JP2013211225A - Nonaqueous electrolytic solution and nonaqueous electrolyte battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery which is excellent in safety during overcharge and excellent in high-temperature storage characteristics, and to provide a nonaqueous electrolytic solution giving it.SOLUTION: The nonaqueous electrolytic solution which contains an electrolyte and a nonaqueous solvent is characterized by containing an ester compound represented by general formula (I). (In the general formula (I), Ar represents an aryl group which may have a substituent, m represents an integer of 2 or more, and Rto Reach represent a C1-C12 hydrocarbon group which may be independently substituted.)

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 laptop 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, improvement of various battery characteristics such as high capacity, low temperature use characteristics, high temperature storage characteristics, cycle characteristics, etc. has been demanded. Yes.

  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 addition, in order to improve battery characteristics such as load characteristics, cycle characteristics, and storage characteristics of such nonaqueous electrolyte batteries, and to improve battery safety during overcharge, various studies have been made on nonaqueous solvents and electrolytes. ing. Patent Document 1 proposes to protect the battery by increasing the internal resistance of the battery by mixing an additive that is polymerized at a battery voltage equal to or higher than the maximum operating voltage of the battery in the electrolyte. In 2 the internal electrical disconnection device provided for overcharge protection is ensured by mixing an additive that generates gas and pressure by polymerizing in the electrolyte at a battery voltage higher than the maximum operating voltage of the battery. It has been proposed to work. Moreover, aromatic compounds, such as biphenyl, thiophene, and furan, are disclosed as those additives. Further, Patent Document 3 discloses a non-aqueous system in which phenylcyclohexane is added in a range of 0.1 to 20 parts by weight in a non-aqueous electrolyte solution in order to suppress deterioration of battery characteristics when biphenyl or thiophene is used. A non-aqueous electrolyte secondary battery system including an electrolyte secondary battery and a charge control system that senses an increase in battery temperature and disconnects a charging circuit has been proposed.

Patent Document 4 discloses a method for containing a benzyl alkyl carbonate or a 5-membered or 6-membered lactone containing a phenyl group in a non-aqueous electrolyte solution in order to improve the cycle characteristics of the non-aqueous electrolyte secondary battery. Has been proposed.
Patent Document 5 proposes the inclusion of an aromatic ester compound or the like in the non-aqueous electrolyte in order to reduce the amount of high-temperature storage gas while maintaining the capacity of the non-aqueous electrolyte secondary battery.

  To increase the capacity, for example, pressurize the active material layer of the electrode to increase the density to reduce the volume occupied by the active material other than the active material inside the battery as much as possible. How to do is being studied. However, when the active material layer of the electrode is pressurized and densified, it becomes difficult to use the active material uniformly, and some lithium precipitates due to a non-uniform reaction or deterioration of the active material is promoted. As a result, a problem that sufficient characteristics cannot be obtained easily occurs. Further, when the use range of the positive electrode is expanded to be used up to a high potential, the activity of the positive electrode is further increased, and the problem that the deterioration is accelerated by the reaction between the positive electrode and the electrolytic solution is likely to occur.

In the non-aqueous electrolyte secondary battery using the electrolyte described in Patent Documents 1 to 3, although the overcharge characteristics are improved as described above, the initial capacity and the high-temperature storage characteristics are deteriorated and still not satisfied. It wasn't good. Moreover, the non-aqueous electrolyte secondary battery using the electrolyte solution described in Patent Documents 4 to 5 is not satisfactory in terms of improving safety during overcharge.

JP-A-9-106835 JP-A-9-171840 JP 2002-50398 A Japanese Patent No. 3870584 Japanese Patent No. 4051947

  In view of the above problems, an object of the present invention is to provide a non-aqueous electrolyte battery that is excellent in safety during overcharge and high-temperature storage characteristics, and a non-aqueous electrolyte that provides the same.

As a result of various studies to achieve the above object, the present inventors have found that the above problems can be solved by including a compound having a specific structure in the electrolytic solution, thereby completing the present invention. I came to let you. That is, the gist of the present invention is as follows.
(1) A nonaqueous electrolytic solution containing an electrolyte and a nonaqueous solvent, wherein the nonaqueous electrolytic solution contains an ester compound represented by the general formula (I).

(In the general formula (I), Ar represents an aryl group which may have a substituent, m represents an integer of 2 or more, and R ^{1 to} R ⁴ may be independently substituted. Represents a good hydrocarbon group having 1 to 12 carbon atoms.)
(2) The nonaqueous electrolytic solution according to (1), wherein Ar in the general formula (I) is a phenyl group which may have a substituent.
(3) The nonaqueous system according to (1) or (2), wherein the proportion of the compound represented by the general formula (I) in the nonaqueous electrolytic solution is 0.001 to 10% by mass Electrolytic solution.
(4) It further contains at least one compound selected from the group consisting of a cyclic carbonate compound having a carbon-carbon unsaturated bond, a cyclic carbonate compound having a fluorine atom, a monofluorophosphate and a difluorophosphate. The nonaqueous electrolytic solution according to any one of (1) to (3) above,
(5) A non-aqueous electrolyte battery including a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is any one of the above (1) to (4) A non-aqueous electrolyte battery characterized by being the non-aqueous electrolyte solution described.

According to the present invention, it is possible to provide a non-aqueous electrolyte battery having a high capacity and particularly excellent high-temperature storage characteristics while enhancing safety during overcharging, and reducing the size and performance of the non-aqueous electrolyte battery. Can be achieved.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
<Non-aqueous electrolyte>
The non-aqueous electrolyte of the present invention is
It contains an electrolyte and a non-aqueous solvent, and further contains an ester compound represented by the general formula (I).

(In the general formula (I), Ar represents an aryl group which may have a substituent, m represents an integer of 2 or more, and R ^{1 to} R ⁴ may be independently substituted. Represents a good hydrocarbon group having 1 to 12 carbon atoms.)
In the general formula (I), the optionally substituted hydrocarbon group represented by R ^{1 to} R ⁴ is an alkyl group having 1 to 12 carbon atoms or an alkenyl group having 2 to 12 carbon atoms. Group, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and the like.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, and n-pentyl. Group, t-amyl group, n-hexyl group, 1,1-dimethylbutyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, etc., preferably 1 carbon number -6, more preferably 1-4, and still more preferably 1-2 chain or cyclic alkyl groups. Examples of the fluorine-substituted group include a trifluoromethyl group, a trifluoroethyl group, and a pentafluoroethyl group.

As a C2-C12 alkenyl group, a vinyl group, a propenyl group, etc. are mentioned, Preferably it is 2-8, Most preferably, the thing of 2-4 is mentioned.
Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a cyclohexylphenyl group, a t-butylphenyl group, and the like, and among them, a phenyl group, a cyclohexylphenyl group, and a t-butylphenyl group are preferable. .

Examples of the aralkyl group having 7 to 12 carbon atoms include benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group, and phenylpentyl group. Among them, phenethyl group and phenylpropyl group are preferable from the viewpoint of improving overcharge characteristics. A phenylbutyl group, most preferably a phenylpropyl group.
The alkyl group, alkenyl group, aryl group and aralkyl group may be substituted with a fluorine atom. Examples of the fluorine-substituted group include a trifluoromethyl group, a trifluoroethyl group and a pentafluoroethyl group. Fluorinated alkyl groups, 2-fluorovinyl groups, fluorinated alkenyl groups such as 3-fluoro-2-propenyl group, 2-fluorophenyl groups, 3-fluorophenyl groups, fluorinated aryl groups such as 4-fluorophenyl groups, Examples thereof include fluorinated aralkyl groups such as a fluorophenylpropyl group.

Moreover, Ar in the said general formula (I) represents the aryl group which may have a substituent. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenyl group, and a terphenyl group. Of these aryl groups, a phenyl group is preferable from the viewpoint of causing no side reaction in the normal operating voltage range of the battery.
The substituent that may be substituted represents, for example, a halogen atom, a hetero atom, or a hydrocarbon group that may have a halogen atom. Here, as a hydrocarbon group, as a C1-C12 hydrocarbon group, a C1-C12 alkyl group, a C2-C12 alkenyl group, a C6-C12 aryl group, or carbon Examples thereof include aralkyl groups of 7 to 12.
Ar in the general formula (I) may have two or more substituents, and may form a heterocyclic ring with Ar in the general formula (I).

  Examples of the hydrocarbon group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n -Pentyl group, t-amyl group, n-hexyl group, 1,1-dimethylbutyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, and in general formula (I) And a substituent which forms a tetrahydronaphthyl group by binding to Ar.

As a C2-C12 alkenyl group, a vinyl group, a propenyl group, etc. are mentioned, Preferably it is 2-8, Most preferably, the thing of 2-4 is mentioned.
Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, a xylyl group, a cyclohexylphenyl group, a t-butylphenyl group, and a substituent that forms a naphthalene group with the benzene ring in the compound (I). Of these, a phenyl group, a cyclohexylphenyl group, and a t-butylphenyl group are preferable.
Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group and a phenethyl group, and among them, a benzyl group is preferable.

  The alkyl group, alkenyl group, aryl group and aralkyl group may be substituted with a fluorine atom. Examples of the fluorine-substituted group include a trifluoromethyl group, a trifluoroethyl group and a pentafluoroethyl group. Fluorinated alkyl groups, 2-fluorovinyl groups, fluorinated alkenyl groups such as 3-fluoro-2-propenyl group, 2-fluorophenyl groups, 3-fluorophenyl groups, fluorinated aryl groups such as 4-fluorophenyl groups, Examples thereof include fluorinated aralkyl groups such as 2-fluorobenzyl group, 3-fluorobenzyl group and 4-fluorobenzyl group.

From the viewpoint of improving safety during overcharge and improving battery characteristics, Ar preferably has no substituent or has an alkyl group having 3 or more carbon atoms, more preferably has a substituent. Or having an alkyl group having 4 or more carbon atoms, more preferably not having a substituent, or having an alkyl group having 5 or more carbon atoms.
Here, the hydrocarbon group having 3 or more carbon atoms is preferably a secondary alkyl group or a tertiary alkyl group, and among them, a sec-butyl group, a t-butyl group, a t-amyl group, 1,1- A dimethylbutyl group, a cyclopentyl group, a cyclohexyl group, a 1-methylcyclohexyl group, and a 1-ethylcyclohexyl group are more preferable. A t-butyl group, a t-amyl group, a 1,1-dimethylbutyl group, a cyclopentyl group, a cyclohexyl group, 1 -Methylcyclohexyl group and 1-ethylcyclohexyl group are more preferable, and t-amyl group, 1,1-dimethylbutyl group, cyclopentyl group, cyclohexyl group, which is a secondary alkyl group or tertiary alkyl group having 5 or more carbon atoms, 1 -Methylcyclohexyl group and 1-ethylcyclohexyl group are particularly preferred.

In general formula (I), m represents an integer of 2 or more. As shown in the examples described later, when m = 1, the effect of the present invention is not observed when an ester group is bonded via an alkyl chain having a certain length or less. In the present invention, the intramolecular distance between Ar and Y in formula (I) is important, and the lower limit of m is preferably an integer of 3 or more, and the upper limit is an integer of 5 or less. It is preferably an integer of 4 or less.
Specific examples of the compound represented by the general formula (I) include the following compounds.

