JP2019169303A - Nonaqueous electrolyte solution for power storage device - Google Patents

Abstract

An object of the present invention is to provide a non-aqueous electrolyte for a power storage device and a power storage device that can reduce the electric resistance of the non-aqueous electrolyte and maintain a high capacity even after repeated charging and discharging. A non-aqueous electrolyte for an electricity storage device obtained by dissolving an electrolyte in a non-aqueous solvent, wherein the electrolyte is a lithium salt that dissolves in the non-aqueous solvent, and is represented by formula (1) or / and ( A non-aqueous electrolyte for a power storage device containing the lithium boron compound represented by 2). (Li) m (B) n (O) p (1) (n is 1 to 8; m, p is 2 to 20; m, p is larger than n and p / m is 2 to 0.5) (Li ) m (B) n (O) x (OR) y (2) (n is 1-4; m, x, y is 1-12; R is hydrogen, an alkyl group, an alkenyl group, an aryl group, a carbonyl group, Sulfonyl group, phenyl group, silyl group, boron-containing group or phosphorus-containing group;) [Selection] None

Description

  The present invention relates to a nonaqueous electrolytic solution for an electricity storage device such as a lithium ion secondary battery.

  In recent years, with the widespread use of various portable electronic devices such as portable electronic terminals typified by mobile phones and notebook computers, secondary batteries play an important role as their power source. Examples of these secondary batteries include an aqueous battery and a non-aqueous electrolyte battery. Among them, the non-aqueous electrolyte secondary battery including a positive electrode and a negative electrode that can occlude and release lithium ions and the like and a non-aqueous electrolyte has a high voltage and high energy density, excellent safety, environmental problems, etc. In this respect, it has various advantages compared with other secondary batteries.

  As non-aqueous electrolyte secondary batteries currently in practical use, for example, a composite oxide of lithium and a transition metal is used as a positive electrode active material, and a material capable of doping and dedoping lithium is used as a negative electrode active material. A lithium ion secondary battery is mentioned. In the negative electrode active material of a lithium ion secondary battery, a carbon material is mentioned as a material which has the outstanding cycling characteristics. Among carbon materials, graphite is expected as a material that can improve the energy density per unit volume.

Further, in order to improve the characteristics of the lithium secondary battery, not only the characteristics of the negative electrode / positive electrode but also the characteristics of the non-aqueous electrolyte responsible for transferring lithium ions are required. As such a non-aqueous electrolyte, a lithium salt such as LiBF ₄ , LiPF ₆ , LiClO ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ CF ₂ CF ₃ ) ₂ was dissolved in an aprotic organic solvent. A non-aqueous solution is used (Non-Patent Document 1). Carbonates are known as typical examples of aprotic organic solvents, and the use of various carbonate compounds such as ethylene carbonate, propylene carbonate, and dimethyl carbonate has been proposed (Patent Documents 1 and 2).

On the other hand, a non-aqueous electrolyte in which LiBF ₄ , LiPF _{6 and the} like are dissolved as an electrolyte of the non-aqueous electrolyte has high conductivity indicating the transfer of lithium ions, and the oxidative decomposition voltage of LiBF ₄ and LiPF ₆ is high. It is known to be stable at high voltage, and contributes to drawing out the characteristics of the lithium secondary battery such as high voltage and high energy density.

  On the other hand, when using a non-aqueous electrolyte secondary battery such as a lithium secondary battery as each power source, the electrical resistance of the non-aqueous electrolyte is lowered to increase the conductivity of lithium ions, and charging, Even after repeated discharges, there is a demand for a long life that suppresses a decrease in battery capacity and maintains a high capacity, so-called cycle characteristics.

In order to achieve such an object, various proposals have conventionally been made for non-aqueous electrolytes to specify the structure of a lithium salt that is an electrolyte or to add a specific compound. For example, Patent Document 3 proposes adding a vinyl sulfone derivative having a specific structure to a nonaqueous electrolytic solution. Patent Document 4 proposes to add a lithium salt other than a bifunctional lithium salt having a specific structure and having no boron atom.
However, conventional non-aqueous electrolytes are not always satisfactory, including the cost, and further techniques are required for non-aqueous electrolytes for power storage devices.

JP-A-4-184872 Japanese Patent Laid-Open No. 10-27625 JP 11-329494 A Japanese Patent Laid-Open No. 2014-22334

  The present invention improves the solubility of the electrolyte in the non-aqueous electrolyte, lowers the electrical resistance of the non-aqueous electrolyte, and maintains a high capacity even after repeated many times of charging and discharging, so-called cycle It aims at providing the nonaqueous electrolyte for electrical storage devices, such as a lithium secondary battery which improved the characteristic, and the electrical storage device using this nonaqueous electrolytic solution.

  As a result of various researches, the present inventors have found a non-aqueous electrolyte solution for an electricity storage device that can achieve the above-described object, and an electricity storage device that uses the non-aqueous electrolyte solution, and have reached the present invention. is there.

The present invention has the following gist.
(1) A nonaqueous electrolytic solution for an electricity storage device obtained by dissolving an electrolyte in a nonaqueous solvent, wherein the electrolyte is a lithium salt dissolved in the nonaqueous solvent, and the following formula (1) or / and the following formula: A nonaqueous electrolytic solution for an electricity storage device, comprising the lithium boron compound represented by (2).
(Li) m (B) n (O) p (1)
(N is 1 to 8, m and p are each independently 2 to 20, m and p are larger than n, and p / m is in the range of 2 to 0.5. )
(Li) m (B) n (O) x (OR) y (2)
(N is 1-4, m, x, y are each independently 1-12, R is hydrogen, an alkyl group, an alkenyl group, an aryl group, a carbonyl group, a sulfonyl group, a silyl group. A boron-containing group or a phosphorus-containing group, and these groups may have a fluorine atom, an oxygen atom, and other substituents.)

