JP2003132946A - Nonaqueous electrolytic solution and secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolytic solution controlling increase of electrode interface resistance and providing further prominent life characteristics, by giving prominent load characteristics and low temperature characteristics to a battery, and a secondary battery with the prominent life characteristics using the nonaqueous electrolytic solution. SOLUTION: The nonaqueous electrolytic solution including borate indicated in a following equation (1), nonaqueous solvent and electrolyte, and the secondary battery using the nonaqueous electrolytic solution are provided. (R<1> -R<3> are hydrogen, a metal or an organic group and they may be bound to each other.) Furthermore, the nonaqueous electrolytic solution including sulfones or sulfonic esters and/or the nonaqueous electrolytic solution including vinylene carbonate derivatives are/is also preferable embodiment of the nonaqueous electrolytic solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte having excellent charge / discharge characteristics and a secondary battery using the same.
More specifically, the present invention relates to a non-aqueous electrolyte suitable for a lithium secondary battery containing a borate ester, and a secondary battery using the same.

[0002]

BACKGROUND OF THE INVENTION Batteries using non-aqueous electrolytes are widely used as power sources for consumer electronic devices because they have high voltage and high energy density and high reliability such as storability. Has been.

As such a battery, there is a non-aqueous electrolyte secondary battery, and a typical one thereof is a lithium ion secondary battery. A non-aqueous electrolytic solution is widely used as an electrolyte material of a lithium ion secondary battery, and a carbonate compound having a high dielectric constant is known as a non-aqueous solvent used therein. As the non-aqueous electrolytic solution, more specifically, a mixed solvent of a carbonate compound solvent having a high dielectric constant such as propylene carbonate or ethylene carbonate and a carbonate solvent having a low viscosity such as dimethyl carbonate or diethyl carbonate may be mixed with LiBF ₄ or LiPF ₄ . ₆ , LiClO ₄ , LiAs
A solution in which an electrolyte such as F ₆ , LiCF ₃ SO ₃ , and LI ₂ SiF ₆ is mixed has been proposed.

On the other hand, research on electrodes is being pursued with the aim of increasing the capacity of batteries, and carbon materials capable of inserting and extracting lithium are used as the negative electrodes of lithium ion secondary batteries. In particular, highly crystalline carbon such as graphite is used as a negative electrode material in many lithium ion secondary batteries currently on the market because it has characteristics such as a flat discharge potential.

However, when highly crystalline carbon such as graphite is used for the negative electrode, when propylene carbonate or 1,2-butylene carbonate, which is a high dielectric constant solvent having a low freezing point, is used as the non-aqueous solvent for the electrolytic solution, The reductive decomposition reaction of the solvent occurs at the time of charging, and the insertion reaction of lithium ions, which is the active material, into graphite becomes difficult to proceed, and as a result, the initial charge / discharge efficiency is reduced and the electrolyte solution Li caused by decomposition products The ionic conductivity is lowered, and the load characteristics of the battery are lowered due to the increase in the electrode interface resistance.

Therefore, as a non-aqueous solvent having a high dielectric constant used for an electrolytic solution, ethylene carbonate is used instead of propylene carbonate, which is a solid at room temperature but is hard to continuously undergo a reductive decomposition reaction. Attempts have been made to suppress the reductive decomposition reaction of the non-aqueous solvent by mixing or mixing, but this is not always sufficient. Further, even when amorphous carbon is used for the negative electrode, a slight reductive decomposition reaction of the solvent occurs, the Li ion conductivity of the electrolytic solution is lowered due to the decomposition product of the electrolytic solution, and the load on the battery due to the increase in the electrode interface resistance Deterioration of characteristics occurs.

Therefore, in order to further suppress the reductive decomposition reaction, it has been proposed to add various additives.
(JP-A-5-13088, JP-A-6-52887, JP-A-63-102173, JP-A-11-162511, JP-A-11-3728)

As an attempt to improve the load characteristics of the battery, in order to improve the ionic conductivity of the electrolytic solution, a low viscosity chain solvent is mixed (Japanese Patent Laid-Open No. 10-27625).
Are also proposed.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-aqueous electrolytic solution which suppresses an increase in the interfacial resistance of electrodes, gives a battery excellent load characteristics and low temperature characteristics, and further has excellent life characteristics. And Another object of the present invention is to provide a secondary battery using this non-aqueous electrolyte and having excellent life characteristics.

[0010]

The present invention provides a non-aqueous electrolytic solution containing a boric acid ester represented by the following general formula (1), a non-aqueous solvent and an electrolyte.

[Chemical 4] (R ^{1 to} R ³ may be the same or different,
It represents hydrogen, a metal or an organic group, which may be bonded to each other. )

The above-mentioned non-aqueous electrolytic solution in which the non-aqueous electrolytic solution further contains a compound represented by the general formula (2) is a preferred embodiment of the present invention.

[Chemical 5] (R ⁴ and R ⁵ may be the same or different, represent an organic group, and may be bonded to each other.)

The non-aqueous electrolyte solution in which the compound represented by the general formula (2) is a benzenesulfone derivative is a preferred embodiment of the present invention.

The above non-aqueous electrolyte solution in which the compound represented by the general formula (2) is a cyclic saturated alkyl sulfonate derivative or a cyclic unsaturated alkyl sulfonate derivative is a preferred embodiment of the present invention.

In addition to the boric acid ester of the general formula (1), or the boric acid ester and the compound represented by the general formula (2), the nonaqueous electrolytic solution has the following general formula (3). The above-mentioned non-aqueous electrolytic solution containing the vinylene carbonate derivative represented by) is a preferred embodiment of the present invention.

[Chemical 6] (R ⁶ and R ⁷ are hydrogen or an organic group.)

The above non-aqueous electrolyte solution in which the organic group in the compounds represented by the above formulas (1) to (3) is an organic group having 1 to 10 carbon atoms is a preferred embodiment of the present invention.

The above non-aqueous electrolyte solution, which is a solvent comprising a cyclic aprotic solvent and / or a chain aprotic solvent, is a preferred embodiment of the present invention.

The above non-aqueous electrolytic solution in which the cyclic aprotic solvent is at least one solvent selected from cyclic carbonates and cyclic esters is a preferred embodiment of the present invention.

The above non-aqueous electrolytic solution in which the chain aprotic solvent is at least one solvent selected from chain carbonates and chain esters is a preferred embodiment of the present invention.

The electrolyte is LiPF ₆ , LiBF ₄ ,
_{LiOSO 2 C k F (2k +} 1) (k = 1~8 _{integer), LiClO 4, LiAsF 6,} LiN (SO 2 C
_k F _{(2 k + 1)} ) ₂ (k = 1 to integer of 8), LiPF
_{n (C k F (2k +} 1)) (6- n) (n = 1~5, k
= Integer of 1 to 8) The above-mentioned non-aqueous electrolyte, which is at least one selected from the above, is a preferred embodiment of the present invention.

