film on the positive electrode and became a resistance component. When such an aromatic ester compound is used in combination with a positive electrode protective agent such as succinonitrile, the oxidation is suppressed to some extent. However, the capacity and rate characteristics after the endurance test are lowered, and the battery is still satisfactory. It was not a thing.
In view of the above problems, an object of the present invention is to provide a non-aqueous electrolyte solution having excellent rate characteristics after a battery durability test while using an aromatic ester, and a non-aqueous electrolyte battery using the non-aqueous electrolyte solution. .

The present inventors have solved the above problem by including an aromatic carboxylic acid ester having a specific substituent on the benzene ring and bonded to an ester group through a specific structure, and adiponitrile in a non-aqueous electrolyte. The inventors have found that this can be solved, and have completed the present invention.
That is, the gist of the present invention is as follows.

[1] A non-aqueous electrolyte solution for a non-aqueous electrolyte battery including a positive electrode and a negative electrode capable of inserting and extracting metal ions, and the non-aqueous electrolyte solution is represented by the following formula (1) together with an electrolyte and a non-aqueous solvent. A non-aqueous electrolyte containing an aromatic carboxylic acid ester and further containing adiponitrile.

(In Formula (1), R ¹ represents a C1-C12 saturated hydrocarbon group which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. Or a hydrocarbon group having 1 to 12 carbon atoms which may be bonded to each other to form a ring, and A may be a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. A C1-C12 alkoxy group, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A may be the same as each other They may be different from each other, and two A may be bonded to each other to form a ring condensed with the benzene ring having A.)

[2] In the formula (1), A is a hydrocarbon group having 4 to 12 carbon atoms, and the carbon atom bonded to the benzene ring of the hydrocarbon group is a quaternary carbon atom. The non-aqueous electrolyte solution according to [1].

[3] The nonaqueous electrolytic solution according to [1], wherein A in the formula (1) is a fluorine atom or a substituent containing a fluorine atom.

[4] In the above formula (1), R ² and R ³ are each independently a hydrocarbon group having 1 to 12 carbon atoms, according to any one of [1] to [3] Aqueous electrolyte.

[5] Any of [1] to [4], wherein the aromatic carboxylic acid ester represented by the formula (1) is contained in a non-aqueous electrolyte solution in an amount of 0.001 to 10% by mass. A non-aqueous electrolyte solution according to claim 1.

[6] The non-aqueous electrolyte solution according to any one of [1] to [5], wherein 0.001 to 10% by mass of the adiponitrile is contained in the non-aqueous electrolyte solution.

[7] The nonaqueous electrolytic solution according to any one of [1] to [6], wherein the nonaqueous electrolytic solution further contains at least one compound selected from cyclic carbonates having fluorine atoms. liquid.

[8] The nonaqueous electrolytic solution further contains at least one compound selected from cyclic carbonates having a carbon-carbon unsaturated bond, according to any one of [1] to [7]. Non-aqueous electrolyte.

[9] A nonaqueous electrolyte battery comprising a positive electrode and a negative electrode, and the nonaqueous electrolyte solution according to any one of [1] to [8].

  ADVANTAGE OF THE INVENTION According to this invention, the non-aqueous electrolyte solution which can implement | achieve the non-aqueous electrolyte battery excellent in the rate characteristic after an endurance test, and a non-aqueous electrolyte battery using the same are provided.

  Hereinafter, the present invention will be described in detail. The following description is an example (representative example) of the present invention, and the present invention is not limited thereto. In addition, the present invention can be implemented with any modifications without departing from the scope of the invention.

[Non-aqueous electrolyte]
The non-aqueous electrolyte solution of the present invention is a non-aqueous electrolyte solution for a non-aqueous electrolyte battery comprising a positive electrode and a negative electrode capable of occluding and releasing metal ions, and the non-aqueous electrolyte solution together with the electrolyte and the non-aqueous solvent is described below. It contains an aromatic carboxylic acid ester represented by the formula (1) (hereinafter sometimes referred to as “aromatic carboxylic acid ester (1)”), and further contains adiponitrile.

(In Formula (1), R ¹ represents a C1-C12 saturated hydrocarbon group which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. Or a hydrocarbon group having 1 to 12 carbon atoms which may be bonded to each other to form a ring, and A may be a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. A C1-C12 alkoxy group, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A may be the same as each other They may be different from each other, and two A may be bonded to each other to form a ring condensed with the benzene ring having A.)

  In the nonaqueous electrolytic solution of the present invention, the aromatic carboxylic acid ester (1) is bonded to the benzene ring having a specific substituent and the carbonyl group side of the ester group via a carbon atom having no hydrogen atom. The hydrocarbon group bonded to the ether oxygen of the ester group is a saturated hydrocarbon group. Aromatic carboxylic acid ester (1) is an aromatic compound having a substituent, so that it is oxidized on the positive electrode that is in a high potential state during overcharge, and is reduced on the negative electrode during the initial charge of the battery, adversely affecting the battery characteristics. However, in the aromatic carboxylic acid ester (1) used in the present invention, the ester group is bonded to the benzene ring via a carbon atom having no hydrogen atom, and a saturated hydrocarbon group is bonded to ether oxygen. Reduction is suppressed. In addition, the introduction of a specific substituent on the benzene ring makes it difficult for a continuous oxidation reaction to occur, thereby improving the rate characteristics after the battery durability test.

  Further, by allowing adiponitrile to coexist in the non-aqueous electrolyte, it is coordinated to the metal oxide of the positive electrode by two cyano groups, and the oxidation of the aromatic carboxylic acid ester (1) is suppressed during the durability test. Even with the same dinitrile, succinonitrile having a smaller number of carbon atoms is not sufficiently coordinated with the positive electrode oxide, has little interaction with the aromatic carboxylic acid ester (1), and is considered to have little effect of suppressing oxidation. . Therefore, by using the aromatic carboxylic acid ester (1) and adiponitrile in combination, the capacity and rate characteristics after the high-temperature storage durability test can be improved without deteriorating the characteristics of the energy device.

[Aromatic carboxylic acid ester (1)]
The non-aqueous electrolyte solution of the present invention contains an aromatic carboxylic acid ester (1). In the aromatic carboxylic acid ester (1) represented by the formula (1), cis-trans isomers and optical isomers cannot be distinguished, and either isomer alone or a mixture thereof It can also be applied.