Methyl (3-phenylpropyl) carbonate, methyl (3- (2-n-pentylphenyl) propyl) carbonate, methyl (3- (3-n-pentylphenyl) propyl) carbonate, methyl (3- (4-n- Pentylphenyl) propyl) carbonate, methyl (3
-(2,4-di-n-pentylphenyl) propyl) carbonate, methyl (3- (3,5-di-n-pentylphenyl) propyl) carbonate, methyl (3- (2-t-amylphenyl) propyl ) Carbonate, methyl (3- (3-t-amylphenyl) propyl) carbonate, methyl (3- (4-t-amylphenyl) propyl) carbonate, methyl (
3- (2,4-di-t-amylphenyl) propyl) carbonate, methyl (3- (3,5-di-t-amylphenyl) propyl) carbonate, methyl (3- (2-cyclopentylphenyl) propyl) Carbonate, methyl (3- (3-cyclopentylphenyl) propyl) carbonate, methyl (3- (4-cyclopentylphenyl) propyl) carbonate, methyl (3- (2-cyclohexylphenyl) propyl) carbonate, methyl (3- (
3-cyclohexylphenyl) propyl) carbonate, methyl (3- (4-cyclohexylphenyl) propyl) carbonate, ethyl (3-phenylpropyl) carbonate, ethyl (3- (2-n-pentylphenyl) propyl) carbonate, ethyl ( 3- (3-n
-Pentylphenyl) propyl) carbonate, ethyl (3- (4-n-pentylphenyl) propyl) carbonate, ethyl (3- (2,4-di-n-pentylphenyl) propyl) carbonate, ethyl (3- (3 , 5-Di-n-pentylphenyl) propyl) carbonate, ethyl (3- (2-t-amylphenyl) propyl) carbonate, ethyl (3- (
3-t-amylphenyl) propyl) carbonate, ethyl (3- (4-t-amylphenyl) propyl) carbonate, ethyl (3- (2,4-di-t-amylphenyl) propyl) carbonate, ethyl (3 -(3,5-di-t-amylphenyl) propyl) carbonate, ethyl (3- (2-cyclopentylphenyl) propyl) carbonate, ethyl (3-
(3-cyclopentylphenyl) propyl) carbonate, ethyl (3- (4-cyclopentylphenyl) propyl) carbonate, ethyl (3- (2-cyclohexylphenyl) propyl) carbonate, ethyl (3- (3-cyclohexylphenyl) propyl) Compounds in which R ¹ is an alkyl group having 1 to 12 carbon atoms and m = 3, such as carbonate, ethyl (3- (4-cyclohexylphenyl) propyl) carbonate;

Vinyl (3-phenylpropyl) carbonate, vinyl (3- (2-n-pentylphenyl) propyl) carbonate, vinyl (3- (3-n-pentylphenyl) propyl) carbonate, vinyl (3- (4-n- Pentylphenyl) propyl) carbonate, vinyl (
3- (2,4-di-n-pentylphenyl) propyl) carbonate, vinyl (3- (3
5-di-n-pentylphenyl) propyl) carbonate, vinyl (3- (2-t-amylphenyl) propyl) carbonate, vinyl (3- (3-t-amylphenyl) propyl)
Carbonate, vinyl (3- (4-t-amylphenyl) propyl) carbonate, vinyl (3- (2,4-di-t-amylphenyl) propyl) carbonate, vinyl (3- (3
5-di-t-amylphenyl) propyl) carbonate, vinyl (3- (2-cyclopentylphenyl) propyl) carbonate, vinyl (3- (3-cyclopentylphenyl) propyl) carbonate, vinyl (3- (4-cyclopentylphenyl) ) Propyl) carbonate, vinyl (3- (2-cyclohexylphenyl) propyl) carbonate, vinyl (3-
(3-cyclohexylphenyl) propyl) carbonate, vinyl (3- (4-cyclohexylphenyl) propyl) carbonate, allyl (3-phenylpropyl) carbonate,
Allyl (3- (2-n-pentylphenyl) propyl) carbonate, allyl (3- (3-
n-pentylphenyl) propyl) carbonate, allyl (3- (4-n-pentylphenyl) propyl) carbonate, allyl (3- (2,4-di-n-pentylphenyl) propyl) carbonate, allyl (3- ( 3,5-di-n-pentylphenyl) propyl) carbonate, allyl (3- (2-t-amylphenyl) propyl) carbonate, allyl (3-
(3-t-amylphenyl) propyl) carbonate, allyl (3- (4-t-amylphenyl) propyl) carbonate, allyl (3- (2,4-di-t-amylphenyl) propyl) carbonate, allyl ( 3- (3,5-di-t-amylphenyl) propyl) carbonate, allyl (3- (2-cyclopentylphenyl) propyl) carbonate, allyl (3
-(3-cyclopentylphenyl) propyl) carbonate, allyl (3- (4-cyclopentylphenyl) propyl) carbonate, allyl (3- (2-cyclohexylphenyl) propyl) carbonate, allyl (3- (3-cyclohexylphenyl) propyl A compound in which R ¹ is an alkenyl group having 2 to 12 carbon atoms and m = 3, such as carbonate), allyl (3- (4-cyclohexylphenyl) propyl) carbonate;

Phenyl (3-phenylpropyl) carbonate, phenyl (3- (2-n-pentylphenyl) propyl) carbonate, phenyl (3- (3-n-pentylphenyl) propyl) carbonate, phenyl (3- (4-n- Pentylphenyl) propyl) carbonate,
Phenyl (3- (2,4-di-n-pentylphenyl) propyl) carbonate, phenyl (3- (3,5-di-n-pentylphenyl) propyl) carbonate, phenyl (3- (
2-t-amylphenyl) propyl) carbonate, phenyl (3- (3-t-amylphenyl) propyl) carbonate, phenyl (3- (4-t-amylphenyl) propyl) carbonate, phenyl (3- (2, 4-di-t-amylphenyl) propyl) carbonate, phenyl (3- (3,5-di-t-amylphenyl) propyl) carbonate, phenyl (3- (2-cyclopentylphenyl) propyl) carbonate, phenyl (3 -(3-cyclopentylphenyl) propyl) carbonate, phenyl (3- (4-cyclopentylphenyl) propyl) carbonate, phenyl (3- (2-cyclohexylphenyl) propyl) carbonate, phenyl (3- (3-cyclohexylphenyl) propyl ) Carbonate, phenyl (3- (4-cyclohexyl) Phenyl) propyl) carbonate, compounds wherein ^{R 1} is m = 3 in the aryl group having 6 to 12 carbon atoms and the like;

Benzyl (3-phenylpropyl) carbonate, benzyl (3- (2-n-pentylphenyl) propyl) carbonate, benzyl (3- (3-n-pentylphenyl) propyl) carbonate, benzyl (3- (4-n- Pentylphenyl) propyl) carbonate,
Benzyl (3- (2,4-di-n-pentylphenyl) propyl) carbonate, benzyl (3- (3,5-di-n-pentylphenyl) propyl) carbonate, benzyl (3- (
2-t-amylphenyl) propyl) carbonate, benzyl (3- (3-t-amylphenyl) propyl) carbonate, benzyl (3- (4-t-amylphenyl) propyl) carbonate, benzyl (3- (2, 4-di-t-amylphenyl) propyl) carbonate, benzyl (3- (3,5-di-t-amylphenyl) propyl) carbonate, benzyl
(
3- (2-cyclopentylphenyl) propyl) carbonate, benzyl (3- (3-cyclopentylphenyl) propyl) carbonate, benzyl (3- (4-cyclopentylphenyl) propyl) carbonate, benzyl (3- (2-cyclohexylphenyl) Propyl) carbonate, benzyl (3- (3-cyclohexylphenyl) propyl) carbonate, benzyl (3- (4-cyclohexylphenyl) propyl) carbonate, di-3-phenylpropyl carbonate, 3-phenylpropyl (3- (2- n-pentylphenyl)
Propyl) carbonate, 3-phenylpropyl (3- (3-n-pentylphenyl) propyl) carbonate, 3-phenylpropyl (3- (4-n-pentylphenyl) propyl) carbonate, 3-phenylpropyl (3- ( 2,4-di-n-pentylphenyl) propyl) carbonate, 3-phenylpropyl (3- (3,5-di-n-pentylphenyl) propyl) carbonate, 3-phenylpropyl (3- (2-t- (Amylphenyl) propyl) carbonate, 3-phenylpropyl (3- (3-t-amylphenyl) propyl)
Carbonate, 3-phenylpropyl (3- (4-t-amylphenyl) propyl) carbonate, 3-phenylpropyl (3- (2,4-di-t-amylphenyl) propyl) carbonate, 3-phenylpropyl (3 -(3,5-di-t-amylphenyl) propyl) carbonate, 3-phenylpropyl (3- (2-cyclopentylphenyl) propyl) carbonate, 3-phenylpropyl (3- (3-cyclopentylphenyl) propyl) carbonate 3-phenylpropyl (3- (4-cyclopentylphenyl) propyl) carbonate, 3-phenylpropyl (3- (2-cyclohexylphenyl) propyl) carbonate, 3-phenylpropyl (3- (3-cyclohexylphenyl) propyl) Carbonate, 3-phenylpropyl (3- (4 Phenyl) propyl) carbonate, compounds wherein _{R 1} is m = 3 in the aralkyl group having 7 to 12 carbon atoms and the like;

Trifluoromethyl (3-phenylpropyl) carbonate, trifluoromethyl (3-
(2-n-pentylphenyl) propyl) carbonate, trifluoromethyl (3- (3-n-pentylphenyl) propyl) carbonate, trifluoromethyl (3- (4-n-pentylphenyl) propyl) carbonate, trifluoro Methyl (3- (2,4-di-n-pentylphenyl) propyl) carbonate, trifluoromethyl (3- (3,5-di-n-pentylphenyl) propyl) carbonate, trifluoromethyl (3- (2 -T-amylphenyl) propyl) carbonate, trifluoromethyl (3- (3-t-amylphenyl) propyl) carbonate, trifluoromethyl (3- (4-t-amylphenyl) propyl) carbonate, trifluoromethyl ( 3- (2,4-di-t-amylphenyl) propyl) carbonate, trifluoro Chill (3- (3,5-di -t- amyl phenyl) propyl) carbonate, trifluoromethyl (3- (2-cyclopentyl-phenyl) propyl) carbonate, trifluoromethyl (3- (3-cyclopentyloxy-phenyl) propyl)
Carbonate, trifluoromethyl (3- (4-cyclopentylphenyl) propyl) carbonate, trifluoromethyl (3- (2-cyclohexylphenyl) propyl) carbonate, trifluoromethyl (3- (3-cyclohexylphenyl) propyl) carbonate, A compound in which R ¹ is a fluorine-substituted alkyl group having 1 to 12 carbon atoms and m = 3, such as trifluoromethyl (3- (4-cyclohexylphenyl) propyl) carbonate;