(2) The lithium boron compound represented by the formula (1) is Li ₃ BO ₃ , Li ₄ B ₂ O ₅ , Li ₅ B ₃ O ₇ , Li ₆ B ₄ O ₉ , Li ₈ B ₂ O ₇ , or a nonaqueous electrolytic solution for an electricity storage device according to (1) is _Li 8 _B 6 _{O 13.}
(3) The nonaqueous electrolytic solution for an electricity storage device according to the above (1), wherein in the formula (2), R is an alkyl group, a carbonyl group, a sulfonyl group, a silyl group, a boron-containing group or a phosphorus-containing group.
(4) The lithium boron compound represented by the formula (2) is LiBO (OCH ₃ ) ₂ , LiBO (OCH ₂ CH ₃ ) ₂ , LiBO (OCH ₂ CF ₃ ) ₂ , LiBO (OC (═O) CH _{3) 2, LiBO (OC (} = O) CF 3) 2, LiBO (OSO 2 CH 3) 2, LiBO (OSO 2 CF 3) 2, Li 2 B 2 O 3 (OCH 3) 2, Li 2 B 2 O ₃ (OCH ₂ CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC (═O) CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC ( _{= O) CF 3) 2,} Li 2 B 2 O 3 (OSO 2 CH 3) 2, Li 2 B 2 O 3 (OSO 2 CF 3) 2, Li 2 B 2 O 3 (OSi (CH 3) 3) ₂ , Li ₂ B ₂ O ₂ (OBF _{3) 2, Li 4 B 2} O (OBF 3) 4, Li 3 B (OBF 3) 3, Li 6 B 4 O 3 (OBF 3) 6, Li 5 B 3 O 2 (OBF 3) 5, Li 2 The nonaqueous electrolytic solution for an electricity storage device according to any one of (1) to (3), which is B ₂ O ₂ (OPF ₅ ) ₂ or Li ₄ B ₂ O (OPF ₅ ) ₄ .
(5) The nonaqueous electrolytic solution for an electricity storage device according to any one of (1) to (4), wherein the lithium salt is contained in an amount of 0.5 to 3 mol / liter.
(6) The electricity storage device according to any one of (1) to (5), containing 0.01 to 10% by mass of the lithium boron compound represented by the formula (1) and / or the following formula (2). Non-aqueous electrolyte for use.
(7) The nonaqueous electrolysis for an electricity storage device according to any one of (1) to (6), wherein the nonaqueous solvent contains a chain carbonate ester, a saturated cyclic carbonate ester, and an unsaturated cyclic carbonate ester. liquid.
(8) The above-mentioned content wherein the chain carbonate ester, saturated cyclic carbonate ester, and unsaturated cyclic carbonate ester content is 30 to 80% by mass, 10 to 50% by mass, and 0.01 to 5% by mass, respectively ( 7) A nonaqueous electrolytic solution for an electricity storage device.
(9) Furthermore, it contains at least one additive selected from the group consisting of sulfur-containing compounds, cyclic acid anhydrides, carboxylic acid compounds, boron fluoride compounds, phosphorus fluoride compounds, silicon-containing compounds and boron-containing compounds. The nonaqueous electrolytic solution for an electricity storage device according to any one of (1) to (8) above.
(10) The lithium salt is LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (FSO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF _{3 SO 2) (C 2 F 5} SO 2), and _{LiN (CF 3 SO 2) (} C 4 F 9 SO 2) selected from the group consisting of at least one kind of lithium salt (1) to (9) The non-aqueous electrolyte for electrical storage devices of any one of these.
(11) An electricity storage device using the nonaqueous electrolytic solution according to any one of (1) to (10).
(12) The livestock device according to any one of (1) to (11), wherein the power storage device is a lithium secondary battery.

The non-aqueous electrolyte according to the present invention not only lowers the electric resistance of the non-aqueous electrolyte by increasing the solubility of the lithium electrolyte in the non-aqueous electrolyte, but also maintains a high capacity even after repeated charging and discharging. However, so-called cycle characteristics are improved. For this reason, electrical storage devices, such as a lithium secondary battery excellent in the favorable initial characteristic and cycling characteristics, are provided.
Although it is not always clear whether the non-aqueous electrolyte of the present invention has the above effects, the lithium boron compound used in the present invention is a lithium ion that becomes a cation, boron and oxygen, or a substituent. It is considered that a film is formed which is easily dissociated in the electrolytic solution and is liable to pass lithium ions on the electrode surface by decomposition of the dissociated anion. In addition, it is considered that an anion composed of boron and oxygen or oxygen introduced with a substituent easily reacts with moisture in the electrolytic solution or on the electrode surface, and moisture that easily affects battery performance is effectively removed.

Hereinafter, the nonaqueous electrolytic solution of the present invention and the electricity storage device using the same will be described.
<Nonaqueous solvent>
As the nonaqueous solvent used in the nonaqueous electrolytic solution of the present invention, various solvents can be used. For example, an aprotic polar solvent is preferable. Specific examples thereof are ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, trifluoromethylethylene carbonate, fluoroethylene carbonate. And cyclic carbonates such as 4,5-difluoroethylene carbonate; lactones such as γ-ptilolactone and γ-valerolactone; cyclic sulfones such as sulfolane; cyclic ethers such as tetrahydrofuran and dioxane; ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate , Methyl isopropyl carbonate, dipropyl carbonate, methyl butyl carbonate, dibutyl carbonate, ethyl Chain carbonates such as propyl carbonate and methyl trifluoroethyl carbonate; nitriles such as acetonitrile; chain ethers such as dimethyl ether; chain carboxylic acid esters such as methyl propionate; chain glycol ethers such as dimethoxyethane; , 2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (CF ₂ HCF ₂ CH ₂ OCF ₂ CF ₂ H), 1,1,2,2-tetrafluoroethyl-2,2 , 3,3,3-pentafluoro-propyl ether _{(CF 3 CF 2 CH 2 OCF} 2 CF 2 H), ethoxy-2,2,2-trifluoro-ethoxy - ethane _{(CF 3 CH 2 OCH 2 CH} 2 OCH 2 CH _And fluorine-containing ethers such as ₃ ). These can be used individually by 1 type or in combination of 2 or more types.