In the formula (1), R ¹ is not particularly limited as long as it is a saturated hydrocarbon group having 1 to 12 carbon atoms, and a cyclic structure may be used regardless of whether it is a linear saturated hydrocarbon group or a branched saturated hydrocarbon group. It may have one or may have a substituent.
The saturated hydrocarbon group for R ¹ is not particularly limited, but the carbon number thereof is 1 to 12, preferably 8 or less, more preferably 5 or less, further preferably 2 or less, and most preferably 1.

As the saturated hydrocarbon group for R ¹ , from the viewpoint of low reactivity, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl Group, n-pentyl group, isopentyl group, sec-pentyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, etc. From the viewpoint of low steric hindrance and high solubility, a methyl group or an ethyl group having 1 to 2 carbon atoms is more preferable, and the viewpoint of being less reactive to intramolecular oxygen and being less reactive To methyl group is more preferable.

When the saturated hydrocarbon group of R ¹ has a substituent, examples of the substituent include those exemplified as the substituents that R ² and R ³ described later may have, but are reduced in the battery. From the viewpoint of not inhibiting the charge / discharge reaction, R ¹ preferably does not have these substituents.

In formula (1), R ² and R ³ are each independently a fluorine atom or an optionally substituted hydrocarbon group having 1 to 12 carbon atoms, and R ² and R ³ are bonded to each other. May form a ring.
When the hydrocarbon group of R ² and R ³ has a substituent, specific examples of the substituent include a fluorine atom; an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, which may be substituted with a fluorine atom, Examples include hydrocarbon groups such as aryl groups; cyano groups, isocyanato groups, ether groups, carbonate groups, carbonyl groups, carboxyl groups, sulfonyl groups, phosphantriyl groups, and phosphoryl groups.

From the viewpoint of solubility in the electrolytic solution, R ² and R ³ are each independently preferably a fluorine atom, an alkyl group which may be substituted with a fluorine atom, or an aryl group which may be substituted with a fluorine atom. Preferred are a fluorine atom and an alkyl group which may be substituted with a fluorine atom, and more preferred is an alkyl group which is not substituted with a fluorine atom.

In the case R ² and R ³ is a hydrocarbon group, although the kind thereof is not particularly limited, the number of carbon atoms from 1 to 12, preferably 10 or less, more preferably 4 or less.

Specific hydrocarbon groups for R ² and R ³ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, and tert-butyl group. An alkyl group having 1 to 4 carbon atoms which may be substituted with a fluorine atom such as trifluoromethyl group; vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl Group, an alkenyl group having 2 to 4 carbon atoms such as 3-butenyl group; an ethynyl group, 1-propynyl group, 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group and the like having 2 to 2 carbon atoms An alkynyl group of 4; an alkyl group having an aromatic group such as a benzyl group or a phenethyl group as a substituent; a phenyl group, a tolyl group, an ethylphenyl group, an n-propylphenyl group, an i-propylphenyl group, -Butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, fluorophenyl group, trifluoromethylphenyl group, xylyl group, methoxyphenyl group, ethoxyphenyl group, trifluoromethoxyphenyl group, etc. Examples of the substituent include a fluorine atom, an alkyl group, a fluoroalkyl group, an alkoxy group, and an aryl group which may have one or more of fluoroalkyl groups.

  Of these, substituted with fluorine atoms such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl, tert-butyl, trifluoromethyl, etc. C1-C4 alkyl group, phenyl group, tolyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i- An aryl group having 10 or less carbon atoms which may have a substituent such as a butylphenyl group, a tert-butylphenyl group, a fluorophenyl group, or a trifluoromethylphenyl group is preferred, and a methyl group, an ethyl group, or an n-propyl group is preferable. Group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group and other alkyl groups having 1 to 4 carbon atoms. Preferred, more preferably a methyl group or an ethyl group.

When R ² and R ³ are bonded to each other to form a ring, the ring formed by R ² and R ³ and the carbon atom to which R ² and R ³ are bonded specifically includes a cyclopropane ring and a cyclobutane A ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and the like, preferably a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring, more preferably a cyclopentane ring and a cyclohexane ring, and still more preferably. Cyclopentane ring.

  In formula (1), A is a substituent on the phenyl group, and is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a fluorine atom, or a substituent containing a fluorine atom. When A is a substituent containing a fluorine atom, the substituent is preferably a hydrocarbon group, and the hydrocarbon group is a hydrocarbon group having 1 to 12 carbon atoms exemplified as the hydrocarbon group of A. Preferably there is.

  That is, A is usually a fluorine atom, a hydrocarbon group having 1 to 12 hydrocarbon groups, an alkoxy group having 1 to 12 carbon atoms, or a hydrocarbon group having 1 to 12 carbon atoms substituted with a fluorine atom. From the viewpoint of being reduced in the battery and not inhibiting the charge / discharge reaction. As the hydrocarbon group of the hydrocarbon group substituted with a fluorine atom, those exemplified as the hydrocarbon group of A exemplified below are preferable.

When A is a hydrocarbon group, the type thereof is not particularly limited, and may be linear, branched, or cyclic, but has 1 to 12 carbon atoms. Preferably, it is 2 or more, more preferably 3 or more, preferably 9 or less, more preferably 6 or less, and still more preferably 4 or less.
Examples of the hydrocarbon group for A include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group. Of these, an alkyl group and an aryl group are preferable, and an alkyl group is more preferable.

Specific hydrocarbon groups include alkyl such as methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, i-butyl, tert-butyl, and cyclohexyl groups. Group: vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group and the like alkenyl groups; ethynyl group, 1-propynyl group, 2-propynyl group , Alkynyl groups such as 1-butynyl group, 2-butynyl group, 3-butynyl group;
Phenyl group, tolyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, cyclohexylphenyl group, An aryl group optionally having an alkyl group or an alkoxy group as a substituent such as a xylyl group, a methoxyphenyl group or an ethoxyphenyl group;
An alkyl group having an aryl group as a substituent such as a benzyl group or a phenethyl group;
Etc.
Alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group; phenyl group, tolyl An alkyl group as a substituent such as a group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, etc. An aryl group having 10 or less carbon atoms, which may be
Alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group and tert-butyl group are more preferable,
A hydrocarbon group having a quaternary carbon atom bonded to the benzene ring is preferable from the viewpoint of suppressing a reaction in the normal operating range of the battery. Among these alkyl groups having a quaternary carbon atom, a tert-butyl group is particularly preferable. preferable.