Methanesulfonic acid (3-phenylpropyl), methanesulfonic acid (3- (2-n-pentylphenyl) propyl), methanesulfonic acid (3- (3-n-pentylphenyl) propyl)
Methanesulfonic acid (3- (4-n-pentylphenyl) propyl), methanesulfonic acid (
3- (2,4-di-n-pentylphenyl) propyl), methanesulfonic acid (3- (3,5-di-n-pentylphenyl) propyl), methanesulfonic acid (3- (2-t-amyl) Phenyl) propyl), methanesulfonic acid (3- (3-t-amylphenyl) propyl), methanesulfonic acid (3- (4-t-amylphenyl) propyl), methanesulfonic acid (3- (2
, 4-di-t-amylphenyl) propyl), methanesulfonic acid (3- (3,5-di-t-amylphenyl) propyl), methanesulfonic acid (3- (2-cyclopentylphenyl) propyl), methane Sulfonic acid (3- (3-cyclopentylphenyl) propyl), methanesulfonic acid (3- (4-cyclopentylphenyl) propyl), methanesulfonic acid (3- (2
-Cyclohexylphenyl) propyl), methanesulfonic acid (3- (3-cyclohexylphenyl) propyl), methanesulfonic acid (3- (4-cyclohexylphenyl) propyl)
Ethanesulfonic acid (3-phenylpropyl), ethanesulfonic acid (3- (2-n-pentylphenyl) propyl), ethanesulfonic acid (3- (3-n-pentylphenyl) propyl), ethanesulfonic acid (3 -(4-n-pentylphenyl) propyl), ethanesulfonic acid (3- (2,4-di-n-pentylphenyl) propyl), ethanesulfonic acid (3- (3,5-di-n-pentylphenyl) ) Propyl), ethanesulfonic acid (3- (2-t-amylphenyl) propyl), ethanesulfonic acid (3- (3-t-amylphenyl) propyl), ethanesulfonic acid (3- (4-t-amyl) Phenyl) propyl), ethanesulfonic acid (3- (2
, 4-di-t-amylphenyl) propyl), ethanesulfonic acid (3- (3,5-di-t-amylphenyl) propyl), ethanesulfonic acid (3- (2-cyclopentylphenyl) propyl), ethane Sulfonic acid (3- (3-cyclopentylphenyl) propyl), ethanesulfonic acid (3- (4-cyclopentylphenyl) propyl), ethanesulfonic acid (3- (2
-Cyclohexylphenyl) propyl), ethanesulfonic acid (3- (3-cyclohexylphenyl) propyl), ethanesulfonic acid (3- (4-cyclohexylphenyl) propyl)
A compound wherein R ² is an alkyl group having 1 to 12 carbon atoms and m = 3;
Vinylsulfonic acid (3-phenylpropyl), vinylsulfonic acid (3- (2-n-pentylphenyl) propyl), vinylsulfonic acid (3- (3-n-pentylphenyl) propyl)
, Vinyl sulfonic acid (3- (4-n-pentylphenyl) propyl), vinyl sulfonic acid (
3- (2,4-di-n-pentylphenyl) propyl), vinyl sulfonic acid (3- (3,5-di-n-pentylphenyl) propyl), vinyl sulfonic acid (3- (2-t-amyl) Phenyl) propyl), vinylsulfonic acid (3- (3-t-amylphenyl) propyl), vinylsulfonic acid (3- (4-t-amylphenyl) propyl), vinylsulfonic acid (3- (2
, 4-di-t-amylphenyl) propyl), vinyl sulfonic acid (3- (3,5-di-t-amylphenyl) propyl), vinyl sulfonic acid (3- (2-cyclopentylphenyl) propyl), vinyl Sulfonic acid (3- (3-cyclopentylphenyl) propyl), vinyl sulfonic acid (3- (4-cyclopentylphenyl) propyl), vinyl sulfonic acid (3- (2
-Cyclohexylphenyl) propyl), vinylsulfonic acid (3- (3-cyclohexylphenyl) propyl), vinylsulfonic acid (3- (4-cyclohexylphenyl) propyl)
Allylsulfonic acid (3-phenylpropyl), allylsulfonic acid (3- (2-n-pentylphenyl) propyl), allylsulfonic acid (3- (3-n-pentylphenyl) propyl), allylsulfonic acid (3 -(4-n-pentylphenyl) propyl), allylsulfonic acid (3- (2,4-di-n-pentylphenyl) propyl), allylsulfonic acid (3- (3,5-di-n-pentylphenyl) ) Propyl), allylsulfonic acid (3- (2-t-amylphenyl) propyl), allylsulfonic acid (3- (3-t-amylphenyl) propyl), allylsulfonic acid (3- (4-t-amyl) Phenyl) propyl), allylsulfonic acid (3- (2
, 4-di-t-amylphenyl) propyl), allylsulfonic acid (3- (3,5-di-t-amylphenyl) propyl), allylsulfonic acid (3- (2-cyclopentylphenyl) propyl), allyl Sulfonic acid (3- (3-cyclopentylphenyl) propyl), allylsulfonic acid (3- (4-cyclopentylphenyl) propyl), allylsulfonic acid (3- (2
-Cyclohexylphenyl) propyl), allylsulfonic acid (3- (3-cyclohexylphenyl) propyl), allylsulfonic acid (3- (4-cyclohexylphenyl) propyl)
A compound in which R ² is an alkenyl group having 2 to 12 carbon atoms and m = 3;

Benzenesulfonic acid (3-phenylpropyl), benzenesulfonic acid (3- (2-n-pentylphenyl) propyl), benzenesulfonic acid (3- (3-n-pentylphenyl) propyl), benzenesulfonic acid (3- (4-n-pentylphenyl) propyl), benzenesulfonic acid (3- (2,4-di-n-pentylphenyl) propyl), benzenesulfonic acid (3- (3,5-di-n-pentylphenyl) Propyl), benzenesulfonic acid (3- (2
-T-amylphenyl) propyl), benzenesulfonic acid (3- (3-t-amylphenyl) propyl), benzenesulfonic acid (3- (4-t-amylphenyl) propyl), benzenesulfonic acid (3- ( 2,4-di-t-amylphenyl) propyl), benzenesulfonic acid (3- (3,5-di-t-amylphenyl) propyl), benzenesulfonic acid (3- (2-
Cyclopentylphenyl) propyl), benzenesulfonic acid (3- (3-cyclopentylphenyl) propyl), benzenesulfonic acid (3- (4-cyclopentylphenyl) propyl), benzenesulfonic acid (3- (2-cyclohexylphenyl) propyl) , Benzenesulfonic acid (3- (3-cyclohexylphenyl) propyl), benzenesulfonic acid (3- (4
A compound in which R ₂ is an aryl group having 6 to 12 carbon atoms and m = 3, such as -cyclohexylphenyl) propyl);

Benzylsulfonic acid (3-phenylpropyl), benzylsulfonic acid (3- (2-n-pentylphenyl) propyl), benzylsulfonic acid (3- (3-n-pentylphenyl) propyl), benzylsulfonic acid (3- (4-n-pentylphenyl) propyl), benzylsulfonic acid (3- (2,4-di-n-pentylphenyl) propyl), benzylsulfonic acid (3- (3,5-di-n-pentylphenyl) Propyl), benzyl sulfonic acid (3- (2
-T-amylphenyl) propyl), benzylsulfonic acid (3- (3-t-amylphenyl) propyl), benzylsulfonic acid (3- (4-t-amylphenyl) propyl), benzylsulfonic acid (3- ( 2,4-di-t-amylphenyl) propyl), benzylsulfonic acid (3- (3,5-di-t-amylphenyl) propyl), benzylsulfonic acid (3- (2-
Cyclopentylphenyl) propyl), benzylsulfonic acid (3- (3-cyclopentylphenyl) propyl), benzylsulfonic acid (3- (4-cyclopentylphenyl) propyl), benzylsulfonic acid (3- (2-cyclohexylphenyl) propyl) , Benzyl sulfonic acid (3- (3-cyclohexylphenyl) propyl), benzyl sulfonic acid (3- (4
-Cyclohexylphenyl) propyl), 3-phenylpropanesulfonic acid (3-phenylpropyl), 3-phenylpropanesulfonic acid (3- (2-n-pentylphenyl) propyl), 3-phenylpropanesulfonic acid (3- ( 3-n-pentylphenyl) propyl),
3-phenylpropanesulfonic acid (3- (4-n-pentylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (2,4-di-n-pentylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (3,5-di-n-pentylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (2-t-amylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (3- t-amylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (4-t-amylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (2,4-di-t-amylphenyl) propyl ), 3-phenylpropanesulfonic acid (3- (3,5-di-t-amylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (2-cyclopentyl) Yl) propyl), 3-phenyl-propanesulfonic acid (3- (3-cyclopentyloxy-phenyl) propyl), 3-phenyl-propanesulfonic acid (3
-(4-cyclopentylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (2-cyclohexylphenyl) propyl), 3-phenylpropanesulfonic acid (3- (3-cyclohexylphenyl) propyl), 3-phenylpropane A compound in which R ₂ is an aralkyl group having 7 to 12 carbon atoms and m = 3, such as sulfonic acid (3- (4-cyclohexylphenyl) propyl);

Trifluoromethanesulfonic acid (3-phenylpropyl), trifluoromethanesulfonic acid (3- (2-n-pentylphenyl) propyl), trifluoromethanesulfonic acid (3-
(3-n-pentylphenyl) propyl), trifluoromethanesulfonic acid (3- (4-n-pentylphenyl) propyl), trifluoromethanesulfonic acid (3- (2,4-di-n-pentylphenyl) propyl) , Trifluoromethanesulfonic acid (3- (3,5-di-n-pentylphenyl) propyl), trifluoromethanesulfonic acid (3- (2-t-amylphenyl) propyl), trifluoromethanesulfonic acid (3- (3 -T-amylphenyl) propyl), trifluoromethanesulfonic acid (3- (4-t-amylphenyl) propyl)
, Trifluoromethanesulfonic acid (3- (2,4-di-t-amylphenyl) propyl), trifluoromethanesulfonic acid (3- (3,5-di-t-amylphenyl) propyl), trifluoromethanesulfonic acid ( 3- (2-cyclopentylphenyl) propyl), trifluoromethanesulfonic acid (3- (3-cyclopentylphenyl) propyl), trifluoromethanesulfonic acid (3- (4-cyclopentylphenyl) propyl), trifluoromethanesulfonic acid (3- (2-cyclohexylphenyl) propyl), trifluoromethanesulfonic acid (3- (3-cyclohexylphenyl) propyl), trifluoromethanesulfonic acid (3
-(4-cyclohexylphenyl) propyl), etc., wherein R ² is a fluorine-substituted alkyl group having 1 to 12 carbon atoms and m = 3;

Dimethyl (3-phenylpropyl) phosphate, dimethyl (3- (2-n-pentylphenyl) propyl) phosphate, dimethyl (3- (3-n-pentylphenyl) propyl)
Phosphate, dimethyl (3- (4-n-pentylphenyl) propyl) phosphate, dimethyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, dimethyl (
3- (3,5-di-n-pentylphenyl) propyl) phosphate, dimethyl (3- (2-t-amylphenyl) propyl) phosphate, dimethyl (3- (3-t-amylphenyl) propyl) phosphate, Dimethyl (3- (4-t-amylphenyl) propyl) phosphate, dimethyl (3- (2,4-di-t-amylphenyl) propyl) phosphate, dimethyl (3- (3,5-di-t-amyl) Phenyl) propyl) phosphate, dimethyl (
3- (2-cyclopentylphenyl) propyl) phosphate, dimethyl (3- (3-cyclopentylphenyl) propyl) phosphate, dimethyl (3- (4-cyclopentylphenyl) propyl) phosphate, dimethyl (3- (2-cyclohexylphenyl) Propyl) phosphate, dimethyl (3- (3-cyclohexylphenyl) propyl) phosphate, dimethyl (3- (4-cyclohexylphenyl) propyl) phosphate, diethyl (3
-Phenylpropyl) phosphate, diethyl (3- (2-n-pentylphenyl) propyl) phosphate, diethyl (3- (3-n-pentylphenyl) propyl) phosphate, diethyl (3- (4-n-pentylphenyl) Propyl) phosphate, diethyl (3-
(2,4-di-n-pentylphenyl) propyl) phosphate, diethyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, diethyl (3- (2-t-amylphenyl) propyl) Phosphate, diethyl (3- (3-t-amylphenyl) propyl) phosphate, diethyl (3- (4-t-amylphenyl) propyl) phosphate, diethyl (3- (2,4-di-t-amylphenyl) Propyl) phosphate, diethyl (3
-(3,5-di-t-amylphenyl) propyl) phosphate, diethyl (3- (2-cyclopentylphenyl) propyl) phosphate, diethyl (3- (3-cyclopentylphenyl) propyl) phosphate, diethyl (3- ( 4-cyclopentylphenyl) propyl)
Phosphate, diethyl (3- (2-cyclohexylphenyl) propyl) phosphate, diethyl (3- (3-cyclohexylphenyl) propyl) phosphate, diethyl (3-
(4-Cyclohexylphenyl) propyl) phosphate, ethylmethyl (3-phenylpropyl) phosphate, ethylmethyl (3- (2-n-pentylphenyl) propyl) phosphate, ethylmethyl (3- (3-n-pentylphenyl) Propyl) phosphate, ethylmethyl (3- (4-n-pentylphenyl) propyl) phosphate, ethylmethyl (
3- (2,4-di-n-pentylphenyl) propyl) phosphate, ethylmethyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, ethylmethyl (3- (2-t-amyl) Phenyl) propyl) phosphate, ethylmethyl (3- (3-t-amylphenyl) propyl) phosphate, ethylmethyl (3- (4-t-amylphenyl) propyl) phosphate, ethylmethyl (3- (2,4- Di-t-amylphenyl) propyl) phosphate, ethylmethyl (3- (3,5-di-t-amylphenyl) propyl) phosphate, ethylmethyl (3- (2-cyclopentylphenyl) propyl) phosphate, ethylmethyl ( 3- (3-cyclopentylphenyl) propyl) phosphate, ethylmethyl (
3- (4-cyclopentylphenyl) propyl) phosphate, ethylmethyl (3- (2-cyclohexylphenyl) propyl) phosphate, ethylmethyl (3- (3-cyclohexylphenyl) propyl) phosphate, ethylmethyl (3- (4- A compound in which R ³ and R ⁴ are alkyl groups having 1 to 12 carbon atoms and m = 3, such as cyclohexylphenyl) propyl) phosphate;

