JP6589718B2 - Non-aqueous electrolyte and non-aqueous electrolyte battery using the same - Google Patents

Description

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

With the rapid progress of portable electronic devices such as mobile phones and notebook personal computers, there is a growing demand for higher performance of secondary batteries used for main power supplies and backup power supplies. Non-aqueous electrolyte batteries such as lithium ion secondary batteries, which have a higher energy density than nickel-hydrogen batteries, are drawing attention.
Nonaqueous Electrolytic Solution The electrolytic solution used for the lithium secondary battery is usually composed mainly of an electrolyte and a nonaqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

  In addition, various non-aqueous solvents, electrolytes, auxiliaries, and the like have been proposed in order to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low-temperature characteristics of batteries using these non-aqueous electrolytes. . For example, Patent Document 1 discloses that high temperature storage characteristics are improved by adding an acid anhydride to an electrolyte. Patent Document 2 discloses that the use of a specific carboxylic acid anhydride improves the OCV drop during discharge storage and the discharge capacity after storage.

  Patent Document 3 discloses that the negative electrode active material contains silicon and the electrolytic solution contains a specific cyclic acid anhydride compound, thereby improving the cycle characteristics of swelling and capacity retention under a high temperature environment. Yes.

JP-A-4-355065 JP 2013-232298 A International Publication No. 2013/038842

As described above, in recent years, demands for higher performance of secondary batteries are increasing, so that improvement of characteristics of lithium secondary batteries, that is, higher capacity, improvement of battery swelling, and the like are required. Under such circumstances, the non-aqueous electrolyte secondary battery using the electrolyte described in Patent Documents 1 to 3 has not yet been satisfactory in that the initial swelling increases.
Therefore, the present invention eliminates the above-mentioned various problems that are manifested in the required performance of secondary batteries in recent years, and in particular, provides a non-aqueous electrolyte battery in which the initial swelling of the battery is improved, Another object of the present invention is to provide a non-aqueous electrolyte suitable for the non-aqueous electrolyte battery.

As a result of intensive studies to solve the above-mentioned problems, the inventors have included a compound represented by the following general formula (1) in a non-aqueous electrolyte used in a non-aqueous electrolyte battery. The inventors have found that a non-aqueous electrolyte battery with improved initial swelling can be realized, and have completed the present invention.
That is, the gist of the present invention is as follows.
(A) a non-aqueous electrolyte solution comprising a positive electrode capable of occluding and releasing metal ions, a negative electrode capable of occluding and releasing metal ions, and a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte. A nonaqueous electrolytic solution used for a secondary battery, wherein the nonaqueous electrolytic solution contains a compound represented by the following general formula (1).

(R ¹ represents an organic group having a heteroelement having 1 to 10 carbon atoms. R ² represents an organic group having 1 to 10 carbon atoms. N represents an integer of 2 or more.)
(B) The nonaqueous electrolytic solution according to (a), wherein R ¹ is an organic group having a heteroelement and an unsaturated bond.
(C) The non-aqueous electrolyte solution according to (a), wherein R ² has 2 or more carbon atoms.
(D) The non-aqueous electrolyte further includes a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton, a fluorinated salt, and a cyclic ether. The nonaqueous electrolytic solution according to any one of (a) to (c), comprising at least one compound selected from the group consisting of a compound, an oxalate salt and a cyclic sulfonate ester.
(E) a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton, a fluorinated salt, a cyclic ether compound, an oxalate salt and a cyclic sulfone The non-aqueous electrolyte solution according to (d), wherein the content of at least one compound selected from the group consisting of acid esters is 0.001% by mass to 10% by mass with respect to the total amount of the non-aqueous electrolyte solution. .
(F) A nonaqueous electrolyte battery including a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a nonaqueous electrolyte solution, wherein the nonaqueous electrolyte solution is any one of (a) to (e) A non-aqueous electrolyte secondary battery characterized by being a non-aqueous electrolyte solution.

ADVANTAGE OF THE INVENTION According to this invention, regarding a lithium non-aqueous electrolyte secondary battery, it is excellent in performance, such as a rate characteristic and a high temperature storage characteristic, and can provide a battery with a good balance of comprehensive performance.
Action and principle that the non-aqueous electrolyte secondary battery manufactured using the non-aqueous electrolyte of the present invention and the non-aqueous electrolyte secondary battery of the present invention become a secondary battery with a good balance of overall performance. Is not clear, but is considered as follows. However, the present invention is not limited to the operations and principles described below.

Since the compound represented by the general formula (1) has two or more phthalic anhydride skeletons in the molecule, the compound produced by the reduction becomes a polyvalent ionic compound, so that it dissolves in the electrolytic solution. It becomes difficult. At that time, since it has a benzene ring structure derived from a phthalic anhydride skeleton, a π-π interaction between benzene rings works and further suppresses solubility in an electrolytic solution. As a result, the negative electrode protective film becomes stable and suppresses the decomposition of the electrolytic solution. In the compound represented by the general formula (1), a phthalic anhydride skeleton is connected via an organic group having a heteroelement having 1 to 10 carbon atoms and an organic group having 1 to 10 carbon atoms. Therefore, it becomes a reduction product with high polarity and flexibility. Therefore, when lithium ions are inserted into the negative electrode during charging, desolvation can be facilitated and decomposition of the solvent on the negative electrode surface can be effectively suppressed. For the above reasons, the generation of reducing gas due to solvent decomposition during charging can be suppressed, which is considered to contribute to the improvement of initial swelling.

Hereinafter, embodiments of the present invention will be described. However, 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.
Here, “% by weight”, “ppm by weight” and “parts by weight” have the same meanings as “% by mass”, “ppm by mass” and “parts by mass”, respectively. Further, for example, when “ppm” is simply described, it means “mass ppm”.

1. Non-aqueous electrolyte 1-1. Nonaqueous Electrolytic Solution of the Present Invention The nonaqueous electrolytic solution of the present invention is characterized by containing a compound represented by the following general formula (1).
1-1-1. Compound represented by general formula (1)

(R ¹ represents an organic group having a heteroelement having 1 to 10 carbon atoms. R ² represents an organic group having 1 to 10 carbon atoms. N represents an integer of 2 or more.)
R ¹ represents an organic group having a hetero element having 1 to 10 carbon atoms. Specific examples of the organic group having a hetero element having 1 to 10 carbon atoms include the partial structure of the following formula (2).

R ³ represents a hydrocarbon group which may be substituted with a fluorine atom having 1 to ³ carbon atoms, and R ⁴ represents a hydrocarbon group which may be substituted with a fluorine atom having 1 to 6 carbon atoms. X is O, NR ⁵ , S, S (═O) ₂ , OS (═O) ₂ , OS (═O) ₂ O, C (═O) O, OC
(= O) represents any linking group selected from O. R ⁵ represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. m1 and m2 each represents 0 or 1. When X is any one of O, NR ⁵ , S, S (═O) ₂ , OS (═O) ₂ , and OS (═O) ₂ O, at least one of m1 and m2 is 1.

R ³ preferably has 2 or more carbon atoms. If it is the above-mentioned range, the softness | flexibility of a film | membrane can be ensured and the increase in resistance can be suppressed.
Specific examples of R ³ include methylene, ethylene, trimethylene, dimethylmethylene, vinylene, ethynylene, propenylene, and propynylene. Among these, vinylene, ethynylene, propenylene, and propynylene are preferable. Since the above-described hydrocarbon group has π electrons, it reacts with a radical component generated by reduction and can form a stronger film.

R ⁴ has preferably 2 or more, more preferably 3 or more. If it is the above-mentioned range, the softness | flexibility of a film | membrane can be ensured and the increase in resistance can be suppressed.
Specific examples of R ⁴ include methylene, ethylene, trimethylene, dimethylmethylene, tetramethylene, pentamethylene, hexamethylene, cyclohexylene, vinylene, propenylene, butenylene, pentenylene, hexenylene, cyclohexenylene, ethynylene, propynylene, butynylene, pentynylene, Examples include hexynylene and phenylene. Among these, vinylene, propenylene, butenylene, pentenylene, hexenylene, cyclohexenylene, ethynylene, propynylene, butynylene, pentynylene, hexynylene, and phenylene are preferable. Since the above-described hydrocarbon group has π electrons, it reacts with a radical component generated by reduction and can form a stronger film.

Specific examples of R ⁵ are not particularly limited as a hydrogen atom or an organic group having 1 to 12 carbon atoms. The carbon number of R ⁵ is preferably 10 or less, more preferably 8 or less, and most preferably 6 or less. If it is the above-mentioned range, the increase in a molecular radius can be suppressed and the viscosity rise of electrolyte solution can be suppressed.
Specific examples of R ⁵ include a hydrogen atom, an alkyl group which may be substituted with a halogen atom, a cycloalkyl group which may be substituted with a halogen atom or an alkyl group, a halogen atom or an alkyl group. An aryl group etc. are mentioned. Of these, a hydrogen atom, an alkyl group, and a cycloalkyl group are preferable. Within the above range, excessive reduction or direct oxidation at the positive electrode can be suppressed.

Specific examples include a methyl group, a trifluoromethyl group, an ethyl group, a trifluoroethyl group, an n-propyl group, a t-butyl group, a cyclohexyl group, a phenyl group, and a naphthyl group.
X is preferably O, S (═O) ₂ , OS (═O) ₂ , OS (═O) ₂ O, C (═O) O, or OC (═O) O. Since the compound itself is not easily oxidized with the above-described linking group, generation of oxidizing gas can be suppressed.

The upper limit of n is not particularly limited, but is preferably 5 or less, more preferably 4 or less, still more preferably 3 or less, and most preferably 2. If it is the above-mentioned range, it can melt | dissolve in electrolyte solution enough as an additive.
R ² represents an organic group having 1 to 10 carbon atoms. The organic group is preferably a functional group composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, phosphorus atoms, boron atoms, sulfur atoms, silicon atoms, oxygen atoms and halogen atoms. Among them, the carbon number is preferably 8 or less, more preferably 6 or less. When the number of carbon atoms is as described above, an increase in the molecular radius of the compound can be suppressed, and an increase in the viscosity of the electrolyte can be suppressed.

When n = 2, the structure of R ² specifically includes an alkylene group or a derivative thereof, an alkenylene group or a derivative thereof, a cycloalkylene group or a derivative thereof, an alkynylene group or a derivative thereof, a cycloalkenylene group or a derivative thereof, an arylene Group or derivative thereof, carbonyl group or derivative thereof, sulfonyl group or derivative thereof, sulfinyl group or derivative thereof, phosphonyl group or derivative thereof, phosphinyl group or derivative thereof, amino group or derivative thereof, amide group or derivative thereof, imide group or Examples thereof include an ether group or a derivative thereof, a thioether group or a derivative thereof, a borinic acid group or a derivative thereof, a borane group or a derivative thereof. Among them, an alkylene group or a derivative thereof, an alkenylene group or a derivative thereof, a cycloalkylene group or a derivative thereof is preferable, and an alkylene group or a derivative thereof, a cycloalkylene group or a derivative thereof is more preferable. The above-described substituents can suppress excessive reduction or direct oxidation at the positive electrode.

Specific examples of R ² include methylene, ethylene, trimethylene, dimethylmethylene, tetramethylene, pentamethylene, hexamethylene, cyclohexylene, vinylene, propenylene, butenylene, pentenylene, hexenylene, cyclohexenylene, ethynylene, propynylene, butynylene, pentynylene, Examples include hexynylene and phenylene. Of these, methylene, ethylene, trimethylene, dimethylmethylene, tetramethylene, pentamethylene, hexamethylene and cyclohexylene are preferred, and methylene, ethylene, trimethylene, dimethylmethylene and cyclohexylene are more preferred. When the number of carbon atoms is as described above, an increase in the molecular radius of the compound can be suppressed, and an increase in the viscosity of the electrolyte can be suppressed.

When n = 3, specific examples of the structure of R ² include partial structures of the following formulas (3) and (4).

(R ²¹ represents hydrogen or a hydrocarbon group which may be substituted with a fluorine atom having 1 to 6 carbon atoms. Y ¹ represents any of a carbon atom, a silicon atom, a boron atom and a phosphorus atom, o, p, q, and r each represents 0 or 1. When Y ¹ is a carbon atom or a silicon atom, r = 1, and when Y ¹ is a boron atom or a phosphorus atom, r = 0.
The hydrocarbon group which may be substituted with hydrogen represented by R ²¹ or a fluorine atom having 1 to 6 carbon atoms is not particularly limited. R ²¹ preferably has 5 or less carbon atoms, more preferably 4 or less, and most preferably 3 or less. If it is the above-mentioned range, the increase in a molecular radius can be suppressed and the viscosity rise of electrolyte solution can be suppressed. Examples thereof include a hydrogen group, an alkyl group optionally substituted with a fluorine atom, a cycloalkyl group optionally substituted with a fluorine atom or an alkyl group, and a phenyl group. Of these, a hydrogen group, an alkyl group, and a cycloalkyl group are preferable. Within the above range, excessive reduction or direct oxidation at the positive electrode can be suppressed.
Specific examples include a hydrogen group, a methyl group, a trifluoromethyl group, an ethyl group, a trifluoroethyl group, an n-propyl group, a t-butyl group, a cyclohexyl group, and a phenyl group.

Y ¹ is preferably a carbon atom or a silicon atom, and most preferably a carbon atom. If the atoms are as described above, excessive oxidation / reduction is unlikely to occur, and side reactions in the battery can be suppressed.
o + p + q is preferably 2 or less, more preferably 1 or less, and most preferably 0. If it is the above-mentioned range, the increase in the molecular radius of a compound can be suppressed and the viscosity increase of electrolyte solution can be suppressed.

When n = 4, specific examples of the structure of R ² include partial structures of the following formulas (5) and (6).

(Y ² represents either a carbon atom or a silicon atom. S, t, u and v all represent 0 or 1)
Y ² is preferably a carbon atom. If the atoms are as described above, excessive oxidation / reduction is unlikely to occur, and side reactions in the battery can be suppressed.
s + t + u + v is preferably 3 or less, more preferably 2 or less, and even more preferably 1 or less. If it is the above-mentioned range, the increase in the molecular radius of a compound can be suppressed and the viscosity increase of electrolyte solution can be suppressed.

  As the compound used in the present invention, a compound represented by the general formula (1) is used, and specific examples thereof include compounds having the following structure.

  Preferably, the compound of the following structures is mentioned. The adverse effect of oxidative decomposition at the positive electrode can be suppressed.

  More preferably, the compound of the following structures is mentioned. The oxidation reactivity on the positive electrode can be suitably controlled.

  The compounding amount of the compound represented by the general formula (1) with respect to the total amount of the non-aqueous electrolyte solution of the present invention is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The total amount of the non-aqueous electrolyte solution of the present invention Is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, and usually 10.0% by mass or less. , Preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and still more preferably 3.0% by mass or less. If it is said density | concentration, the reaction frequency and reactivity on an electrode can be adjusted suitably, and it will become possible to optimize a battery characteristic. The compound represented by the general formula (1) may be used alone or in combination of two or more.

When the above range is satisfied, effects such as rate characteristics and high temperature characteristics are further improved.
In addition, the method of mix | blending the compound represented with General formula (1) with the electrolyte solution of this invention is not restrict | limited in particular. In addition to the method of directly adding the compound to the electrolytic solution, a method of generating the compound in the battery or in the electrolytic solution can be mentioned. Examples of a method for generating the compound include a method in which a compound other than these compounds is added and a battery component such as an electrolytic solution is generated by oxidation, reduction, hydrolysis, or the like. Furthermore, a method of generating a battery by applying an electrical load such as charge / discharge is also mentioned.