  The alkoxy group having 1 to 12 carbon atoms which may be substituted with a fluorine atom of A is preferably an alkoxy group having 1 to 4 carbon atoms which may be substituted with a fluorine atom, and more preferably 1 carbon atom. It is an alkoxy group of ~ 4. Specific examples thereof include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, monofluoromethoxy group, difluoromethoxy group, trifluoromethoxy group. Groups and the like.

Examples of the fluorine atom of A or a substituent containing a fluorine atom include a fluorine atom, a fluorinated alkyl group, a fluorinated alkenyl group, a fluorinated alkoxy group, and a fluorinated aryl group. Of these, a fluorine atom, a fluorinated alkyl group, and a fluorinated aryl group are preferable, and a fluorine atom is more preferable.
Specific examples of the fluorine atom and the hydrocarbon group containing a fluorine atom include a fluorine atom; monofluoromethyl group, difluoromethyl group, trifluoromethyl group, monofluoroethyl group, difluoroethyl group, trifluoroethyl group, tetrafluoroethyl. Group, fluorinated alkyl group such as pentafluoroethyl group; fluorinated alkenyl group such as monofluorovinyl group, difluorovinyl group, trifluorovinyl group; monofluorophenyl group, 2-fluorotolyl group, 3-fluorotolyl group, And fluoroaryl groups such as 4-fluorotolyl group and trifluoromethylphenyl group,
Fluorine atom, trifluoromethyl group, monofluorophenyl group, 2-fluorotolyl group, 3-fluorotolyl group, 4-fluorotolyl group, trifluoromethylphenyl group and the like are preferable,
More preferred is a fluorine atom.

  In formula (1), m representing the number of A is 1 to 5, preferably 1 to 3, more preferably 1 to 2, and even more preferably 1 from the viewpoint of solubility. When m is 2 or more, the plurality of A may be the same or different. Two A's may be bonded to each other to form a ring condensed with a benzene ring. In this case, examples of the ring condensed with the benzene ring include a cyclohexane ring, a cyclopentane ring, a 2-methyl-2-phenyl-4,4-dimethylcyclopentane ring, and a benzene ring.

  The substitution position of A substituted on the benzene ring in formula (1) is preferably the 2-position, the 3-position or the 4-position when the carbon atom substituted by the group having an ester group is the 1-position, and is overcharged. The 4th position is preferred from the viewpoint of reactivity at the time.

Specific examples of the aromatic carboxylic acid ester (1) include compounds having the following substituents in the formula (1).
R ¹ is methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl. A group selected from a group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group,
R ² and R ³ are each independently a fluorine atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group, trifluoro C1-C4 alkyl group such as methyl group, phenyl group, tolyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butyl A phenyl group, a tert-butylphenyl group, a fluorophenyl group, a trifluoromethylphenyl group, or a group selected from those in which R ² and R ³ are bonded to each other to form a cyclobutane ring, a cyclopentane ring, or a cyclohexane ring; Yes,
A is an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, and tert-butyl group, phenyl Group, tolyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, fluorine atom, trifluoro A group selected from a methyl group, a monofluorophenyl group, a 2-fluorotolyl group, a 3-fluorotolyl group, a 4-fluorotolyl group, a trifluoromethylphenyl group, and a trifluoromethoxyphenyl group;
m is 1 to 3 (when m is 2 to 3, 2 to 3 A may be the same or different),
A is substituted at the 2-position, 3-position, and 4-position of the benzene ring.

Among these, from the viewpoint of solubility and durability, the aromatic carboxylic acid ester (1) is more preferably a compound in which each substituent in the formula (1) is as follows.
R ^{1 is a} methyl group or an ethyl group.
R ² and R ³ : fluorine atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group, R ² and R ³ Are groups selected from a cyclopentane ring and a cyclohexane ring which are bonded to each other to form a ring.
A: a group selected from a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group, a tert-butyl group, and a fluorine atom, and m = 1 Or when m = 2, A may be the same or different and is substituted at the 2-position, 3-position or 4-position of the benzene ring.

  As aromatic carboxylic acid ester (1), the following compounds are more preferable.

  The aromatic carboxylic acid ester (1) is most preferably the following compound.

  The aromatic carboxylic acid ester (1) may be used alone or in combination of two or more.

  The proportion of the aromatic carboxylic acid ester (1) in the non-aqueous electrolyte solution of the present invention is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably. Is 0.3% by mass or more, usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and particularly preferably 1.0% by mass or less. . When the content of the aromatic carboxylic acid ester (1) in the non-aqueous electrolytic solution is within the above range, the effect of the present invention can be easily achieved, and an increase in battery resistance can be prevented.

[Adiponitrile]
The non-aqueous electrolyte of the present invention further contains adiponitrile in addition to the aromatic carboxylic acid ester (1).
The proportion of adiponitrile in the non-aqueous electrolyte of the present invention is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.3% by mass or more. Moreover, it is 10 mass% or less normally, Preferably it is 8 mass% or less, More preferably, it is 5 mass% or less, More preferably, it is 3 mass% or less, Most preferably, it is 1.0 mass% or less. When the content of adiponitrile in the nonaqueous electrolytic solution is within the above range, the effect of the present invention is easily exhibited, and an increase in battery resistance can be prevented.

[Cyclic carbonate having a fluorine atom]
The non-aqueous electrolyte of the present invention contains a cyclic carbonate having a fluorine atom (hereinafter sometimes referred to as “fluorinated cyclic carbonate”) in addition to the aromatic carboxylic acid ester (1) and adiponitrile. In addition, the battery performance can be further improved by including a fluorinated cyclic carbonate.
The fluorinated cyclic carbonate contained in the non-aqueous electrolyte of the present invention is not particularly limited as long as it is a cyclic carbonate having a fluorine atom, and may or may not have an unsaturated bond. .

  Examples of the fluorinated cyclic carbonate include fluorinated cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, and derivatives thereof. For example, a fluorinated ethylene carbonate (hereinafter referred to as “fluorinated ethylene carbonate”). And derivatives thereof. Examples of the derivatives of fluorinated ethylene carbonate include fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Of these, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferred.

In particular,
Monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methyl Ethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate, 4- (fluoro Methyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene Boneto, 4,4-difluoro-5,5-dimethylethylene carbonate.

  Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate gives high ionic conductivity and suitably forms an interface protective film. And more preferable.