Divinyl (3-phenylpropyl) phosphate, divinyl (3- (2-n-pentylphenyl) propyl) phosphate, divinyl (3- (3-n-pentylphenyl) propyl) phosphate, divinyl (3- (4-n- Pentylphenyl) propyl) phosphate,
Divinyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, divinyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, divinyl (3- (
2-t-amylphenyl) propyl) phosphate, divinyl (3- (3-t-amylphenyl) propyl) phosphate, divinyl (3- (4-t-amylphenyl) propyl) phosphate, divinyl (3- (2, 4-di-t-amylphenyl) propyl) phosphate, divinyl (3- (3,5-di-t-amylphenyl) propyl) phosphate, divinyl (3- (2-cyclopentylphenyl) propyl) phosphate, divinyl (3 -(3-cyclopentylphenyl) propyl) phosphate, divinyl (3- (4-cyclopentylphenyl) propyl) phosphate, divinyl (3- (2-cyclohexylphenyl) propyl) phosphate, divinyl (3- (3-cyclohexylphenyl) propyl ) Phosphate, divinyl (3- (4-cyclohexyl) Phenyl) propyl) phosphates, diallyl (
3-phenylpropyl) phosphate, diallyl (3- (2-n-pentylphenyl) propyl) phosphate, diallyl (3- (3-n-pentylphenyl) propyl) phosphate, diallyl (3- (4-n-pentylphenyl) ) Propyl) phosphate, diallyl (3
-(2,4-di-n-pentylphenyl) propyl) phosphate, diallyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, diallyl (3- (2-t-amylphenyl) propyl ) Phosphate, diallyl (3- (3-t-amylphenyl) propyl) phosphate, diallyl (3- (4-t-amylphenyl) propyl) phosphate,
Diallyl (3- (2,4-di-t-amylphenyl) propyl) phosphate, diallyl (
3- (3,5-di-t-amylphenyl) propyl) phosphate, diallyl (3- (2-cyclopentylphenyl) propyl) phosphate, diallyl (3- (3-cyclopentylphenyl) propyl) phosphate, diallyl (3- (4-Cyclopentylphenyl) propyl) phosphate, diallyl (3- (2-cyclohexylphenyl) propyl) phosphate, diallyl (3- (3-cyclohexylphenyl) propyl) phosphate, diallyl (3- (4-cyclohexylphenyl) propyl) Compounds in which R ³ and R ⁴ are alkenyl groups having 2 to 12 carbon atoms and m = 3, such as phosphates;

Diphenyl (3-phenylpropyl) phosphate, diphenyl (3- (2-n-pentylphenyl) propyl) phosphate, diphenyl (3- (3-n-pentylphenyl) propyl) phosphate, diphenyl (3- (4-n- Pentylphenyl) propyl) phosphate, diphenyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, diphenyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, diphenyl (3 -(2-t-amylphenyl) propyl) phosphate, diphenyl (3- (3
-T-amylphenyl) propyl) phosphate, diphenyl (3- (4-t-amylphenyl) propyl) phosphate, diphenyl (3- (2,4-di-t-amylphenyl) propyl) phosphate, diphenyl (3- (3,5-di-t-amylphenyl) propyl) phosphate, diphenyl (3- (2-cyclopentylphenyl) propyl) phosphate, diphenyl (3- (3-cyclopentylphenyl) propyl) phosphate, diphenyl (3- (4 -Cyclopentylphenyl) propyl) phosphate, diphenyl (3- (2-
Cyclohexylphenyl) propyl) phosphate, diphenyl (3- (3-cyclohexylphenyl) propyl) phosphate, diphenyl (3- (4-cyclohexylphenyl) propyl) phosphate, etc. R ³ and R ⁴ are aryl having 6 to 12 carbon atoms A compound wherein m = 3 in the group;

Dibenzyl (3-phenylpropyl) phosphate, dibenzyl (3- (2-n-pentylphenyl) propyl) phosphate, dibenzyl (3- (3-n-pentylphenyl) propyl) phosphate, dibenzyl (3- (4-n- Pentylphenyl) propyl) phosphate, dibenzyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, dibenzyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, dibenzyl (3 -(2-t-amylphenyl) propyl) phosphate, dibenzyl (3- (3
-T-amylphenyl) propyl) phosphate, dibenzyl (3- (4-t-amylphenyl) propyl) phosphate, dibenzyl (3- (2,4-di-t-amylphenyl) propyl) phosphate, dibenzyl (3- (3,5-di-t-amylphenyl) propyl) phosphate, dibenzyl (3- (2-cyclopentylphenyl) propyl) phosphate, dibenzyl (3- (3-cyclopentylphenyl) propyl) phosphate, dibenzyl (3- (4 -Cyclopentylphenyl) propyl) phosphate, dibenzyl (3- (2-
Cyclohexylphenyl) propyl) phosphate, dibenzyl (3- (3-cyclohexylphenyl) propyl) phosphate, dibenzyl (3- (4-cyclohexylphenyl) propyl) phosphate, tri-3-phenylpropylphosphate, di-3-phenylpropyl (3- (2-n-pentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (3-n-pentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (4-n- Pentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (3,5-di-n-) Pentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (2 -T-amylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (3-t-amylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (4-t-amylphenyl) propyl) Phosphate, di-3-phenylpropyl (3- (2,4-di-t-amylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (3,5-di-t-amylphenyl) propyl) Phosphate, di-3-phenylpropyl (3- (2-cyclopentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (3-cyclopentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- ( 4-Cyclopentylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (2-cyclohexylphene) N) propyl) phosphate, di-3-phenylpropyl (3- (3-cyclohexylphenyl) propyl) phosphate, di-3-phenylpropyl (3- (4-cyclohexylphenyl) propyl) phosphate, R ³ , R ^A compound wherein ⁴ is an aralkyl group having 7 to 12 carbon atoms and m = 3;

Trifluoromethyl (3-phenylpropyl) phosphate, trifluoromethyl (3-
(2-n-pentylphenyl) propyl) phosphate, trifluoromethyl (3- (3-n-pentylphenyl) propyl) phosphate, trifluoromethyl (3- (4-n-pentylphenyl) propyl) phosphate, trifluoro Methyl (3- (2,4-di-n-pentylphenyl) propyl) phosphate, trifluoromethyl (3- (3,5-di-n-pentylphenyl) propyl) phosphate, trifluoromethyl (3- (2 -T-amylphenyl) propyl) phosphate, trifluoromethyl (3- (3-t-amylphenyl) propyl) phosphate, trifluoromethyl (3- (4-t-amylphenyl) propyl) phosphate, trifluoromethyl ( 3- (2,4-di-t-amylphenyl) propyl) phosphate, trifluoro Chill (3- (3,5-di -t- amyl phenyl) propyl) phosphates, trifluoromethyl (3- (2-cyclopentyl-phenyl) propyl) phosphates, trifluoromethyl (3- (3-cyclopentyloxy-phenyl) propyl)
Phosphate, trifluoromethyl (3- (4-cyclopentylphenyl) propyl) phosphate, trifluoromethyl (3- (2-cyclohexylphenyl) propyl) phosphate, trifluoromethyl (3- (3-cyclohexylphenyl) propyl) phosphate, A compound in which R ³ and R ⁴ are fluorinated alkyl groups having 1 to 12 carbon atoms and m = 3, such as trifluoromethyl (3- (4-cyclohexylphenyl) propyl) phosphate;

Among the above compounds, R ^{1 to} R ⁴ in the general formula (I) are an alkyl group having 1 to 3 carbon atoms, a phenyl group, and an aralkyl from the viewpoint of improving safety during overcharge and improving high-temperature storage characteristics. Preferably, Ar is a phenyl group, and the substituent on the phenyl group is a group selected from hydrogen, a secondary alkyl group having 4 or more carbon atoms, and a tertiary alkyl group. It is preferable that m represents an integer of 3 or more and 5 or less.

R ^{1 to} R ⁴ in the general formula (I) are more preferably a group selected from a methyl group, an ethyl group, a phenyl group, and a 3-phenylpropyl group, and Ar is more preferably a phenyl group. More preferably, the substituent on the phenyl group is a group selected from hydrogen, t-butyl group, t-amyl group, cyclopentyl group, and cyclohexyl group, and m represents an integer of 3 to 5. More preferred.

In the general formula (I), R ^{1 to} R ⁴ are more preferably a group selected from a methyl group, an ethyl group, and a 3-phenylpropyl group, and Ar is more preferably a phenyl group. The substituent on the group is more preferably a group selected from hydrogen, t-amyl group, cyclopentyl group, and cyclohexyl group, and more preferably m represents an integer of 3 or more and 5 or less.

In addition, R ^{1 to} R ⁴ in the general formula (I) are particularly preferably a group selected from a methyl group, an ethyl group, and a 3-phenylpropyl group, and Ar is more preferably a phenyl group. It is particularly preferable that the substituent on the group is hydrogen, and it is particularly preferable that m represents an integer of 3 to 5.
Here, Y in the general formula (I) is

Represents any of the three types, preferably

Represents one of the two types, more preferably

Represents.
The compounds represented by formula (I) may be used alone or in combination of two or more. The proportion of the compound represented by the general formula (I) in the non-aqueous electrolyte is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.05% by mass or more, particularly Preferably it is 0.1 mass% or more. If the concentration is lower than this, the effects of the present invention may not be easily exhibited. On the other hand, if the concentration is too high, the capacity of the battery may decrease, so it is preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less, and particularly preferably 3% by mass or less. Most preferably, it is 2 mass% or less.

The reason why the non-aqueous electrolyte according to the present invention is excellent in safety during overcharge and excellent in high-temperature storage characteristics is not clear, and the present invention is not limited to the following operation principle, It is guessed as follows.
The compound represented by the general formula (I) has an Ar (aryl group) to which an alkyl chain having a certain length or more is bonded in the molecule, and an ester bond in Y bonded to the alkyl group.

  In general, a compound having an aryl group substituted with an alkyl group has a benzylic hydrogen that is easily oxidized, and therefore has a lower oxidation potential than a compound having an aryl group substituted with an ester group, and at an earlier stage during overcharge. It can react to increase safety during overcharge. Usually, a compound having a low oxidation potential reacts at a site where the activity of the electrode is high even at high temperature storage, and deteriorates battery characteristics after high temperature storage.

However, in the present invention, an ester group is intentionally bonded to an aryl group via an alkyl group, so that an unshared electron pair of ether oxygen in the ester group stabilizes the benzylic carbon in the molecule and causes a side reaction on the electrode. We think that we suppress. In addition, when m = 1, no effect is seen when an ester group is bonded through an alkyl chain having a certain length or less. Therefore, the distance between the aryl group and the ester group in the molecule is important. Conceivable. In the high-temperature storage test, the kinetic factor is the dominant factor, but the thermodynamic factor is dominant during overcharge, so it is assumed that the stabilization effect due to ether oxygen does not interfere with the overcharge reaction.
In particular, as in the present invention, by a compound in which an Ar (aryl) group and an ester group are bonded via an alkyl group having 2 or more carbon atoms, a side reaction with a highly active positive electrode having a high stabilizing effect by ether oxygen is further performed. It can be suppressed, and it is considered that the effect of suppressing deterioration of battery characteristics after high-temperature storage is high while enhancing safety during overcharge.

(Electrolytes)
There is no restriction | limiting in the electrolyte used for the non-aqueous electrolyte of this invention, A well-known thing can be used arbitrarily if it is used as an electrolyte for the target non-aqueous electrolyte secondary battery.
When the nonaqueous electrolytic solution of the present invention is used for a lithium secondary battery, a lithium salt is usually used as an electrolyte.

Specific examples of the electrolyte include LiClO ₄ , LiAsF ₆ , LiPF ₆ , and LiBF _4.
Inorganic lithium salts such as LiFSO ₃ ; LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-tetrafluoroethanedisulfonylimide, lithium cyclic 1 , 3-hexafluoropropanedisulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiPF
₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂
, LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C
₂ F ₅ ) ₂ , LiBF ₂ (CF ₃ SO ₂ ) ₂ , LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂
Fluorine-containing organic lithium salts such as lithium bis (oxalato) borate, lithium difluorooxalatoborate, lithium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalatophosphate and the like; Etc.