1-2. It consists of a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton, a fluorinated salt, a cyclic ether compound, an oxalate salt and a cyclic sulfonate ester. At least one specific compound selected from the group The non-aqueous electrolyte solution of the present invention includes, in addition to the compound represented by the general formula (1), a cyclic carbonate having a carbon-carbon unsaturated bond and a cyclic carbonate having a fluorine atom. At least one specific compound selected from the group consisting of a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton, a fluorinated salt, a cyclic ether compound, an oxalate salt and a cyclic sulfonate ester Further includes It is preferable from the viewpoint of improving battery characteristics.

Among these, from the viewpoint of improving battery characteristics, a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, a cyclic ether compound, a compound having an isocyanuric acid skeleton, and a cyclic sulfonate ester are more preferable. A cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, a cyclic ether compound, and a cyclic sulfonate ester are more preferable, a cyclic carbonate having a carbon-carbon unsaturated bond, and a cyclic carbonate having a fluorine atom A nitrile compound is particularly preferable, and a cyclic carbonate having a carbon-carbon unsaturated bond and a cyclic carbonate having a fluorine atom are most preferable.

The compound represented by the general formula (1) undergoes a reduction reaction on the negative electrode surface to form an anion (nucleophilic species) in the structure. In addition, since the specific compound has a nucleophilic attack accepting site in the molecular structure, a complex film may be formed by reacting with the reduction product of the compound represented by the general formula (1). Conceivable.
As described above, these specific compounds and the compound represented by the general formula (1) are co-added to the non-aqueous electrolyte solution to react with each other on the electrode to form a composite film. For this reason, since the reaction of the non-aqueous electrolyte on the surface of the active material is further suppressed than when each compound is added alone, the battery characteristics are improved. Hereinafter, the specific compounds will be described individually.

1-2-1. Cyclic carbonate having a carbon-carbon unsaturated bond The non-aqueous electrolyte solution of the present invention further contains a cyclic carbonate having a carbon-carbon unsaturated bond in addition to the compound represented by the general formula (1). This is preferable from the viewpoint of improving the characteristics.
As the cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter sometimes referred to as “unsaturated cyclic carbonate”), any cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond may be used. There is no limit. Any unsaturated carbonate can be used as the unsaturated cyclic carbonate. In addition, the cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate. The unsaturated cyclic carbonate may have a fluorine atom (also referred to as a fluorinated unsaturated carbonate). In that case, the fluorine atom is usually 6 or less, preferably 4 or less, and 1 or 2 Most preferably it is.

As unsaturated cyclic carbonates, vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, Catechol carbonates etc. are mentioned.
Examples of the vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5 A fluoro vinylene carbonate etc. are mentioned.

Specific examples of ethylene carbonates substituted with a substituent having the aromatic ring or carbon-carbon double bond or carbon-carbon triple bond include:
Vinylethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5 -Ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4-allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate,
4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene Carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5- Difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-diflu B-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro- Examples include 5-phenylethylene carbonate and 4,5-difluoro-4-phenylethylene carbonate.

Among the examples mentioned above, preferred unsaturated cyclic carbonates are:
Vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5 -Diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, 4-fluorovinylene carbonate Bonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro-4-allyl ethylene Carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5- Difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro- , 5-divinyl ethylene carbonate, and 4,5-difluoro-4,5-diallyl carbonate.

Vinylene carbonate, vinyl ethylene carbonate, and ethynyl ethylene carbonate are particularly preferable because they form a particularly stable interface protective film.
The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 80 or more and 250 or less. If it is this range, it will be easy to ensure the solubility of the unsaturated cyclic carbonate with respect to a non-aqueous electrolyte solution, and the effect of this invention will fully be expressed easily. The molecular weight of the unsaturated cyclic carbonate is more preferably 85 or more, and more preferably 150 or less.

The production method of the unsaturated cyclic carbonate described above is not particularly limited, and can be produced by arbitrarily selecting a known method.
In the non-aqueous electrolyte solution of the present invention, the unsaturated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio. Moreover, the compounding quantity of unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more in 100% by mass of the non-aqueous electrolyte solution. Particularly preferably, it is 1% by mass or more, and is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.

1-2-2. The cyclic carbonate which has a fluorine atom as a cyclic carbonate which has a fluorine atom which is a specific compound includes the fluoride of the cyclic carbonate which has a C2-C6 alkylene group, and its derivative (s). Examples thereof include fluorinated ethylene carbonate and derivatives thereof. Examples of the derivative of the fluorinated ethylene carbonate include a fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). As the cyclic carbonate having a fluorine atom, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferable. In addition, about the cyclic carbonate which has a fluorine atom and has an unsaturated bond, said 1-2-1. It is described in.

Specific examples are:
Monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methyl Ethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate, 4- (fluoro Methyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene Boneto, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among these, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate gives high ionic conductivity and suitably forms an interface protective film. This is more preferable.
One cyclic carbonate having a fluorine atom may be used alone, or two or more cyclic carbonates may be used in any combination and ratio.

  There is no restriction | limiting in the compounding quantity of the cyclic carbonate which has a fluorine atom with respect to the whole non-aqueous electrolyte solution of this invention, Unless the effect of this invention is impaired remarkably, it is arbitrary. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more in 100% by mass of the non-aqueous electrolyte solution. Particularly preferably, it is 1% by mass or more, and is usually 10% by mass or less, preferably 7% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less. However, monofluoroethylene carbonate may be used as a solvent, and in that case, the content is not limited to the above.

1-2-3. Nitrile compound The nitrile compound as a specific compound is not particularly limited as long as it is a compound having a cyano group in the molecule.
Specific examples of nitrile compounds include, for example,
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, decane nitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, Methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexene Nitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitri Nitrile groups such as 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, pentafluoropropionitrile, etc. A compound having one of the following:

Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, t-butylmalononitrile, methylsuccinonitrile 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, 2,3,3-trimethylsuccinonitrile, 2,2,3,3-tetramethylsuccinonitrile, 2,3-diethyl- 2,3-dimethylsuccinonitrile, 2,2-diethyl-3,3-dimethylsuccinonitrile, bicyclohexyl-1,1-dicarbonitrile, bicyclohexyl-2,2-dicarbonitrile, bicyclohexyl-3 , 3 Dicarbonitrile, 2,5-dimethyl-2,5-hexanedicarbonitrile, 2,3-diisobutyl-2,3-dimethylsuccinonitrile, 2,2-diisobutyl-3,3-dimethylsuccinonitrile, 2, -Methyl glutaronitrile, 2,3-dimethyl glutaronitrile, 2,4-dimethyl glutaronitrile, 2,2,3,3-tetramethyl glutaronitrile, 2,2,4,4-tetramethyl glutaro Nitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglutaronitrile, maleonitrile, fumaronitrile, 1,4-dicyanopentane, 2,6-dicyanoheptane, 2, 7-dicyanooctane, 2,8-dicyanononane, 1,6-dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene Zen, 1,4-dicyanobenzene, 3,3 ′-(ethylenedioxy) dipropionitrile, 3,3 ′-(ethylenedithio) dipropionitrile, 3,9-bis (2-cyanoethyl) -2,4 , 8,10-tetraoxaspiro [5,5] undecane, 3,3′-oxydipropionitrile, 3,3′-thiodipropionitrile and other compounds having two nitrile groups;
Cyclohexanetricarbonitrile, triscyanoethylamine, triscyanoethoxypropane, tricyanoethylene, pentanetricarbonitrile, 1,3,5-pentanetricarbonitrile, propanetricarbonitrile, 1,2,3-propanetricarbonitrile, And compounds having three cyano groups such as heptanetricarbonitrile.

  Of these, valeronitrile, decane nitrile, lauronitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, fumaronitrile, 3,9-bis (2-Cyanoethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane is preferred from the viewpoint of improving the storage characteristics of the non-aqueous electrolyte. In addition, valeronitrile, decane nitrile, lauronitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, 3,9-bis (2-cyanoethyl) -2,4,8,10-tetraoxaspiro [ 5,5] Nitrile compounds such as undecane are particularly preferred.

A nitrile compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. There is no restriction | limiting in the compounding quantity of the nitrile compound with respect to the whole non-aqueous electrolyte solution of this invention, and it is arbitrary unless the effect of this invention is impaired remarkably. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, in 100% by mass of the nonaqueous electrolytic solution. , Preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, and most preferably 1% by mass or less. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics of the nonaqueous electrolyte secondary battery are further improved.

1-2-4. Isocyanate compound The isocyanate compound as a specific compound is not particularly limited as long as it is a compound having an isocyanate group in the molecule.
Specific examples of the isocyanate compound include, for example,
Hydrocarbon monoisocyanate compounds such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, t-butyl isocyanate, pentyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate and fluorophenyl isocyanate;
Monoisocyanate compounds having a carbon-carbon unsaturated bond, such as vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, propynyl isocyanate;
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-diisocyanate Natopropane, 1,4-diisocyanato-2-butene, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2,3-difluorobutane, 1,5-diisocyanato-2-pentene, 1,5 -Diisocyanato-2-methylpentane, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-hexene, 1,6 Diisocyanato-3-fluorohexane, 1,6-diisocyanato-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, tolylene diisocyanate, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanato) Methyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, dicyclohexylmethane-1,1 ′ -Diisocyanate, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, bicyclo [2.2.1] heptane 2,5-diylbis (methylisocyanate), bicyclo [2.2.1] heptane-2,6-diylbis (methylisocyanate), isophorone diisocyanate, carbonyl diisocyanate, 1,4-diisocyanatobutane-1,4- Hydrocarbon diisocyanate compounds such as dione, 1,5-diisocyanatopentane-1,5-dione, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate;
Isocyanate compounds such as diisocyanatosulfone, (ortho-, meta-, para-) toluenesulfonyl isocyanate, benzenesulfonyl isocyanate, fluorosulfonyl isocyanate, phenoxysulfonyl isocyanate, pentafluorophenoxysulfonyl isocyanate, methoxysulfonyl isocyanate;
Etc.

Among these, monoisocyanate compounds having a carbon-carbon unsaturated bond, such as vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, propynyl isocyanate;
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-bis ( Isocyanatomethyl) cyclohexane, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1] heptane-2,5-diylbis (methylisocyanate), bicyclo [2.2.1] heptane-2,6- Diylbis (methyl isocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate Hydrocarbon-based diisocyanate compounds such as 2,4,4-trimethylhexamethylene diisocyanate;
Isocyanate compounds such as diisocyanatosulfone, (ortho-, meta-, para-) toluenesulfonyl isocyanate, benzenesulfonyl isocyanate, fluorosulfonyl isocyanate, phenoxysulfonyl isocyanate, pentafluorophenoxysulfonyl isocyanate, methoxysulfonyl isocyanate;
Is preferable from the viewpoint of improving cycle characteristics and storage characteristics of the non-aqueous electrolyte secondary battery.

  More preferred are allyl isocyanate, hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, diisocyanato sulfone, (ortho-, meta-, para-) toluenesulfonyl isocyanate, and particularly preferred is hexamethylene. Diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, (ortho-, meta-, para-) toluenesulfonyl isocyanate, most preferably hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane is there.

Moreover, as an isocyanate compound, the isocyanate compound which has a branched chain is preferable.
The isocyanate compound used in the present invention may be a trimer compound derived from a compound having at least two isocyanate groups in the molecule, or an aliphatic polyisocyanate obtained by adding a polyhydric alcohol thereto. Examples of such aliphatic polyisocyanates include biurets, isocyanurates, adducts, and bifunctional types of modified poly-polymers represented by the following general formulas (1-2-1) to (1-2-4). An isocyanate etc. can be illustrated (in the following general formulas (1-2-1) to (1-2-4), R and R ′ are each independently an arbitrary hydrocarbon group).

  Among the isocyanate compounds used in the present invention, the compounds having at least two isocyanate groups in the molecule include so-called blocked isocyanates that are blocked with a blocking agent to enhance storage stability. Examples of the blocking agent include alcohols, phenols, organic amines, oximes, and lactams. Specific examples thereof include n-butanol, phenol, tributylamine, diethylethanolamine, methyl ethyl ketoxime, ε-caprolactam and the like can be mentioned.

For the purpose of accelerating the reaction based on the compound having at least two isocyanate groups in the molecule and obtaining a higher effect, a metal catalyst such as dibutyltin dilaurate or the like, 1,8-diazabicyclo [5.4.0] undecene It is also preferable to use an amine catalyst such as -7 in combination.
The isocyanate compound demonstrated above may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  There is no restriction | limiting in the compounding quantity of the isocyanate compound with respect to the whole non-aqueous electrolyte solution of this invention, and it is arbitrary unless the effect of this invention is impaired remarkably. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less with respect to the non-aqueous electrolyte solution of the present invention. The amount is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less.

When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics of the nonaqueous electrolyte secondary battery are further improved.
1-2-5. Compound having isocyanuric acid skeleton Examples of the compound having an isocyanuric acid skeleton which is a specific compound include compounds represented by the following general formula (U).

In formula (U), R ^{7 to} R ⁹ are each independently an organic group having 1 to 20 carbon atoms which may have a substituent. However, at least one of R ^{7 to} R ⁹ has a carbon-carbon unsaturated bond or a cyano group. Preferably, in formula (U), R ^{7 to} R ⁹ are each independently an organic group having 1 to 10 carbon atoms which may have a substituent. More preferably, in formula (U), at least one of R ^{7 to} R ⁹ is an organic group having a carbon-carbon unsaturated bond.

Here, the organic group represents a functional group composed of atoms selected from the group consisting of carbon atoms, hydrogen atoms, nitrogen atoms, oxygen atoms, silicon atoms, sulfur atoms and halogen atoms.
Specific examples of the organic group having 1 to 20 carbon atoms that may have a substituent include an alkyl group having 1 to 20 carbon atoms, an alkenyl group, an alkynyl group, an aryl group, a cyano group, an acrylic group, a methacryl group, A vinyl sulfonyl group, a vinyl sulfo group, etc. are mentioned.

Examples of the substituent herein include a halogen atom and an alkylene group. In addition, an unsaturated bond or the like may be included in a part of the alkylene group. Of the halogen atoms, a fluorine atom is preferred.
Specific examples of the alkyl group which may have a substituent include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an s-butyl group and a t-butyl group. Examples thereof include a linear or branched alkyl group, and a cyclic alkyl group such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

Specific examples of the alkenyl group that may have a substituent include a vinyl group, an allyl group, a methallyl group, and a 1-propenyl group.
Specific examples of the alkynyl group which may have a substituent include ethynyl group, propargyl group, 1-propynyl group and the like.
Specific examples of the aryl group which may have a substituent include a phenyl group, a tolyl group, a benzyl group, and a phenethyl group.

More preferable substituents that may have a substituent described above are an alkyl group, an alkenyl group, an alkynyl group, an acrylic group, a methacryl group, and a cyano group that may have a substituent.
Particularly preferred are an alkyl group, an alkenyl group, an acrylic group, a methacryl group, and a cyano group, which may have a substituent.

Most preferably, they are a methyl group, an ethyl group, a propyl group, an allyl group or a methallyl group which may have a substituent. In particular, unsubstituted allyl group and methallyl group are preferable. An allyl group is preferable from the viewpoint of film forming ability.
Specific examples of the compound represented by the general formula (U) include compounds having the following structure.