The present invention also provides a secondary battery containing the above non-aqueous electrolyte.

Further, according to the present invention, as a negative electrode active material, metallic lithium, lithium-containing alloy, lithium ion doping /
Carbon material that can be dedoped, lithium ion doping,
Can be doped with tin oxide or lithium ion
A negative electrode containing titanium oxide that can be dedoped, niobium oxide or vanadium oxide, or silicon or tin that can be doped or dedoped with lithium ions, and a transition metal oxide or a transition metal sulfide as a positive electrode active material, Provided is a lithium secondary battery including a positive electrode containing any one of a composite oxide of lithium and a transition metal, a conductive polymer material, a carbon material, or a mixture thereof, and the above non-aqueous electrolyte.

In the lithium ion secondary battery, the carbon material capable of doping / dedoping lithium ions has an interplanar distance (d002) on the (002) plane of 0.340 nm or less measured by X-ray analysis. Is a preferred embodiment of the present invention.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The non-aqueous electrolytic solution according to the present invention and the non-aqueous electrolytic solution secondary battery using this non-aqueous electrolytic solution will be specifically described.

The non-aqueous electrolytic solution according to the present invention is a non-aqueous electrolytic solution containing a borate ester, a non-aqueous solvent and an electrolyte. When the boric acid ester is contained in the electrolytic solution of the present invention, an increase in the interfacial resistance of the electrode during initial charging is suppressed, so that a desirable non-aqueous electrolytic solution is obtained. A non-aqueous electrolyte secondary battery using this non-aqueous electrolyte exhibits excellent load characteristics.

Boric Acid Ester The boric acid ester used in the present invention has the general formula (1):
Is a compound represented by.

[Chemical 7]

In the formula, R ^{1 to} R ³ may be the same or different from each other, represent hydrogen, a metal or an organic group, and may be bonded to each other. The metal is preferably an alkali metal or an alkaline earth metal, and most preferably lithium.

Preferred examples of the organic group include a hydrocarbon group and a hetero atom-containing hydrocarbon group. As the organic group, an organic group having 1 to 10 carbon atoms is preferable, and an organic group having 1 to 8 carbon atoms is more preferable. Examples of the hydrocarbon group include saturated hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group and octyl group, double bond-containing hydrocarbon groups such as vinyl group and allyl group, ethynyl group and propargyl group. An unsaturated hydrocarbon group such as a triple bond-containing hydrocarbon group may be mentioned.

Examples of the hetero atom in the hetero atom-containing hydrocarbon group include oxygen, nitrogen, sulfur, phosphorus and boron. Preferable examples of the hetero atom-containing hydrocarbon group include an oxygen-containing hydrocarbon group containing an ether bond, an ester bond, a carbonate bond and the like such as a methoxyethyl group and a methoxycarbonylethyl group, and a nitrogen-containing hydrocarbon group containing an amino group. Can be mentioned. As the hetero atom, oxygen or nitrogen is preferable.

The organic group may be substituted with a halogen atom. Examples of the halogen atom include fluorine, chlorine and bromine, with fluorine being preferred. Examples of the organic group substituted with a halogen atom include a halogenated hydrocarbon group such as a trifluoroethyl group, a hydrocarbon group substituted with a halogen-containing group, and a halogenated heteroatom-containing hydrocarbon group. A halogenated hydrocarbon group is particularly preferable.

Specific examples of the boric acid esters represented by the general formula (1) include the following compounds. Trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, tripentyl borate, diethyl methyl borate, tri (methoxyethyl) borate, dimethyl hydroxyborate, dimethyl monolithium borate,
Alkyl borate esters such as boric acid monomethyldilithium salt.

Alkyl esters of boric acid condensates such as trimethoxyboroxine and dimethoxyboroxine monolithium salts. N, such as triethanolamine borate
Compounds having a containing substituent. In addition, the following R
A compound in which two or more of ^{1 to} R ³ are bonded to each other.

[0032]

[Chemical 8]

Tri (trifluoroethyl) borate, Methyldi (trifluoroethyl) borate, Tri (trichloroethyl) borate, Tri (tetrafluoroethyl) borate, Tri (monofluoroethyl) borate, Triborate (Pentafluoropropyl), tri (hexafluoropropyl) borate, tri (2-methyl-1,1, borate)
1,3,3,3-hexafluoropropyl), tri (2-phenyl-1,1,1,3,3,3-hexafluoropropyl) borate, tri (trifluoroethoxyethyl) borate, boric acid Halogen-containing borate esters such as methyldi (trifluoroethoxyethyl) and other compounds in which the following substitution machines are bonded to each other.

[0034]

[Chemical 9]

The halogen-containing borate ester is preferable because the oxidation resistance stability to the positive electrode is enhanced by the electron-withdrawing effect of the halogen atom.

Further, boric acid esters in which R ^{1 to} R ³ are the above-mentioned unsaturated hydrocarbon group having a carbon-carbon triple bond are also preferable examples of the present invention. Specific examples of such compounds include triethynyl borate, tripropargyl borate, tributenyl borate, methyldipropargyl borate, ethyldipropargyl borate, dimethylpropargyl borate, and other substituents such as the following are bonded to each other. Examples of the compound include

[0037]

[Chemical 10]

These compounds are preferable because they form a film on the negative electrode by the carbon-carbon triple bond and stabilize the negative electrode.

The amount of boric acid ester added to the electrolytic solution is
0.01 to 5% by weight is desirable, and further 0.05 to 2
Weight percent is preferred. If the addition amount is small, the effect is small, and if the addition amount is too large, the viscosity of the electrolytic solution is increased, and the like.
Battery characteristics deteriorate.

Compound Represented by General Formula (2) The non-aqueous electrolytic solution of the present invention contains the boric acid ester represented by the general formula (1), the non-aqueous solvent and the electrolyte, and further the general formula (2) ) Can be included. When the non-aqueous electrolyte further contains the compound represented by the following general formula (2), the effect of suppressing the increase in interfacial resistance during initial charging is enhanced. In addition, it is desirable not only during initial charging but also for suppressing an increase in interfacial resistance after repeated use and storage at high temperature.

[0041]

[Chemical 11]

In the formula, R ⁴ and R ⁵ may be the same or different, represent an organic group, and may be bonded to each other.

Preferred examples of the organic group include a hydrocarbon group and a hetero atom-containing hydrocarbon group. As the organic group, an organic group having 1 to 10 carbon atoms is preferable, and an organic group having 1 to 8 carbon atoms is more preferable. The organic group may be substituted with a halogen atom.