  In addition, these fluorinated cyclic carbonates may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  Moreover, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes referred to as “fluorinated unsaturated cyclic carbonate”) as the fluorinated cyclic carbonate. The number of fluorine atoms contained in the fluorinated unsaturated cyclic carbonate is not particularly limited as long as it is 1 or more. Among them, the fluorine atom is usually 6 or less, preferably 4 or less, and most preferably 1 or 2.

Examples of the fluorinated unsaturated cyclic carbonate include a fluorinated vinylene carbonate derivative, a fluorinated ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon double bond.
Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- And vinyl vinylene carbonate.

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

  Among them, particularly preferred fluorinated unsaturated cyclic carbonates for use in combination with the aromatic carboxylic acid ester (1) and adiponitrile include 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5- Vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro-4-allyl ethylene carbonate, 4-fluoro-5-vinyl ethylene carbonate, 4-fluoro-5- Allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene Carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5 -Diallyl ethylene carbonate is more preferably used because it forms a stable interface protective coating.

The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the fluorinated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will be easy to be expressed.
The production method of the fluorinated unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

  In addition, these fluorinated unsaturated cyclic carbonates may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

  When the nonaqueous electrolytic solution of the present invention contains a fluorinated cyclic carbonate, the content of the fluorinated cyclic carbonate (total amount in the case of two or more) in the nonaqueous electrolytic solution is 0.001% by mass or more, preferably 0.01 mass% or more, more preferably 0.1 mass% or more, further preferably 0.2 mass% or more, particularly preferably 0.5 mass% or more, and 10 mass% or less, preferably 5 It is at most 4% by mass, more preferably at most 3% by mass, particularly preferably at most 2% by mass.

The fluorinated cyclic carbonate can also be used as a non-aqueous solvent. In that case, the content in the non-aqueous electrolyte is 100% by volume of the non-aqueous solvent, preferably 1% by volume or more, more preferably 5% by volume. More preferably, it is 10% by volume or more, preferably 50% by volume or less, more preferably 35% by volume or less, and still more preferably 25% by volume or less.
If it is within this range, the energy device is likely to exhibit a sufficient cycle characteristics improvement effect, and it is easy to avoid a situation in which the high temperature storage characteristics are deteriorated, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. .

[Cyclic carbonate having a carbon-carbon unsaturated bond]
The non-aqueous electrolyte solution of the present invention contains a cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter sometimes abbreviated as “unsaturated cyclic carbonate”) in addition to the aromatic carboxylic acid ester (1) and adiponitrile. The battery performance may be further improved by including an unsaturated cyclic carbonate.

  The unsaturated cyclic carbonate contained in the nonaqueous electrolytic solution of the present invention is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond, and any unsaturated cyclic carbonate is used. be able to. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate. Examples of unsaturated cyclic carbonates include vinylene carbonates, aromatic carbonates, ethylene carbonates substituted with a substituent having a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, Catechol carbonates etc. are mentioned.

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

  Specific examples of the ethylene carbonate substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond include vinyl ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5- Vinyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, 4-allyl -5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate Over DOO, 4,5 diallyl carbonate, 4-methyl-5-allyl carbonate and the like.

  Among them, particularly preferred unsaturated cyclic carbonates for use in combination with the aromatic carboxylic acid ester (1) and adiponitrile are vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl. Vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, allyl ethylene carbonate, 4,5-diallyl ethylene carbonate, 4 -Methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4 Methyl-5-ethynyl ethylene carbonate include 4-vinyl-5-ethynyl-ethylene carbonate. Vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate are particularly preferable because they form a more stable interface protective film.

  The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 86 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 86 or more and 150 or less. The production method of the unsaturated cyclic carbonate is not particularly limited, and can be produced by arbitrarily selecting a known method.

  An unsaturated cyclic carbonate may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios.

  When the non-aqueous electrolyte of the present invention contains an unsaturated cyclic carbonate, the content is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the unsaturated cyclic carbonate is 100% by mass of the non-aqueous electrolyte solution, preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more. Moreover, Preferably it is 5 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less. Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.

[Nonaqueous solvent]
The non-aqueous electrolyte solution of the present invention usually contains a non-aqueous solvent that dissolves an electrolyte described later as a main component, as in the case of a general non-aqueous electrolyte solution. There is no restriction | limiting in particular about the nonaqueous solvent used here, A well-known organic solvent can be used. The organic solvent preferably includes at least one selected from saturated cyclic carbonate, chain carbonate, chain carboxylic acid ester, cyclic carboxylic acid ester, ether compound, and sulfone compound, but is not particularly limited thereto. . These can be used alone or in combination of two or more.

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

  When the non-aqueous electrolytic solution of the present invention contains a saturated cyclic carbonate as a non-aqueous solvent, the content is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the content is usually 3% by volume or more, preferably 5% by volume or more, in 100% by volume of the nonaqueous solvent. By setting this range, it is possible to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and to make the large current discharge characteristics, stability to the negative electrode, and cycle characteristics of the power storage device within a favorable range. . Moreover, an upper limit is 90 volume% or less normally, Preferably it is 85 volume% or less, More preferably, it is 80 volume% or less. By setting this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the input / output characteristics of the electricity storage device are further improved, and the durability such as cycle characteristics and storage characteristics is improved. It is preferable because it can be further improved.

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

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

  A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  When the non-aqueous electrolyte of the present invention contains a chain carbonate as a non-aqueous solvent, the content is not particularly limited, but is usually 15% by volume or more, preferably 20% by volume or more in 100% by volume of the non-aqueous solvent. More preferably, the content is 25% by volume or more. Moreover, it is 90 volume% or less normally, Preferably it is 85 volume% or less, More preferably, it is 80 volume% or less. By setting the content of the chain carbonate within the above range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, and the decrease in ionic conductivity is suppressed, and thus the input / output characteristics and charge / discharge rate characteristics of the electricity storage device are excellent. It becomes easy to be a range. In addition, a decrease in electrical conductivity resulting from a decrease in the dielectric constant of the non-aqueous electrolyte solution can be avoided, and the input / output characteristics and charge / discharge rate characteristics of the electricity storage device can be easily set in a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula. Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate. Among these, the viscosity of methyl acetate, ethyl acetate, acetate-n-propyl, acetate-n-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoints of improvement in ion conductivity due to a decrease and suppression of battery swelling during a durability test such as cycling and storage.

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

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms are preferable.

  Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl Ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2, 2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl -N-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro Olo-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2 , 2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3 -Fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) ) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) Ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3 , 3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, ( 3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3 3,3-triflu (Ro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-penta Fluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2,3 3,3-pentafluoro-n-propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2 -Fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fur Roethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) ( 2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2, 2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ) Ethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroeth) Xyl) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2 -Fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2, 2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) Ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. And the like.

  Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.

  Among these, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions, and lithium ion dissociation properties It is preferable at the point which improves. Particularly preferred are dimethoxymethane, diethoxymethane, and ethoxymethoxymethane because they have low viscosity and give high ionic conductivity.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.

  Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

  The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter sometimes abbreviated as “sulfolane” including sulfolane). As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable.

  Among these, 2-methyl sulfolane, 3-methyl sulfolane, 2-fluoro sulfolane, 3-fluoro sulfolane, 2,2-difluoro sulfolane, 2,3-difluoro sulfolane, 2,4-difluoro sulfolane, 2,5-difluoro Sulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3 -Methyl sulfolane, 4-fluoro-2-methyl sulfolane, 5-fluoro-3-methyl sulfolane, 5-fluoro-2-methyl sulfolane, 2-fluoromethyl sulfolane, 3-fluoromethyl sulfolane, 2-difluoromethyl sulfolane, 3 -Difluoromethylsulfola 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoro Methyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output.

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

  Among these, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl Methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl Pentafluoroethylsulfone, trifluoromethyl-n-propylsulfone, trifluoromethylisopropylsulfone , Trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, trifluoromethyl-n-butylsulfone, trifluoromethyl-t-butylsulfone, etc. are preferable in terms of high ionic conductivity and high input / output. .

[Electrolytes]
The non-aqueous electrolyte solution of the present invention usually contains an electrolyte. In particular, when the non-aqueous electrolyte of the present invention is a lithium ion secondary battery, a lithium salt is usually included. The following lithium salt (A) is used to increase the ionic conductivity of the non-aqueous electrolyte, and lithium salts other than the lithium salt (A) are used to further improve the desired performance of the non-aqueous electrolyte of the present invention. (B) can also be used. Moreover, when using the non-aqueous electrolyte solution of this invention for a sodium ion secondary battery, it is preferable to use the sodium salt which replaced the lithium ion with the sodium ion about each of the lithium salt illustrated below.

The lithium salt which can be used in the non-aqueous electrolyte solution of the present invention (A), for _{example, LiClO 4, LiBF 4, LiPF} 6, LiAsF 6, LiTaF 6 , and the like. Among these, it is preferable to include at least one of LiBF ₄ and LiPF ₆ . Moreover, lithium salt (A) may be used only by 1 type, and may be used in combination of 2 or more types.

  When the non-aqueous electrolyte solution of the present invention contains a lithium salt (A), the content thereof is preferably 0.5 mol / L or more, more preferably 0.6 mol / L or more with respect to the non-aqueous solvent, More preferably, it is 0.7 mol / L or more, on the other hand, preferably 3 mol / L or less, more preferably 2 mol / L or less, still more preferably 1.8 mol / L or less. When the content of the lithium salt (A) is within the above range, the ionic conductivity can be appropriately increased.

As the lithium salt can be used in the non-aqueous electrolyte solution of the present invention _{(B), LiCF 3 SO 3} , LiC 4 F 9 SO 3, Li (CF 3 SO 2) 2 N, Li (C 2 F 5 _{SO 2) 2 N, Li (} CF 3) SO 2) 3 C, LiBF 3 (C 2 F 5), LiB (C 2 O 4) 2, LiB (C 6 F 5) 4, LiPF 3 (C 2 F ₅ ) ₃ , LiPO ₂ F ₂ , LiFSO _{3 and the} like. These may be used alone or in combination of two or more.

  When the non-aqueous electrolyte solution of the present invention contains a lithium salt (B), the content thereof is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the non-aqueous solvent. On the other hand, it is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the content of the lithium salt (B) is within the above range, the ionic conductivity can be appropriately increased.

  In addition, there is no restriction | limiting in particular as a method of measuring content of the lithium salt quoted above, A well-known method can be used arbitrarily. Examples of such a method include ion chromatography and F magnetic resonance spectroscopy.

[Other additives]
In addition to the various compounds listed above, the non-aqueous electrolyte solution of the present invention includes, as a storage property improver, malononitrile, succinonitrile, glutaronitrile, pimelonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile. Compounds having a cyano group other than adiponitrile, such as 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-phenylene diisocyanate, 1,4 A diisocyanate compound such as -phenylene diisocyanate, 1,2-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene; Acrylic anhydride, 2 Methylacrylic anhydride, 3-methylacrylic anhydride, benzoic anhydride, 2-methylbenzoic anhydride, 4-methylbenzoic anhydride, 4-tert-butylbenzoic anhydride, 4-fluorobenzoic acid Auxiliaries such as carboxylic anhydride compounds such as anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, methoxyformic anhydride, ethoxyformic anhydride; cyclohexylbenzene as an overcharge inhibitor , T-butylbenzene, t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, diphenyl ether, dibenzofuran, etc. it can. These compounds may be used in appropriate combination.

[Non-aqueous electrolyte battery]
The non-aqueous electrolyte solution of the present invention, the positive electrode, and the negative electrode can be used as a non-aqueous electrolyte solution (hereinafter sometimes referred to as “non-aqueous electrolyte battery of the present invention”). Examples of the non-aqueous electrolyte battery include a lithium ion secondary battery and a sodium ion secondary battery, but a lithium ion secondary battery is preferable. A lithium ion secondary battery usually has a non-aqueous electrolyte solution of the present invention, a current collector and a positive electrode active material layer provided on the current collector, a positive electrode capable of inserting and extracting lithium ions, and a current collector. And a negative electrode active material layer provided on the current collector, and a negative electrode capable of inserting and extracting lithium ions.

[Positive electrode]
The positive electrode used for the non-aqueous electrolyte battery of the present invention usually contains a composite oxide, a polyanion compound, a fluoride and the like. The positive electrode usually has a positive electrode active material layer on a current collector, and the positive electrode active material layer contains a positive electrode active material. Hereinafter, the positive electrode active material will be described.

As said complex oxide, what is represented by following formula (2) is mentioned, for example.
Li _x M _1-y N _y O ₂ (2)

  In formula (2), 0 <x <1.2 and 0 <y <1.

  M in the formula (2) is a transition metal, preferably Mn, Fe, Co, or Ni. M in the formula (2) may be contained in the composite oxide only in one kind or in a plurality of different kinds.