  Among the compounds represented by the general formula (U), a compound having the following structure is preferable.

  More preferably, it is a compound of the following structure.

  Particularly preferred is a compound having the following structure.

  Most preferred is a compound having the following structure:

  Of these most preferred compounds, compounds having the following structure are preferred from the viewpoint of film-forming ability.

  There is no limit to the amount of the compound having the isocyanuric acid skeleton described above (the compound represented by the general formula (U)) with respect to the entire non-aqueous electrolyte solution of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. is there. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass with respect to the whole non-aqueous electrolyte solution of the present invention. Hereinafter, it is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less.

When the above range is satisfied, effects such as output characteristics, load characteristics, cycle characteristics, high-temperature storage characteristics, and battery swelling of the nonaqueous electrolyte secondary battery are further improved.
1-2-6. Fluorinated salt Although there is no particular limitation on the fluorinated salt which is a specific compound, since it has a highly detachable fluorine atom in the structure, for example, a compound represented by the general formula (1) Difluorophosphate, fluorosulfonate, fluoroboron salt and fluoroimide salt are preferred because they can suitably react with anions (nucleophilic species) produced by reduction reaction to form a composite film. Since the elimination of fluorine atoms is particularly high and the reaction with the nucleophilic species proceeds favorably, fluoroboron salts, fluorosulfonates and difluorophosphates are more preferred, and fluoroboron salts and difluorophosphates are preferred. Particularly preferred. Hereinafter, these various salts will be described.

(Difluorophosphate)
The counter cation of the difluorophosphate is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³ R ¹⁴ R ¹⁵ R ¹⁶ (wherein R ^{13 to} R ¹⁶ represents each independently a hydrogen atom or an organic group having 1 to 12 carbon atoms).

Although it does not specifically limit as a C1-C12 organic group represented by R < ¹³ > -R < ¹⁶ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. 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 them, it is preferable that R ^{13 to} R ¹⁶ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

Specific examples of difluorophosphate include
Examples include lithium difluorophosphate, sodium difluorophosphate, and potassium difluorophosphate, and lithium difluorophosphate is preferred.
A difluorophosphate may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of a difluorophosphate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.

The blending amount of the difluorophosphate is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass in 100% by mass of the non-aqueous electrolyte. % Or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.
Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.

(Fluorosulfonate)
The counter cation of the fluorosulfonate is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³ R ¹⁴ R ¹⁵ R ¹⁶ (wherein R ^{13 to} R Examples of the ammonium include ^{16 and} the like, each independently representing a hydrogen atom or an organic group having 1 to 12 carbon atoms.

Although it does not specifically limit as a C1-C12 organic group represented by R < ¹³ > -R < ¹⁶ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. 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 them, it is preferable that R ^{13 to} R ¹⁶ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

As specific examples of fluorosulfonate,
Examples thereof include lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, cesium fluorosulfonate and the like, and lithium fluorosulfonate is preferable.
A fluorosulfonate may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of a fluorosulfonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.

The blending amount of the fluorosulfonate is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass in 100% by mass of the non-aqueous electrolyte. % Or less, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, and most preferably 1% by mass or less.
Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.

(Fluoro boron salt)
Is not particularly limited as the counter cation of the fluoroborate Motoshio, lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium ^{and,, NR 13 R 14 R 15} R 16 ( ^wherein, R 13 ^{to R 16} Are each independently a hydrogen atom or an organic group having 1 to 12 carbon atoms).

Although it does not specifically limit as a C1-C12 organic group represented by R < ¹³ > -R < ¹⁶ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. 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 them, it is preferable that R ^{13 to} R ¹⁶ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

Specific examples of fluoroboron salts include
_{LiBF 4, LiB (CiF 2i +} 1) j (F) 4-j , and the like, LiBF ₄ are preferred. Note that i represents an integer of 1 to 10, and j represents an integer of 1 to 4.
A fluoroboron salt may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of a fluoro boron salt is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.

The blending amount of the fluoroboron salt is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 3% by mass in 100% by mass of the non-aqueous electrolyte. Hereinafter, it is preferably 1% by mass or less, more preferably 0.8% by mass or less, further preferably 0.5% by mass or less, and most preferably 0.3% by mass or less.
Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.

(Fluoroimide salt)
The counter cation of the fluoroimide salt is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³ R ¹⁴ R ¹⁵ R ¹⁶ (wherein R ^{13 to} R ¹⁶ Each independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms.) Examples thereof include ammonium and the like.

Although it does not specifically limit as a C1-C12 organic group represented by R < ¹³ > -R < ¹⁶ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. 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 them, it is preferable that R ^{13 to} R ¹⁶ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

As a specific example of the fluoroimide salt,
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), and LiN (FSO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , and LiN (C ₂ F ₅ SO ₂ ) ₂ are preferable.

A fluoroimide salt may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of a fluoroimide salt is not restrict | limited in particular, Unless the effect of this invention is impaired remarkably, it is arbitrary.
The blending amount of the fluoroimide salt is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass in 100% by mass of the non-aqueous electrolyte. Hereinafter, it is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.

Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.
1-2-7. Cyclic ether compound Examples of the cyclic ether compound that is a specific compound include a cyclic ether compound that is an aliphatic compound having an oxygen atom in the molecule and a cyclic ether compound that is an aromatic compound having an oxygen atom in the molecule. A cyclic ether compound which is an aliphatic compound having an oxygen atom in the molecule is preferable because the oxidation potential is moderate and the amount of side reaction at room temperature can be reduced.

Specific examples of the cyclic ether compound include the following.
Ethylene oxide, propylene oxide, butylene oxide, styrene oxide, oxetane, 2-methyloxetane, 3-methyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 3-methyltetrahydrofuran, 3-ethyltetrahydrofuran, 2,2-dimethyl Tetrahydrofuran, 2,3-dimethyltetrahydrofuran, 2-vinyltetrahydrofuran, 3-vinyltetrahydrofuran, 2-ethynyltetrahydrofuran, 3-ethynyltetrahydrofuran, 2-phenyltetrahydrofuran, 3-phenyltetrahydrofuran, tetrahydropyran, 2-methyltetrahydropyran, 2- Ethyltetrahydropyran, 3-methyltetrahydropyran, 3-ethyltetrahydropyran 4-methyltetrahydropyran, 4-ethyltetrahydropyran, 2,2-dimethyltetrahydropyran, 2,3-dimethyltetrahydropyran, 2,4-dimethyltetrahydropyran, 3,3-dimethyltetrahydropyran, 3,4-dimethyl Tetrahydropyran, 4,4-dimethyltetrahydropyran, 2-vinyltetrahydropyran, 3-vinyltetrahydropyran, 4-vinyltetrahydropyran, 2-ethynyltetrahydropyran, 3-ethynyltetrahydropyran, 4-ethynyltetrahydropyran, 2-phenyl Tetrahydropyran, 3-phenyltetrahydropyran, 4-phenyltetrahydropyran, hexamethylene oxide, 2-methylhexamethylene oxide, 3-methylhexamethylene oxide, 4-ethylhexa Methylene oxide, 2-vinylhexamethylene oxide, 3-ethynylhexamethylene oxide, 4-phenylhexamethylene oxide, heptamethylene oxide, 2-methylheptamethylene oxide, 3-methylheptamethylene oxide, 4-ethylheptamethylene oxide, octa Methylene oxide, nonamethylene oxide, decamethylene oxide, 1,3-dioxolane, 2-methoxy-1,3-dioxolane, 2-methyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 4 -Methyl-1,3-dioxolane, 2-ethoxy-1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2,2-diethyl-1,3-dioxolane, 4-ethyl-1,3-dioxolane 2,2,4-trimethyl-1,3-dioxy Lan, 2,2,4-triethyl-1,3-dioxolane, 1,3-dioxane, 4-methyl-1,3-dioxane, 2,4-dimethyl-1,3-dioxane, 2,2,4- Trimethyl-1,3-dioxane, 4-ethyl-1,3-dioxane, 2,4-diethyl-1,3-dioxane, 2,2,4-triethyl-1,3-dioxane, 4-phenyl-1, 3-dioxane, 3-methyl-1,3-dioxane, 5,5-dimethyl-1,3-dioxane, 2,5,5-trimethyl-1,3-dioxane, 4,6-dimethyl-1,3- Dioxane, 2,5-dimethyl-1,3-dioxane, 1,4-dioxane.

Among these, propylene oxide, butylene oxide, styrene oxide, oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 3-methyltetrahydrofuran, 3-ethyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, 2-methyl Tetrahydropyran, 2-ethyltetrahydropyran, 3-methyltetrahydropyran, 3-ethyltetrahydropyran, 4-methyltetrahydropyran, 4-ethyltetrahydropyran, 2,2-dimethyltetrahydropyran, hexamethylene oxide, 1,3-dioxane 4-methyl-1,3-dioxane is preferred,
Propylene oxide, styrene oxide, oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, 2-methyltetrahydropyran, 2-ethyltetrahydropyran, 2,2-dimethyltetrahydropyran, More preferred are hexamethylene oxide, 1,3-dioxane, 4-methyl-1,3-dioxane,
Oxetane, tetrahydrofuran, tetrahydropyran, hexamethylene oxide, 1,3-dioxane, 4-methyl-1,3-dioxane are particularly preferred,
Tetrahydrofuran, tetrahydropyran, and 1,3-dioxane are more preferable,
Tetrahydropyran is most preferred.
This is because when the compounds mentioned in the preferred examples are used, the effect of suppressing gas generation is particularly great.

  A cyclic ether compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. There is no restriction | limiting in particular in the compounding quantity of the cyclic ether compound with respect to the whole non-aqueous electrolyte solution of this invention, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, in 100% by mass of the nonaqueous electrolytic solution. Preferably, it is 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 1.5 mass% or less, Most preferably, it is 1.0 mass% or less. By using it with said content, while being able to fully exhibit the gas generation | occurrence | production suppression effect, an unnecessary resistance raise can be suppressed.

1-2-8. Oxalate salt The counter cation of the oxalate salt which is a specific compound is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³ R ¹⁴ R ¹⁵ R ¹⁶ (wherein R ^{13 to} R ¹⁶ each independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms).

Although it does not specifically limit as a C1-C12 organic group represented by R < ¹³ > -R < ¹⁶ > of the said ammonium, For example, it is substituted by the alkyl group, the halogen atom, or the alkyl group which may be substituted by the halogen atom. 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 them, it is preferable that R ^{13 to} R ¹⁶ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

Specific examples of oxalate salts include
Lithium difluorooxalatoborate, lithium bis (oxalato) borate, lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate, etc.
Lithium bis (oxalato) borate and lithium difluorobis (oxalato) phosphate are preferred.

One oxalate salt may be used alone, or two or more oxalate salts may be used in any combination and ratio. Moreover, the compounding quantity of an oxalate salt is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.
The amount of the oxalate salt is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less in 100% by mass of the non-aqueous electrolyte. Preferably, it is 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 2 mass% or less, Most preferably, it is 1.5 mass% or less.

Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics are reduced, the amount of gas generation is increased, and the discharge capacity maintenance rate is reduced. Easy to avoid the situation.
1-2-9. Cyclic sulfonic acid ester The type of cyclic sulfonic acid ester which is a specific compound is not particularly limited.

Specific examples of the cyclic sulfonate ester include, for example,
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-methyl-1,3-propane sultone 2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone, 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene -1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1-fluoro-2-propene-1,3-sultone, 2 -Fluoro-2-propene-1,3-sultone, 3-fluoro-2-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene -1,3-sultone, 3-methyl-1-propene-1,3-sultone, 1-methyl-2-propene-1,3-sultone, 2-methyl-2-propene-1,3-sultone, 3 -Methyl-2-propene-1,3-sultone, 1,4-butane sultone, 1-fluoro-1,4-butane sultone, 2-fluoro-1,4-butane sultone, 3-fluoro-1,4-butane sultone, 4 -Fluoro-1,4-butane sultone, 1-methyl-1,4-butane sultone, 2-methyl-1,4-butane sultone, 3-methyl-1,4-butane sultone, 4-methyl-1,4-butane sultone, 1 -Butene-1,4-sultone, 2-butene-1,4-sultone, 3-butene-1,4-sultone, 1-fluoro-1-butene-1,4-sultone, 2-fluoro- -Butene-1,4-sultone, 3-fluoro-1-butene-1,4-sultone, 4-fluoro-1-butene-1,4-sultone, 1-fluoro-2-butene-1,4-sultone 2-fluoro-2-butene-1,4-sultone, 3-fluoro-2-butene-1,4-sultone, 4-fluoro-2-butene-1,4-sultone, 1-fluoro-3-butene -1,4-sultone, 2-fluoro-3-butene-1,4-sultone, 3-fluoro-3-butene-1,4-sultone, 4-fluoro-3-butene-1,4-sultone, 1 -Methyl-1-butene-1,4-sultone, 2-methyl-1-butene-1,4-sultone, 3-methyl-1-butene-1,4-sultone, 4-methyl-1-butene-1 , 4-sultone, 1-methyl-2-butene-1,4 -Sultone, 2-methyl-2-butene-1,4-sultone, 3-methyl-2-butene-1,4-sultone, 4-methyl-2-butene-1,4-sultone, 1-methyl-3 -Butene-1,4-sultone, 2-methyl-3-butene-1,4-sultone, 3-methyl-3-butene-1,4-sultone, 4-methyl-3-butene-1,4-sultone 1,5-pentane sultone, 1-fluoro-1,5-pentane sultone, 2-fluoro-1,5-pentane sultone, 3-fluoro-1,5-pentanthruton, 4-fluoro-1,5-pentane Sultone, 5-fluoro-1,5-pentanthruton, 1-methyl-1,5-pentanthruton, 2-methyl-1,5-pentanthruton, 3-methyl-1,5-pentanthruton, 4-methyl- 1,5- N-pentene sultone, 5-methyl-1,5-pentanthrutone, 1-pentene-1,5-sultone, 2-pentene-1,5-sultone, 3-pentene-1,5-sultone, 4-pentene-1,5 -Sultone, 1-fluoro-1-pentene-
1,5-sultone, 2-fluoro-1-pentene-1,5-sultone, 3-fluoro-1-pentene-1,5-sultone, 4-fluoro-1-pentene-1,5-sultone, 5- Fluoro-1-pentene-1,5-sultone, 1-fluoro-2-pentene-1,5-sultone, 2-fluoro-2-pentene-1,5-sultone, 3-fluoro-2-pentene-1, 5-sultone, 4-fluoro-2-pentene-1,5-sultone, 5-fluoro-2-pentene-1,5-sultone, 1-fluoro-3-pentene-1,5-sultone, 2-fluoro- 3-pentene-1,5-sultone, 3-fluoro-3-pentene-1,5-sultone, 4-fluoro-3-pentene-1,5-sultone, 5-fluoro-3-pentene-1,5- Sultone, 1- Luo-4-pentene-1,5-sultone, 2-fluoro-4-pentene-1,5-sultone, 3-fluoro-4-pentene-1,5-sultone, 4-fluoro-4-pentene-1, 5-sultone, 5-fluoro-4-pentene-1,5-sultone, 1-methyl-1-pentene-1,5-sultone, 2-methyl-1-pentene-1,5-sultone, 3-methyl- 1-pentene-1,5-sultone, 4-methyl-1-pentene-1,5-sultone, 5-methyl-1-pentene-1,5-sultone, 1-methyl-2-pentene-1,5- Sultone, 2-methyl-2-pentene-1,5-sultone, 3-methyl-2-pentene-1,5-sultone, 4-methyl-2-pentene-1,5-sultone, 5-methyl-2- Pentene-1,5-sultone, -Methyl-3-pentene-1,5-sultone, 2-methyl-3-pentene-1,5-sultone, 3-methyl-3-pentene-1,5-sultone, 4-methyl-3-pentene-1 , 5-sultone, 5-methyl-3-pentene-1,5-sultone, 1-methyl-4-pentene-1,5-sultone, 2-methyl-4-pentene-1,5-sultone, 3-methyl Sultone compounds such as -4-pentene-1,5-sultone, 4-methyl-4-pentene-1,5-sultone, 5-methyl-4-pentene-1,5-sultone;