Examples of the hydrocarbon group include saturated hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group and octyl group, double bond-containing hydrocarbon groups such as vinyl group and allyl group, ethynyl group and propargyl group. And unsaturated hydrocarbon groups such as triple bond-containing hydrocarbon groups such as groups.

Another preferred example of the organic group is a hetero atom-containing hydrocarbon group. Heteroatoms include oxygen, nitrogen,
Examples include sulfur, phosphorus, and boron. Examples of the hetero atom-containing hydrocarbon group include an oxygen atom-containing group such as an oxy group and an oxo group, a nitrogen-containing group such as an amide group, an amino group and a urea group, a sulfur-containing group such as a sulfonic acid group and a sulfonic acid ester group. Hydrocarbon groups containing heteroatoms including Among them, a hetero atom-containing hydrocarbon group containing oxygen or nitrogen is preferable.

The organic group may be substituted with a halogen atom. Examples of the halogen element include fluorine, chlorine, bromine and the like, and fluorine is preferable. Examples of the organic group substituted with a halogen atom include a halogenated hydrocarbon group such as a trifluoroethyl group and a hydrocarbon group substituted with a halogen-containing group, and a halogen-containing hydrocarbon group having a hetero atom. A hydrogen group etc. can be mentioned.

Preferred examples of R ⁴ and R ⁵ in the general formula (2) are allyl group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, t-butyl group, pentyl group, Saturated hydrocarbon groups such as phenyl group, methylphenyl group, ethylphenyl group, vinylphenyl group, ethynylphenyl group; vinyl group, ethynyl group, 1
-Propenyl group, 2-propenyl group, 1-propynyl group, 2-propynyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, etc. Unsaturated hydrocarbon group; such as trifluoroethyl group, pentafluoropropyl group, vinylfluorophenyl group, ethynylfluorophenyl group, fluorophenyl group, difluorophenyl group, pentafluorophenyl group, trifluoromethylphenyl group, chlorophenyl group, etc. Halogenated hydrocarbon group; trifluoroethoxy group, pentafluoropropoxy group, methoxy group, ethoxy group, allyloxy group, vinyloxy group, ethynyloxy group, proproxy group, isopropyloxy group, 1-propenyloxy group, 2-propenyloxy group, 1 -Propynyloxy group, 2-propynyloxy , Butoxy group, sec-butoxy group, t-butoxy group, 1-butenyloxy group, 2-butenyloxy group, 3-butenyloxy group, 1-butynyloxy group, 2-butynyloxy group, 3-butynyloxy group, pentyloxy group, phenoxy group, Saturated or unsaturated oxy groups such as methylphenoxy group, ethylphenoxy group, vinylphenoxy group, ethynylphenoxy group, vinylfluorophenoxy group, ethynylfluorophenoxy group, fluorophenoxy group, difluorophenoxy group, trifluoromethylphenoxy group and chlorophenoxy group. A group etc. can be mentioned.

The compounds represented by the above general formula (2) of the present invention are preferably sulfones or sulfonates.

As a preferred example of the compound represented by the general formula (2), a benzenesulfone derivative represented by the general formula (4) can be exemplified.

[0050]

[Chemical 12]

In the formula, R ^{8 to} R ¹³ may be the same or different and are hydrogen, metal, halogen, hydroxy group, sulfonic acid ester group, sulfonic acid metal group, carboxylic acid ester group, carboxylic acid metal group, organic group. Represents a group selected from the groups.

Examples of the metal include alkali metals and alkaline earth metals, and alkali metals are particularly desirable.
The most preferable alkali metal is lithium.

Preferred organic groups include hydrocarbon groups and heteroatom-containing hydrocarbon groups. The organic group is preferably an organic group having 1 to 10 carbon atoms, more preferably 1 carbon atom.
~ 8 organic groups. As the hydrocarbon group, a methyl group,
Saturated hydrocarbon group such as ethyl group, propyl group, butyl group, octyl group, hydrocarbon group containing double bond such as vinyl group and allyl group, hydrocarbon group containing triple bond such as ethynyl group and propargyl group An unsaturated hydrocarbon group etc. can be mentioned.

Examples of the hetero atom of the hetero atom-containing hydrocarbon group include oxygen, nitrogen, sulfur, phosphorus and boron. Preferable examples of the hetero atom-containing hydrocarbon group include an oxygen-containing hydrocarbon group containing an ether bond, an ester bond, a carbonate bond and the like such as a methoxyethyl group and a methoxycarbonylethyl group, and a nitrogen-containing hydrocarbon group containing an amino group. Can be mentioned. As the hetero atom, oxygen or nitrogen is preferable.

The organic group may be substituted with a halogen atom. Examples of the halogen element include fluorine, chlorine, bromine and the like, and fluorine is preferable. Examples of the organic group substituted with a halogen atom include a halogenated hydrocarbon group such as a trifluoroethyl group, a hydrocarbon group substituted with a halogen-containing group, and a halogenated heteroatom-containing hydrocarbon group. A halogenated hydrocarbon group is particularly preferable.

Specific examples of the compound represented by the general formula (4) include methyl naphthalenesulfonate, ethyl benzenesulfonate, phenylethylsulfone, benzenedi (methylsulfonate), benzenedi (allylsulfonate),
(Phenyl) (allyl) sulfone, benzenedi (vinyl sulfonate), (phenyl) (vinyl) sulfone, benzenedi (ethynyl sulfonate), (phenyl) (ethynyl) sulfone, benzene tri (methyl sulfonate), sulfobenzoic anhydride Substance, dimethyl sulfobenzoate, methyl benzenedi (methyl sulfonate) carboxylate, methyl toluenesulfonate, (tolyl) (methyl) sulfone, toluene di (ethyl sulfonate), toluentry (propyl sulfonate), trifluoromethylbenzene sulfone Methyl acid, (trifluoromethylphenyl) (methyl)
Sulfone, trifluoromethylbenzenedi (methyl sulfonate), trifluoromethylbenzene tri (ethyl sulfonate), (methylsulfo) (trifluoromethyl)
Methyl benzoate, lithium naphthalenesulfonate, lithium benzenesulfonate, lithium trifluoromethylbenzenesulfonate, dilithium benzenedisulfonate, dilithium trifluoromethylbenzenedisulfonate, trilithium benzenetrisulfonate,
Sulfobenzoic acid dilithium salt, vinyloxycarbonylbenzenesulfonic acid lithium salt, allyloxycarbonylbenzenesulfonic acid lithium salt, ethenyloxycarbonylbenzenesulfonic acid lithium salt, propargyloxycarbonylbenzenesulfonic acid lithium salt, trifluoroethyloxycarbonylbenzenesulfone Acid lithium salt, toluenesulfonic acid lithium salt, toluenedisulfonic acid dilithium salt, naphthalenesulfonic acid sodium salt, benzenetrisulfonic acid trisodium salt, sulfobenzoic acid disodium salt, toluenesulfonic acid sodium salt, toluenedisulfonic acid disodium salt, Naphthalenesulfonic acid potassium salt, benzenesulfonic acid potassium salt, benzenedisulfonic acid dipotassium salt, benzenetrisulfonic acid triacid Potassium salts, sulfobenzoic acid dipotassium salt, sulfobenzoic acid potassium salt, potassium toluene sulfonate, toluene disulfonic acid dipotassium salt, benzene disulfonic acid, sulfobenzoic acid.
These compounds may be used alone or in combination.