  As the non-aqueous solvent, it is more preferable to use a carbonate-based solvent such as cyclic carbonate and chain carbonate from the viewpoint of ion conductivity. It is more preferable to use a combination of a cyclic carbonate and a chain carbonate as the carbonate solvent. Among the above, as the cyclic carbonate, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate are preferable. Among the above-mentioned chain carbonates, ethyl methyl carbonate, dimethyl carbonate, and diethyl carbonate are preferable. In the case of using a carbonate-based solvent, another non-aqueous solvent such as a nitrile compound or a sulfone-based solvent can be further added as necessary from the viewpoint of improving battery physical properties.

  As the nonaqueous solvent, in the present invention, it is particularly preferable to contain a chain carbonate ester, a saturated cyclic carbonate ester, and an unsaturated cyclic carbonate ester. In the case of containing these three kinds of carbonates, it is particularly preferable since the effects of the present invention are exhibited. In the nonaqueous solvent used in the present invention, the chain carbonate ester, the saturated cyclic carbonate ester, and the unsaturated cyclic carbonate ester are 30 to 80% by weight, 10 to 50% by weight, respectively, in the nonaqueous electrolytic solution. And 0.01 to 5% by weight, and more preferably 50 to 70% by weight, 20 to 30% by weight, and 0.1 to 2% by weight, respectively.

  When the chain carbonate ester is smaller than 30% by weight, the viscosity of the electrolytic solution is increased, and in addition, it solidifies at a low temperature, so that sufficient characteristics cannot be obtained. If it is large, the dissociation / solubility of the lithium salt will decrease, and the ionic conductivity of the electrolyte will decrease. When the saturated cyclic carbonate is less than 10% by weight, the dissociation / solubility of the lithium salt is lowered, and the ionic conductivity of the electrolyte is lowered. Conversely, when the saturated cyclic carbonate is more than 50% by weight, the electrolyte In addition, the viscosity of the resin increases and, at the same time, solidifies at a low temperature, so that sufficient characteristics cannot be obtained.

  In addition, when the unsaturated cyclic carbonate is smaller than 0.01% by weight, a good film is not formed on the negative electrode surface, so that the cycle characteristics are deteriorated. Conversely, when the unsaturated cyclic carbonate is larger than 5% by weight, for example, When stored at a high temperature, the electrolyte solution is likely to generate gas, and the pressure in the battery is increased, which is undesirable in practice.

  Examples of the chain carbonate used in the present invention include chain carbonates having 3 to 9 carbon atoms. Specifically, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, di-n-butyl carbonate, di-t-butyl carbonate, n-butyl isobutyl carbonate, n-butyl-t-butyl carbonate, isobutyl-t-butyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate, n-butyl-n-propyl carbonate, isobutyl-n- B pills carbonate, t- butyl -n- propyl carbonate, n- butyl isopropyl carbonate, isobutyl isopropyl carbonate, and t-butyl isopropyl carbonate. Among these, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate are preferable, but are not particularly limited. Two or more of these chain carbonates may be mixed.

  Examples of the saturated cyclic carbonate used in the present invention include ethylene carbonate, propylene carbonate, butylene carbonate, and fluoroethylene carbonate. Among these, ethylene carbonate, propylene carbonate, and fluoroethylene carbonate are more preferable. By using propylene carbonate, a stable nonaqueous electrolytic solution can be provided in a wide temperature range. Two or more of these saturated cyclic carbonates may be mixed.

Examples of the unsaturated cyclic carbonate used in the present invention include vinylene carbonate derivatives represented by the following general formula (I).

In the above general formula (I), R ₁ and R ₂ are each independently a hydrogen atom, a halogen atom, or an alkyl group that may contain a halogen atom having 1 to 12 carbon atoms. Among them, preferably R ₁ and R ₂ are hydrogen (a vinylene carbonate).

  Specific examples of the vinylene carbonate derivative include the following compounds. Vinylene carbonate, fluorovinylene carbonate, methyl vinylene carbonate, fluoromethyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate, butyl vinylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, dipropyl vinylene carbonate, etc. are limited thereto. It is not a thing.

Among these compounds, vinylene carbonate is effective and advantageous in terms of cost. In addition, regarding the said vinylene carbonate derivative, it is at least 1 type, and it is also possible to be independent or to mix.
Moreover, as another unsaturated cyclic carbonate used by this invention, the alkenyl ethylene carbonate represented by the following general formula (II) is mentioned.

In the above formula (II), R _{3 to} R ₆ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group that may contain a halogen atom having 1 to 12 carbon atoms, or a carbon number of 2 to 2. 12 alkenyl groups, at least one of which is an alkenyl group having 2 to 12 carbon atoms. Especially, when one of R < ₃ > -R < ₆ > is a vinyl group and the remainder is hydrogen (the compound of (II) is 4-vinyl ethylene carbonate), it is preferable.

  Specific examples of the alkenylethylene carbonate include compounds such as 4-vinylethylene carbonate, 4-vinyl-4-methylethylene carbonate, 4-vinyl-4-ethylethylene carbonate, 4-vinyl-4-n-propylethylene carbonate, and the like. Can be mentioned.