Sulfate compounds such as methylene sulfate, ethylene sulfate, propylene sulfate;
Disulfonate compounds such as methylene methane disulfonate and ethylene methane disulfonate;
1,2,3-oxathiazolidine-2,2-dioxide, 3-methyl-1,2,3-oxathiazolidine-2,2-dioxide, 3H-1,2,3-oxathiazol-2,2-dioxide 5H-1,2,3-oxathiazol-2,2-dioxide, 1,2,4-oxathiazolidine-2,2-dioxide, 4-methyl-1,2,4-oxathiazolidine-2,2- Dioxide, 3H-1,2,4-oxathiazole-2,2-dioxide, 5H-1,2,4-oxathiazole-2,2-dioxide, 1,2,5-oxathiazolidine-2,2-dioxide 5-methyl-1,2,5-oxathiazolidine-2,2-dioxide, 3H-1,2,5-oxathiazole-2,2-dioxide, 5H-1,2,5-oxathiazole-2 2-dioxide, 1,2,3-oxathiazinane-2,2-dioxide, 3-methyl-1,2,3-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,3-oxathiazine- 2,2-dioxide, 1,2,4-oxathiazinane-2,2-dioxide, 4-methyl-1,2,4-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,4- Oxathiazine-2,2-dioxide, 3,6-dihydro-1,2,4-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,4-oxathiazine-2,2-dioxide, 1, 2,5-oxathiazinane-2,2-dioxide, 5-methyl-1,2,5-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,5-oxathiazine-2 2-dioxide, 3,6-dihydro-1,2,5-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,5-oxathiazine-2,2-dioxide, 1,2,6- Oxathiazinane-2,2-dioxide, 6-methyl-1,2,6-oxathiazinane-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide, 3,4- Nitrogen-containing compounds such as dihydro-1,2,6-oxathiazine-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide;

1,2,3-oxathiaphoslane-2,2-dioxide, 3-methyl-1,2,3-oxathiaphoslane-2,2-dioxide, 3-methyl-1,2,3-oxathi Aphoslane-2,2,3-trioxide, 3-methoxy-1,2,3-oxathiaphoslane-2,2,3-trioxide, 1,2,4-oxathiaphoslane-2,2-dioxide 4-methyl-1,2,4-oxathiaphoslane-2,2-dioxide, 4-methyl-1,2,4-oxathiaphoslane-2,2,4-trioxide, 4-methoxy-1 , 2,4-Oxathiaphoslane-2,2,4-trioxide, 1,2,5-oxathiaphoslane-2,2-dioxide, 5-methyl-1,2,5-oxathiaphoslane- 2,2-dioxide, 5-methyl-1,2,5-oxathia Suranium-2,2,5-trioxide, 5-methoxy-1,2,5-oxathiaphoslane-2,2,5-trioxide, 1,2,3-oxathiaphosphinan-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphinan-2,2-dioxide, 3-methyl-1,2,3-oxathiaphosphinan-2,2,3-trioxide, 3-methoxy-1, 2,3-oxathiaphosphinan-2,2,3-trioxide, 1,2,4-oxathiaphosphinan-2,2-dioxide, 4-methyl-1,2,4-oxathiaphosphinan-2 , 2-dioxide, 4-methyl-1,2,4-oxathiaphosphinan-2,2,3-trioxide, 4-methyl-1,5,2,4-dioxathiaphosphinan-2,4- Dioxide, 4-methoxy 1,5,2,4-dioxathiaphosphinan-2,4-dioxide, 3-methoxy-1,2,4-oxathiaphosphinan-2,2,3-trioxide, 1,2,5-oxa Thiaphosphinan-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinan-2,2-dioxide, 5-methyl-1,2,5-oxathiaphosphinan-2,2, 3-trioxide, 5-methoxy-1,2,5-oxathiaphosphinan-2,2,3-trioxide, 1,2,6-oxathiaphosphinan-2,2-dioxide, 6-methyl-1, 2,6-oxathiaphosphinan-2,2-dioxide, 6-methyl-1,2,6-oxathiaphosphinan-2,2,3-trioxide, 6-methoxy-1,2,6-oxathia Phosphinan-2,2 Phosphorus-containing compounds such as 1,3-trioxide;
Is mentioned.

Among these, 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-1, 3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1,4- Butane sultone, methylene methane disulfonate, and ethylene methane disulfonate are preferred from the viewpoint of improving the storage characteristics of the non-aqueous electrolyte,
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-1,3-sultone More preferred.

  A cyclic sulfonic acid ester may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. There is no restriction | limiting in particular in the compounding quantity of the cyclic sulfonic acid ester with respect to the whole non-aqueous electrolyte solution of this invention, Unless the effect of this invention is impaired remarkably, it is arbitrary. The blending amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, in 100% by mass of the nonaqueous electrolytic solution. , Preferably 5% by mass or less, more preferably 3% by mass or less, particularly preferably 2% by mass or less, and most preferably 1% by mass or less. When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics of the nonaqueous electrolyte secondary battery are further improved.

1-3. Electrolyte <Alkali metal salt>
As the electrolyte, an alkali metal salt is used, but a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, inorganic lithium salts LiTaF 6, LiWF ₇ and the like;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ Sulfonic acid lithium salts such as CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium imide salts such as lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) ;

Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiBF 3 C 3} F 7, LiBF 2 (CF 3) 2, LiBF 2 (C 2 F 5) 2, LiBF 2 (CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2 Fluorine-containing organic lithium salts such as;

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

These lithium salts may be used alone or in combination of two or more. A preferable example in the case of using two or more kinds in combination is a combination of LiPF ₆ and LiBF ₄ , LiPF ₆ and LiN (FSO ₂ ) ₂ , LiPF ₆ and FSO ₃ Li, etc., and an effect of improving load characteristics and cycle characteristics There is.
In this case, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by mass of the entire non-aqueous electrolyte solution is not limited as long as it does not significantly impair the effects of the present invention. On the other hand, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, and usually 30% by mass or less, preferably 20% by mass or less.

Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has the effect of suppressing deterioration due to high-temperature storage. As the organic lithium salt, CF ₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalate phosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ LiPF ₃ (C ₂ F ₅ ) ₃ or the like is preferable. In this case, the ratio of the organic lithium salt to 100% by mass of the entire non-aqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and preferably 30% by mass or less. Especially preferably, it is 20 mass% or less.

  The concentration of these lithium salts in the non-aqueous electrolyte solution is not particularly limited as long as the effects of the present invention are not impaired, but the electric conductivity of the electrolyte solution is in a good range, and good battery performance is ensured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and further preferably 0.5 mol / L or more. Preferably it is 3 mol / L or less, More preferably, it is 2.5 mol / L or less, More preferably, it is 2.0 mol / L or less.

When the total molar concentration of lithium is within the above range, the electric conductivity of the electrolytic solution becomes sufficient, and the decrease in electric conductivity due to the increase in viscosity and the decrease in battery performance resulting therefrom are prevented.
1-4. Nonaqueous solvent There is no restriction | limiting in particular about the nonaqueous solvent in this invention, It is possible to use a well-known organic solvent. Examples thereof include cyclic carbonates having no fluorine atom, chain carbonates, cyclic carboxylic acid esters, ether compounds, sulfone compounds, and the like.

<Cyclic carbonate without fluorine atoms>
Examples of the cyclic carbonate having no fluorine atom include cyclic carbonates having an alkylene group having 2 to 4 carbon atoms.
Specific examples of the cyclic carbonate having 2 to 4 carbon atoms and having no fluorine atom include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

The cyclic carbonate which does not have a fluorine atom may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
The blending amount of the cyclic carbonate having no fluorine atom is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. However, the blending amount when one kind is used alone is 100% by volume of the nonaqueous solvent. Among them, the content is 5% by volume or more, more preferably 10% by volume or more. By setting this range, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, stability to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery are in a good range. And it will be easier. Moreover, it is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte battery are easily set in a favorable range.

<Chain carbonate>
As the chain carbonate, a chain carbonate having 3 to 7 carbon atoms is preferable, and a dialkyl carbonate having 3 to 7 carbon atoms is more preferable.
Specific examples of the chain carbonate include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl. Examples include carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate, and the like.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.
Further, chain carbonates having a fluorine atom (hereinafter sometimes referred to as “fluorinated chain carbonate”) can also be suitably used.

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

Fluorinated dimethyl carbonate and derivatives thereof include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoromethyl) carbonate, bis (trifluoromethyl) carbonate, and the like. It is done.
Fluorinated ethyl methyl carbonate and derivatives thereof include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2 -Trifluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, ethyl trifluoromethyl carbonate, etc. are mentioned.

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

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set in an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily set in a favorable range. The chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, and particularly preferably 80% by volume or less in 100% by volume of the non-aqueous solvent. By setting the upper limit in this way, it is possible to avoid a decrease in electrical conductivity resulting from a decrease in the dielectric constant of the non-aqueous electrolyte solution, and to make the large current discharge characteristics of the non-aqueous electrolyte battery within a favorable range.

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

A cyclic carboxylic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. If it is this range, it will become easy to improve the electrical conductivity of a non-aqueous electrolyte solution, and to improve the large current discharge characteristic of a non-aqueous electrolyte battery. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

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

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.

An ether type compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The compounding amount of the ether compound is usually in 100% by volume of the nonaqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less.

If it is this range, it will be easy to ensure the improvement effect of the ionic conductivity derived from the improvement of the lithium ion dissociation degree and viscosity reduction of the chain ether, and when the negative electrode active material is a carbonaceous material, the chain ether together with the lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.
<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.

As cyclic sulfone having 3 to 6 carbon atoms,
Monosulfone compounds trimethylene sulfones, tetramethylene sulfones, hexamethylene sulfones;
Examples include disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones.

Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.
As sulfolanes, sulfolane and / or sulfolane derivatives (hereinafter sometimes referred to as “sulfolanes” including sulfolane) are preferable. The sulfolane derivative is preferably one in which one or more hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group.

  Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane , 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output characteristics.

In addition, as the chain sulfone having 2 to 6 carbon atoms,
Dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, n-propylethylsulfone, di-n-propylsulfone, isopropylmethylsulfone, isopropylethylsulfone, diisopropylsulfone, n-butylmethylsulfone, n-butylethyl Sulfone, t-butylmethylsulfone, t-butylethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone, difluoroethylmethylsulfone, trifluoroethylmethylsulfone, pentafluoro Ethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, perf Oroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di (trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone, trifluoromethyl- n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, pentafluoroethylisopropylsulfone , Trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, pentafluoroethyl- - butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

  Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is high ion conductivity, preferable because the input-output characteristic is high.

A sulfone compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 1% by volume or more, further preferably 5% by volume or more in 100% by volume of the nonaqueous solvent, and preferably 40%. Volume% or less, More preferably, it is 35 volume% or less, More preferably, it is 30 volume% or less.

Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte solution can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.
<When using a cyclic carbonate having a fluorine atom as a non-aqueous solvent>
The cyclic carbonate having a fluorine atom is used in a non-aqueous electrolyte solution as a 1-2-2. As can be seen, it can be used as an auxiliary agent and can also be used as a non-aqueous solvent.

In the present invention, when a cyclic carbonate having a fluorine atom is used as a non-aqueous solvent, as the non-aqueous solvent other than the cyclic carbonate having a fluorine atom, one of the non-aqueous solvents exemplified above is used as a cyclic carbonate having a fluorine atom. You may use in combination and may use 2 or more types together with the cyclic carbonate which has a fluorine atom.
For example, one preferred combination of non-aqueous solvents is a combination mainly composed of a cyclic carbonate having a fluorine atom and a chain carbonate. Among them, the total of the cyclic carbonate having a fluorine atom and the chain carbonate in the non-aqueous solvent is preferably 60% by volume or more, more preferably 80% by volume or more, still more preferably 90% by volume or more, and fluorine atoms. The ratio of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having a chain and the chain carbonate is 3% by volume or more, preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more. Also, it is usually 60% by volume or less, preferably 50% by volume or less, more preferably 40% by volume or less, further preferably 35% by volume or less, particularly preferably 30% by volume or less, and most preferably 20% 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 produced using the non-aqueous solvent may be improved.
For example, as a specific example of a preferable combination of a cyclic carbonate having a fluorine atom and a chain carbonate,
Monofluoroethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoro Examples thereof include ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

  Among the combinations of cyclic carbonates having a fluorine atom and chain carbonates, those containing symmetric chain alkyl carbonates as chain carbonates are more preferable, and in particular, monofluoroethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, Cycle characteristics include monofluoroethylene carbonate, symmetric chain carbonates and asymmetric chain carbonates such as fluoroethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate. And a large current discharge characteristic are preferable. Among these, the symmetric chain carbonate is preferably dimethyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

  A combination in which a cyclic carbonate having no fluorine atom is further added to the combination of the cyclic carbonate having a fluorine atom and the chain carbonate is also mentioned as a preferable combination. Among them, the total of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom in the non-aqueous solvent is preferably 10% by volume or more, more preferably 15% by volume or more, and further preferably 20% by volume or more. The ratio of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom is 1% by volume or more, preferably 3% by volume or more, more preferably 5% by volume or more. More preferably 10% by volume or more, particularly preferably 20% by volume or more, and preferably 95% by volume or less, more preferably 85% by volume or less, still more preferably 75% by volume or less, particularly preferably 60% by volume. It is as follows.

When a cyclic carbonate having no fluorine atom is contained in this concentration range, the electrical conductivity of the electrolytic solution can be maintained while forming a stable protective film on the negative electrode.
As a specific example of a preferable combination of a cyclic carbonate having a fluorine atom and a cyclic carbonate having no fluorine atom and a chain carbonate,
Monofluoroethylene carbonate and ethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and ethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoro Ethylene carbonate, ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate Monofluoroethylene carbonate and propylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and propylene carbonate and diethyl carbonate, monofluoroethylene carbonate and propylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate, dimethyl carbonate and diethyl carbonate, Monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate Cylmethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, monofluoroethylene Carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate and propylene carbonate Examples include diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Among the combinations of cyclic carbonates having fluorine atoms and cyclic carbonates not having fluorine atoms and chain carbonates, those containing asymmetric chain alkyl carbonates as chain carbonates are more preferred,
Monofluoroethylene carbonate and ethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate and dimethyl carbonate Ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate Ethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate And dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Since the balance of Le characteristics and large-current discharge characteristics may preferably. Among them, the asymmetric chain carbonate is preferably ethyl methyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

  When ethyl methyl carbonate is contained in the non-aqueous solvent, the proportion of ethyl methyl 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. In particular, it is 30% by volume or more, preferably 95% by volume or less, more preferably 90% by volume or less, still more preferably 85% by volume or less, and particularly preferably 80% by volume or less. The load characteristics of the battery may be improved.