As another example of the compound represented by the general formula (2), a cyclic saturated alkyl sulfonic acid ester represented by the following general formula (5) can be exemplified.

[Chemical 13]

As another example of the compound represented by the general formula (2), a cyclic unsaturated alkyl sulfonic acid ester represented by the following general formula (6) can be exemplified.

[0059]

[Chemical 14]

In the general formulas (5) and (6), R ^{14 to} R
²³ is hydrogen, a halogen atom, or a hydrocarbon group which may contain a halogen atom. n is an integer of 0 to 3, preferably 1 or 2, and more preferably 1.

Examples of the halogen atom include fluorine, chlorine and bromine, and fluorine is preferable.

The hydrocarbon group which may contain a halogen atom preferably has 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms.

Specific examples of the hydrocarbon group which may contain a halogen atom include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a t-butyl group and a 1-methylenepropyl group. , Pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-methyl-2-methylpropyl group, 2,2-dimethylpropyl group, phenyl group, methylphenyl group, ethylphenyl group, hexyl group , Cyclohexyl group, heptyl group, octyl group,
Saturated hydrocarbon groups such as nonyl group, decyl group, undecyl group, dodecyl group, naphthyl group, biphenyl group; vinyl group, ethynyl group, 1-propenyl group, 2-propenyl group, 1-
Propynyl group, 2-propynyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group, 2-methyl-2-propenyl group, 1-
Unsaturated hydrocarbon groups such as methyl-2-propenyl group, 1,2-dimethylvinyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, vinylphenyl group, ethynylphenyl group;
Difluoromethyl group, monofluoromethyl group, trifluoromethyl group, trifluoroethyl group, difluoroethyl group, pentafluoroethyl group, pentafluoropropyl group, tetrafluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluoropentyl group Fluorohexyl group, perfluorocyclohexyl group, perfluoroheptyl group, perfluorooctyl group, perfluorononyl group, perfluorodecyl group, perfluoroundecyl group, perfluorododecyl group, fluorophenyl group, difluorophenyl group, trifluoro group Examples thereof include a fluorine-containing hydrocarbon group such as a phenyl group, a perfluorophenyl group and a trifluoromethylphenyl group.

Specific examples of the compounds represented by the above general formulas (5) and (6) include cyclic saturated alkyl sulfonates such as 1,3-propane sultone and 1,4.
-Butane sultone and the like are exemplified, and examples of the cyclic unsaturated alkyl sulfonic acid ester include 1,3-propene sultone, 1,4-butene sultone, and 1,5-pentene sultone.

Other specific examples of the compound represented by the general formula (2) include dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, divinyl sulfone, methyl vinyl sulfone, sulfolane, 3-sulfolene, busulfan, methyl methanesulfonate, Ethyl methanesulfonate, vinyl methanesulfonate, allyl methanesulfonate, methyl trifluoromethanesulfonate, vinyl trifluoromethanesulfonate, acetic acid methanesulfonic anhydride, trifluoroacetic acid trifluoromethanesulfonic anhydride, trifluoroacetic acid methanesulfonic acid Compounds such as anhydrides, acrylic acid methanesulfonic anhydride, and acrylic acid trifluoromethanesulfonic anhydride can be mentioned.

Among the compounds represented by the general formula (2),
Particularly, a benzene sulfone derivative, a cyclic saturated alkyl sulfonic acid derivative, and a cyclic unsaturated alkyl sulfonic acid derivative are preferable.

The amount of the compound represented by the general formula (2) added to the non-aqueous electrolyte is preferably 0.01 to 10% by weight,
Further, 0.05 to 5% by weight is desirable.

Vinylene Carbonate Derivative The non-aqueous electrolytic solution of the present invention comprises the borate ester represented by the general formula (1), or the borate ester represented by the general formula (1) and the general formula (2). In addition to containing the compound represented by the formula (1), it may further contain a vinylene carbonate derivative represented by the following general formula (3).

The non-aqueous electrolyte of the present invention has the following general formula (3):
By containing the vinylene carbonate derivative represented by, the effect of suppressing an increase in interfacial resistance at the time of initial charging is further enhanced, and in addition, the retention rate of the battery capacity during a cycle test or a high temperature storage test is improved.

[0070]

[Chemical 15]

In the formula, R ⁷ and R ⁸ may be the same or different and each is hydrogen or an organic group having 1 to 10 carbon atoms. Preferred examples of the organic group include a hydrocarbon group and a hetero atom-containing hydrocarbon group.

Examples of the hydrocarbon group include saturated hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group and octyl group, double bond-containing hydrocarbon groups such as vinyl group and allyl group, ethynyl group and propargyl group. And unsaturated hydrocarbon groups such as triple bond-containing hydrocarbon groups such as groups.

Examples of the hetero atom in the hetero atom-containing hydrocarbon group include oxygen, nitrogen, sulfur, phosphorus and boron. Preferable examples of the hetero atom-containing hydrocarbon group include an oxygen-containing hydrocarbon group containing an ether bond, an ester bond, a carbonate bond and the like such as a methoxyethyl group and a methoxycarbonylethyl group, and a nitrogen-containing hydrocarbon group containing an amino group. Can be mentioned.

The organic group may be substituted with a halogen atom. Examples of the halogen element include fluorine, chlorine, bromine and the like, and fluorine is preferable. Examples of the organic group substituted with a halogen atom include a halogenated hydrocarbon group such as a trifluoroethyl group, a hydrocarbon group substituted with a halogen-containing group, and a halogenated heteroatom-containing hydrocarbon group. A halogenated hydrocarbon group is particularly preferable.

The organic group is preferably a hydrocarbon group having 1 to 10 carbon atoms or a halogenated hydrocarbon group having 1 to 10 carbon atoms.

Specific examples of the vinylene carbonate derivative represented by the general formula (3) include vinylene carbonate, methylvinylene carbonate, ethylvinylene carbonate, propylethylene carbonate, dimethylvinylene carbonate, diethylvinylene carbonate, dipropylvinylene carbonate and fluoro. Examples thereof include vinylene carbonate and trifluoromethyl vinylene carbonate. Of these, vinylene carbonate is preferred.