  The nonaqueous solvent used in the present invention may contain other various solvents in addition to the above components. Examples of these various other solvents include cyclic carboxylic acid esters, chain esters having 3 to 9 carbon atoms, and chain ethers having 3 to 6 carbon atoms. These various other solvents are preferably contained in the nonaqueous electrolytic solution in an amount of 0.2 to 10% by weight, particularly preferably 0.5 to 5% by weight.

  Examples of the cyclic carboxylic acid ester (lactone compound having 3 to 9 carbon atoms) include γ-butyrolactone, γ-valerolactone, γ-caprolactone, and ε-caprolactone. Among these, γ-butyrolactone and γ-valerolactone are more preferable, but not particularly limited. Two or more of these cyclic carboxylic acid esters may be mixed.

  Examples of the chain ester having 3 to 9 carbon atoms include methyl acetate, ethyl acetate, acetic acid-n-propyl, acetic acid-isopropyl, acetic acid-n-butyl, acetic acid isobutyl, acetic acid-t-butyl, and methyl propionate. And ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, isobutyl propionate and t-butyl propionate. Of these, ethyl acetate, methyl propionate, and ethyl propionate are preferred.

  Examples of the chain ether having 3 to 6 carbon atoms include dimethoxymethane, dimethoxyethane, diethoxymethane, diethoxyethane, ethoxymethoxymethane, and ethoxymethoxyethane. Of these, dimethoxyethane and diethoxyethane are more preferable.

  Further, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, dioxolane, 4-methyldioxolane, N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene and the like can be used. .

<Lithium salt>
A lithium salt is used as the solute of the nonaqueous electrolytic solution of the present invention. The lithium salt is not particularly limited as long as it can be dissolved in the non-aqueous solvent. Specific examples thereof are as follows.
(A) Inorganic lithium salt:
LiPF _6, LiAsF _6, inorganic fluoride salts LiBF ₄ or the _{like, LiClO 4, LiBrO 4, LiIO} 4, perhalogenate etc. like.

(B) Organic lithium salt:
Organic sulfonates such as LiCF ₃ SO ₃ ; perfluoro such as LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) Alkyl sulfonic acid imide salt; Perfluoroalkyl sulfonic acid methide salt such as LiC (CF ₃ SO ₂ ) ₃ ; LiPF (CF ₃ ) ₅ , LiPF ₂ (CF ₃ ) ₄ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₂ ( _{C 2 F 5) 4, LiPF} 3 (C 2 F 5) 3, LiPF (n-C 3 F 7) 5, LiPF 2 (n-C 3 F 7) 4, LiPF 3 (n-C 3 F 7) _{3, LiPF (iso-C 3} F 7) 5, LiPF 2 (iso-C 3 F 7) 4, LiPF 3 (iso-C 3 F 7) 3, LiB (CF 3) 4, LiBF (CF 3 _{3, LiBF 2 (CF 3)} 2, LiBF 3 (CF 3), LiB (C 2 F 5) 4, LiBF (C 2 F 5) 3, LiBF 2 (C 2 F 5) 2, LiBF 3 (C 2 _{F 5), LiB (n-} C 3 F 7) 4, LiBF (n-C 3 F 7) 3, LiBF 2 (n-C 3 F 7) 2, LiBF 3 (n-C 3 F 7), LiB Some fluorine such as (iso-C ₃ F ₇ ) ₄ , LiBF (iso-C ₃ F ₇ ) ₃ , LiBF ₂ (iso-C ₃ F ₇ ) ₂ , LiBF ₃ (iso-C ₃ F ₇ ) Examples thereof include inorganic fluoride salt fluorophosphate substituted with a perfluoroalkyl group, and fluorine-containing organic lithium salt of perfluoroalkyl.

In the present invention, among the above, LiPF ₆ , LiBF ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ ) LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) is more preferable. Two or more of these lithium salts may be mixed.

  The concentration of the lithium salt, which is the solute of the nonaqueous electrolytic solution of the present invention, is preferably 0.5 to 3 mol / liter, particularly 0.7 to 2 mol / liter. If this concentration is too low, the ionic conductivity of the non-aqueous electrolyte is insufficient due to an absolute concentration shortage. If the concentration is too high, the ionic conductivity decreases due to an increase in viscosity, and precipitation at a low temperature occurs. Since it is likely to occur and causes problems, the performance of the nonaqueous electrolyte battery is undesirably lowered.

<Lithium boron compound>
The nonaqueous electrolytic solution of the present invention contains a lithium boron compound represented by the following formula (1) or / and the following formula (2).
(Li) m (B) n (O) p (1)
In formula (1), n is 1-8, m and p are each independently 2-20, m and p are larger than n, and p / m is 2-0. The range is 5.
(Li) m (B) n (O) x (OR) y (2)
In formula (2), n is 1-4, m, x, and y are each independently 1-12, and R is hydrogen, an alkyl group, an alkenyl group, an aryl group, a carbonyl group, A sulfonyl group, a phenyl group, a silyl group, a boron-containing group, or a phosphorus-containing group, and these groups may have a fluorine atom, an oxygen atom, and other substituents.

In the formula (1), n is preferably 1 to 8, particularly preferably 1 to 6. m and p are preferably 2 to 20 and particularly preferably 3 to 15. Further, p / m is preferably in the range of 2 to 0.5, particularly preferably in the range of 1.8 to 1.
Moreover, 1-4 is preferable among formula (2), and 1-4 are especially preferable. m, x, and y are preferably 1 to 12, and particularly preferably 1 to 10.
R is preferably an alkyl group, an alkenyl group, an aryl group, a carbonyl group, a sulfonyl group, a phenyl group, a silyl group, a boron-containing group, or a phosphorus-containing group, and an alkyl group, a carbonyl group, a sulfonyl group, a phenyl group, a silyl group A boron-containing group or a phosphorus-containing group is particularly preferable.