Among these, LiPF ₆ , LiBF ₄ , LiFSO ₃ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-tetrafluoroethanedisulfonylimide , Lithium cyclic 1,3-hexafluoropropane disulfonylimide, lithium bis (oxalato) borate, lithium difluorooxalatoborate, lithium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalatophosphate In particular, LiPF ₆ and LiBF ₄ are preferable.

Moreover, these lithium salts may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. In particular, the combined use of specific inorganic lithium salts and the combined use of inorganic lithium salts with fluorine-containing organic lithium salts and carboxylic acid complex lithium salts suppresses gas generation during high-temperature storage or suppresses deterioration after high-temperature storage. Therefore, it is preferable.
In particular, the combination and the LiPF ₆ and LiBF _4, and an inorganic lithium salt such as _{LiPF 6, LiBF 4, LiCF 3} SO 3, LiN (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, lithium Fluorine-containing organic lithium salts such as cyclic 1,2-tetrafluoroethanedisulfonylimide and lithium cyclic 1,3-hexafluoropropanedisulfonylimide, lithium bis (oxalato) borate, lithium difluorooxalatoborate, lithium tris ( Oxalato) phosphate, lithium difluorobis (oxalato) phosphate, dicarboxylic acid complex lithium salt such as lithium tetrafluorooxalatophosphate is preferably used in combination.

When used in combination LiPF ₆ and LiBF ₄ are the content of LiBF ₄ to the total of LiPF ₆ and LiBF ₄ is preferably 0.01 mass% or more, more preferably 0.0
5 mass% or more, more preferably 0.1 mass% or more, preferably 20 mass% or less, more preferably 10 mass% or less, still more preferably 5 mass% or less, and particularly preferably 3 mass% or less.
If it is less than this range, the desired effect may not be obtained, and if it exceeds this range, battery characteristics such as high load discharge characteristics may deteriorate.

On the other hand, inorganic lithium salts such as LiPF ₆ and LiBF ₄ and LiCF ₃ SO ₃ and LiN
Fluorine-containing organic materials such as (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-tetrafluoroethanedisulfonylimide, and lithium cyclic 1,3-hexafluoropropane disulfonylimide When using lithium salt or lithium salt of dicarboxylic acid complex such as lithium bis (oxalato) borate, lithium difluorooxalatoborate, lithium tris (oxalato) phosphate, lithium difluorobis (oxalato) phosphate, lithium tetrafluorooxalatophosphate The content of the inorganic lithium salt in the total of both is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, preferably 99% by mass or less, more preferably 95% by mass. % Or less

  The concentration of these electrolytes in the non-aqueous electrolyte solution is not particularly limited in order to exhibit the effects of the present invention, but is preferably 0.5 mol / liter or more, more preferably 0.8 mol / liter or more. More preferably, it is 1.0 mol / liter or more. Further, it is preferably 3 mol / liter or less, more preferably 2 mol / liter or less, still more preferably 1.8 mol / liter or less, and particularly preferably 1.6 mol / liter or less. If the concentration is too low, the electrical conductivity of the electrolyte solution may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity, and the battery performance may decrease. .

(Non-aqueous solvent)
The non-aqueous solvent can also be appropriately selected from conventionally known solvents for non-aqueous electrolyte solutions. For example, cyclic carbonates, chain carbonates, cyclic carboxylic acid esters, chain carboxylic acid esters, cyclic ethers, chain ethers, sulfur-containing organic solvents, phosphorus-containing organic solvents, aromatic fluorine-containing solvents, etc. Can be mentioned.

  Examples of the cyclic carbonates include alkylene carbonates having an alkylene group having 2 to 4 carbon atoms such as ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are preferable from the viewpoint of improving battery characteristics. In particular, ethylene carbonate is preferred. Further, a part of hydrogen of these compounds may be substituted with fluorine.

  Examples of cyclic carbonates substituted with fluorine include fluoroethylene carbonate, 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, tetrafluoroethylene carbonate, 1-fluoro- Such as 2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, etc. Examples include alkylene carbonates having an alkylene group substituted with fluorine having 2 to 4 carbon atoms. Among these, fluoroethylene carbonate, 1,2-difluoroethylene carbonate, trifluoromethyl Ethylene carbonate is preferred.

As the chain carbonates, dialkyl carbonates are preferable, and the number of carbon atoms of the alkyl group constituting each is preferably 1 to 5, particularly preferably 1 to 4. Specifically, for example, symmetrical chain alkyl carbonates such as dimethyl carbonate, diethyl carbonate, and di-n-propyl carbonate; asymmetric chain alkyl such as ethyl methyl carbonate, methyl-n-propyl carbonate, and ethyl-n-propyl carbonate Examples include carbonates, and among them, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are preferable from the viewpoint of improving battery characteristics. Further, a part of hydrogen of the alkyl group may be substituted with fluorine. Examples of chain carbonates substituted with fluorine include bis (fluoromethyl) carbonate, bis (difluoromethyl) carbonate, bis (trifluoromethyl) carbonate, bis (2-fluoroethyl) carbonate, and bis (2,2-difluoroethyl). ) Carbonate, bis (2,2,2-trifluoroethyl) carbonate, 2-fluoroethyl methyl carbonate, 2,2-difluoroethyl methyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, and the like.

  Examples of the cyclic carboxylic acid esters include γ-butyrolactone, γ-valerolactone, and the like, and compounds obtained by substituting a part of hydrogen of these compounds with fluorine. Examples of chain carboxylates include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, sec-butyl acetate, isobutyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, propion Examples include isopropyl acid, methyl butyrate, ethyl butyrate, propyl butyrate, methyl valerate, ethyl valerate, etc., and compounds in which part of hydrogen of these compounds such as propyl trifluoroacetate and butyl trifluoroacetate is substituted with fluorine. Methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, and methyl valerate are more preferred.

Examples of the cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran and the like, and compounds obtained by substituting a part of hydrogen of these compounds with fluorine.
Examples of chain ethers include dimethoxyethane, diethoxyethane, and the like, and compounds obtained by substituting a part of hydrogen of these compounds with fluorine. Bis trifluoroethoxyethane, ethoxytrifluoroethoxyethane, methoxytrifluoroethoxyethane, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-trifluoromethyl-pentane, 1,1,1,2,2,3,4,5 , 5,5-decafluoro-3-ethoxy-4-trifluoromethyl-pentane, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-propoxy-4-tri Fluoromethyl-pentane, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 2,2-difluoroethyl-2,2,3,3- Tiger fluoropropyl ether.

Examples of the sulfur-containing organic solvent include sulfolane, 2-methylsulfolane, 3-methylsulfolane, diethylsulfone, ethylmethylsulfone, methylpropylsulfone, and the like, and compounds in which part of hydrogen of these compounds is substituted with fluorine.
Examples of the phosphorus-containing organic solvent include trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl diethyl phosphate, ethylene methyl phosphate, ethylene ethyl phosphate, etc., and compounds in which part of hydrogen of these compounds is substituted with fluorine Is mentioned.

Examples of the aromatic fluorine-containing solvent include fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, benzotrifluoride and the like.
These may be used alone or in combination of two or more, but it is preferable to use in combination of two or more. For example, it is preferable to use a high dielectric constant solvent such as cyclic carbonates or cyclic carboxylic acid esters in combination with a low viscosity solvent such as chain carbonates or chain carboxylic acid esters.

One preferable combination of the non-aqueous solvents is a combination mainly composed of alkylene carbonate and dialkyl carbonate. Among them, the total of alkylene carbonate and dialkyl carbonate in the non-aqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, still more preferably 90% by volume or more, and alkylene carbonate and dialkyl carbonate. The proportion of alkylene carbonate with respect to the total amount of is preferably 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more, preferably 50% by volume or less, more preferably 35% by volume or less, still more preferably Is 30% by volume or less, particularly preferably 25% by volume or less. When a combination of these non-aqueous solvents is used, the balance between the cycle characteristics and high-temperature storage characteristics (particularly, the remaining capacity and high-load discharge capacity after high-temperature storage) of a battery manufactured using the non-aqueous solvent may be improved.

As the alkylene carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate are preferable from the viewpoint of improving the cycle characteristics and high-temperature storage characteristics of the battery.
Specific examples of preferred combinations of ethylene carbonate and dialkyl carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and ethyl methyl. Examples thereof include carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

A combination in which propylene carbonate is further added to a combination of these ethylene carbonate and dialkyl carbonates is also mentioned as a preferable combination.
In the case of containing propylene carbonate, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 40:60, particularly preferably 95: 5 to 50:50. Furthermore, the proportion of propylene carbonate in the whole non-aqueous solvent is preferably 0.1% by volume or more, more preferably 1% by volume or more, still more preferably 2% by volume or more, and preferably 20% by volume or less, more preferably Is 8% by volume or less, more preferably 5% by volume or less. It is preferable to contain propylene carbonate in this concentration range because the low temperature characteristics may be further improved while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonate.

  Among the combinations of ethylene carbonate and dialkyl carbonate, those containing asymmetrical chain alkyl carbonates as dialkyl carbonate are more preferred, especially ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate. Those containing ethylene carbonate, symmetric chain alkyl carbonates and asymmetric chain alkyl carbonates, such as ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, are preferable because of a good balance between cycle characteristics and large current discharge characteristics. Among them, the asymmetric chain alkyl carbonate is preferably ethyl methyl carbonate, and the alkyl group of the alkyl carbonate preferably has 1 to 2 carbon atoms.

  Specific examples of preferred combinations of fluoroethylene carbonate and dialkyl carbonate include fluoroethylene carbonate and dimethyl carbonate, fluoroethylene carbonate and diethyl carbonate, fluoroethylene carbonate and ethyl methyl carbonate, fluoroethylene carbonate and dimethyl carbonate and diethyl carbonate, and fluoroethylene carbonate. And dimethyl carbonate and ethyl methyl carbonate, fluoroethylene carbonate, diethyl carbonate and ethyl methyl carbonate, fluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

A combination obtained by further adding ethylene carbonate and / or propylene carbonate to the combination of these fluoroethylene carbonate and dialkyl carbonate is also mentioned as a preferable combination.
When diethyl carbonate is contained in the non-aqueous solvent, the proportion of diethyl carbonate in the total non-aqueous solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and further preferably 25% by volume or more. It is particularly preferably 30% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less, still more preferably 75% by volume or less, and particularly preferably 70% by volume or less. And gas generation during high temperature storage may be suppressed.

  When dimethyl carbonate is contained in the non-aqueous solvent, the proportion of dimethyl carbonate in the total non-aqueous solvent is preferably 10% by volume or more, more preferably 20% by volume or more, and further preferably 25% by volume or more. It is particularly preferably 30% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less, still more preferably 75% by volume or less, and particularly preferably 70% by volume or less. As a result, the load characteristics of the battery may be improved.

Above all, it contains dimethyl carbonate and ethyl methyl carbonate, and by increasing the content ratio of dimethyl carbonate over the content ratio of ethyl methyl carbonate, the battery characteristics after high-temperature storage are improved while ensuring the electrical conductivity of the electrolyte. This is preferable.
The capacity ratio of dimethyl carbonate to ethyl methyl carbonate in all non-aqueous solvents (dimethyl carbonate / ethyl methyl carbonate) is 1.1 or more in terms of improving the electrical conductivity of the electrolyte and improving the battery characteristics after storage. Is preferably 1.5 or more, more preferably 2.5 or more. The capacity ratio (dimethyl carbonate / ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 8 or less, from the viewpoint of improving battery characteristics at low temperatures.

  Further, in the combination mainly composed of the alkylene carbonates and dialkyl carbonates, cyclic carbonates other than the alkylene carbonates and dialkyl carbonates, chain carbonates, cyclic carboxylic acid esters, chain carboxylic acid esters, Other solvents such as cyclic ethers, chain ethers, sulfur-containing organic solvents, phosphorus-containing organic solvents, and aromatic fluorine-containing solvents may be mixed.

Another example of the preferred non-aqueous solvent is an organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate and butylene carbonate, or a mixed solvent consisting of two or more organic solvents selected from the group. It occupies 60% by volume or more. A non-aqueous electrolyte using this mixed solvent may reduce solvent evaporation and liquid leakage even when used at high temperatures. Among them, the total of ethylene carbonate and propylene carbonate in the non-aqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, still more preferably 90% by volume or more, and the capacity of ethylene carbonate and propylene carbonate. When the ratio is preferably 30:70 to 60:40, the balance between cycle characteristics and high-temperature storage characteristics may be improved.
In the present specification, the capacity of the non-aqueous solvent is a measured value at 25 ° C., but a measured value at the melting point is used for a solid at 25 ° C. such as ethylene carbonate.