In the combination mainly composed of the cyclic carbonate having a fluorine atom and the chain carbonate, in addition to the cyclic carbonate having no fluorine atom, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, a chain Other solvents such as a chain ether, a sulfur-containing organic solvent, a phosphorus-containing organic solvent, and a fluorine-containing aromatic solvent may be mixed.
<When using a cyclic carbonate having a fluorine atom as an auxiliary agent>
In the present invention, when a cyclic carbonate having a fluorine atom is used as an auxiliary agent, as the non-aqueous solvent other than the cyclic carbonate having a fluorine atom, the above-exemplified non-aqueous solvent may be used alone, or two or more thereof. May be used in any combination and ratio.

For example, one preferred combination of non-aqueous solvents is a combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate.
Among them, the total of the cyclic carbonate having no fluorine atom and the chain carbonate in the non-aqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, further preferably 90% by volume or more, and The ratio of the cyclic carbonate having no fluorine atom to the total of the cyclic carbonate having no fluorine atom and the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more. In addition, it is preferably 50% by volume or less, more preferably 35% by volume or less, further preferably 30% by volume or less, and 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 produced using the non-aqueous solvent may be improved.
For example, as a specific example of a preferable combination of a cyclic carbonate having no fluorine atom and a chain carbonate,
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 carbonate, ethylene carbonate and diethyl carbonate and ethyl methyl carbonate, ethylene carbonate And dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, propylene carbonate and ethyl methyl carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate, propylene carbonate, ethyl methyl carbonate and dimethyl carbonate.

  Among the combinations of cyclic carbonates having no fluorine atoms and chain carbonates, those containing asymmetric chain alkyl carbonates as chain carbonates are more preferable, and in particular, ethylene carbonate and ethyl methyl carbonate, propylene carbonate and ethyl Cycling characteristics and large current are methyl carbonate, ethylene carbonate and ethyl methyl carbonate and dimethyl carbonate, ethylene carbonate and ethyl methyl carbonate and diethyl carbonate, propylene carbonate and ethyl methyl carbonate and dimethyl carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate, etc. This is preferable because the discharge characteristics are well balanced.

Among them, the asymmetric chain carbonate is preferably ethyl methyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.
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 even more preferably 25% by volume or more. Preferably it is 30% by volume or more, preferably 90% by volume or less, more preferably 80% by volume or less, further preferably 75% by volume or less, and particularly preferably 70% by volume or less. 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 electric conductivity of the electrolyte can be maintained, but the battery characteristics after high temperature storage are improved. This is preferable.
The volume 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 electric conductivity of the electrolyte and improving the battery characteristics after storage. Is preferable, 1.5 or more is more preferable, and 2.5 or more is more preferable. The volume ratio (dimethyl carbonate / ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, further preferably 10 or less, and particularly preferably 8 or less, from the viewpoint of improving battery characteristics.

In the combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, a chain ether, a sulfur-containing organic solvent, a phosphorus-containing solvent You may mix other solvents, such as an organic solvent and an aromatic fluorine-containing solvent.
In this specification, the volume of the non-aqueous solvent is a measured value at 25 ° C., but the measured value at the melting point is used for a solid at 25 ° C. such as ethylene carbonate.

1-5. Auxiliary agent In the non-aqueous electrolyte battery of the present invention, the compound represented by the general formula (A), a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, an isocyanuric acid skeleton In addition to the compound having a fluorophosphate, a fluorophosphate, a fluorosulfonate, and a cyclic sulfonate ester, an auxiliary may be appropriately used depending on the purpose. Examples of the auxiliary agent include acid anhydride compounds, fluorinated unsaturated cyclic carbonates, compounds having a triple bond, and other auxiliary agents shown below.

1-5-1. Acid anhydride compound Acid anhydride compounds include carboxylic acid anhydride, sulfuric acid anhydride, nitric acid anhydride, sulfonic acid anhydride, phosphoric acid anhydride, phosphorous acid anhydride, cyclic acid anhydride, chain The structure of the acid anhydride compound is not particularly limited as long as it is an acid anhydride compound.

Specific examples of the acid anhydride compound include, for example,
Malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, glutaconic anhydride, itaconic anhydride, phthalic anhydride, phenylmaleic anhydride 2,3-diphenylmaleic anhydride, cyclohexane-1,2-dicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 4 , 4′-oxydiphthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride, phenylsuccinic anhydride, 2-phenylglutaric anhydride Allyl succinic anhydride, 2-buten-11-yl succinic anhydride, (2-methyl-2-propenyl) succinic anhydride, tetra Fluorosuccinic anhydride, diacetyl-tartaric anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (2,5-dioxo Tetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, methacrylic acid anhydride, acrylic acid anhydride, crotonic acid anhydride, methanesulfonic acid anhydride, trifluoromethanesulfonic acid anhydride, nona Examples include fluorobutanesulfonic anhydride, acetic anhydride and the like.

Of these,
Succinic anhydride, maleic anhydride, citraconic anhydride, phenylmaleic anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (2 , 5-Dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-
Particularly preferred are dicarboxylic anhydride, allyl succinic anhydride, acetic anhydride, methacrylic anhydride, acrylic anhydride, and methanesulfonic anhydride.

An acid anhydride compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
There is no limit to the amount of the acid anhydride compound with respect to the entire non-aqueous electrolyte of the present invention, and it is optional as long as the effects of the present invention are not significantly impaired. % By mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 2% by mass. It is contained at a concentration of not more than mass%, particularly preferably not more than 1 mass%, most preferably not more than 0.5 mass%.

When the above range is satisfied, effects such as output characteristics, load characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.
1-5-2. Fluorinated unsaturated cyclic carbonate As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes referred to as “fluorinated unsaturated cyclic carbonate”). The number of fluorine atoms contained in the fluorinated unsaturated cyclic carbonate is not particularly limited as long as it is 1 or more. Among them, the fluorine atom is usually 6 or less, preferably 4 or less, and most preferably 1 or 2.

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

As the fluorinated ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon double bond,
4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene Carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fu Oro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate.

Among these, as a preferable fluorinated unsaturated cyclic carbonate,
4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro- 4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate 4,5-difluoro-4,5-divinyl ethylene carbonate, 4,5-difluoro-4,5-diallyl ethylene carbonate, because it forms a stable interface protective coating, more preferably used.

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

A fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Moreover, the compounding quantity of a fluorinated unsaturated cyclic carbonate is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary.
The compounding amount of the fluorinated unsaturated cyclic carbonate is usually in 100% by mass of the nonaqueous electrolytic solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.5% by mass or more. Moreover, it is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3% by mass or less, and particularly preferably 2% by mass or less.

Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.
1-5-3. Compound having triple bond The compound having a triple bond is not particularly limited as long as it is a compound having one or more triple bonds in the molecule.

Specific examples of the compound having a triple bond include the following compounds.
1-pentyne, 2-pentyne, 1-hexyne, 2-hexyne, 3-hexyne, 1-heptin, 2-heptin, 3-heptin, 1-octyne, 2-octyne, 3-octyne, 4-octyne, 1- Nonin, 2-nonine, 3-nonine, 4-nonine, 1-dodecin, 2-dodecin, 3-dodecin, 4-dodecin, 5-dodecin, phenylacetylene, 1-phenyl-1-propyne, 1-phenyl-2 -Propyne, 1-phenyl-1-butyne, 4-phenyl-1-butyne, 4-phenyl-1-butyne, 1-phenyl-1-pentyne, 5-phenyl-1-pentyne, 1-phenyl-1-hexyne Hydrocarbon compounds such as 6-phenyl-1-hexyne, diphenylacetylene, 4-ethynyltoluene, and dicyclohexylacetylene;

2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-propynylpropyl carbonate, 2-propynylbutyl carbonate, 2-propynylphenyl carbonate, 2-propynylcyclohexyl carbonate, di-2-propynyl carbonate, 1-methyl-2-propynyl Methyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-butynylmethyl carbonate, 3-butynylmethyl carbonate, 2-pentynylmethyl carbonate, 3-pentynylmethyl carbonate, 4-pentynylmethyl carbonate, etc. Monocarbonate of
2-butyne-1,4-diol dimethyl dicarbonate, 2-butyne-1,4-diol diethyl dicarbonate, 2-butyne-1,4-diol dipropyl dicarbonate, 2-butyne-1,4-diol dibutyl Dicarbonate, 2-butyne-1,4-
Dicarbonates such as diol diphenyl dicarbonate and 2-butyne-1,4-diol dicyclohexyl dicarbonate;

  2-propynyl acetate, 2-propynyl propionate, 2-propynyl butyrate, 2-propynyl benzoate, 2-propynyl cyclohexylcarboxylate, acetic acid 1, 1-dimethyl-2-propynyl, 1, propionic acid 1, 1-dimethyl-2- Propynyl, butyric acid 1,1-dimethyl-2-propynyl, benzoic acid 1,1-dimethyl-2-propynyl, cyclohexylcarboxylic acid 1,1-dimethyl-2-propynyl, 2-butynyl acetate, 3-butynyl acetate, acetic acid 2 -Pentynyl, 3-pentynyl acetate, 4-pentynyl acetate, methyl acrylate, ethyl acrylate, propyl acrylate, vinyl acrylate, 2-propenyl acrylate, 2-butenyl acrylate, 3-butenyl acrylate, methyl methacrylate , Ethyl methacrylate, propyl methacrylate, methacrylate Vinyl proprate, 2-propenyl methacrylate, 2-butenyl methacrylate, 3-butenyl methacrylate, methyl 2-propinate, ethyl 2-propinate, propyl 2-propinate, vinyl 2-propinate, 2-propionic acid 2-propenyl, 2-butenyl 2-propanoate, 3-butenyl 2-propinate, methyl 2-butyrate, 2-ethyl butyrate, propyl 2-butyrate, vinyl 2-butyrate, 2-butynoic acid 2- Propenyl, 2-butenyl 2-butyrate, 3-butenyl 2-butyrate, methyl 3-butyrate, ethyl 3-butyrate, propyl 3-butyrate, vinyl 3-butyrate, 2-propenyl 3-butyrate, 2-butenyl 3-butynoate, 3-butenyl 3-butyrate, methyl 2-pentynoate, ethyl 2-pentynoate, propyl 2-pentynoate, 2- Vinyl pentinate, 2-propenyl 2-pentylate, 2-butenyl 2-pentinate, 3-butenyl 2-pentinate, methyl 3-pentinate, ethyl 3-pentanoate, propyl 3-pentanoate, 3-pentynoic acid Vinyl, 2-propenyl 3-pentynoate, 2-butenyl 3-pentynoate, 3-butenyl 3-pentynoate, methyl 4-pentynoate, ethyl 4-pentynoate, propyl 4-pentynoate, vinyl 4-pentynoate, Monocarboxylic acid esters such as 2-propenyl 4-pentynoate, 2-butenyl 4-pentynoate and 3-butenyl 4-pentynoate;

2-butyne-1,4-diol diacetate, 2-butyne-1,4-diol dipropionate, 2-butyne-1,4-diol dibutyrate, 2-butyne-1,4-diol dibenzoate, 2-butyne Dicarboxylic acid esters such as -1,4-diol dicyclohexanecarboxylate;
Methyl oxalate 2-propynyl, ethyl oxalate 2-propynyl, propyl oxalate 2-propynyl, 2-propynyl oxalate vinyl, allyl oxalate 2-propynyl, di-2-propynyl oxalate, 2-butynyl methyl oxalate, 2-butynylethyl oxalate, 2-butynylpropyl oxalate, 2-butynyl vinyl oxalate, allyl 2-butynyl oxalate, di-2-butynyl oxalate, 3-butynyl methyl oxalate, 3-butynyl ethyl oxalate Oxalic acid diesters such as 3-butynylpropyl oxalate, 3-butynyl vinyl oxalate, allyl 3-butynyl oxalate, and di-3-butynyl oxalate;

Methyl (2-propynyl) (vinyl) phosphine oxide, divinyl (2-propynyl) phosphine oxide, di (2-propynyl) (vinyl) phosphine oxide, di (2-propenyl) 2 (-propynyl) phosphine oxide, di (2 Phosphine oxides such as -propynyl) (2-propenyl) phosphine oxide, di (3-butenyl) (2-propynyl) phosphine oxide, and di (2-propynyl) (3-butenyl) phosphine oxide;
2-propynyl methyl (2-propenyl) phosphinate, 2-propynyl 2-butenyl (methyl) phosphinate, 2-propynyl di (2-propenyl) phosphinate, 2-propynyl di (3-butenyl) phosphinate, methyl ( 2-propenyl) phosphinic acid 1,1-dimethyl-2-propynyl, 2-butenyl (methyl) phosphinic acid 1,1-dimethyl-
2-propynyl, di (2-propenyl) phosphinic acid 1,1-dimethyl-2-propynyl, and di (3-butenyl) phosphinic acid 1,1-dimethyl-2-propynyl, methyl (2-propynyl) phosphinic acid 2 -Propenyl, methyl (2-propynyl) phosphinic acid 3-butenyl, di (2-propynyl) phosphinic acid 2-propenyl, di (2-propynyl) phosphinic acid 3-butenyl, 2-propynyl (2-propenyl) phosphinic acid 2 Phosphinic acid esters such as propenyl and 2-propynyl (2-propenyl) phosphinic acid 3-butenyl;

2-propenylphosphonic acid methyl 2-propynyl, 2-butenylphosphonic acid methyl (2-propynyl), 2-propenylphosphonic acid (2-propynyl) (2-propenyl), 3-butenylphosphonic acid (3-butenyl) (2-propynyl) ), 2-propenylphosphonic acid (1,1-dimethyl-2-propynyl) (methyl), 2-butenylphosphonic acid (1,1-dimethyl-2-propynyl) (methyl), 2-propenylphosphonic acid (1,1 -Dimethyl-2-propynyl) (2-propenyl), and 3-butenylphosphonic acid (3-butenyl) (1,1-dimethyl-2-propynyl), methylphosphonic acid (2-propynyl) (2-propenyl), methylphosphonic acid (3-butenyl) (2-propynyl), methylphosphonic acid (1,1-dimethyl-2-prop Pinyl) (2-propenyl), methylphosphonic acid (3-butenyl) (1,1-dimethyl-2-propynyl), ethylphosphonic acid (2-propynyl) (2-propenyl), ethylphosphonic acid (3-butenyl) ( 2-propynyl), phosphonic acid esters such as ethylphosphonic acid (1,1-dimethyl-2-propynyl) (2-propenyl), and ethylphosphonic acid (3-butenyl) (1,1-dimethyl-2-propynyl) ;
Phosphoric acid (methyl) (2-propenyl) (2-propynyl), phosphoric acid (ethyl) (2-propenyl) (2-propynyl), phosphoric acid (2-butenyl) (methyl) (2-propynyl), phosphoric acid (2-butenyl) (ethyl) (2-propynyl), phosphoric acid (1,1-dimethyl-2-propynyl) (methyl) (2-propenyl), phosphoric acid (1,1-dimethyl-2-propynyl) ( Ethyl) (2-propenyl), phosphoric acid (2-butenyl) (1,1-dimethyl-2-propynyl) (methyl), and phosphoric acid (2-butenyl) (ethyl) (1,1-dimethyl-2-phenyl) Phosphate esters such as propynyl);
Among these, a compound having an alkynyloxy group is preferable because it forms a negative electrode film more stably in the electrolytic solution.

further,
2-propynylmethyl carbonate, di-2-propynyl carbonate, 2-butyne-1,4-diol dimethyl dicarbonate, 2-propynyl acetate, 2-butyne-1,4-diol diacetate, methyl oxalate 2-propynyl, A compound such as di-2-propynyl oxalate is particularly preferred from the viewpoint of improving storage characteristics.