As the alkyl group, a linear or cyclic alkyl group having 1 to 8 carbon atoms is preferable. Preferable examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group, a hydroxyethyl group, a trifluoromethyl group, and a hexafluoroethyl group.
As a preferred example of the alkenyl group, an alkenyl group having 2 to 5 carbon atoms contained in a double bond is preferred. Examples of the alkenyl group having 2 to 5 carbon atoms contained in the double bond include a vinyl group, a propenyl group, a butbutenyl group, and a heptenyl group.
Preferable examples of the aryl group include phenyl group, benzyl group, tolyl group, xylyl group and the like.

Preferable examples of the carbonyl group include a methylcarbonyl group, an ethylcarbonyl group, a propylcarbonyl group, a butylcarbonyl group, a cyclopropylcarbonyl group, a cyclobutylcarbonyl group, a trifluoromethylcarbonyl group, a pentafluoroethylcarbonyl group and the like.
Preferable examples of the sulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a propylsulfonyl group, a benzylsulfonyl group, a trifluoromethylsulfonyl group, a pentafluoroethylsulfonyl group, and the like.
Preferable examples of the silyl group include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and a butyldimethylsilyl group.
Preferable examples of the boron-containing group include dimethylboryl group, dimethoxyboryl group, boron fluoride, boron difluoride, boron trifluoride and the like.

Examples of the lithium boron _{compounds, Li 3 BO 3, Li 4} B 2 O 5, Li 5 B 3 O 7, Li 6 B 4 O 9, Li 8 B 2 O 7, Li 8 B 6 O 13, LiBO (OCH ₃ ) ₂ , LiBO (OCH ₂ CH ₃ ) ₂ , LiBO (OCH ₂ CF ₃ ) ₂ , LiBO (OC (═O) CH ₃ ) ₂ , LiBO (OC (═O) CF ₃ ) ₂ , LiBO ( OSO ₂ CH ₃ ) ₂ , LiBO (OSO ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₂ CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC (═O) CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC (═O) CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSO ₂ CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSO ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSi (CH ₃ ) ₃ ) ₂ , Li ₂ B ₂ O ₂ (OBF ₃ ) ₂ , Li ₄ B ₂ O (OBF ₃ ) ₄ , Li ₃ B (OBF ₃ ) ₃ , Li ₆ B ₄ O ₃ (OBF ₃ ) ₆ , Li ₅ B ₃ O ₂ (OBF ₃ ) ₅ , Li ₂ B ₂ O ₂ (OPF ₅ ) ₂ , Li ₄ B ₂ O ( OPF ₅ ) _{4 and the} like.

  The lithium boron compound can be easily obtained by a production method similar to lithium salts such as lithium tetraborate. For example, a precursor crystal can be easily obtained by maintaining an aqueous solution of boric acid and a lithium compound such as lithium hydroxide or lithium carbonate or a corresponding carboxylic acid compound at 20 to 80 ° C. The obtained crystal is dehydrated under conditions of 200 to 400 ° C., and the lithium boron compound can be suitably obtained.

  The content of the lithium boron compound in the nonaqueous electrolytic solution of the present invention is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and particularly preferably 0.1 to 2% by mass. It is. When the concentration is less than 0.01% by mass, the resistance reduction effect is reduced. On the other hand, if it exceeds 10% by weight, the film resistance becomes high and the life performance deteriorates.

<Other additive substances>
In the non-aqueous electrolyte of the present invention, other additive substances may be contained in addition to the lithium salt and the lithium boron compound in order to improve the life performance and resistance performance of the electricity storage device. Examples of such other additive substances are selected from the group consisting of sulfur-containing compounds (excluding the organic carboxylates represented by the above formula (1)), cyclic acid anhydrides, carboxylic acid compounds, and boron-containing compounds. One or more compounds can be used.

  Examples of the sulfur-containing compound include 1,3-propane sultone (PS), propene sultone, ethylene sulfite, hexahydrobenzo [1,3,2] dioxathiolane-2-oxide (1,2-cyclohexanediol cyclic sulfite Also), 5-vinyl-hexahydro 1,3,2-benzodioxathiol-2-oxide, 1,4-butanediol dimethanesulfonate, 1,3-butanediol dimethanesulfonate, methylenemethane disulfonic acid, ethylene Examples include methanedisulfonic acid, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide, divinylsulfone, 1,2-bis (vinylsulfonyl) methane, and the like.

  Examples of the cyclic acid anhydride include glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, succinic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phenylsuccinic anhydride, 2- Carboxylic anhydride such as phenylglutaric anhydride, phthalic anhydride, pyromellitic anhydride, fluorosuccinic anhydride, tetrafluorosuccinic anhydride, 1,2-ethanedisulfonic anhydride, 1,3-propanedisulfone Acid anhydride, 1,4-butanedisulfonic anhydride, 1,2-benzenedisulfonic anhydride, tetraf Oro-1,2-ethanedisulfonic anhydride, hexafluoro-1,3-propanedisulfonic anhydride, octafluoro-1,4-butanedisulfonic anhydride, 3-fluoro-1,2-benzenedisulfonic anhydride Products, 4-fluoro-1,2-benzenedisulfonic anhydride, 3,4,5,6-tetrafluoro-1,2-benzenedisulfonic anhydride, and the like.

  Examples of the carboxylic acid compound include lithium oxalate, lithium malonate, lithium difluoromalonate, lithium succinate, lithium tetrafluorosuccinate, lithium adipate, lithium glutarate, lithium acetonedicarboxylate, lithium 2-oxobutyrate, and oxal. Lithium acetate, lithium 2-oxoglutarate, lithium acetoacetate, lithium 3-oxocyclobutanecarboxylate, lithium 3-oxocyclopentanecarboxylate, lithium 2-oxovalerate, lithium pyruvate, lithium glyoxylate, 3,3-dimethyl Lithium 2-oxobutyrate, lithium 2-hydroxypropionate, lithium 2-methyl lactate, lithium tartrate, lithium cyanoacetate, lithium 2-mercaptopropionate, lithium methylenebis (thioglycolate) thio 3-succinate (Tilthio) lithium propionate, lithium 3,3′-thiodipropionate, lithium dithiodiglycolate, lithium 2,2′-thiodiglycolate, lithium thiazolidine-2,4-dicarboxylate, lithium acetylthioacetate, etc. It is done.