The amount of the vinylene carbonate derivative added to the electrolytic solution is preferably 0.05 to 5% by weight based on the whole non-aqueous electrolytic solution.

The non-aqueous electrolyte containing the boric acid ester represented by the general formula (1), the compound represented by the general formula (2) and the vinylene carbonate derivative represented by the general formula (3) is the present invention. Is a preferred embodiment of the non-aqueous electrolyte solution. A non-aqueous electrolyte containing the borate ester represented by the general formula (1) and the vinylene carbonate derivative represented by the general formula (3) is also a preferred embodiment of the non-aqueous electrolyte of the present invention.

Among these, the borate esters represented by the general formula (1), the non-aqueous electrolyte containing the compound represented by the general formula (2), and the vinylene carbonate represented by the general formula (3). A non-aqueous electrolyte containing a derivative is a more preferable embodiment.

Non-Aqueous Solvent The non-aqueous electrolytic solution of the present invention has a composition in which the compound described above is contained in a solution prepared by dissolving an electrolyte in a non-aqueous solvent.

In the present invention, the non-aqueous solvent preferably comprises a cyclic aprotic solvent and / or a chain aprotic solvent. Examples of the cyclic aprotic solvent include cyclic carbonates such as ethylene carbonate, cyclic esters such as γ-butyrolactone, and cyclic ethers such as dioxolane, and examples of the chain aprotic solvent include chains such as dimethyl carbonate. Examples thereof include linear carbonates, chain carboxylic acid esters such as methyl propionate, chain ethers such as dimethoxyethane, and chain phosphoric acid esters such as trimethyl phosphate.

When it is specifically intended to improve the load characteristics and low temperature characteristics of the battery, it is preferable that the non-aqueous solvent is a combination of a cyclic aprotic solvent and a chain aprotic solvent. Further, in view of the electrochemical stability of the electrolytic solution, it is preferable to apply a cyclic carbonate to the cyclic aprotic solvent and a chain carbonate to the chain aprotic solvent.

Specific examples of the cyclic carbonate include ethylene carbonate, propylene carbonate and 1,2-
Examples thereof include butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, and 2,3-pentylene carbonate. Among them, ethylene carbonate and propylene carbonate, which have a high dielectric constant, are preferably used. In the case of a battery using graphite as the negative electrode active material, ethylene carbonate is preferred. You may use these cyclic carbonates in mixture of 2 or more types.

Specific examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate,
Methyl butyl carbonate, dibutyl carbonate, ethyl propyl carbonate, methyl trifluoroethyl carbonate, etc. can be mentioned. Among them, low viscosity dimethyl carbonate, methyl ethyl carbonate,
Diethyl carbonate is preferably used. You may use these chain carbonates in mixture of 2 or more types.

Specific examples of the combination of cyclic carbonate and chain carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and methyl ethyl carbonate, and propylene. Carbonate and diethyl carbonate,
Ethylene carbonate and propylene carbonate and dimethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, and ethylene carbonate. Methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl ethyl carbonate,
Examples thereof include ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate.

The mixing ratio of the cyclic carbonate and the chain carbonate is expressed by weight ratio, and the cyclic carbonate: chain carbonate is 5:95 to 80:20, more preferably 10:90 to 70:30, and particularly preferably. 15:85
˜55: 45.

With such a ratio, the increase in viscosity of the electrolytic solution can be suppressed and the dissociation degree of the electrolyte can be increased, so that the conductivity of the electrolytic solution relating to the charge / discharge characteristics of the battery can be increased. The solubility of the electrolyte can be further increased. As a result, an electrolytic solution having excellent electrical conductivity from room temperature to low temperature can be obtained, so that the load characteristics of the battery at room temperature to low temperature can be improved.

In order to improve the flash point of the solvent in order to improve the safety of the battery, a cyclic aprotic solvent may be used alone as the non-aqueous solvent, or a chain aprotic solvent may be used. It is desirable to limit the mixing amount of the solvent to less than 20% by weight based on the whole non-aqueous solvent.

As the cyclic aprotic solvent in this case, it is particularly preferable to mix one kind selected from ethylene carbonate, propylene carbonate, γ-butyrolactone, methyloxazolinone or a mixture thereof. Specific solvent combinations include ethylene carbonate and sulfolane, ethylene carbonate and γ.
Examples include butyrolactone, ethylene carbonate and propylene carbonate, ethylene carbonate and propylene carbonate, and gamma butyrolactone.

When the amount of the chain-like aprotic solvent to be mixed is 20% or less by weight of the whole non-aqueous solvent,
Examples of the chain aprotic solvent include chain carbonate, chain carboxylic acid ester, and chain phosphoric acid ester, and particularly, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate,
Diheptyl carbonate, methyl ethyl carbonate,
Chain carbonates such as methyl propyl carbonate, methyl butyl carbonate and methyl heptyl carbonate are desirable.

The non-aqueous electrolytic solution according to the present invention may contain a solvent other than the above as the non-aqueous solvent. Specific examples of the other solvent include amides such as dimethylformamide and methyl- Examples thereof include chain carbamates such as N, N-dimethylcarbamate, cyclic amides such as N-methylpyrrolidone, cyclic ureas such as N, N-dimethylimidazolidinone, and ethylene glycol derivatives represented by the following general formula. . HO (CH ₂ CH
₂ O) _a H, HO {CH ₂ CH (CH ₃ ) O} _b H, C
H ₃ O (CH ₂ CH ₂ O) _c H, CH ₃ O {CH ₂ CH
(CH ₃ ) O} _d H, CH ₃ O (CH ₂ CH ₂ O) _e C
H ₃ , CH ₃ O {CH ₂ CH (CH ₃ ) O} _f CH ₃ ,
C ₉ H ₁₉ PhO (CH ₂ CH ₂ O) _g {CH (C
H ₃ ) O} _h CH ₃ (Ph is a phenyl group), CH ₃ O
{CH ₂ CH (CH ₃ ) O} _i CO {O (CH ₃ ) CH
CH ₂ } _j OCH ₃ (wherein a to f are integers from 5 to 250, g to j are integers from 2 to 249, 5 ≦ g + h ≦ 250,
5 ≦ i + j ≦ 250. ) Non-Aqueous Electrolyte Solution The non-aqueous electrolyte solution of the present invention contains an electrolyte dissolved in a non-aqueous solvent and further contains the above-mentioned compounds. As the electrolyte to be used, any electrolyte can be used as long as it is usually used as an electrolyte for a non-aqueous electrolytic solution.