  The said compound which has a triple bond may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. The compounding amount of the compound having a triple bond with respect to the entire non-aqueous electrolyte solution of the present invention is not limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. 01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less Let When the above range is satisfied, effects such as output characteristics, load characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-5-4. Other auxiliaries As other auxiliaries, known auxiliaries other than the above auxiliaries can be used. As other auxiliaries,
Carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate;
Spiro compounds such as 2,4,8,10-tetraoxaspiro [5.5] undecane and 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane;
Ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide, vinyl Methyl sulfonate, ethyl vinyl sulfonate, allyl vinyl sulfonate, propargyl vinyl sulfonate, methyl allyl sulfonate, ethyl allyl sulfonate, allyl sulfonate, propargyl allyl sulfonate, 1,2-bis (vinylsulfonoxy) Sulfur-containing compounds such as ethane, lithium methyl sulfate, lithium ethyl sulfate, lithium propargyl sulfate;

Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide;
Trimethyl phosphite, triethyl phosphite, triphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methylphosphonate, diethyl ethylphosphonate, dimethyl vinylphosphonate, diethyl vinylphosphonate, dimethylphosphine Phosphorus-containing compounds such as methyl acid, ethyl diethylphosphinate, trimethylphosphine oxide, triethylphosphine oxide;
Hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane;
Fluorine-containing aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene and benzotrifluoride;

2-propynyl 2- (diethoxyphosphoryl) acetate, 1-methyl-2-propynyl 2- (diethoxyphosphoryl) acetate, 1,1-dimethyl-2-propynyl 2- (diethoxyphosphoryl) acetate, pentafluorophenylmethane Sulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate, pentafluorophenyl trifluoroacetate, methyl pentafluorophenyl carbonate, 2-propynyl 2- (methanesulfonyloxy) propionate, 2- (methanesulfonyloxy) propionic acid 2 -Methyl, 2-ethyl 2- (methanesulfonyloxy) propionate, 2-propynyl methanesulfonyloxyacetate, 2-methylmethanesulfonyloxyacetate, methanesulfonyloxy Ethyl acetate, lithium ethyl methyloxycarbonylphosphonate, lithium ethyl ethyloxycarbonylphosphonate, lithium ethyl 2-propynyloxycarbonylphosphonate, lithium ethyl 1-methyl-2-propynyloxycarbonylphosphonate, lithium ethyl 1,1-dimethyl-2-propynyl Oxycarbonylphosphonate, lithium methyl sulfate, lithium ethyl sulfate, lithium 2-propynyl sulfate, lithium 1-methyl-2-propynyl sulfate, lithium 1,1-dimethyl-2-propynyl sulfate, lithium 2,2,2-trifluoroethyl Sulfate, methyl trimethylsilyl sulfate, ethyl trimethylsilyl sulfate, 2-propynyl Trimethylsilyl sulfate, dilithium ethylene disulfate, 2-butyne-1,4-diyl dimethanesulfonate, 2-butyne-1,4-diyl diethanesulfonate, 2-butyne-1,4-diyl diformate, 2-butyne-1, 4-diyl diacetate, 2-butyne-1,4-diyl dipropionate, 4-hexadiyne-1,6-diyl dimethanesulfonate, 2-propynyl methanesulfonate, 1-methyl-2-propynyl methanesulfonate, 1,1- Dimethyl-2-propynyl methanesulfonate, 2-propynyl ethanesulfonate, 2-propynyl vinylsulfonate, methyl 2-propynyl carbonate, ethyl 2-propynyl carbonate, bis (2-propynyl) carbonate, methyl 2- Ropinyl oxalate, ethyl 2-propynyl oxalate, bis (2-propynyl) oxalate, 2-propynyl acetate, 2-propynyl formate, 2-propynyl methacrylate, di (2-propynyl) glutarate, 2,2-dioxide-1,2- Oxathiolan-4-yl acetate, 2,2-dioxide-1,2-oxathiolan-4-yl propionate, 5-methyl-1,2-oxathiolan-4-one 2,2-dioxide, 5,5-dimethyl-1 , 2-oxathiolan-4-one 2,2-dioxide, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2- (2-isocyanatoethoxy) ethyl acrylate, 2- ( 2-isocyanate Toethoxy) ethyl methacrylate, 2- (2-isocyanatoethoxy) ethyl crotonate, 2-allyl succinic anhydride, 2- (1-penten-3-yl) succinic anhydride, 2- (1-hexen-3-yl) ) Succinic anhydride, 2- (1-hepten-3-yl) succinic anhydride, 2- (1-octen-3-yl) succinic anhydride, 2- (1-nonen-3-yl) succinate Acid anhydride, 2- (3-buten-2-yl) succinic anhydride, 2- (2-methylallyl) succinic anhydride, 2- (3-methyl-3-buten-2-yl) succinic anhydride Thing etc. are mentioned. These may be used individually by 1 type, or may use 2 or more types together. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

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

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

2. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte battery of the present invention can adopt a known structure. Typically, the negative electrode and the positive electrode capable of occluding and releasing ions (for example, lithium ions), and the non-aqueous electrolysis of the present invention described above. Liquid.

2-1. Negative electrode The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. Specific examples include a carbonaceous material, a negative electrode active material containing metal particles that can be alloyed with Li, and graphite particles. These may be used alone or in combination of two or more.

<Negative electrode active material>
Examples of the negative electrode active material include a carbonaceous material, a negative electrode active material containing metal particles that can be alloyed with Li, and graphite particles.
Examples of the carbonaceous material include (1) natural graphite, (2) artificial graphite, (3) amorphous carbon, (4) carbon-coated graphite, (5) graphite-coated graphite, and (6) resin-coated graphite. .

(1) Examples of natural graphite include scaly graphite, scaly graphite, soil graphite, and / or graphite particles obtained by subjecting these graphites to spheroidization or densification. Among these, spherical or ellipsoidal graphite subjected to spheroidizing treatment is particularly preferable from the viewpoints of particle filling properties and charge / discharge rate characteristics.
As an apparatus used for the spheroidization treatment, for example, an apparatus that repeatedly gives mechanical action such as compression, friction, shearing force, etc. including the interaction of particles mainly with impact force to the particles can be used.

Specifically, it has a rotor with a large number of blades installed inside the casing, and mechanical action such as impact compression, friction, shearing force, etc. on the carbon material introduced inside the rotor by rotating at high speed. And a device for performing the spheroidizing treatment is preferable. Moreover, it is preferable to have a mechanism that repeatedly gives mechanical action by circulating the carbon material.
For example, when the spheroidizing treatment is performed using the above-described apparatus, the peripheral speed of the rotating rotor is preferably 30 to 100 m / second, more preferably 40 to 100 m / second, and 50 to 100 m / second. More preferably. The treatment can be performed by simply passing a carbonaceous material, but it is preferable to circulate or stay in the apparatus for 30 seconds or longer, and it is preferable to circulate or stay in the apparatus for 1 minute or longer. More preferred.

  (2) Artificial graphite includes coal tar pitch, coal heavy oil, atmospheric residue, petroleum heavy oil, aromatic hydrocarbon, nitrogen-containing cyclic compound, sulfur-containing cyclic compound, polyphenylene, polyvinyl chloride, Organic compounds such as polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymer, polyphenylene sulfide, polyphenylene oxide, furfuryl alcohol resin, phenol-formaldehyde resin, imide resin are usually in the range of 2500 ° C. or higher and usually 3200 ° C. or lower. Examples thereof include those produced by graphitization at a temperature and, if necessary, pulverized and / or classified. At this time, a silicon-containing compound, a boron-containing compound, or the like can be used as a graphitization catalyst. In addition, artificial graphite obtained by graphitizing mesocarbon microbeads separated in the heat treatment process of pitch can be mentioned. Furthermore, the artificial graphite of the granulated particle which consists of primary particles is also mentioned. For example, by mixing mesocarbon microbeads and graphitizable carbonaceous material powders such as coke, graphitizable binders such as tar and pitch, and graphitization catalyst, graphitizing, and pulverizing as necessary Examples of the resulting graphite particles include a plurality of flat particles and aggregated or bonded so that the orientation planes are non-parallel.

(3) As amorphous carbon, amorphous carbon that has been heat-treated at least once in a temperature range (400 to 2200 ° C.) in which no graphitizable carbon precursor such as tar or pitch is used as a raw material. Examples thereof include amorphous carbon particles obtained by heat treatment using particles or a non-graphitizable carbon precursor such as a resin as a raw material.
(4) Carbon-coated graphite can be obtained by mixing natural graphite and / or artificial graphite with a carbon precursor that is an organic compound such as tar, pitch, or resin, and heat-treating it at least once in the range of 400 to 2300 ° C. Examples thereof include a carbon graphite composite in which natural graphite and / or artificial graphite is used as nuclear graphite, and amorphous carbon coats the nuclear graphite. The composite form may be the whole or part of the surface coated, or a composite of a plurality of primary particles using carbon originating from the carbon precursor as a binder. Carbon can also be deposited (CVD) by reacting natural graphite and / or artificial graphite with hydrocarbon gases such as benzene, toluene, methane, propane, and aromatic volatiles at a high temperature to deposit carbon on the graphite surface. A graphite composite can also be obtained.

(5) As graphite-coated graphite, natural graphite and / or artificial graphite and a carbon precursor of an easily graphitizable organic compound such as tar, pitch or resin are mixed and once in a range of about 2400 to 3200 ° C. Examples thereof include graphite-coated graphite in which natural graphite and / or artificial graphite obtained by heat treatment is used as nuclear graphite, and graphitized material covers the entire surface or a part of the nuclear graphite.
(6) As the resin-coated graphite, natural graphite and / or artificial graphite obtained by mixing natural graphite and / or artificial graphite with a resin and drying at a temperature of less than 400 ° C. is used as nuclear graphite, and the resin is nuclear graphite. And resin-coated graphite covering the surface.

Moreover, the carbonaceous material of (1)-(6) may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
Examples of organic compounds such as tar, pitch and resin used in the above (2) to (5) include coal-based heavy oil, direct-current heavy oil, cracked heavy petroleum oil, aromatic hydrocarbon, N-ring compound. , S ring compounds, polyphenylene, organic synthetic polymers, natural polymers, organic compounds that can be carbonized selected from the group consisting of thermoplastic resins and thermosetting resins. The raw material organic compound may be used after being dissolved in a low molecular organic solvent in order to adjust the viscosity at the time of mixing.

Moreover, as natural graphite and / or artificial graphite used as a raw material of nuclear graphite, natural graphite subjected to spheroidization treatment is preferable.
As an alloy material used as the negative electrode active material, as long as lithium can be occluded / released, lithium alone, simple metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides thereof Any of compounds such as products or phosphides may be used and is not particularly limited. The single metal and alloy forming the lithium alloy are preferably materials containing group 13 and group 14 metal / metalloid elements (that is, excluding carbon), more preferably aluminum, silicon and tin single metals and An alloy or compound containing these atoms. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

<Physical properties of carbonaceous materials>
When using a carbonaceous material as a negative electrode active material, it is desirable to have the following physical properties.
(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002 plane) obtained by X-ray diffraction by the Gakushin method of carbonaceous materials is usually 0.335 nm or more, and usually 0.360 nm or less, and 0.350 nm. The following is preferable, and 0.345 nm or less is more preferable. Further, the crystallite size (Lc) of the carbonaceous material obtained by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more, and more preferably 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) obtained by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and 7 μm. The above is particularly preferable, and is usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 25 μm or less.

If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, a non-uniform coating surface tends to be formed, which may be undesirable in the battery production process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and laser diffraction / scattering particle size distribution. This is performed using a meter (for example, LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(Raman R value)
The Raman R value of the carbonaceous material is a value measured using a laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1. 5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge / discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics.
On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

The Raman spectrum is measured by using a Raman spectrometer (for example, a Raman spectrometer manufactured by JASCO Corporation) to drop the sample naturally into the measurement cell and filling the sample cell with argon ion laser light (or a semiconductor). While irradiating a laser beam, the cell is rotated in a plane perpendicular to the laser beam. The resulting Raman spectrum, the intensity IA of a peak PA around 1580 cm ^-1, and measuring the intensity IB of the peak PB around 1360 cm ^-1, and calculates the intensity ratio R (R = IB / IA) . The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention.

Moreover, said Raman measurement conditions are as follows.
・ Laser wavelength: Ar ion laser 514.5 nm (semiconductor laser 532 nm)
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
-Raman R value: background processing,
-Smoothing processing: Simple average, 5 points of convolution

(BET specific surface area)
BET specific surface area of the carbonaceous material is a value of the measured specific surface area using the BET method is usually 0.1 m ² · ^{g -1} or more, 0.7 m ² · ^{g -1} or more, 1. 0 m ² · ^{g -1} or more, and particularly preferably 1.5 m ² · ^{g -1} or more, generally not more than 100 m ² · ^{g -1,} preferably ^{25 m} 2 · ^{g -1} or less, 15 m ² · g ^-1 more preferably less, ^{10 m} 2 · ^{g -1} or less are especially preferred.

  When the value of the BET specific surface area is less than this range, the acceptability of lithium is likely to deteriorate during charging when used as a negative electrode material, lithium is likely to precipitate on the electrode surface, and stability may be reduced. On the other hand, if it exceeds this range, when used as a negative electrode material, the reactivity with the non-aqueous electrolyte increases, gas generation tends to increase, and a preferable battery may be difficult to obtain.

  The specific surface area is measured by the BET method using a surface area meter (for example, a fully automated surface area measuring device manufactured by Okura Riken), preliminarily drying the sample at 350 ° C. for 15 minutes under nitrogen flow, Using a nitrogen helium mixed gas that is accurately adjusted so that the relative pressure value of nitrogen is 0.3, the nitrogen adsorption BET one-point method is performed by a gas flow method.

(Roundness)
When the circularity is measured as the degree of the sphere of the carbonaceous material, it is preferably within the following range. The circularity is defined as “circularity = (peripheral length of an equivalent circle having the same area as the particle projection shape) / (actual perimeter of the particle projection shape)”, and is theoretical when the circularity is 1. Become a true sphere.

  The circularity of the particles having a particle size of 3 to 40 μm in the range of the carbonaceous material is desirably closer to 1, and is preferably 0.1 or more, more preferably 0.5 or more, and more preferably 0.8 or more, 0.85 or more is more preferable, and 0.9 or more is particularly preferable. High current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material is lowered, the resistance between particles is increased, and the high current density charge / discharge characteristics may be lowered for a short time.

  The circularity is measured using a flow type particle image analyzer (for example, FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample was dispersed in a 0.2% by mass aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate as a surfactant, and irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. The detection range is specified as 0.6 to 400 μm, and the particle size is measured in the range of 3 to 40 μm.

  The method for improving the circularity is not particularly limited, but a sphere-shaped sphere is preferable because the shape of the interparticle void when the electrode body is formed is preferable. Examples of spheroidizing treatment include a method of mechanically approaching a sphere by applying a shearing force and a compressive force, a mechanical / physical processing method of granulating a plurality of fine particles by the binder or the adhesive force of the particles themselves, etc. Is mentioned.