(Other compounds)
The nonaqueous electrolytic solution according to the present invention is a cyclic carbonate compound having a carbon-carbon unsaturated bond, a cyclic carbonate compound having a fluorine atom, a monofluorophosphate, and a difluorophosphate within a range not impairing the effects of the present invention. Various other compounds such as at least one compound selected from the group consisting of and a conventionally known overcharge inhibitor may be contained as an auxiliary agent.
Among these, when containing at least one compound selected from the group consisting of a cyclic carbonate compound having a carbon-carbon unsaturated bond, a cyclic carbonate compound having a fluorine atom, a monofluorophosphate, and a difluorophosphate, a negative electrode In order to form a highly stable film, cycle characteristics and battery characteristics after high-temperature storage may be improved, which is preferable.

((Cyclic carbonate compound having a carbon-carbon unsaturated bond))
Examples of the cyclic carbonate compound having a carbon-carbon unsaturated bond include vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, 1,2-dimethyl vinylene carbonate, 1,2-diethyl vinylene carbonate, fluoro vinylene carbonate, trifluoromethyl. Vinylene carbonate compounds such as vinylene carbonate; vinyl ethylene carbonate, 1-methyl-2-vinylethylene carbonate, 1-ethyl-2-vinylethylene carbonate, 1-n-propyl-2-vinylethylene carbonate, 1-methyl-2- Vinyl ethylene carbonate compounds such as vinyl ethylene carbonate, 1,1-divinyl ethylene carbonate, 1,2-divinyl ethylene carbonate; 1,1-dimethyl-2- Chi Ren ethylene carbonate, methylene ethylene carbonate compounds such as 1,1-diethyl-2-methylene-ethylene carbonate. Among these, vinylene carbonate, vinyl ethylene carbonate, and 1,2-divinyl ethylene carbonate are preferable from the viewpoint of improving cycle characteristics and capacity maintenance characteristics after high-temperature storage, among which vinylene carbonate or vinyl ethylene carbonate is more preferable, and vinylene carbonate is particularly preferable. preferable. These may be used alone or in combination of two or more.
When using 2 or more types together, it is preferable to use together vinylene carbonate and vinyl ethylene carbonate.

((Cyclic carbonate compound having fluorine atom))
Examples of the cyclic carbonate compound having a fluorine atom include fluoroethylene carbonate, 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate, tetrafluoroethylene carbonate, 1- Fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate Etc. Of these, fluoroethylene carbonate, 1,2-difluoroethylene carbonate, and 1-fluoro-2-methylethylene carbonate are preferable from the viewpoint of improving cycle characteristics and high-temperature storage characteristics. These may be used alone or in combination of two or more.
In addition, it may be used in combination with a cyclic carbonate compound having a carbon-carbon unsaturated bond and the monofluorophosphate and difluorophosphate described below, and is used in combination from the viewpoint of improving cycle characteristics and high-temperature storage characteristics. Is preferred.

((Monofluorophosphate and difluorophosphate))
The counter cation of monofluorophosphate and difluorophosphate is not particularly limited, but lithium, sodium, potassium, magnesium, calcium, and NR ¹ R ² R ³ R ⁴ (wherein R ^{1 to} R ⁴ Are each independently a hydrogen atom or carbon number 1-12.
Represents an organic group of As an example, ammonium represented by
Although there is no particular limitation on the organic group having 1 to 12 carbon atoms represented by R ¹ to R ⁴ of the above ammonium, for example, which may be substituted with a halogen atom an alkyl group, substituted with a halogen atom or an alkyl group Examples thereof include an cycloalkyl group which may be substituted, an aryl group which may be substituted with a halogen atom or an alkyl group, and a nitrogen atom-containing heterocyclic group which may have a substituent. Among these, as R ^{1 to} R ⁴ , a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group is preferable.

  Specific examples of monofluorophosphate and difluorophosphate include lithium monofluorophosphate, sodium monofluorophosphate, potassium monofluorophosphate, tetramethylammonium monofluorophosphate, tetraethylammonium monofluorophosphate, difluoro Examples include lithium phosphate, sodium difluorophosphate, potassium difluorophosphate, tetramethylammonium difluorophosphate, tetraethylammonium difluorophosphate, etc., preferably lithium monofluorophosphate and lithium difluorophosphate, more preferably lithium difluorophosphate. preferable.

These may be used alone or in combination of two or more.
Moreover, you may use together with the cyclic carbonate compound which has a carbon-carbon unsaturated bond, and the cyclic carbonate compound which has a fluorine atom, and it is preferable to use together from the point of a cycling characteristic improvement or the characteristic improvement after high temperature storage.
When the non-aqueous electrolyte contains a cyclic carbonate compound having a carbon-carbon unsaturated bond, the proportion in the non-aqueous electrolyte is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, More preferably, it is 0.1 mass% or more, Most preferably, it is 0.3 mass% or more. If the proportion of the cyclic carbonate compound having a carbon-carbon unsaturated bond is too small, the effect of improving the cycle characteristics of the battery and the capacity maintenance characteristics after high-temperature storage may not be sufficiently exhibited. However, if the ratio of the cyclic carbonate compound having a carbon-carbon unsaturated bond is too large, the amount of gas generated may increase during storage at high temperatures, or the discharge characteristics at low temperatures may decrease. More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less.

  When the non-aqueous electrolyte contains a cyclic carbonate compound having a fluorine atom as an auxiliary agent, the proportion in the non-aqueous electrolyte is preferably 0.001% by mass or more, more preferably 0.1% by mass or more, and further Preferably it is 0.3% by mass or more, particularly preferably 0.5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 4% by mass or less, particularly preferably 3% by mass. It is as follows.

If the ratio is less than the above range, the effect of improving the cycle characteristics and high temperature storage characteristics of the battery may not be sufficiently exhibited. The discharge characteristics may deteriorate.
When the non-aqueous electrolyte contains a monofluorophosphate and / or difluorophosphate, the proportion in the non-aqueous electrolyte is preferably 0.001% by mass or more, more preferably 0.01% by mass or more. More preferably, it is 0.1% by mass or more, particularly preferably 0.2% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass or less.

If the ratio is less than the above range, there is a possibility that the effect of improving the cycle characteristics and high-temperature storage characteristics of the battery may not be sufficiently exhibited. Tend.
Conventionally known overcharge inhibitors include alkylbiphenyls such as biphenyl, 2-methylbiphenyl, 2-ethylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclopentylbenzene, cyclohexylbenzene, cis-1-propyl-4 -Phenylcyclohexane, trans-1-propyl-4-phenylcyclohexane, cis-1-butyl-4-phenylcyclohexane, trans-1-butyl-4-phenylcyclohexane, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran , Methyl phenyl carbonate, ethyl phenyl carbonate, diphenyl carbonate, triphenyl phosphate, tris (2-t-butylphenyl) phosphate, tris (3-t
-Butylphenyl) phosphate, tris (4-t-butylphenyl) phosphate, tris (2-t-amylphenyl) phosphate, tris (3-t-amylphenyl) phosphate, tris (4-t-amylphenyl) phosphate, Aromatic compounds such as tris (2-cyclohexylphenyl) phosphate, tris (3-cyclohexylphenyl) phosphate, tris (4-cyclohexylphenyl) phosphate; 2-fluorobiphenyl, 3-fluorobiphenyl, 4-fluorobiphenyl, 4,4 Partially fluorinated products of the above aromatic compounds such as' -difluorobiphenyl, 2,4-difluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difur Examples thereof include fluorine-containing anisole compounds such as oroanisole, 2,6-difluoroanisole, and 3,5-difluoroanisole.

  Among these, alkylbiphenyl such as biphenyl and 2-methylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclopentylbenzene, cyclohexylbenzene, cis-1-propyl-4-phenylcyclohexane, trans-1-propyl-4- Phenylcyclohexane, cis-1-butyl-4-phenylcyclohexane, trans-1-butyl-4-phenylcyclohexane, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran, methylphenyl carbonate, diphenyl carbonate, triphenyl phosphate, Aromatic compounds such as tris (4-t-butylphenyl) phosphate, tris (4-cyclohexylphenyl) phosphate; 2-fluorobiphenyl, 3-fluorobiphenyl , 4-fluorobiphenyl, 4,4′-difluorobiphenyl, partial fluorinated products of the above aromatic compounds such as o-cyclohexyl fluorobenzene, p-cyclohexyl fluorobenzene, etc. are preferable, partially hydrogenated terphenyl, cyclopentylbenzene, cyclohexyl Benzene, cis-1-propyl-4-phenylcyclohexane, trans-1-propyl-4-phenylcyclohexane, cis-1-butyl-4-phenylcyclohexane, trans-1-butyl-4-phenylcyclohexane, t-butylbenzene , T-amylbenzene, methylphenyl carbonate, diphenyl carbonate, triphenyl phosphate, tris (4-t-butylphenyl) phosphate, tris (4-cyclohexylphenyl) phosphate, o Cyclohexyl fluorobenzene, more preferably p- cyclohexyl fluorobenzene, partially hydrogenated member and cyclohexylbenzene terphenyl is particularly preferred.

  Two or more of these may be used in combination. When two or more types are used in combination, in particular, a partially hydrogenated terphenyl, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, or a partially hydrogenated biphenyl, alkylbiphenyl, terphenyl or terphenyl. It is overcharged to use together those selected from oxygen-free aromatic compounds such as cyclohexylbenzene, t-butylbenzene, t-amylbenzene and those selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran. This is preferable from the viewpoint of the balance between prevention characteristics and high-temperature storage characteristics.

  The content ratio of these overcharge inhibitors in the non-aqueous electrolyte is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and particularly preferably 0%. 0.5% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass or less. If the concentration is too low, the desired effect of the overcharge inhibitor may hardly be exhibited. On the other hand, if the concentration is too high, battery characteristics such as high-temperature storage characteristics tend to deteriorate.

Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate, methoxyethyl-ethyl carbonate, ethoxyethyl-methyl carbonate, ethoxyethyl-ethyl carbonate; succinic anhydride Carboxylic acids such as glutaric anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, glutaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride Anhydride: dimethyl succinate, diethyl succinate, diallyl succinate, dimethyl maleate, diethyl maleate, diallyl maleate, dipropyl maleate, dibutyl maleate, bis maleate (trifluoro Dicarboxylic acid diester compounds such as bis (pentafluoroethyl) maleate, bis (2,2,2-trifluoroethyl) maleate; 2,4,8,10-tetraoxaspiro [5.5] undecane Spiro compounds such as 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, propylene sulfite, 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, 1,4-butene sultone, methyl methanesulfonate, ethyl methanesulfonate, methyl-methoxymethanesulfonate, methyl-2-methoxyethanesulfonate, busulfan, diethylene glycol dimethanesulfonate, 1,2-ethanediol bis ( 2,2,2-Trifluo Ethanesulfonate), 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate), sulfolane, 3-sulfolene, 2-sulfolene, dimethylsulfone, diethylsulfone, divinylsulfone, diphenylsulfone, bis (methylsulfonyl) ) Methane, bis (methylsulfonyl) ethane, bis (ethylsulfonyl) methane, bis (ethylsulfonyl) ethane, bis (vinylsulfonyl) methane, bis (vinylsulfonyl) ethane, N, N-dimethylmethanesulfonamide, N, N -Sulfur-containing compounds such as diethylmethanesulfonamide, N, N-dimethyltrifluoromethanesulfonamide, N, N-diethyltrifluoromethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl Nitrogen-containing compounds such as 2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; heptane, octane, nonane, decane, cycloheptane, methylcyclohexane, ethylcyclohexane, propylcyclohexane, n -Hydrocarbon compounds such as butylcyclohexane, t-butylcyclohexane, dicyclohexyl; fluorinated benzenes such as fluorobenzene, difluorobenzene, pentafluorobenzene, hexafluorobenzene; 2-fluorotoluene, 3-fluorotoluene, 4-fluorotoluene, Fluorinated toluene such as benzotrifluoride; Nitto such as acetonitrile, propionitrile, butyronitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, etc. Methyl dimethyl phosphinate, ethyl dimethyl phosphinate, ethyl diethyl phosphinate, trimethylphosphonoformate, triethylphosphonoformate, trimethylphosphonoacetate, triethylphosphonoacetate, trimethyl-3-phosphonopropionate, Examples thereof include phosphorus-containing compounds such as triethyl-3-phosphonopropionate. Among these, ethylene sulfite, 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, 1,4-butene sultone, busulfan, 1,4 in terms of improving battery characteristics after high-temperature storage -Sulfur-containing compounds such as butanediol bis (2,2,2-trifluoroethanesulfonate); nitrile compounds such as acetonitrile, propionitrile, butyronitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, and pimelonitrile are preferable.