Examples of the boron-containing compound include LiBF ₂ (C ₂ O ₄ ), LiB (C ₂ O ₄ ) ₂ , LiBF ₂ (CO ₂ CH ₂ CO ₂ ), LiB (CO ₂ CH ₂ CO ₂ ) ₂ , LiB (CO ₂ CF ₂ CO ₂ ) ₂ , LiBF ₂ (CO ₂ CF ₂ CO ₂ ), LiBF ₃ (CO ₂ CH ₃ ), LiBF ₃ (CO ₂ CF ₃ ), LiBF ₂ (CO ₂ CH ₃ ) ₂ , LiBF ₂ ( _{CO 2 CF 3) 2, LiBF} (CO 2 CH 3) 3, LiBF (CO 2 CF 3) 3, LiB (CO 2 CH 3) 4, LiB (CO 2 CF 3) 4, Li 2 B 2 O 7, li ₂ B ₂ O ₄ and the like.

  As said 2nd additive substance, each 1 type may be used independently and 2 or more types may be used together. In addition, when the water electrolyte adds the second additive substance, the content of the second additive substance in the non-aqueous electrolyte is 0.01 to 5% by mass, although it varies depending on the second additive substance. Preferably, it is 0.1-2 mass%.

<Power storage device>
The non-aqueous electrolyte of the present invention is used in various power storage devices such as a lithium ion secondary battery, an electric double layer capacitor, a hybrid battery in which one of a positive electrode and a negative electrode is a battery and the other electrode is a double layer. it can. Hereinafter, a lithium ion secondary battery as a representative example will be described.

  As a negative electrode active material constituting a negative electrode in a lithium ion secondary battery, a carbon material capable of doping / dedoping lithium ions, metallic lithium, a lithium-containing alloy, or silicon capable of being alloyed with lithium , Silicon alloy, tin, tin alloy, tin oxide capable of doping / de-doping lithium ion, silicon oxide, transition metal oxide capable of doping / de-doping lithium ion, lithium ion Any of the transition metal nitrogen compounds that can be doped / dedoped, or a mixture thereof can be used.

  The negative electrode generally has a configuration in which a negative electrode active material is formed on a current collector such as a copper foil or expanded metal. In order to improve the adhesion of the negative electrode active material to the current collector, for example, it may contain a polyvinylidene fluoride binder, a latex binder, etc., and carbon black, amorphous whisker carbon, etc. are added as a conductive aid. May be used.

As the carbon material constituting the negative electrode active material, for example, pyrolytic carbons, cokes (pitch coke, needle coke, petroleum coke, etc.), graphites, organic polymer compound fired bodies (phenol resin, furan resin, etc.) are suitable. And carbonized by firing at a suitable temperature), carbon fiber, activated carbon and the like. The carbon material may be graphitized. As the carbon material, a carbon material having a (002) plane spacing (d002) of 0.340 nm or less, particularly measured by X-ray diffraction, is preferable, or a graphite having a true density of 1.70 g / cm ³ or more or close thereto. A highly crystalline carbon material having properties is desirable. When such a carbon material is used, the energy density of the nonaqueous electrolyte battery can be increased.

  Further, those containing boron in the carbon material, those coated with a metal such as gold, platinum, silver, copper, Sn, Si, or those coated with amorphous carbon can be used. One type of these carbon materials may be used, or two or more types may be used in combination as appropriate.

  Silicon, silicon alloy, tin, tin alloy that can be alloyed with lithium, tin oxide that can be doped / undoped with lithium ions, silicon oxide, transition metals that can be doped / undoped with lithium ions In the case of using an oxide, any of the above-described carbonaceous materials has a higher theoretical capacity per weight and is a suitable material.

On the other hand, the positive electrode active material constituting the positive electrode can be formed from various materials that can be charged and discharged. Examples thereof include lithium-containing transition metal oxides, lithium-containing transition metal composite oxides using one or more transition metals, transition metal oxides, transition metal sulfides, metal oxides, and olivine-type metal lithium salts. For _example, in _{LiCoO 2, LiNiO 2, LiMn 2} O 4, LixMO 2 such as LiMnO ₂ (where, M is one or more transition metals, x is different according to the charge and discharge state of the battery, usually 0.05 ≦ x ≦ 1.20), and a composite oxide of lithium and one or more transition metals (lithium transition metal composite oxide).

Furthermore, some of the transition metal atoms that are the main component of the lithium transition metal composite oxide are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, It is possible to use complex oxides substituted with other metals such as Si and Yb, chalcogenides of transition elements such as FeS ₂ , TiS ₂ , V ₂ 0 ₅ , MoO ₃ and MoS _2, or polymers such as polyacetylene and polypyrrole. it can. Of these, lithium transition metal composite oxides capable of doping and dedoping Li and metal composite oxide materials in which transition metal atoms are partially substituted are preferable.

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

  The positive electrode generally has a configuration in which a positive electrode active material is formed on a current collector such as an aluminum, titanium, or stainless steel foil, or an expanded metal. In order to improve the adhesion of the positive electrode active material to the current collector, for example, polyvinylidene fluoride binder and latex binder, carbon black, amorphous whisker, graphite etc. to improve the electron conductivity in the positive electrode It may contain.