  N in Formula (2) is at least one selected from V, Fe, Cu, Nb, Mo, Ta, W, Zn, Ti, Zr, Al, B, Mg, Li, Na, and K. Among these, from the viewpoint of improving the output, at least one selected from V, Fe, Cu, Nb, Mo, Ta, and W is preferable, and among these, at least one selected from Nb, Mo, Ta, and W is more preferable. On the other hand, from the viewpoint of capacity retention after the durability test, at least one selected from Zn, Ti, Zr, Al, B, Mg, Li, Na and K is preferable, and among these, selected from Zr, Al, Mg and Li. More preferred is at least one of the above.

Preferable examples of the composite oxide, for _{example, Na 2/3 Fe 1/} 2 Mn 1/2 O 2, Na 2/3 Ni 1/2 Mn 1/2 O 2, Na 2/3 Ni 1/3 Mn _{2/3 O 2, Na 4} /5 Ni 1/3 Mn 2/3 O 2, NaCoO 2, NaCrO 2, NaNi 1/3 Co 1/3 Mn 1/3 O 2, NaNi 1/3 Fe 1/3 Mn _1/3 O _2, and the like.

As said polyanion compound, what is represented by following formula (3) is mentioned, for example.
Na _x Ｍ M ′ _{y ｀} (QO ₄ ) _z (3)

  In formula (3), 1 <x ｀ <2, 1 <y ｀ <3, 1 <z <3.

  M ′ in the formula (3) is a transition metal, preferably Mn, Fe, Co, or Ni. M ′ in formula (3) may be included in the polyanion compound alone or in a plurality of different types.

  Q in Formula (3) is at least one selected from P, As, Sb, Bi, S, Se, Te, Po, Si, Ge, Sn, and Pb. Among these, from the viewpoint of the stability of the compound, at least one selected from P, S, and Si is preferable, and among these, at least one selected from P and S is more preferable.

Preferred examples of the polyanion compound include LiFePO ₄ , Li ₂ Fe ₃ (PO ₄ ) ₃ , Li ₂ Fe ₂ (SO ₄ ) ₃ , Li ₂ Fe ₂ (SiO ₄ ) ₃ , LiMnPO ₄ , LiMnFe ₂ (PO _{4) 3, Li 2 Mn 2} (SO 4) 3, Li 2 Mn 2 (SiO 4) 3 and the like.

Examples of the fluoride include LiM ″ F ₃ , Li ₂ M ″ PO ₄ F (where M ″ is a transition metal, preferably Mn, Fe, Co, Ni, Or a plurality of different types may be included. More specifically, LiFeF ₃ , Li ₂ FePO ₄ F, LiFMnF ₃ , Li ₂ MnPO ₄ F, LiFNiF ₃ , li ₂ NiPO ₄ F, and the like.

The positive electrode used in the present invention preferably includes a composite oxide, a polyaniline compound, and a fluoride among those mentioned above. However, other positive electrode active materials may be included as long as the effects of the present invention are not impaired. The other positive electrode active material is not particularly limited as long as it does not correspond to any of the composite oxide, the polyanion compound, and the fluoride, and can electrochemically occlude and release s-block metal ions. For example, a substance containing an alkali metal and at least one transition metal is preferred. Specific examples include lithium-containing transition metal composite oxides, lithium-containing transition metal phosphate compounds, and lithium-containing transition metal silicate compounds. For _{example, Na 2 FeP 2 O 7,} Na 4 Fe 3 (PO 4) 2 (P 2 O 7) , and the like. Said other positive electrode active material may be used independently, and may be used in combination of 2 or more type.

[Negative electrode]
The negative electrode usually has a negative electrode active material layer on a current collector, and the negative electrode active material layer contains a negative electrode active material. Hereinafter, the negative electrode active material will be described.

  The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release s-block metal ions such as lithium ions, lithium ions, potassium ions, and magnesium ions. Specific examples thereof include carbonaceous materials, metal alloy materials, and s-block metal-containing metal composite oxide materials. These may be used individually by 1 type, and may be used together combining 2 or more types arbitrarily.

  Examples of the carbonaceous material used as the negative electrode active material include natural graphite, non-graphitizable carbon, and artificial carbonaceous material, but there is no particular limitation. Usually, lithium ions can be inserted and removed and has a pore structure. do it. Specifically, a porous single-phase material described in International Publication No. 2014/188722 is preferable from the viewpoint of high capacity.

[Separator]
Usually, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.

  There is no restriction | limiting in particular about the material and shape of a separator, As long as the effect of this invention is not impaired remarkably, a well-known thing can be employ | adopted arbitrarily. Among these, a resin, glass fiber, inorganic material, etc., which is formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention, is used. It is preferable to use it.

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

  Although the thickness of the separator is arbitrary, it is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. Moreover, when it is thicker than the said range, not only battery performance, such as a rate characteristic, may fall, but the energy density as the whole electrical storage device may fall.

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

  Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.

  On the other hand, as the inorganic material, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Things are used.

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

[Conductive material]
The positive electrode and the negative electrode described above may contain a conductive material in order to improve conductivity. A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbonaceous materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The conductive material is usually 0.01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and usually 50 parts by mass or less, preferably 100 parts by mass of the positive electrode material or the negative electrode material. Is used in an amount of 30 parts by mass or less, more preferably 15 parts by mass or less. If the content of the conductive material is lower than the above range, the conductivity may be insufficient. Moreover, when it exceeds the said range, battery capacity may fall.

[Binder]
The positive electrode and the negative electrode described above may contain a binder in order to improve the binding property. The binder is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used during electrode production.

  In the case of the coating method, the binder may be any material that can be dissolved or dispersed in the liquid medium described later used at the time of electrode production. Specific examples include polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic Polymers such as aromatic polyamide, cellulose and nitrocellulose; rubbery polymers such as SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine atom rubber, isoprene rubber, butadiene rubber and ethylene / propylene rubber Styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer Or its hydrogenation Thermoplastic elastomeric polymers such as products; soft resinous polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; Fluorine atom polymers such as vinylidene (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene / ethylene copolymers; polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions) Thing etc. are mentioned. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the binder is usually 0.1 parts by mass or more, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and usually 50 parts by mass with respect to 100 parts by mass of the positive electrode material or the negative electrode material. 30 parts by mass or less, preferably 10 parts by mass or less, and more preferably 8 parts by mass or less. When the ratio of the binder is within the above range, the binding property of the electrode can be sufficiently maintained and the mechanical strength of the electrode is maintained, which is preferable from the viewpoint of cycle characteristics, battery capacity, and conductivity.