Two or more of these may be used in combination.
The content ratio of these auxiliaries in the non-aqueous electrolyte solution is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. Yes, 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% by mass or less. The addition of these auxiliaries is preferable in terms of improving capacity maintenance characteristics and cycle characteristics after high-temperature storage. If the concentration is lower than this lower limit, the effect of the auxiliary agent may be hardly exhibited. Conversely, if the concentration is too high, battery characteristics such as high load discharge characteristics may be degraded.

(Preparation of electrolyte)
The nonaqueous electrolytic solution according to the present invention can be prepared by dissolving an electrolyte, a compound represented by the general formula (I), and, if necessary, other compounds in a nonaqueous solvent. In preparing the non-aqueous electrolyte solution, each raw material is preferably dehydrated in advance in order to reduce the water content when the electrolyte solution is used. The dehydration is preferably performed to 50 ppm or less, more preferably 30 ppm or less, and even more preferably 10 ppm or less. Moreover, you may implement dehydration, a deoxidation process, etc. after electrolyte solution preparation.
The non-aqueous electrolyte solution of the present invention is suitable for use as a non-aqueous electrolyte solution for a secondary battery, that is, a non-aqueous electrolyte secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention will be described.

<Non-aqueous electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present invention is a non-aqueous electrolyte battery including a negative electrode and a positive electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte, and the non-aqueous electrolyte is a non-aqueous electrolyte of the present invention. It is an aqueous electrolyte solution.

(Battery configuration)
The non-aqueous electrolyte secondary battery according to the present invention can occlude and release lithium ions as in the case of a conventionally known non-aqueous electrolyte secondary battery except that it is produced using the non-aqueous electrolyte of the present invention. A non-aqueous electrolyte battery including a negative electrode and a positive electrode and a non-aqueous electrolyte solution. Usually, the positive electrode and the negative electrode are accommodated in a case through a porous film impregnated with the non-aqueous electrolyte solution of the present invention. can get. Therefore, the shape of the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

(Negative electrode active material)
The negative electrode active material is not particularly limited as long as it can occlude and release lithium ions. Specific examples thereof include carbonaceous materials, alloy-based materials, lithium-containing metal composite oxide materials, and the like.
These negative electrode active materials may be used alone or in combination of two or more. Of these, carbonaceous materials and alloy materials are preferred.

Among the carbonaceous materials, amorphous carbon materials, graphite, and those in which the surface of graphite is coated with amorphous carbon compared to graphite are preferred, and in particular, the surface of graphite or graphite is amorphous compared to graphite. Those coated with carbon are generally preferred because of their high energy density.
Graphite preferably has a lattice plane (002 plane) d value (interlayer distance) of 0.335 to 0.338 nm, particularly 0.335 to 0.337 nm, as determined by X-ray diffraction using the Gakushin method. The crystallite size (Lc) determined by X-ray diffraction by the Gakushin method is preferably 10 nm or more, more preferably 50 nm or more, and still more preferably 100 nm or more. The ash content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.1% by mass or less.

  The graphite surface coated with amorphous carbon is preferably graphite having a d-value of 0.335 to 0.338 nm on the lattice plane (002 plane) in X-ray diffraction as a core material. A carbonaceous material having a larger d-value on the lattice plane (002 plane) in X-ray diffraction than the core material is attached, and the d-value on the lattice plane (002 plane) in X-ray diffraction is greater than that of the core material and the core material. The ratio with respect to the carbonaceous material having a large is 99/1 to 80/20 in mass ratio. When this is used, a negative electrode having a high capacity and hardly reacting with the electrolytic solution can be produced.

The particle size of the carbonaceous material is a median diameter by a laser diffraction / scattering method, preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, particularly preferably 7 μm or more, preferably 100 μm or less, more preferably Is 50 μm or less, more preferably 40 μm
μm or less, particularly preferably 30 μm or less.
The specific surface area of the carbonaceous material by the BET method is preferably 0.3 m ² / g or more, more preferably 0.5 m ² / g or more, still more preferably 0.7 m ² / g or more, and particularly preferably 0.00.
8 m ² / g or more, preferably 25.0 m ² / g or less, more preferably 20.0 m
² / g or less, more preferably 15.0 m ² / g or less, and particularly preferably 10.0 m ² / g or less.

Further, the carbonaceous material is analyzed by Raman spectrum using argon ion laser light, the peak is the peak intensity of the peak _{P A} in the range of 1570~1620cm ^-1 _I A, in the range of 1300~140cm ^-1 P If the peak intensity of the _B was _{I B,} R value represented by the ratio of _{I B} and _{I a (= I B / I} a) is what is preferably in the range of 0.01 to 0.7. Further, the half width of the peak in the range of 1570～1620Cm ^-1 is, 26cm ^-1 or less, are preferred in particular 25 cm ^-1 or less.

  The alloy material is not particularly limited as long as it can occlude / release lithium, and single metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides, and phosphides thereof. Any of these compounds may be used. Preferably, it is a material containing a single metal and an alloy forming a lithium alloy, more preferably a material containing a group 13 and group 14 metal / metalloid element (that is, excluding carbon), and further, aluminum, silicon, and It is preferably a simple metal of tin (which may be hereinafter referred to as “specific metal element”), and an alloy or compound containing these elements.

  Examples of the negative electrode active material having at least one element selected from specific metal elements include a single metal element of any one specific metal element, an alloy composed of two or more specific metal elements, one type, or two or more types An alloy composed of the specific metal element and one or more other metal elements, a compound containing one or more specific metal elements, and oxides, carbides, nitrides of the compounds, Examples include composite compounds such as silicides, sulfides, and phosphides. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

  Moreover, the compound which these complex compounds combined with several elements, such as a metal simple substance, an alloy, or a nonmetallic element, can also be mentioned as an example. More specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. In addition, for example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element can also be used. .

Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one metal element of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element A material, carbide, nitride or the like is preferable, and silicon and / or tin metal alone, an alloy, an oxide, carbide, nitride, or the like is particularly preferable because of its large capacity per unit mass.
In addition, although the capacity per unit mass is inferior to that of using a single metal or an alloy, the following compounds containing silicon and / or tin are also preferred because of excellent cycle characteristics.

The element ratio of silicon and / or tin to oxygen is preferably 0.5 or more, more preferably 0.7 or more, still more preferably 0.9 or more, and preferably 1.5 or less, more preferably Silicon and / or tin oxides of 1.3 or less, more preferably 1.1 or less.
The element ratio of silicon and / or tin and nitrogen is preferably 0.5 or more, more preferably 0.7 or more, still more preferably 0.9 or more, and preferably 1.5 or less, more preferably Silicon and / or tin nitride of 1.3 or less, more preferably 1.1 or less.

The element ratio of silicon and / or tin to carbon is preferably 0.5 or more, more preferably 0.7 or more, still more preferably 0.9 or more, and preferably 1.5 or less, more preferably Silicon and / or tin carbides of 1.3 or less, more preferably 1.1 or less.
These alloy materials may be in the form of powder or thin film, and may be crystalline or amorphous.

  The average particle size of the alloy-based material is not particularly limited in order to exhibit the effects of the present invention, but is preferably 50 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less, preferably 0.1 μm or more, More preferably, it is 1 micrometer or more, More preferably, it is 2 micrometers or more. If the particle size is too large, the expansion of the electrode is increased, and the cycle characteristics may be deteriorated. Moreover, when too small, it will become difficult to collect current, and capacity | capacitance may not fully express.

The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium. However, a lithium-titanium composite oxide (hereinafter referred to as “lithium-titanium composite oxide”) (Abbreviated) is preferred.
In addition, a part of lithium or titanium in the lithium titanium composite oxide is selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Mg, Cr, Ga, Cu, Zn, and Nb. Those substituted with at least one element are also preferred.

Furthermore, it is a lithium titanium composite oxide represented by Li _x Ti _y M _z O ₄ , and 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, and 0 ≦ z ≦ 1.6. It is preferable that the structure at the time of occlusion / release of lithium ions is stable (M is a group consisting of Na, K, Co, Al, Fe, Mg, Cr, Ga, Cu, Zn, and Nb). Represents at least one element selected).

Among them, when Z = 0 of the lithium titanium composite oxide represented by Li _x Ti _y M _z O ₄ , the structure in the case where x and y satisfy any of the following (a) to (c): This is preferable because of a good balance of battery performance.
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
More preferred representative compositions are Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), and Li _4/5 Ti _11/5 O ₄ in (c). .
As for the structure when Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3
O ₄ is mentioned as a preferable one.

(Positive electrode active material)
The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions. A substance containing lithium and at least one transition metal is preferable, and examples thereof include a lithium transition metal composite oxide and a lithium-containing transition metal phosphate compound.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable as the transition metal of the lithium transition metal composite oxide. Specific examples include lithium-cobalt composite oxides such as LiCoO ₂ and LiNiO ₂ . Examples of the lithium / nickel composite oxide include lithium / manganese composite oxides such as LiMnO ₂ , LiMn ₂ O ₄ , and Li ₂ MnO ₃ . In addition, a part of the transition metal atom that is the main component of the lithium transition metal composite oxide is replaced with another metal, that is, a part of Co in the lithium-cobalt composite oxide is replaced with Al, Ti, V, Cr. , Mn, Fe, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si substituted with other metals, part of Ni in the lithium-nickel composite oxide is Al, Ti, V, Cr, Mn, Fe, Co, L
i, Cu, Zn, Mg, Ga, Zr, Si and other metals substituted, part of Mn of lithium-manganese composite oxide is Al, Ti, V, Cr, Fe, Co, Li, Ni , Cu, Zn, Mg, Ga, Zr, Si substituted with other metals, and the like. Among those in which a part of the transition metal atom that is the main component of the lithium transition metal composite oxide is substituted with another metal, LiNi _1-ab Mn _a Co _b O ₂ (a and b are 0 or more and less than 1) Li, except for the case where a and b are both 0), LiNi _1-c- De Co _C Al _d Mg _e O ₂ (c, d, e represents a number from 0 to less than 1, , D, and e are preferably 0), and LiNi _{1 -ab} Mn _a Co _b O ₂ (0 ≦ a <0.4, 0 ≦ b <0.4), LiNi _{1− c-d-e Co c Al} d Mg e O 2 (0 ≦ c <0.3,0 ≦ d <0.1,0 ≦ e <0.05) are preferred, in _{particular, LiNi} 1/3 _{Co 1 / 3}
Mn _1/3 O ₂ , LiNi _0.5 Co _0.3 Mn _0.2 O ₂ , LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _{0 .85} Co _0.10 Al _0.03 Mg _0.02 O ₂ is preferred.

As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable. Specific examples include, for example, LiFePO ₄ , Li _3.
Examples thereof include iron phosphates such as F ₂ (PO ₄ ) ₃ and LiFeP ₂ O _{7 and} cobalt phosphates such as LiCoPO ₄ . In addition, a part of the transition metal atom that is the main component of the lithium transition metal phosphate compound is substituted with another metal, that is, a part of Fe of iron phosphates is Al, Ti, V, Cr, Mn, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si and other metals substituted, Co cobalt phosphates part of Co Al, Ti, V, Cr, Mn, Fe , Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si substituted with other metals, and the like.