Specific examples of the electrolyte include LiPF ₆ , L
iBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF
₆ , LiC ₄ F ₉ SO ₃ , LiC ₈ F ₁₇ SO ₃ and other lithium salts. Further, a lithium salt represented by the following general formula can also be used. LiOSO
₂ R ⁸ , LiN (SO ₂ R ⁹ ) (SO ₂ R ¹⁰ ), Li
C (SO ₂ R ¹¹ ) (SO ₂ R ¹² ) (SO
₂ R ¹³ ), LiN (SO ₂ OR ¹⁴ ) (SO ₂ OR
¹⁵ ) (Here, R < ⁸ > -R < ¹⁵ >, which may be the same or different, are perfluoroalkyl groups having 1 to 6 carbon atoms). These lithium salts may be used alone or in combination of two or more.

Of these, especially LiPF ₆ and LiB
^{_{F 4, LiOSO 2 R 8,}} LiN (SO 2 R 9) (SO
^{_{2 R 10), LiC (SO}} 2 R 11) (SO 2 R 12)
(SO ₂ R ¹³ ), LiN (SO ₂ OR ¹⁴ ) (SO ₂
OR ¹⁵ ) is preferred.

It is desirable that such an electrolyte is contained in the non-aqueous electrolyte at a concentration of 0.1 to 3 mol / liter, preferably 0.5 to 2 mol / liter.

The non-aqueous electrolytic solution in the present invention contains the above-mentioned compounds, the non-aqueous solvent and the electrolyte as essential components, but other additives may be added if necessary.

Other additives include carboxylic acid anhydrides such as maleic anhydride, norbornene dicarboxylic acid anhydride and diglycolic acid; vinyl ethylene carbonate, divinyl ethylene carbonate, methylene-1,2-ethylene carbonate and the like. Saturated hydrocarbon-substituted cyclic carbonates; hydrogen fluoride and the like can be mentioned.

When hydrogen fluoride is used as an additive, the method of adding it to the electrolytic solution may be to directly blow a predetermined amount of hydrogen fluoride gas into the electrolytic solution. When the lithium salt used in the present invention is a lithium salt containing fluorine such as LiPF ₆ or LiBF ₄ , water is converted into water by utilizing the reaction between an active proton compound such as water and an electrolyte shown below. It may be added to the electrolytic solution and generated in the electrolytic solution.

LiMF _n + H ₂ O → LiPF
_(N-2) O + 2HF (where M represents P, B, etc., and when M = P, n
= 6 and M = B, n = 4. )

When water is added to the electrolytic solution to indirectly generate HF in the electrolytic solution, two molecules of HF are almost quantitatively produced from one molecule of water. Calculate and add according to the concentration. Specifically, the desired H
It is preferable to add 0.45 times the amount of F (weight ratio) of water.

Specific examples of other protic compounds include:
Examples thereof include trifluoroacetic acid, methanol, ethanol, ethylene glycol, propylene glycol and the like.

The amount of hydrogen fluoride added is 0.0001.
~ 0.7wt%, preferably 0.001-0.3wt
%, More preferably 0.001 to 0.1 wt%.

The non-aqueous electrolytic solution according to the present invention is suitable not only as a non-aqueous electrolytic solution for a lithium ion secondary battery but also as a non-aqueous electrolytic solution for a primary battery.

Secondary Battery A non-aqueous electrolyte secondary battery according to the present invention comprises a negative electrode, a positive electrode, and
It is configured to basically include the above non-aqueous electrolyte,
Usually, a separator is provided between the negative electrode and the positive electrode.

As the negative electrode active material constituting the negative electrode, metallic lithium, a lithium alloy, a carbon material capable of doping and dedoping lithium ions, tin oxide capable of doping and dedoping lithium ions, and oxidation. Any of niobium or vanadium oxide, titanium oxide that can be doped and dedoped with lithium ions, or silicon or tin that can be doped and dedoped with lithium ions can be used. Among these, carbon materials that can dove and dedove lithium ions are preferable. Such carbon material may be graphite or amorphous carbon, and activated carbon, carbon fiber, carbon black, mesocarbon microbeads, natural graphite and the like are used.

As the negative electrode active material, the interplanar spacing (d002) of the (002) plane measured by X-ray analysis was 0.340 nm.
The following carbon materials are preferable, and the density is 1.70 g / cm ^3.
The above-mentioned graphite or a highly crystalline carbon material having properties close to that is desirable. When such a carbon material is used, the energy density of the battery can be increased.

As the positive electrode active material forming the positive electrode, Mo is used.
S_Two, TiS_Two, MnO_Two, V_TwoO ₅Transition metal acids such as
Or transition metal sulfide, LiCoO_Two, LiMnO
_Two, LiMn_TwoO_Four, LiNiO_Two, LiNi_xCo
_(1-x)O_Two, LiNi_xMn_yCo_(1-x-y)
O_TwoComplex oxides composed of lithium and transition metals such as
Polyaniline, polythiophene, polypyrrole, polya
Cetylene, polyacene, dimercaptothiadiazole /
Conductive polymer materials such as polyaniline composites are listed.
To be Among these, especially lithium and transition metals
A complex oxide consisting of The negative electrode is lithium metal or
Is a lithium alloy, use a carbon material as the positive electrode
You can also Also, as the positive electrode, lithium and transition
It is also possible to use a mixture of a metal complex oxide and a carbon material.
it can.

The separator is a film that electrically insulates the positive electrode and the negative electrode and is permeable to lithium ions, and examples thereof include a porous film and a polymer electrolyte. A microporous polymer film is preferably used as the porous film, and examples of the material thereof include polyolefin, polyimide, and polyvinylidene fluoride. In particular, a porous polyolefin film is preferable, and specific examples thereof include a porous polyethylene film, a porous polypropylene film, and a multilayer film of a porous polyethylene film and polypropylene. Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved and a polymer swollen with an electrolytic solution. The electrolytic solution of the present invention may be used for the purpose of swelling a polymer to obtain a polymer electrolyte.

Such a non-aqueous electrolyte secondary battery can be formed in a cylindrical shape, a coin shape, a square shape, a film shape or any other shape. However, the basic structure of the battery is the same regardless of the shape, and the design can be changed according to the purpose. Next, the structures of the cylindrical type and coin type batteries will be described. The negative electrode active material, the positive electrode active material, and the separator constituting each battery are the same as those described above.

For example, in the case of a cylindrical non-aqueous electrolyte secondary battery, a negative electrode obtained by coating a negative electrode current collector with a negative electrode active material,
The positive electrode current collector is coated with a positive electrode active material, and the positive electrode is wound around a separator into which a non-aqueous electrolyte is injected, and the insulating plates are placed on the upper and lower sides of the wound body and stored in a battery can. ing.