[Liquid medium]
When forming a positive electrode and a negative electrode by a coating method, as a liquid medium for forming a slurry, dissolve or disperse an active material, a conductive material, a binder, and a thickener used as necessary. As long as the solvent can be used, the type of the solvent is not particularly limited, and either an aqueous solvent or an organic solvent may be used.

  Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of organic media include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone. Esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine and N, N-dimethylaminopropylamine; ethers such as diethyl ether and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) and dimethylformamide And amides such as dimethylacetamide; aprotic polar solvents such as hexamethylphosphalamide and dimethyl sulfoxide. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

[Thickener]
When an aqueous medium is used as a liquid medium for forming a slurry when forming a positive electrode and a negative electrode by a coating method, it is slurried using a thickener and a latex such as styrene-butadiene rubber (SBR). preferable. A thickener is usually used to adjust the viscosity of the slurry.

  The thickener is not limited as long as the effect of the present invention is not significantly limited. Specifically, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof Etc. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  When using these thickeners, the amount used is usually 0.1 parts by mass or more, preferably 0.5 parts by mass or more, more preferably 0.6 parts by mass with respect to 100 parts by mass of the positive electrode material or the negative electrode material. It is desirable that the amount is not less than 5 parts by mass, usually not more than 5 parts by mass, preferably not more than 3 parts by mass, more preferably not more than 2 parts by mass. If it falls below the above range, applicability may be significantly reduced, and if it exceeds the above range, the proportion of the active material in the active material layer decreases, and the battery capacity decreases and resistance between the active materials increases. There is a case.

[Current collector]
There is no restriction | limiting in particular as a material of a collector, A well-known thing can be used arbitrarily. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, tantalum, and copper; and carbonaceous materials such as carbon cloth and carbon paper. Among these, metal materials, particularly aluminum, are preferable.

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, foam metal, etc. A carbon thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape.

  The thickness of the current collector is arbitrary, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. When the thickness of the current collector is within the above range, the strength required for the current collector is maintained, and it is also preferable from the viewpoint of handleability.

[Battery design]
<Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed via the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape via the separator. Either may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, and 80% or less. preferable. When the electrode group occupancy is below the above range, the battery capacity decreases. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Current collection structure>
The current collecting structure is not particularly limited, but in order to more effectively realize the improvement of the discharge characteristics by the non-aqueous electrolyte solution of the present invention, it is necessary to make the structure to reduce the resistance of the wiring part and the joint part. preferable. Thus, when internal resistance is reduced, the effect of using the non-aqueous electrolyte solution of this invention is exhibited especially favorable.

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

[Exterior case]
The non-aqueous electrolyte battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an outer case (exterior body). There is no restriction | limiting in this exterior case, A well-known thing can be arbitrarily employ | adopted unless the effect of this invention is impaired remarkably.

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

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

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

[Protective element]
In the non-aqueous electrolyte battery of the present invention, as a protective element, PTC (Positive Temperature Coefficient) whose resistance increases when abnormal heat generation or excessive current flows, a temperature fuse, a thermistor, battery internal pressure or internal temperature during abnormal heat generation A valve (current cutoff valve) or the like that cuts off the current flowing in the circuit due to a rapid rise in the voltage may be provided. It is preferable to select a protective element that does not operate under normal use at a high current. From the viewpoint of high output, it is more preferable to design the protective element so as not to cause abnormal heat generation or thermal runaway even without the protective element.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples unless it exceeds the gist.

  The structures of the aromatic carboxylic acid ester (1) used in the following Examples and the compounds used in Comparative Examples are shown below.

[Example 1]
<Preparation of non-aqueous electrolyte solution>
Under a dry argon atmosphere, LiPF ₆ is 1.2 mol / L with respect to a non-aqueous solvent in which ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate are mixed at 30% by volume, 40% by volume, and 30% by volume, respectively. Dissolved in. Further, 2.0% by mass of vinylene carbonate and 2.0% by mass of monofluoroethylene carbonate were added. This is referred to as “reference electrolyte solution 1”.

  A non-aqueous electrolyte solution of Example 1 was prepared by adding 0.5% by mass of adiponitrile and 0.4% by mass of compound (A) to the reference electrolyte solution 1.

<Preparation of positive electrode>
97% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and 1.5% by mass of polyvinylidene fluoride (PVdF) as a binder, N-methylpyrrolidone In a solvent, the mixture was slurried by mixing with a disperser. This was uniformly applied on both sides of a 15 μm thick aluminum foil, dried, and then pressed to obtain a positive electrode.

<Production of negative electrode>
Natural graphite powder as negative electrode active material, aqueous dispersion of sodium carboxymethylcellulose as thickener (carboxymethylcellulose sodium concentration 1 mass%), aqueous dispersion of styrene butadiene rubber as binder (concentration of styrene butadiene rubber 50 mass%) ) And mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 10 μm thick copper foil, dried, and then pressed to obtain a negative electrode. In addition, in the negative electrode after drying, it produced so that it might become the mass ratio of natural graphite: carboxymethylcellulose sodium: styrene-butadiene rubber = 98: 1: 1.

<Production of lithium secondary battery>
The above positive electrode, negative electrode, and polypropylene separator were laminated in the order of the negative electrode, separator, positive electrode, separator, and negative electrode to produce a battery element. After inserting this battery element into a bag made of a laminate film in which both surfaces of aluminum (thickness 40 μm) are coated with a resin layer while projecting positive and negative terminals, a non-aqueous electrolyte solution is injected into the bag, Vacuum sealing was performed to produce a sheet-like lithium secondary battery.

The following initial charge / discharge test and high-temperature storage durability test were carried out using the lithium secondary battery produced above. The evaluation results are shown in Table 1.
In Table 1, adiponitrile is abbreviated as “AdpCN”, and succinonitrile used in the comparative example is abbreviated as “SN”.