(Tap density)
The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, preferably 0.5 g · cm ⁻³ or more, more preferably 0.7 g · cm ⁻³ or more, and 1 g · cm ⁻³ or more. Particularly preferable, 2 g · cm ⁻³ or less is preferable, 1.8 g · cm ⁻³ or less is more preferable, and 1.6 g · cm ⁻³ or less is particularly preferable. When the tap density is below the above range, the packing density is difficult to increase when used as a negative electrode, and a high-capacity battery may not be obtained. On the other hand, when the above range is exceeded, there are too few voids between particles in the electrode, it is difficult to ensure conductivity between the particles, and it may be difficult to obtain preferable battery characteristics.

The tap density is measured by passing through a sieve having an opening of 300 μm, dropping the sample onto a 20 cm ³ tapping cell and filling the sample to the upper end surface of the cell, and then measuring a powder density measuring device (for example, manufactured by Seishin Enterprise Co., Ltd.). Using a tap denser, tapping with a stroke length of 10 mm is performed 1000 times, and the tap density is calculated from the volume at that time and the mass of the sample.

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high-density charge / discharge characteristics may deteriorate. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. Set the molding obtained by filling 0.47 g of the sample into a molding machine with a diameter of 17 mm and compressing it with 58.8 MN · m ^{-2 so} that it is flush with the surface of the sample holder for measurement. X-ray diffraction is measured. From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(Aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more and usually 10 or less, preferably 8 or less, and more preferably 5 or less. When the aspect ratio exceeds the above range, streaking or a uniform coated surface cannot be obtained when forming an electrode plate, and the high current density charge / discharge characteristics may deteriorate. The lower limit of the above range is the theoretical lower limit value of the aspect ratio of the carbonaceous material.

  The aspect ratio is measured by magnifying and observing the carbonaceous material particles with a scanning electron microscope. Carbonaceous material particles when three-dimensional observation is performed by selecting arbitrary 50 graphite particles fixed to the end face of a metal having a thickness of 50 μm or less and rotating and tilting the stage on which the sample is fixed. The longest diameter A and the shortest diameter B orthogonal thereto are measured, and the average value of A / B is obtained.

(Coverage)
The negative electrode active material of the present invention may be coated with a carbonaceous material or a graphite material. Among these, it is preferable that it is coated with an amorphous carbonaceous material from the viewpoint of lithium ion acceptability, and this coverage is usually 0.5% to 30%, preferably 1% to 25%, more preferably. Is 2% or more and 20% or less. If this content is too high, the amorphous carbon portion of the negative electrode active material increases, and the reversible capacity when the battery is assembled tends to be small. If the content is too small, the amorphous carbon sites are not uniformly coated on the graphite particles serving as nuclei, and strong granulation is not performed, and when pulverized after firing, the particle size tends to be too small.

In addition, the content (coverage) of the carbide derived from the organic compound of the negative electrode active material finally obtained is the amount of the negative electrode active material, the amount of the organic compound, and the residual measured by a micro method in accordance with JIS K 2270. It can be calculated by the following formula based on the charcoal rate.
Formula: coverage of organic compound-derived carbide (%) = (mass of organic compound × remaining carbon ratio × 100) / {mass of negative electrode active material + (mass of organic compound × remaining carbon ratio)}
(Internal porosity)
The internal porosity of the negative electrode active material is usually 1% or more, preferably 3% or more, more preferably 5% or more, and further preferably 7% or more. Further, it is usually less than 50%, preferably 40% or less, more preferably 30% or less, and still more preferably 20% or less. If this internal porosity is too small, the amount of liquid in the particles tends to be small, and charge / discharge characteristics tend to deteriorate. If the internal porosity is too large, there is little inter-particle gap when used as an electrode, and electrolyte diffusion Tend to be insufficient. In addition, the voids are filled with substances that buffer the expansion and contraction of metal particles that can be alloyed with Li, such as amorphous carbon, graphite, and resin. It may be.

<Anode active material containing metal particles capable of being alloyed with Li and graphite particles>.
In the present invention, the negative electrode active material containing Li and alloyable metal particles and graphite particles may be a mixture in which Li and alloyable metal particles and graphite particles are mixed in the form of independent particles. Further, it may be a composite in which metal particles that can be alloyed with Li are present on the surface or inside of the graphite particles. In the present specification, the composite (also referred to as composite particle) is not particularly limited as long as it is a particle containing metal particles and carbonaceous materials that can be alloyed with Li, but preferably Li and an alloy. Metal particles and carbonaceous materials that can be converted into particles are integrated by physical and / or chemical bonds. As a more preferable form, the solid particles are dispersed and present in the particles so that the metal particles and carbonaceous materials that can be alloyed with Li are present at least on the composite particle surface and in the bulk. In order to integrate them by physical and / or chemical bonding, the carbonaceous material is present. More specifically, a preferable form is a composite material composed of at least metal particles capable of being alloyed with Li and graphite particles, and the graphite particles, preferably, natural graphite has a folded structure with a curved structure. Further, the negative electrode active material is characterized in that metal particles that can be alloyed with Li are present in the gaps in the folded structure having the curved surface. Further, the gap may be a gap, or a substance that buffers expansion and contraction of metal particles that can be alloyed with Li, such as amorphous carbon, graphite, and resin, is present in the gap. Also good.

・ Metal particles that can be alloyed with Li As methods for confirming that the metal particles are metal particles that can be alloyed with Li, identification of the metal particle phase by X-ray diffraction and observation of the particle structure by an electron microscope And elemental analysis, elemental analysis by fluorescent X-rays, and the like.
As the metal particles that can be alloyed with Li, any conventionally known metal particles can be used. From the viewpoint of capacity and cycle life, the metal particles are, for example, Fe, Co, Sb, Bi, Pb, Ni, Ag. Si, Sn, Al, Zr, Cr, P, S, V, Mn, As, Nb, Mo, Cu, Zn, Ge, In, Ti, and a metal selected from the group consisting of W and W or a compound thereof. preferable. Further, an alloy composed of two or more kinds of metals may be used, and the metal particles may be alloy particles formed of two or more kinds of metal elements. Among these, a metal selected from the group consisting of Si, Sn, As, Sb, Al, Zn, and W or a metal compound thereof is preferable.

Examples of the metal compound include a metal oxide, a metal nitride, and a metal carbide. Moreover, you may use the alloy which consists of 2 or more types of metals.
Among metal particles that can be alloyed with Li, Si or Si metal compounds are preferable. The Si metal compound is preferably a Si metal oxide. Si or Si metal compound is preferable in terms of increasing the capacity. In the present specification, Si or Si metal compounds are collectively referred to as Si compounds. Specific examples of the Si compound include SiO _x , SiN _x , SiC _x , and SiZ _x O _y (Z═C, N). The Si compound is preferably a Si metal oxide, and the Si metal oxide is SiOx in a general formula. The general formula SiO _x is obtained using Si dioxide (SiO ₂ ) and metal Si (Si) as raw materials, and the value of x is usually 0 ≦ x <2. SiOx has a larger theoretical capacity than graphite. Furthermore, amorphous Si or nano-sized Si crystals easily allow alkali ions such as lithium ions to enter and exit, so that a high capacity can be obtained.

The Si metal oxide is specifically represented as SiO _x , where x is 0 ≦ x <2, more preferably 0.2 or more and 1.8 or less, and still more preferably 0. .4 or more and 1.6 or less, particularly preferably 0.6 or more and 1,4 or less, and X = 0 is particularly preferable. Within this range, it is possible to reduce the irreversible capacity due to the combination of Li and oxygen at the same time as the capacity is high.
-Average particle diameter of metal particles that can be alloyed with Li (d50)
The average particle diameter (d50) of the metal particles that can be alloyed with Li is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and further preferably 0.3 μm, from the viewpoint of cycle life. These are usually 10 μm or less, preferably 9 μm or less, more preferably 8 μm or less. When the average particle diameter (d50) is within the above range, volume expansion associated with charge / discharge is reduced, and good cycle characteristics can be obtained while maintaining charge / discharge capacity.

The average particle diameter (d50) is determined by a laser diffraction / scattering particle size distribution measuring method or the like.
BET specific surface area of metal particles that can be alloyed with Li The specific surface area is usually 0.5 to 60 m ² / g, preferably ^{1 to} 40 m ² / g by the BET method of metal particles that can be alloyed with Li. . It is preferable that the specific surface area by the BET method of the metal particles that can be alloyed with Li is in the above-mentioned range since the charge / discharge efficiency and discharge capacity of the battery are high, lithium can be taken in and out quickly, and the rate characteristics are excellent.

-The amount of oxygen contained in metal particles that can be alloyed with Li The amount of oxygen contained in metal particles that can be alloyed with Li is not particularly limited, but is usually 0.01 to 8% by mass, 0.05 to 5% by mass. Preferably there is. The oxygen distribution state in the particle may exist near the surface, may exist inside the particle, or may exist uniformly within the particle, but is preferably present near the surface. It is preferable that the amount of oxygen contained in the metal particles that can be alloyed with Li is in the above-mentioned range because volume expansion associated with charge / discharge is suppressed due to strong bonding between Si and O, and cycle characteristics are excellent.

-Content ratio of metal particles that can be alloyed with Li The content ratio of metal particles that can be alloyed with Li with respect to the sum of metal particles that can be alloyed with Li and graphite particles is usually 1 mass% or more, preferably 2 mass%. That's it. Also, it is usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 25% by mass or less, still more preferably 20% by mass or less, particularly Preferably it is 15 mass% or less, Most preferably, it is 10 mass% or less. In this range, the coating composed of the compound represented by the formula (A) can suitably cover the metal particles that can be alloyed with Li, and can improve the adhesion to the graphite particles. preferable.

  The negative electrode can be manufactured using any known method. Specifically, as a manufacturing method of the negative electrode, for example, a method in which a negative electrode active material added with a binder or a conductive material is roll-formed as it is to form a sheet electrode, or a compression-molded pellet electrode and The above negative electrode is usually applied to a negative electrode current collector (hereinafter also referred to as “negative electrode current collector”) by a method such as a coating method, a vapor deposition method, a sputtering method, or a plating method. A method of forming a thin film layer (negative electrode active material layer) containing an active material is used. In this case, by adding a binder, a thickener, a conductive material, a solvent, etc. to the above-mentioned negative electrode active material to form a slurry, applying this to the negative electrode current collector, drying, and pressing to increase the density A negative electrode active material layer is formed on the negative electrode current collector.

Examples of the material of the negative electrode current collector include steel, copper alloy, nickel, nickel alloy, and stainless steel. Of these, copper foil is preferred from the viewpoint of easy processing into a thin film and cost.
The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. If the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely, if it is too thin, handling may be difficult.

  In addition, in order to improve the binding effect with the negative electrode active material layer formed on the surface, the surface of these negative electrode current collectors is preferably subjected to a roughening treatment in advance. Surface roughening methods include blasting, rolling with a rough surface roll, abrasive cloth paper with abrasive particles fixed, grinding wheel, emery buff, machine that polishes the current collector surface with a wire brush equipped with steel wire, etc. Examples thereof include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method.

Further, in order to reduce the mass of the negative electrode current collector and improve the energy density per mass of the battery, a perforated negative electrode current collector such as an expanded metal or a punching metal can be used. This type of negative electrode current collector can be freely changed in mass by changing its aperture ratio. Further, when a negative electrode active material layer is formed on both surfaces of this type of negative electrode current collector, the negative electrode active material layer is further less likely to peel due to the rivet effect through the hole. However, when the aperture ratio becomes too high, the contact area between the negative electrode active material layer and the negative electrode current collector becomes small, and thus the adhesive strength may be lowered.

The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a thickener and the like to the negative electrode material. In addition, the “negative electrode material” in this specification refers to a material in which a negative electrode active material and a conductive material are combined.
The content of the negative electrode active material in the negative electrode material is usually 70% by mass or more, particularly 75% by mass or more, and usually 97% by mass or less, particularly preferably 95% by mass or less. When the content of the negative electrode active material is too small, the capacity of the secondary battery using the obtained negative electrode tends to be insufficient. When the content is too large, the content of the conductive agent is relatively insufficient, so that It tends to be difficult to ensure conductivity. When two or more negative electrode active materials are used in combination, the total amount of the negative electrode active materials may be set to satisfy the above range.

  Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; carbon materials such as graphite and carbon black. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material acts as an active material. The content of the conductive material in the negative electrode material is usually 3% by mass or more, particularly 5% by mass or more, and usually 30% by mass or less, and particularly preferably 25% by mass or less. When the content of the conductive material is too small, the conductivity tends to be insufficient. When the content is too large, the content of the negative electrode active material and the like is relatively insufficient, and thus the battery capacity and strength tend to decrease. Note that when two or more conductive materials are used in combination, the total amount of the conductive materials may satisfy the above range.

  As the binder used for the negative electrode, any material can be used as long as it is a material safe with respect to the solvent and the electrolytic solution used at the time of producing the electrode. Examples thereof include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene / butadiene rubber / isoprene rubber, butadiene rubber, ethylene / acrylic acid copolymer, and ethylene / methacrylic acid copolymer. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. It is preferable that the content of the binder is usually 0.5 parts by mass or more, particularly 1 part by mass or more, and usually 10 parts by mass or less, particularly 8 parts by mass or less with respect to 100 parts by mass of the negative electrode material. When the content of the binder is too small, the strength of the obtained negative electrode tends to be insufficient. When the content is too large, the content of the negative electrode active material and the like is relatively insufficient, and thus the battery capacity and conductivity tend to be insufficient. It becomes. In addition, when using two or more binders together, what is necessary is just to make it the total amount of a binder satisfy | fill the said range.

  Examples of the thickener used for the negative electrode include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The thickener may be used as necessary, but when used, the thickener content in the negative electrode active material layer is usually in the range of 0.5% by mass or more and 5% by mass or less. Is preferred.

The slurry for forming the negative electrode active material layer is prepared by mixing a conductive agent, a binder, and a thickener as necessary with the negative electrode active material, and using an aqueous solvent or an organic solvent as a dispersion medium. The As the aqueous solvent, water is usually used, and an organic solvent such as alcohols such as ethanol and cyclic amides such as N-methylpyrrolidone is used in combination within a range of 30% by mass or less with respect to water. You can also. As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic carbonization such as anisole, toluene and xylene Examples thereof include alcohols such as hydrogens, butanol and cyclohexanol, among which cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable. . Any one of these may be used alone, or two or more may be used in any combination and ratio.

The obtained slurry is applied onto the above-described negative electrode current collector, dried, and then pressed to form a negative electrode active material layer. The method of application is not particularly limited, and a method known per se can be used. The drying method is not particularly limited, and a known method such as natural drying, heat drying, or reduced pressure drying can be used.
<Configuration and production method of negative electrode>
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.