These positive electrode active materials may be used alone or in combination.
In addition, a material in which a substance (surface adhering substance) having a composition different from that of the substance constituting the main cathode active material is attached to the surface of the cathode active material can be used. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

  The amount of the surface adhering substance is not particularly limited in order to exhibit the effect of the present invention, but is preferably 0.1 ppm or more, more preferably 1 ppm or more, and still more preferably, by mass with respect to the positive electrode active material. It is used at 10 ppm or more, preferably 20% or less, more preferably 10% or less, still more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the non-aqueous electrolyte solution on the surface of the positive electrode active material, and can improve the battery life. However, when the amount of the adhering quantity is too small, the effect is not sufficiently exhibited. If the amount is too large, the resistance may increase in order to inhibit the entry and exit of lithium ions.

(Manufacture of electrodes)
As the binder for binding the active material, any material can be used as long as it is a material that is stable with respect to the solvent and the electrolyte used in manufacturing the electrode. For example, fluorine resins such as polyvinylidene fluoride and polytetrafluoroethylene, polyolefins such as polyethylene and polypropylene, polymers having unsaturated bonds such as styrene / butadiene rubber, isoprene rubber and butadiene rubber, ethylene-acrylic acid copolymers, An acrylic acid polymer such as an ethylene-methacrylic acid copolymer may be used.

The electrode may contain a thickener, a conductive material, a filler and the like in order to increase mechanical strength and electrical conductivity.
Examples of the thickener include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein.

Examples of the conductive material include metal materials such as copper and nickel, and carbon materials such as graphite and carbon black.
The electrode may be manufactured by a conventional method. For example, it can be formed by adding a binder, a thickener, a conductive material, a solvent or the like to a negative electrode or a positive electrode active material to form a slurry, applying the slurry to a current collector, drying it, and then pressing it.

In addition, a material obtained by adding a binder or a conductive material to an active material is roll-formed as it is to form a sheet electrode, a pellet electrode is formed by compression molding, and an electrode is formed on the current collector by techniques such as vapor deposition, sputtering, or plating. A thin film of material can also be formed.
When graphite is used for the negative electrode active material, the density of the negative electrode active material layer after drying and pressing is preferably 1.45 g / cm ³ or more, more preferably 1.55 g / cm ³ or more, and still more preferably 1.
. 60 g / cm ³ or more, particularly preferably 1.65 g / cm ³ or more, it is.

The density after drying and pressing of the positive electrode active material layer is preferably 2.0 g / cm ³ or more,
More preferably, it is 2.5 g / cm ³ or more, and further preferably 3.0 g / cm ³ or more.
Various types of current collectors can be used, but metals and alloys are usually used. Examples of the current collector for the negative electrode include copper, nickel, and stainless steel, and copper is preferred. Examples of the positive electrode current collector include metals such as aluminum, titanium, and tantalum, and alloys thereof, and aluminum or an alloy thereof is preferable.

(Separator, exterior body)
A porous film (separator) is interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the electrolytic solution is used by impregnating the porous membrane. The material and shape of the porous film are not particularly limited as long as it is stable to the electrolytic solution and excellent in liquid retention, and a porous sheet or nonwoven fabric made of a polyolefin such as polyethylene or polypropylene is preferable.

The material of the battery casing used in the battery according to the present invention is also arbitrary, and nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, a laminate film, or the like is used.
The operating voltage of the above-described non-aqueous electrolyte secondary battery of the present invention is usually in the range of 2V to 4.9V.

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 as long as the gist thereof is not exceeded.
In addition, each evaluation method of the battery obtained by the following Example and the comparative example is shown below.
[Capacity evaluation]
The sheet-like non-aqueous electrolyte secondary battery is charged to 4.1 V with a constant current corresponding to 0.3 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. The battery was discharged to 3V with a constant current of 3C. This is done for 5 cycles to stabilize the battery. In the 4th cycle, after charging to 4.1 V with a constant current of 0.3 C, charging is performed until the current value reaches 0.05 C with a constant voltage of 4.1 V. The initial discharge capacity was determined by discharging to 3 V with a constant current of 0.3C.
Here, 1C represents a current value for discharging the reference capacity of the battery in one hour, for example, 0.3C
Represents a current value 0.3 times that.

[Overcharge characteristics evaluation]
The battery after the capacity evaluation test was charged to 4.1 V at a constant current of 0.3 C at 25 ° C., and then charged until the current value reached 0.05 C at a constant voltage of 4.1 V, in an ethanol bath. After measuring the volume by immersion, apply a constant current of 1.0C at 45 ° C, cut the current when it reaches 4.9V, and measure the open circuit voltage (OCV) of the battery after the overcharge test did. Next, the volume was measured by immersion in an ethanol bath, and the amount of gas generated from the volume change before and after overcharging was determined.

The lower the OCV of the battery after the overcharge test, the lower the overcharge depth and the higher the safety during overcharge. Further, the larger the amount of gas generated after overcharging, the more preferable the battery that senses this when the internal pressure rises abnormally due to an abnormality such as overcharging and operates the safety valve because the safety valve can be activated earlier. .
In addition, the greater the difference between the amount of gas generated after overcharging and the amount of gas generated during high-temperature storage, etc., prevents the safety valve from malfunctioning during high-temperature storage, etc., while reliably operating the safety valve during overcharging. Is preferable.

[Evaluation of high-temperature storage characteristics]
The battery after the capacity evaluation test was charged to 4.1 V at a constant current of 0.3 C at 25 ° C., and then charged until the current value reached 0.05 C at a constant voltage of 4.1 V, in an ethanol bath. The volume was measured by immersing in a high temperature, and a high temperature storage test was conducted at 75 ° C. for 72 hours (3 days).
After the high temperature storage test, the battery was cooled to 25 ° C. and then immersed in an ethanol bath to measure the volume, and the amount of gas generated from the volume change before and after high temperature storage was determined.

After the amount of generated gas was measured, it was discharged to 3 V at a constant current of 0.3 C at 25 ° C., and the remaining capacity after the high temperature storage test was measured.
Next, at 25 ° C., after charging to 4.1 V with a constant current of 0.3 C, charging is performed until the current value becomes 0.05 C with a constant voltage of 4.1 V, and 3 V with a constant current of 0.3 C. The 0.3 C discharge capacity after the high temperature storage test was measured.

Example 1
[Production of positive electrode]
90% by mass of lithium cobalt nickel manganese oxide (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ) as a positive electrode active material, 7% by mass of acetylene black as a conductive material, and polyvinylidene fluoride as a binder (PVdF) 3% by mass was mixed with a disperser in an N-methylpyrrolidone solvent to form a slurry. This was uniformly applied to both sides of the aluminum foil, dried, and then pressed to obtain a positive electrode.

[Manufacture of negative electrode]
A negative electrode was obtained by mixing 98 parts by mass of graphite powder as a negative electrode active material and 2 parts by mass of PVdF, adding N-methylpyrrolidone into a slurry, and applying and drying on one side of a current collector made of copper. .
[Manufacture of electrolyte]
Under a dry argon atmosphere, a mixture of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (volume ratio 3: 4: 3) and methyl (3-phenylpropyl) as a content in the non-aqueous electrolyte as shown in Table 1 2% by mass of carbonate was mixed, and then sufficiently dried LiPF ₆ was dissolved at a rate of 1.0 mol / liter to obtain an electrolytic solution.

[Manufacture of non-aqueous electrolyte secondary batteries]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, the positive electrode, the separator, and the negative electrode to produce a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and then the electrolyte was poured into the bag and vacuum sealed. The sheet-like battery was manufactured and the overcharge characteristics and the high temperature storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Example 2)
A sheet-like battery was produced in the same manner as in Example 1 except that 0.5% by mass of vinylene carbonate was further added to the electrolytic solution of Example 1, and the overcharge characteristics and the high-temperature storage characteristics were evaluated. The evaluation results are shown in Table 1.
(Reference Example 1)
A sheet-like battery was prepared in the same manner as in Example 1 except that methyl (3-phenylpropyl) carbonate was not mixed in the electrolytic solution of Example 1, and the overcharge characteristics and the high-temperature storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Reference Example 2)
A sheet-like battery was prepared in the same manner as in Example 1 except that cyclohexylbenzene was used in place of methyl (3-phenylpropyl) carbonate in the electrolytic solution of Example 1, and the overcharge characteristics and high-temperature storage characteristics were evaluated. went. The evaluation results are shown in Table 1.
(Reference Example 3)
A sheet-like battery was prepared in the same manner as in Example 1 except that methylphenyl carbonate was used instead of methyl (3-phenylpropyl) carbonate in the electrolytic solution of Example 1, and evaluation of overcharge characteristics and high-temperature storage characteristics was made. Went. The evaluation results are shown in Table 1.

(Reference Example 4)
In the electrolytic solution of Example 1, instead of methyl (3-phenylpropyl) carbonate, n
-Except having used butylbenzene, the sheet-like battery was produced like Example 1 and the overcharge characteristic and the high temperature storage characteristic were evaluated. The evaluation results are shown in Table 1.
(Reference Example 5)
A sheet-like battery was produced in the same manner as in Example 1 except that 3-phenylpropyl acetate was used in place of methyl (3-phenylpropyl) carbonate in the electrolytic solution of Example 1, and overcharge characteristics and high temperature storage characteristics were obtained. Was evaluated. The evaluation results are shown in Table 1.

(Reference Example 6)
In the electrolytic solution of Example 1, a sheet-like battery was prepared in the same manner as in Example 1 except that phenethyl butyrate was used instead of methyl (3-phenylpropyl) carbonate, and evaluation of overcharge characteristics and high-temperature storage characteristics was performed. went. The evaluation results are shown in Table 1.
(Reference Example 7)
A sheet-like battery was produced in the same manner as in Example 1 except that 0.5% by mass of vinylene carbonate was used instead of methyl (3-phenylpropyl) carbonate in the electrolytic solution of Example 1, and the overcharge characteristics and high temperature were increased. Storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Reference Example 8)
A sheet-like battery was prepared in the same manner as in Example 1 except that 2% by mass of cyclohexylbenzene and 0.5% by mass of vinylene carbonate were used in the electrolytic solution of Example 1 instead of methyl (3-phenylpropyl) carbonate. The overcharge characteristics and the high temperature storage characteristics were evaluated. The evaluation results are shown in Table 1.

* Initial capacity, remaining capacity after high temperature storage, and amount of overcharged gas were normalized with the value of Reference Example 1 as 1.
As is clear from Table 1, the batteries of Reference Examples 1 and 7 are excellent in the initial characteristics and the characteristics after the high-temperature storage test, but the amount of gas generated after overcharging is small and the safety during overcharging is low. The batteries of Reference Examples 2 to 6 and 8 have a large amount of gas generated after overcharging and are excellent in safety, but the characteristics after the high-temperature storage test are inferior. The batteries of Examples 1 and 2 have a large amount of gas generation after overcharge, high safety during overcharge, and excellent characteristics after a high-temperature storage test. Therefore, it can be seen that the battery using the non-aqueous electrolyte according to the present invention has high safety during overcharge and is excellent in high-temperature continuous charge characteristics.

The non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention has high capacity and excellent high-temperature continuous charge characteristics while improving safety during overcharge, and therefore can be used for various known applications. Is possible. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorcycle, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, Load A power source for leveling, a natural energy storage power source, and the like can be given.

Claims (5)

A non-aqueous electrolytic solution containing an electrolyte and a non-aqueous solvent, wherein the non-aqueous electrolytic solution contains an ester compound represented by the general formula (I).

(In the general formula (I), Ar represents an aryl group which may have a substituent, m represents an integer of 2 or more, and R ^{1 to} R ⁴ may be independently substituted. Represents a good hydrocarbon group having 1 to 12 carbon atoms.)   The nonaqueous electrolytic solution according to claim 1, wherein Ar in the general formula (I) is a phenyl group which may have a substituent.   The ratio of the compound represented by general formula (I) to nonaqueous electrolyte solution is 0.001-10 mass%, The nonaqueous electrolyte solution of Claim 2 characterized by the above-mentioned.   Furthermore, it contains at least one compound selected from the group consisting of a cyclic carbonate compound having a carbon-carbon unsaturated bond, a cyclic carbonate compound having a fluorine atom, a monofluorophosphate and a difluorophosphate. The non-aqueous electrolyte solution according to any one of claims 1 to 3.   5. A non-aqueous electrolyte battery comprising a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is a non-aqueous electrolyte solution according to claim 1. A non-aqueous electrolyte battery characterized by the above.