  The separator is preferably a membrane that electrically insulates the positive electrode from the negative electrode and is permeable to lithium ions. For example, a porous membrane such as a microporous polymer film is used. As the microporous polymer film, a porous polyolefin film is particularly preferable, and more specifically, a porous polyethylene film, a porous polypropylene film, or a multilayer film of a porous polyethylene film and a polypropylene film is preferable. Furthermore, a polymer electrolyte can also be used as a separator. As the polymer electrolyte, for example, a polymer material in which a lithium salt is dissolved, a polymer material swollen with an electrolytic solution, and the like can be used, but the polymer electrolyte is not limited thereto.

The non-aqueous electrolyte of the present invention may be used for the purpose of obtaining a polymer electrolyte by swelling a polymer substance with the non-aqueous electrolyte, or a separator having a combination of a porous polyolefin film and a polymer electrolyte. A non-aqueous electrolyte may be soaked in.
The shape of the lithium ion secondary battery using the non-aqueous electrolyte of the present invention is not particularly limited, and may be various shapes such as a cylindrical shape, a square shape, an aluminum laminate type, a coin shape, and a button shape. Can do.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples, and can be modified within the scope of the present invention.

<Production of battery>
A positive electrode formed by applying a positive electrode mixture to an aluminum current collector and a negative electrode formed by applying a negative electrode mixture to a copper current collector are 23 μm thick separators (F23DHA, manufactured by Toray Battery Separator Film Co., Ltd.)) The flat wound electrode group wound through the case was housed in a case, and a battery cell having a rectangular parallelepiped shape of 30 mm length × 30 mm width × 2.0 mm thickness was produced. Using this battery cell, a battery was prepared according to the following procedure.

The positive electrode comprises 5% by mass of polyvinylidene fluoride as a binder, 4% by mass of acetylene black as a conductive agent, and a positive electrode active material LiNi ₀₅ Mn ₀₃ Co ₀₂ that is a composite oxide powder of lithium-nickel-manganese-cobalt. N-methylpyrrolidone is added to a positive electrode mixture formed by mixing 91 mass% of O ₂ to prepare a paste, which is applied to both surfaces of an 18 μm thick aluminum foil current collector, and the solvent is removed by drying. Then, it was produced by rolling with a roll press.

  The negative electrode is a slurry prepared by mixing 95.8% by mass of artificial graphitizable carbon powder, 2.0% by mass of styrene butadiene rubber (SBR) as a binder and 2.2% by mass of carboxymethyl cellulose and using water as a dispersion medium. The slurry was applied to both sides of a copper foil having a thickness of 12 μm, and the solvent was dried and removed, followed by rolling with a roll press. A polyethylene microporous membrane was used for the separator.

Using the battery cell produced above, a battery was produced in the following procedure.
a. 0.55 g of various electrolytes were weighed, poured into the injection port of the battery cell, and after reducing the pressure, the injection port was sealed.
b. In a state where the sealed battery cell was kept in an atmosphere of 25 ° C., the battery cell was charged at 8 mA to 4.2 V, and then discharged at 8 mA to 3.0 V.
c. The internal gas of the battery cell discharged to 3.0 V was removed under reduced pressure to produce a battery.

<Battery evaluation>
About the battery produced above, the charge / discharge characteristic was measured as follows.
a. Resistance change rate Before high temperature cycle test, charge to SOC (State of Charge) 50% at 25 ° C, and under each environment at 0.2C, 0.5C, 1.0C, 2.0C respectively After discharging for 10 seconds, the initial DC resistance value was determined.
Then, after charging to 4.2 V at 1 C rate in a 45 ° C. atmosphere, discharging to 3.0 V at 1 C rate in the same atmosphere and repeating until reaching 200 cycles, the same as before the high temperature cycle test The DC resistance value after cycling was determined under the conditions.

From the initial DC resistance value and the DC resistance value after the cycle, the resistance change rate (%) was obtained using the following formula (2).
Resistance change rate (%) = (resistance value after cycle / initial resistance value) × 100 (2)

b. Capacity maintenance rate After charging to 4.2 V at a 1C rate in a 45 ° C. atmosphere, discharging was performed to 3.0 V at a 1C rate in the same atmosphere, and the discharge capacity value was taken as the initial capacity value. Then, the same conditions were repeated until 200 cycles were reached. From the initial capacity value and the capacity value after the cycle, the capacity retention rate (%) was obtained using the following formula (3).
Capacity retention rate (%) = (capacity value after cycle / initial capacity value) × 100 (3)

<Examples 1 to 10, Comparative Example 1>
LiPF ₆ as a lithium salt is dissolved in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio is 30:70) to a concentration of 1 mol / liter, and the total mass is 100 g. 1 g of vinylene carbonate (VC) was added so that the reference electrolyte solution 1 was prepared.
Next, the lithium boron compound shown in Table 1 was added to the reference electrolyte solution 1 so as to have the addition amount shown in Table 1, and the electrolyte solutions used in Examples 1 to 10 and Comparative Example 1 were prepared. The addition amount in Table 1 is the mass (%) of the lithium boron compound with respect to the total mass (100 mass%) of the reference electrolyte solution 1 and the lithium boron compound.

  Using the electrolytic solution prepared above, according to the above-described battery manufacturing procedure, after preparing the laminated batteries of Examples 1 to 10 and Comparative Example 1, according to the above-described resistance change rate and capacity maintenance rate procedure, The resistance change rate and the capacity retention rate were obtained for each. The results are shown in Table 1.

  As shown in Table 1, the addition of the lithium boron compound has an effect of improving the capacity retention rate after the cycle. Especially, Example 3, 4, 5, 7 can improve significantly. Moreover, the resistance change rate of a high temperature cycle can be significantly reduced by adding a lithium boron compound. The effect is remarkable by increasing the addition amount.