[Initial charge / discharge test (initial capacity)]
The lithium secondary battery was charged under constant pressure at 25 ° C. with a current corresponding to 0.05 C for 6 hours, and then discharged at a constant current of 0.2 C to 3.0 V. Furthermore, after a constant current-constant voltage charge (also referred to as “CC-CV charge”) (0.05 C cut) to 4.1 V with a current corresponding to 0.2 C, it was left under conditions of 45 ° C. and 72 hours. . Then, it discharged to 3.0V with a constant current of 0.2C. Next, after CC-CV charge (0.05C cut) to 4.4V at 0.2C, it was discharged again to 3.0V at 0.5C, and this was used as the initial capacity. Here, 1C represents a current value for discharging the reference capacity of the battery in one hour, and for example, 0.2C represents a current value of 1/5 thereof.

[High temperature storage durability test (capacity after storage, high rate capacity after storage)]
The lithium secondary battery that was initially charged and discharged was CC-CV charged (0.05 C cut) to 4.4 V at 0.2 C at 25 ° C. Thereafter, high temperature storage was performed at 85 ° C. for 1 day. Next, a constant current was discharged to 3.0 V at 0.2 C at 25 ° C. Thereafter, CC-CV charge (0.05 C cut) to 4.4 V was performed at a constant current of 0.2 C at 25 ° C., and then discharged again to 3.0 V at 0.5 C, and this was defined as the capacity after storage. Furthermore, after CC-CV charge (0.05C cut) to 4.4V at 0.2C, it discharged to 3.0V at 1.0C, and this was made into the high rate capacity | capacitance after a preservation | save.

[Example 2]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of adiponitrile and 0.8% by mass of compound (A) were further added to the reference electrolyte solution 1 was used. Then, the above evaluation was performed.

[Example 3]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of adiponitrile and 0.5% by mass of compound (B) were further added to the reference electrolyte solution 1 was used. Then, the above evaluation was performed.

[Example 4]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of adiponitrile and 1.0% by mass of compound (B) were further added to the reference electrolyte solution 1 was used. Then, the above evaluation was performed.

[Comparative Example 1]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of adiponitrile and 0.4% by mass of compound (C) were further added to the reference electrolyte solution 1 was used. The above evaluation was carried out.

[Comparative Example 2]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of succinonitrile and 0.4% by mass of compound (C) were further added to the reference electrolyte solution 1 was used. The above evaluation was performed.

[Comparative Example 3]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of succinonitrile and 0.4% by mass of the compound (A) were further added to the reference electrolyte solution 1 was used. The above evaluation was performed.

[Comparative Example 4]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolyte solution in which 0.5% by mass of succinonitrile and 0.5% by mass of compound (B) were further added to the reference electrolyte solution 1 was used. The above evaluation was performed.

From Table 1, when the non-aqueous electrolytes of Examples 1 to 4 according to the present invention are used, the initial capacity is impaired as compared with the case where the aromatic carboxylic acid ester (1) is not added together with adiponitrile (Comparative Example 1). It can be seen that the capacity after storage and the high-rate capacity after storage are improved. Moreover, when the non-aqueous electrolyte solution of Examples 1-4 is used, compared with the case where the aromatic carboxylic acid ester (1) is added together with succinonitrile which is an additive other than adiponitrile (Comparative Examples 3 and 4), the initial capacity It can be seen that the capacity after storage and the high-rate capacity after storage are improved without substantially impairing the storage capacity.
In Examples 1 to 4 and Comparative Examples 1 to 4, various evaluations are modeled after a short-term durability test, but the actual use of non-aqueous electrolyte secondary batteries lasts for several years. In some cases, the difference in the result of the high rate capacity after storage becomes more remarkable especially when long-term use is assumed.
As described above, according to the present invention, by adding the aromatic carboxylic acid ester (1) together with adiponitrile, decomposition of the non-aqueous electrolyte is suppressed, and electrochemical side reaction on the electrode of the decomposition product is suppressed. The existence of a synergistic effect was suggested.
Therefore, it is clear that the non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention has excellent characteristics.

  The non-aqueous electrolyte of the present invention is useful because it can improve the charge / discharge efficiency and rate characteristics after a high-temperature storage durability test of an energy device such as a non-aqueous electrolyte battery containing the non-aqueous electrolyte. . Therefore, the non-aqueous electrolyte solution and the non-aqueous electrolyte battery of the present invention can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Home Backup power source, office backup power source, load leveling power source, natural energy storage power source and the like.

Claims (9)

A non-aqueous electrolyte solution for a non-aqueous electrolyte battery comprising a positive electrode and a negative electrode capable of inserting and extracting metal ions, wherein the non-aqueous electrolyte solution together with the electrolyte and the non-aqueous solvent is represented by the following formula (1) A non-aqueous electrolyte containing a group carboxylic acid ester and further containing adiponitrile.

(In Formula (1), R ¹ represents a C1-C12 saturated hydrocarbon group which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. Or a hydrocarbon group having 1 to 12 carbon atoms which may be bonded to each other to form a ring, and A may be a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. A C1-C12 alkoxy group, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A may be the same as each other They may be different from each other, and two A may be bonded to each other to form a ring condensed with the benzene ring having A.)   2. In the formula (1), A is a hydrocarbon group having 4 to 12 carbon atoms, and the carbon atom bonded to the benzene ring of the hydrocarbon group is a quaternary carbon atom. The non-aqueous electrolyte solution described in 1.   The non-aqueous electrolyte solution according to claim 1, wherein A in the formula (1) is a fluorine atom or a substituent containing a fluorine atom. 4. The non-aqueous electrolyte solution according to claim 1, wherein in the formula (1), R ² and R ³ are each independently a hydrocarbon group having 1 to 12 carbon atoms. 5. .   The aromatic carboxylic acid ester represented by the formula (1) is contained in a non-aqueous electrolyte solution in an amount of 0.001 to 10% by mass, according to any one of claims 1 to 4. Non-aqueous electrolyte.   The non-aqueous electrolyte solution according to any one of claims 1 to 5, wherein the adiponitrile is contained in the non-aqueous electrolyte solution in an amount of 0.001 to 10% by mass.   The nonaqueous electrolytic solution according to any one of claims 1 to 6, wherein the nonaqueous electrolytic solution further contains at least one compound selected from cyclic carbonates having fluorine atoms.   The non-aqueous electrolyte according to any one of claims 1 to 7, wherein the non-aqueous electrolyte solution further contains at least one compound selected from cyclic carbonates having a carbon-carbon unsaturated bond. Electrolytic solution.   A nonaqueous electrolyte battery comprising a positive electrode and a negative electrode, and the nonaqueous electrolyte solution according to any one of claims 1 to 8.