In the case of using an alloy-based material, a method of forming a thin film layer (negative electrode active material layer) containing the above-described negative electrode active material by a method such as vapor deposition, sputtering, or plating is also used.
(Electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, below the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

2-2. Positive electrode <Positive electrode active material>
The positive electrode active material (lithium transition metal compound) used for the positive electrode is described below.
<Lithium transition metal compound>
A lithium transition metal compound is a compound having a structure capable of desorbing and inserting Li ions, and examples thereof include sulfides, phosphate compounds, and lithium transition metal composite oxides. Examples of sulfides include compounds having a two-dimensional layered structure such as TiS ₂ and MoS ₂ , and solid compounds represented by the general formula Me _x Mo ₆ S ₈ (Me is various transition metals including Pb, Ag, and Cu). Examples thereof include a chevrel compound having a three-dimensional skeleton structure. Examples of the phosphate compound include those belonging to the olivine structure, and are generally represented by LiMePO ₄ (Me is at least one or more transition metals), specifically LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO _4, and the like. Examples of the lithium transition metal composite oxide include spinel structures capable of three-dimensional diffusion and those belonging to a layered structure capable of two-dimensional diffusion of lithium ions. Those having a spinel structure are generally expressed as LiMe ₂ O ₄ (Me is at least one transition metal), specifically, LiMn ₂ O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O. ₄ , LiCoVO _{4 and the} like. Those having a layered structure are generally expressed as LiMeO ₂ (Me is at least one transition metal). LiCoO _{2 Specifically, LiNiO 2, LiNi 1-x} Co x O 2, LiNi 1-x-y Co x Mn y O 2, LiNi 0.5 Mn 0.5 O 2, Li 1.2 Cr 0. _{4 Mn 0.4 O 2, Li 1.2} Cr 0.4 Ti 0.4 O 2, LiMnO 2 , and the like.

<composition>
Moreover, the lithium transition metal compound is, for example, a lithium transition metal compound represented by the following composition formula (F) or (G).
1) In the case of a lithium transition metal compound represented by the following composition formula (F)
Li _{1 + x} MO ₂ (F)
However, x is usually 0 or more and 0.5 or less. M is an element composed of Ni and Mn or Ni, Mn and Co, and the Mn / Ni molar ratio is usually 0.1 or more and 5 or less. The Ni / M molar ratio is usually 0 or more and 0.5 or less. The Co / M molar ratio is usually 0 or more and 0.5 or less. In addition, the rich portion of Li represented by x may be replaced with the transition metal site M.

  In the composition formula (F), the atomic ratio of the oxygen amount is described as 2 for convenience, but there may be some non-stoichiometry. Moreover, x in the said compositional formula is the preparation composition in the manufacture stage of a lithium transition metal type compound. Usually, batteries on the market are aged after the batteries are assembled. For this reason, the Li amount of the positive electrode may be deficient with charge / discharge. In this case, x may be measured to be −0.65 or more and 1 or less when discharged to 3 V in composition analysis.

A lithium transition metal-based compound is excellent in battery characteristics when fired at a high temperature in an oxygen-containing gas atmosphere in order to enhance the crystallinity of the positive electrode active material.
Furthermore, the lithium transition metal-based compound represented by the composition formula (F) may be a solid solution with Li ₂ MO ₃ called a 213 layer, as shown in the general formula (F ′) below.
αLi ₂ MO ₃ · (1-α) LiM′O ₂ (F ′)
In the general formula, α is a number satisfying 0 <α <1.

M is at least one metal element having an average oxidation number of 4+, specifically, at least one metal element selected from the group consisting of Mn, Zr, Ti, Ru, Re, and Pt. .
M ′ is at least one metal element having an average oxidation number of 3+, preferably at least one metal element selected from the group consisting of V, Mn, Fe, Co, and Ni, and more preferably Is at least one metal element selected from the group consisting of Mn, Co and Ni.

2) A lithium transition metal compound represented by the following general formula (B).
_{Li [Li a M b Mn 2} -b-a] O 4 + δ ··· (G)
However, M is an element comprised from at least 1 sort (s) of the transition metals chosen from Ni, Cr, Fe, Co, Cu, Zr, Al, and Mg.
The value of b is usually 0.4 or more and 0.6 or less.

If the value of b is this range, the energy density per unit mass in a lithium transition metal type compound will be high.
The value of a is usually 0 or more and 0.3 or less. Moreover, a in the above composition formula is a charged composition in the production stage of the lithium transition metal compound. Usually, batteries on the market are aged after the batteries are assembled. For this reason, the Li amount of the positive electrode may be deficient with charge / discharge. In this case, a may be measured to be −0.65 or more and 1 or less when discharged to 3 V in composition analysis.

When the value of a is within this range, the energy density per unit mass in the lithium transition metal compound is not significantly impaired, and good load characteristics can be obtained.
Furthermore, the value of δ is usually in the range of ± 0.5.
If the value of δ is within this range, the stability as a crystal structure is high, and the cycle characteristics and high-temperature storage of a battery having an electrode produced using this lithium transition metal compound are good.

Here, the chemical meaning of the lithium composition in the lithium nickel manganese composite oxide, which is the composition of the lithium transition metal compound, will be described in more detail below.
In order to obtain a and b in the composition formula of the lithium transition metal compound, each transition metal and lithium are analyzed with an inductively coupled plasma emission spectrometer (ICP-AES) to obtain a ratio of Li / Ni / Mn. It is calculated by the thing.

From a structural point of view, it is considered that lithium related to a is substituted for the same transition metal site. Here, due to the lithium according to a, the average valence of M and manganese becomes larger than 3.5 due to the principle of charge neutrality.
Further, the lithium transition metal based compound may be substituted with fluorine, it is expressed as _{LiMn 2 O 4-x F 2x} .

<blend>
Specific examples of the lithium transition metal compound having the above composition include, for example, Li _{1 + x} Ni _0.5 Mn _0.5 O ₂ , Li _{1 + x} Ni _0.85 Co _0.10 Al _0.05 O ₂ , Li _{1 + x} Ni _0.33 Mn _0.33 Co _0.33 O ₂ , Li _{1 + x} Ni _0.45 Mn _0.45 Co _0.1 O ₂ , Li _{1 + x} Mn _1.8 Al _0.2 O ₄ , Li _{1 + x} Mn _1.5 Ni _0.5 O ₄ and the like. These lithium transition metal compounds may be used alone or in a blend of two or more.

<Introduction of foreign elements>
Moreover, a different element may be introduce | transduced into a lithium transition metal type compound. As the different elements, B, Na, Mg, Al, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Ru, Rh, Pd, Ag, In, Sb, Te , Ba, Ta, Mo, W, Re, Os, Ir, Pt, Au, Pb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Bi , N, F, S, Cl, Br, I, As, Ge, P, Pb, Sb, Si, and Sn. These foreign elements may be incorporated into the crystal structure of the lithium transition metal compound, or may not be incorporated into the crystal structure of the lithium transition metal compound, and may be a single element or compound on the particle surface or grain boundary. May be unevenly distributed.

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

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

When a thin film is used as the positive electrode current collector, its thickness is arbitrary, but a range of usually 1 μm or more and 100 mm or less is suitable. If it is thinner than the above range, the strength required for the current collector may be insufficient. On the other hand, if it is thicker than the above range, the handleability may be impaired.
The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that is stable with respect to the liquid medium used during electrode production may be used. Specific examples include polyethylene, Resin polymers such as polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, SBR (styrene butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene・ Rubber polymers such as propylene rubber, styrene / butadiene / styrene block copolymers and hydrogenated products thereof, EPDM (ethylene / propylene / diene terpolymers), styrene / ethylene / butadiene / ethylene copolymers, Styrene / isoprene styrene bromide Copolymer and its hydrogenated thermoplastic elastomeric polymer, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Fluorine polymers such as soft resinous polymers, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers, ion conductivity of alkali metal ions (especially lithium ions) And a polymer composition having the same. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more and 80% by mass or less. If the proportion of the binder is too low, the positive electrode active material cannot be sufficiently retained and the positive electrode has insufficient mechanical strength, which may deteriorate battery performance such as cycle characteristics. Battery capacity and conductivity may be reduced.
The positive electrode active material layer usually contains a conductive material in order to increase conductivity. There are no particular restrictions on the type, but specific examples include metal materials such as copper and nickel, graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. The carbon material etc. of this can be mentioned. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. The proportion of the conductive material in the positive electrode active material layer is usually 0.01% by mass or more and 50% by mass or less. If the proportion of the conductive material is too low, the conductivity may be insufficient, and conversely if it is too high, the battery capacity may be reduced.

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

The content ratio of the lithium transition metal-based compound powder as the positive electrode material in the positive electrode active material layer is usually 10% by mass or more and 99.9% by mass or less. If the proportion of the lithium transition metal compound powder in the positive electrode active material layer is too large, the strength of the positive electrode tends to be insufficient, and if it is too small, the capacity may be insufficient.
The thickness of the positive electrode active material layer is usually about 10 to 200 μm.

The electrode density after pressing the positive electrode is usually 2.2 g / cm ³ or more and 4.2 g / cm ³ or less.
The positive electrode active material layer obtained by coating and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the positive electrode active material.
Thus, a positive electrode for a lithium secondary battery can be prepared.

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

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

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.
Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.

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

  The characteristics of the separator in the non-electrolyte secondary battery can be grasped by the Gurley value. The Gurley value indicates the difficulty of air passage in the film thickness direction, and is expressed as the number of seconds required for 100 ml of air to pass through the film. It means that it is harder to go through. That is, a smaller value means better communication in the thickness direction of the film, and a larger value means lower communication in the thickness direction of the film. Communication is the degree of connection of holes in the film thickness direction. If the Gurley value of the separator of the present invention is low, it can be used for various purposes. For example, when used as a separator for a non-aqueous lithium secondary battery, a low Gurley value means that lithium ions can be easily transferred and is preferable because of excellent battery performance. Although the Gurley value of a separator is arbitrary, Preferably it is 10-1000 second / 100ml, More preferably, it is 15-800 second / 100ml, More preferably, it is 20-500 second / 100ml. If the Gurley value is 1000 seconds / 100 ml or less, the electrical resistance is substantially low, which is preferable as a separator.

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

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

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

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

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

(Exterior body)
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body (exterior case). There is no restriction | limiting in this exterior body, As long as the effect of this invention is not impaired remarkably, a well-known thing can be employ | adopted arbitrarily.
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum or an aluminum alloy, a magnesium alloy, nickel, titanium, or a metal, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

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

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

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
The compounds used in the examples and comparative examples are shown below.

<Examples 1-5, Comparative Examples 1-6>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, 1.0 mol / L (as a concentration in the non-aqueous electrolyte) of LiPF ₆ sufficiently dried was dissolved in a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7). (This is referred to as the reference electrolyte 1). A compound was added to the entire reference electrolyte solution 1 at a ratio shown in Table 1 below to prepare an electrolyte solution. However, Comparative Example 2 is the reference electrolyte 1 itself. In addition, "content (mass%)" in a table | surface is the density | concentration in 100 mass% of non-aqueous electrolyte solution.

[Production of positive electrode]
97% by mass of lithium cobaltate (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and 1.5% by mass of polyvinylidene fluoride (PVdF) as a binder, N-methylpyrrolidone In a solvent, the mixture was slurried by mixing with a disperser. This was uniformly applied to both sides of a 21 μm thick aluminum foil, dried, and then pressed to obtain a positive electrode.

[Production of negative electrode]
Natural graphite powder as a negative electrode active material, thickener, and aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by weight of carboxymethylcellulose sodium) and aqueous dispersion of styrene-butadiene rubber (of styrene-butadiene rubber) The mixture was mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a 12 μm thick copper foil, dried, and then pressed to obtain a negative electrode. In addition, it produced so that it might become a mass ratio of natural graphite: carboxymethylcellulose sodium: styrene-butadiene rubber = 98: 1: 1 in the negative electrode after drying.

[Manufacture of non-aqueous electrolyte batteries (pouch type)]
The positive electrode, the negative electrode, and a polypropylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element.
The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and each of the electrolyte solutions shown in Table 1 was placed in the bag. And pouch-type batteries were prepared, and batteries used in Examples 1 to 5 and Comparative Examples 1 to 6, respectively, were prepared.

<Evaluation of non-aqueous electrolyte secondary battery>
[Initial conditioning]
The lithium secondary battery was immersed in an ethanol bath to measure the volume, and then ethanol was air-dried. Thereafter, in order to improve the adhesion between the electrodes, the battery is sandwiched between glass plates, and charged at 25 ° C. with a constant current corresponding to 0.2 C for one and a half hours, and discharged to 3 V with a constant current of 0.2 C. . Thereafter, charging to 4.1 V with a constant current corresponding to 0.2 C and discharging to 3 V with a constant current of 0.2 C are repeated twice. Furthermore, after constant current-constant voltage charging (0.05 C cut) to 4.2 V at 0.2 C, discharging to 3 V at a constant current of 0.2 C was repeated twice. Here, 1C represents a current value that discharges the reference capacity of the battery in one hour, 0.5C represents a current value that is 1/2 that of the current value, and 0.2C represents a current value that is 1/5 that of the current value. To express. Then, the volume change amount by charging / discharging was computed by immersing in an ethanol bath and measuring a volume. At this time, Table 1 below shows the results of setting the values normalized with reference to the volume change amount of Comparative Example 2 as the initial swelling.

  As is clear from Table 1, when a non-aqueous electrolyte containing the specific compound represented by the general formula (1) of the present invention was used (Examples 1 to 4), Comparative Example 1 containing no specific compound 1 and 2 have been shown to improve initial blistering. Moreover, even if it adds compounds other than the specific compound represented by General formula (1) like Comparative Examples 3-6, compared with the case where the compound represented by General formula (1) is contained, the initial swelling is carried out. It has been shown to decline. From this, it can be seen that the initial swelling is improved by using a non-aqueous electrolyte obtained by adding a compound having a structure represented by the general formula (1) to the non-aqueous electrolyte.

According to the nonaqueous electrolytic solution of the present invention, non-aqueous electrolysis that has a good balance of overall performance with respect to performance such as durability, capacity, resistance, and output characteristics, and can improve rate characteristics and high-temperature storage characteristics in a balanced manner. Liquid and non-aqueous electrolyte batteries can be provided. Therefore, the non-aqueous electrolyte can be suitably used in all fields such as electronic devices in which the non-aqueous electrolyte secondary battery is used.
The application of the non-aqueous electrolyte solution and the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and can be used for various known applications. Specific examples of applications include laptop computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, mobile audio players, small video cameras, LCD TVs, handy cleaners, transceivers, electronic notebooks, calculators, and memories. Cards, portable tape recorders, radios, backup power supplies, automobiles, motorcycles, motorbikes, bicycles, lighting equipment, toys, game machines, watches, electric tools, strobes, cameras, etc.

Claims (4)

A non-aqueous electrolyte secondary battery comprising a positive electrode capable of occluding and releasing metal ions, a negative electrode capable of occluding and releasing metal ions, and a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte A non-aqueous electrolyte solution used, wherein the non-aqueous electrolyte solution is a small amount of compounds having the following structures:
A non-aqueous electrolyte characterized by containing at least one .

The non-aqueous electrolyte further includes a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton, a fluorinated salt, a cyclic ether compound, and an oxalate. The non-aqueous electrolyte solution according to claim 1, comprising at least one compound selected from the group consisting of a salt and a cyclic sulfonic acid ester. A cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic carbonate having a fluorine atom, a nitrile compound, an isocyanate compound, a compound having an isocyanuric acid skeleton,
The content of at least one compound selected from the group consisting of a fluorinated salt, a cyclic ether compound, an oxalate salt and a cyclic sulfonic acid ester is 0.001% by mass or more and 10% by mass with respect to the total amount of the nonaqueous electrolytic solution. % Non-aqueous electrolyte solution of Claim 2 which is% or less. Negative and positive lithium ions capable of occluding and releasing, as well as non-aqueous or non-aqueous electrolyte battery comprising an electrolyte solution, nonaqueous electrolyte solution according to the nonaqueous electrolyte solution any one of claims 1 to 3 A non-aqueous electrolyte secondary battery characterized by the above.