<Examples 11 to 18, Comparative Example 2>
LiPF ₆ as a lithium salt is dissolved in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) (volume ratio is 30:70) to a concentration of 1 mol / liter, and the total mass is 100 g. Thus, 0.5 g of 1,3-propane sultone was added to prepare a reference electrolyte solution 2.
Next, the lithium boron compound shown in Table 2 was added to the reference electrolyte solution 2 so as to have the addition amount shown in Table 2, and the electrolyte solutions used in Examples 11 to 18 and Comparative Example 2 were prepared. The addition amount in Table 2 is the mass (%) of the lithium boron compound with respect to the total mass (100 mass%) of the reference electrolyte solution 2 and the lithium boron compound.

  Using the electrolytic solution prepared above, according to the battery manufacturing procedure described above, the laminated batteries of Examples 11 to 18 and Comparative Example 2 were manufactured, and then according to the resistance change rate and capacity maintenance rate procedures described above. The resistance change rate and the capacity retention rate were obtained for each. The results are shown in Table 2.

  As shown in Table 2, it can be seen that by adding a lithium boron compound, the resistance change rate of the high-temperature cycle is further greatly reduced and the capacity retention rate after the cycle is improved.

  The non-aqueous electrolyte for power storage devices of the present invention is widely used for power storage devices such as power supplies for various consumer devices such as mobile phones and laptop computers, power supplies for industrial equipment, storage batteries, and power supplies for automobiles.

Claims (12)

A nonaqueous electrolytic solution for an electricity storage device obtained by dissolving an electrolyte in a nonaqueous solvent, wherein the electrolyte is a lithium salt dissolved in the nonaqueous solvent, and the following formula (1) and / or the following formula (2) A nonaqueous electrolytic solution for an electricity storage device, comprising a lithium boron compound represented by the formula:
(Li) m (B) n (O) p (1)
(In the formula, n is 1 to 8, m and p are each independently 2 to 20, m and p are larger than n, and p / m is 2 to 0.5. Range.)
(Li) m (B) n (O) x (OR) y (2)
(In the formula, n is 1 to 4, m, x and y are each independently 1 to 12, and R is hydrogen, alkyl group, alkenyl group, aryl group, carbonyl group, sulfonyl group. , A silyl group, a boron-containing group, or a phosphorus-containing group, and these groups may have a fluorine atom, an oxygen atom, and other substituents.) The lithium boron compound represented by the formula (1) is Li ₃ BO ₃ , Li ₄ B ₂ O ₅ , Li ₅ B ₃ O ₇ , Li ₆ B ₄ O ₉ , Li ₈ B ₂ O ₇ , or Li _8. The nonaqueous electrolytic solution for an electricity storage device according to claim 1, wherein the nonaqueous electrolyte solution is B ₆ O ₁₃ .   2. The nonaqueous electrolytic solution for an electricity storage device according to claim 1, wherein in the formula (2), R is an alkyl group, a carbonyl group, a sulfonyl group, a silyl group, a boron-containing group, or a phosphorus-containing group. The lithium boron compound represented by the formula (2) is LiBO (OCH ₃ ) ₂ , LiBO (OCH ₂ CH ₃ ) ₂ , LiBO (OCH ₂ CF ₃ ) ₂ , LiBO (OC (═O) CH ₃ ) _2. , LiBO (OC (═O) CF ₃ ) ₂ , LiBO (OSO ₂ CH ₃ ) ₂ , LiBO (OSO ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₃ ) ₂ , Li ₂ B ₂ O ₃ ( OCH ₂ CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OCH ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC (═O) CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OC (═O) CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSO ₂ CH ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSO ₂ CF ₃ ) ₂ , Li ₂ B ₂ O ₃ (OSi (CH ₃ ) ₃ ) ₂ , Li ₂ B ₂ O ₂ (OBF ₃ ) ₂ , Li ₄ B ₂ O (OBF ₃ ) ₄ , Li ₃ B (OBF ₃ ) ₃ , Li ₆ B ₄ O ₃ (OBF ₃ ) ₆ , Li ₅ B ₃ O ₂ (OBF ₃ ) ₅ , Li ₂ B ₂ O _{2 (OPF 5) 2} or _{Li 4 B 2 O (OPF 5} ) a nonaqueous electrolytic solution for an electricity storage device according to claim 1 which is _4.   The non-aqueous electrolyte for electrical storage devices in any one of Claims 1-4 which contains the said lithium salt 0.5-3 mol / liter.   The non-aqueous electrolyte for electrical storage devices in any one of Claims 1-5 containing 0.01-10 mass% of lithium boron compounds represented by the said Formula (1) or / and following formula (2).   The nonaqueous electrolytic solution for an electricity storage device according to any one of claims 1 to 6, wherein the nonaqueous solvent contains a chain carbonate ester, a saturated cyclic carbonate ester, and an unsaturated cyclic carbonate ester.   The chain carbonate ester, saturated cyclic carbonate ester, and unsaturated cyclic carbonate ester content are 30 to 80% by mass, 10 to 50% by mass, and 0.01 to 5% by mass, respectively. Non-aqueous electrolyte for electricity storage devices.   Furthermore, it contains at least one additive selected from the group consisting of sulfur-containing compounds, cyclic acid anhydrides, carboxylic acid compounds, boron fluoride compounds, phosphorus fluoride compounds, silicon-containing compounds and boron-containing compounds. The nonaqueous electrolyte for electrical storage devices of any one of -8. The lithium salt is LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (FSO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ). _{(C 2 F 5 SO 2)} , and _{LiN (CF} 3 SO ₂₎ in any one of claims 1 to 9 _{(C 4} F 9 SO ₂₎ is at least one lithium salt selected from the group consisting of The non-aqueous electrolyte for electrical storage devices of description.   The electrical storage device which uses the nonaqueous electrolyte solution in any one of Claims 1-10.   The livestock device according to claim 11, wherein the electricity storage device is a lithium secondary battery.