The non-aqueous electrolyte secondary battery according to the present invention can also be applied to a coin type non-aqueous electrolyte secondary battery. In the coin-type battery, a disc-shaped negative electrode, a separator, a disc-shaped positive electrode, and a stainless steel plate or an aluminum plate are stacked in this order and housed in a coin-type battery can.

[0111]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Examples 1 to 10) 1. Battery preparation < Preparation of non-aqueous electrolyte> Ethylene carbonate (EC) and methyl ethyl carbonate (MEC)
= 4: 6 (weight ratio), and then LiPF ₆ as an electrolyte was dissolved in a non-aqueous solvent to prepare a non-aqueous electrolytic solution so that the electrolyte concentration was 1.0 mol / liter. Next, with respect to this non-aqueous electrolyte (100% by weight), Table 1
The additives shown in Table 1 were added in the proportions shown in Table 1.

<Production of Negative Electrode> Natural graphite (LF made by Chuetsu Graphite
-18A) 87 parts by weight and a binder polyvinylidene fluoride (PVDF) 13 parts by weight were mixed and dispersed in a solvent N-methylpyrrolidinone to prepare a natural graphite mixture slurry. Next, this negative electrode mixture slurry was applied to a negative electrode current collector made of strip-shaped copper foil having a thickness of 18 μm, dried, and then compression molded, and this was punched into a disc shape of 14 mm to obtain coin-shaped natural graphite. An electrode was obtained. The thickness of this natural graphite electrode mixture is 1
10 μm, weight is 20 m per area of a circle with a diameter of 14 mm
It was g.

<Preparation of LiCoO ₂ Electrode> LiCoO ₂
(Honjo FMC Energy Systems Co., Ltd. HLC-2
1) 90 parts by weight, 6 parts by weight of graphite as a conductive agent, 1 part by weight of acetylene black, and polyvinylidene fluoride 3 as a binder
Parts by weight were mixed and dispersed in N-methylpyrrolidone as a solvent to prepare a LiCoO ₂ mixture slurry. This LiC
Apply the oO ₂ mixture slurry to an aluminum foil with a thickness of 20 μm,
It was dried, compression molded, and punched out to have a diameter of 13 mm to prepare a LiCoO ₂ electrode. This LiCoO ₂ mixture had a thickness of 90 μm and a weight of 35 mg per area of a circle having a diameter of 13 mm.

<Production of Battery> Natural graphite electrode having a diameter of 14 mm, LiCoO ₂ electrode having a diameter of 13 mm, thickness of 25 μm,
A separator made of a microporous polypropylene film having a diameter of 16 mm was placed in a stainless steel 2032 size battery can, a natural graphite electrode, a separator, and LiCoO ₂
The electrodes were stacked in this order. Then, 0.03 ml of the non-aqueous electrolyte was injected into the separator, and an aluminum plate (thickness 1.2 mm, diameter 16 mm, and spring) was housed.
Finally, by caulking the battery can lid through the polypropylene gasket, the airtightness inside the battery is maintained,
A coin-type battery having a diameter of 20 mm and a height of 3.2 mm was produced.

2. Evaluation of battery characteristics <Measurement of initial characteristics of battery> (1) Measurement of initial low-load discharge capacity The coin-shaped battery prepared as described above was used, and this battery was operated at a constant current of 0.5 mA and a constant voltage of 4.2 V. And 4.2V
Charge until the current value at constant voltage reaches 0.05mA,
After that, under the condition of 0.5 mA constant current and 3.0 V constant voltage,
It was discharged until the current value at a constant voltage of 3.0 V became 0.05 mA. The discharge capacity of the coin battery at this time will be referred to as "initial low-load discharge capacity". The initial low load discharge capacity was around 4.5 mAh for all the batteries.

(2) Measurement of initial medium load discharge capacity Next, this battery was charged under the conditions of a constant current of 4.2 mA and a constant current of 3 mA until the current value at a constant voltage of 4.2 V was 0.05 mA. , Then the battery voltage is 3.0 with 5mA current
It was discharged to V. The discharge capacity of the coin type battery at this time will be referred to as "initial medium load discharge capacity".

<Measurement of Interfacial Resistance of Electrodes> After charging the coin type battery to 4.2 V, 0.2 Hz and 2500 Hz
Was measured, and the impedance value obtained by subtracting the impedance value at 2500 Hz from the impedance value at 0.2 Hz was defined as "electrode interface resistance".

<Measurement of Storage Characteristics of Battery> (1) Measurement of Discharge Capacity After discharging the battery once to 3V, the current value at a constant voltage of 4.1V was measured under the condition of 3mA constant current and 4.1V constant voltage. 0.05
It was charged until it reached mA. The amount of charge at this time was defined as "charge capacity before storage". This battery was stored at 50 ° C. for 1 week and then stored under conditions of 0.5 mA constant current and 3.0 V constant voltage to 3.0.
It was discharged until the current value at a constant V voltage was 0.05 mA. The amount of discharge at this time was defined as “discharge capacity after storage”.
The difference between the "discharge capacity after storage" and the "charge capacity before storage" was defined as "high temperature storage self-discharge capacity"("discharge capacity after storage"-"charge capacity before storage" = "high temperature storage self discharge capacity").

(2) Measurement of medium load discharge capacity after storage Next, this battery was charged under the condition of a constant current of 3 mA and a constant voltage of 4.2 V until the current value at a constant voltage of 4.2 V was 0.05 mA. Then, the voltage of the battery is 3.0 with the current of 5mA.
It was discharged to V. The discharge capacity of the coin-type battery at this time will be referred to as "medium load discharge capacity after storage".

The evaluation results of the battery characteristics of Examples 1 to 10 are shown in Table 2.

(Comparative Example 1) A non-aqueous electrolytic solution was prepared in the same manner as in <Preparation of non-aqueous electrolytic solution> of Example 1 except that addition of additives was omitted. Using, the battery was manufactured in the same manner as in Example 1 and the battery characteristics were evaluated. The "electrode interface resistance" and "high temperature storage self-discharge capacity" measured in Comparative Example 1 are referred to as "blank electrode interface resistance" and "blank high temperature storage self-discharge capacity", respectively. The results of evaluation of battery characteristics are shown in Table 2.

The evaluation of the battery characteristics shown in Table 2 was carried out according to Example 1
-10 and the experimental result in the comparative example 1, it performed using the following indexes. The unit is%. “Electrode interface resistance ratio” = {“Electrode interface resistance of battery using test electrolyte” / “Blank electrode interface resistance”} × 100 “Initial load characteristic index” = {“Initial medium load discharge capacity” /
"Initial low load discharge capacity"} x 100 "Load characteristic maintenance rate" = {"Medium load discharge capacity after storage" /
“Initial medium-load discharge capacity”} × 100 “Self-discharge ratio” = {“High-temperature storage self-discharge capacity of test electrolyte solution” / “Blank high-temperature storage self-discharge capacity”} × 10
0

[0124]

[Table 1]

[0125]

[Table 2]

From Table 2, no matter which of the electrolyte solutions of Examples 1 to 10 was used, the initial interface resistance was smaller than that of the blank (Comparative Example 1), and batteries having excellent load characteristics were obtained. I found out that

Further, from Table 2, it is understood that when the electrolytic solution contains the compound represented by the general formula (2) in addition to the borate esters, a battery with less deterioration in load characteristics after storage at high temperature can be obtained. When the electrolytic solution further contains the vinylene carbonate derivative represented by the general formula (3),
It can be seen that deterioration of load characteristics and self-discharge after storage at high temperature are suppressed, and a battery having further excellent characteristics can be obtained.

[0128]

INDUSTRIAL APPLICABILITY The present invention provides a non-aqueous electrolyte solution which is particularly suitable as an electrolyte solution for a lithium ion secondary battery.
By using the non-aqueous electrolyte of the present invention, in the initial properties, or in the initial properties and properties after high temperature storage,
It is possible to obtain a non-aqueous electrolyte secondary battery having a low electrode interface resistance and excellent load characteristics.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tatsurei Ishida             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company (72) Inventor Chiho Hirano             580-32 Nagaura, Sodegaura-shi, Chiba Mitsui Chemicals, Inc.             Inside the company F-term (reference) 5H029 AJ02 AJ05 AJ06 AK02 AK03                       AK05 AK06 AK16 AL02 AL06                       AL11 AL12 AM02 AM03 AM05                       AM07 HJ02 HJ10 HJ13                 5H050 AA02 AA06 AA07 AA12 BA16                       BA17 CA02 CA07 CA11 CA14                       CB02 CB07 CB11 CB12 DA18                       HA02 HA13

Claims (23)

[Claims] 1. A non-aqueous electrolytic solution containing a boric acid ester represented by the following general formula (1), a non-aqueous solvent and an electrolyte. [Chemical 1] (R ^{1 to} R ³ may be the same or different,
It represents hydrogen, a metal or an organic group, which may be bonded to each other. ) 2. The nonaqueous electrolytic solution according to claim 1, wherein at least one of R ^{1 to} R ³ is a halogen-containing organic group. 3. The non-aqueous electrolyte solution according to claim 1, wherein at least one of R ^{1 to} R ³ is an organic group containing a carbon-carbon triple bond. 4. The non-aqueous electrolyte solution according to claim 1, wherein the organic group has 1 to 10 carbon atoms. 5. The non-aqueous electrolyte solution according to claim 1, further comprising a compound represented by the following general formula (2). [Chemical 2] (R ⁴ and R ⁵ may be the same or different, represent an organic group, and may be bonded to each other.) 6. The non-aqueous electrolyte according to claim 5, wherein the organic group has 1 to 10 carbon atoms. 7. The non-aqueous electrolytic solution according to claim 5, wherein the compound represented by the general formula (2) is a benzenesulfone derivative. 8. The non-aqueous electrolyte according to claim 5, wherein the compound represented by the general formula (2) is a cyclic saturated alkyl sulfonate derivative. 9. The non-aqueous electrolytic solution according to claim 5, wherein the compound represented by the general formula (2) is a cyclic unsaturated alkyl sulfonic acid ester derivative. 10. The non-aqueous electrolyte according to claim 1, further comprising a vinylene carbonate derivative represented by the following general formula (3). [Chemical 3] (R ⁶ and R ⁷ are hydrogen or an organic group.) 11. The non-aqueous electrolytic solution according to claim 10, wherein the organic group has 1 to 10 carbon atoms. 12. The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous solvent comprises a cyclic aprotic solvent and / or a chain aprotic solvent. 13. The non-aqueous electrolytic solution according to claim 12, wherein the cyclic aprotic solvent is at least one solvent selected from cyclic carbonates and cyclic esters. 14. The non-aqueous electrolyte solution according to claim 13, wherein the cyclic aprotic solvent is at least one solvent selected from ethylene carbonate, propylene carbonate, butylene carbonate and γ-butyrolactone. 15. The nonaqueous electrolysis according to claim 12, wherein the chain aprotic solvent is at least one solvent selected from chain carbonates and chain esters. liquid. 16. The chain aprotic solvent is at least one solvent selected from dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl propionate and propyl acetate. The nonaqueous electrolytic solution according to claim 15. 17. The electrolyte is LiPF.₆, LiBF_Four,
LiOSO_TwoC_kF_{( 2k + 1)}(K = 1 to 8
Number), LiClO_Four, LiAsF₆, LiN (SO _TwoC
_kF_{(2k + 1)})_Two(K = 1 integer of 8), LiPF
_n(C_kF_{(2k + 1)})_(6-n)(N = 1 to 5, k
= 1 to 8) at least one selected from
The non-water according to any one of claims 1 to 16,
Electrolyte. 18. The boric acid ester represented by the general formula (1) is contained in an amount of 0.05 to 2% by weight based on the whole non-aqueous electrolyte. The non-aqueous electrolytic solution described in 1. 19. The compound represented by the general formula (2) is contained in an amount of 0.05 to 5% by weight with respect to the whole non-aqueous electrolyte solution. The non-aqueous electrolyte described. 20. The vinylene carbonate derivative represented by the general formula (3) is added to the non-aqueous electrolyte solution in an amount of 0.
05 to 5% by weight is contained.
20. The non-aqueous electrolyte solution according to any one of claims 1 to 19. 21. A secondary battery containing the non-aqueous electrolyte solution according to claim 1. 22. As a negative electrode active material, metallic lithium, a lithium-containing alloy, a carbon material capable of doping / dedoping lithium ions, tin oxide capable of doping / dedoping lithium ions, and a doping / dedoping of lithium ions are used. Possible titanium oxide, niobium oxide or vanadium oxide,
Alternatively, a negative electrode containing either silicon or tin capable of being doped or dedoped with lithium ions, and a transition metal oxide, a transition metal sulfide, a composite oxide of lithium and a transition metal, or a conductive polymer material as a positive electrode active material. A positive electrode comprising any of a carbon material, a carbon material, or a mixture thereof;
21. A lithium secondary battery containing the non-aqueous electrolyte according to any one of 20. 23. The carbon material capable of doping / dedoping lithium ions was measured by X-ray analysis (002).
The surface distance (d002) on the surface is 0.340 nm
The lithium ion secondary battery according to claim 22, wherein: