Non-aqueous electrolyte and non-aqueous electrolyte battery using the same

Abstract

The present invention relates to: [1] a non-aqueous electrolyte comprising a compound (A) represented by general formula (1), and an anion (B) represented by general formula (2); and [2] a non-aqueous electrolyte battery provided with the non-aqueous electrolyte, a negative electrode, and a positive electrode having positive electrode active material that can store and release lithium ions.

Description

[Technical Field]

[0001] The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery using the same. [Background technology]

[0002] Nonaqueous electrolyte batteries such as lithium ion secondary batteries are being put to practical use in a wide range of applications, from so-called consumer power sources for mobile phones, laptop computers, etc. to on-board power sources for driving automobiles, etc. However, in recent years, there has been an increasing demand for higher performance for nonaqueous electrolyte batteries, and in particular, there has been a demand for improvements in various battery characteristics such as higher capacity, low-temperature usage characteristics, high-temperature storage characteristics, cycle characteristics, and safety during overcharge. To date, numerous technologies have been investigated for various battery components, including the active materials of the positive and negative electrodes and the nonaqueous electrolyte, as means for improving the high-temperature storage characteristics and cycle characteristics of nonaqueous electrolyte secondary batteries.

[0003] Patent Document 1 discloses a non-aqueous electrolyte solution containing specific amounts of vinylene carbonate and 2-propynyl methyl carbonate as a non-aqueous electrolyte solution for producing a lithium secondary battery with excellent cycle characteristics. Patent Document 2 discloses a nonaqueous electrolyte solution that can improve electrochemical properties at high temperatures and reduce not only the discharge capacity retention rate but also the rate of increase in electrode thickness after a high-temperature cycle test. The nonaqueous electrolyte solution contains a specific diisocyanato compound and also contains a specific amount of at least one compound selected from a specific phosphate ester compound, a cyclic sulfonate ester compound, an isocyanato compound, and a triple bond-containing compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-101959 [Patent Document 2] International Publication No. 2017 / 06146 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in recent years, there has been an increasing demand for higher performance batteries, and there is a demand for achieving high capacity, high-temperature storage characteristics, and cycle characteristics at a high level. One method of increasing the capacity of non-aqueous electrolyte batteries is to pack as much electrode active material as possible into a limited battery volume. For example, methods such as pressurizing the electrode active material layer to increase density and designing the battery to minimize the volume occupied by materials other than the active material (e.g., the amount of electrolyte) inside the battery have been investigated. However, increasing the capacity reduces the void space inside the battery, which can lead to a significant increase in the internal battery pressure if even a small amount of gas is generated by decomposition of the electrolyte. In particular, in non-aqueous electrolyte secondary batteries used in mobile devices and automobiles, when stored in a high-temperature environment, the electrolyte tends to decompose and generate gas, which can cause the current cutoff valve to malfunction, rendering the battery unusable, or the battery to swell, damaging the device.

[0006] Therefore, an object of the present invention is to provide a nonaqueous electrolyte that can suppress gas generation in a high-temperature environment in a nonaqueous electrolyte battery, and a nonaqueous electrolyte battery that uses the nonaqueous electrolyte. [Means for solving the problem]

[0007] In view of the above circumstances, the present inventors conducted extensive research and found that the above problems can be solved by adding a compound having a specific terminal alkyne skeleton and a specific anion to a non-aqueous electrolyte solution, and thus completed the present invention. That is, the gist of the present invention is as follows.

[0008] [1] A non-aqueous electrolyte solution containing a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2): [ka] [In formula (1), X 1 and X 2 Y each independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. 1 is a divalent atomic group selected from the group of structures represented by the following formula (1-1). Z 1 represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-4): [ka] (The * in formula (1-1) indicates the bonding site to the oxygen atom in formula (1).) [ka] [In formula (1-4), Z 2 represents an alkyl group or alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms which may be substituted with a halogen atom. 3 and X 4 each independently represents a hydrogen atom or a halogen atom, and n represents an integer of 1 or more and 5 or less. Note that ** in formula (1-4) represents Y in formula (1). 1 The bond position is shown.

[0009] [ka] [In formula (2), Z 3 represents a fluorine atom, an alkyl group or alkoxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, or an alkenyl group or alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom.

[0010] [2] Y in general formula (1) 1is a divalent atomic group selected from the group of structures represented by the following formula (1-2): [ka] (The * in formula (1-2) indicates the bonding site with the oxygen atom in formula (1).)

[0011] [3] Z in general formula (2) 3 is a fluorine atom. [4] A non-aqueous electrolyte battery comprising a positive electrode having a positive electrode active material capable of absorbing and releasing lithium ions, a negative electrode, and the non-aqueous electrolyte according to any one of [1] to [3]. [5] The nonaqueous electrolyte battery according to [4], wherein the positive electrode contains, as a positive electrode active material, a lithium transition metal composite oxide represented by the following general formula (13): Li a1 Ni b1 M c1 O2(13) [In formula (13), a1, b1, and c1 are 0.90≦a1≦1.10, 0.40≦b1≦0.98, and 0≦c1≦0.20, respectively, and b1+c1=1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.] [6] The nonaqueous electrolyte battery according to [5], wherein b1 satisfies 0.40≦b1≦0.80. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a nonaqueous electrolyte that can suppress gas generation in a high-temperature environment in a nonaqueous electrolyte battery, and a nonaqueous electrolyte battery that uses the nonaqueous electrolyte. DETAILED DESCRIPTION OF THE INVENTION

[0013] [1.Non-aqueous electrolyte] The non-aqueous electrolyte solution of the present invention contains a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2).

[0014] [ka] [In formula (1), X 1 and X 2 Y each independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. 1 is a divalent atomic group selected from the group of structures represented by the following formula (1-1). Z 1 represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-4):

[0015] [ka] (The * in formula (1-1) indicates the bonding site to the oxygen atom in formula (1).)

[0016] [ka] [In formula (1-4), Z 2 represents an alkyl group or alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms which may be substituted with a halogen atom. 3 and X 4 each independently represents a hydrogen atom or a halogen atom, and n represents an integer of 1 or more and 5 or less. Note that ** in formula (1-4) represents Y in formula (1). 1 The bond position is shown.

[0017] [ka] [In formula (2), Z3 represents a fluorine atom, an alkyl group or alkoxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, or an alkenyl group or alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom.

[0018] A nonaqueous electrolyte battery fabricated using the nonaqueous electrolyte of the present invention can suppress gas generation in a high-temperature environment. The mechanism and principle behind this mechanism are not entirely clear, but are presumed to be as follows. However, the present invention is not limited to the mechanism and principle described below. Compound (A) represented by general formula (1) has a terminal alkyne moiety with little steric hindrance, so it coordinates with the transition metal element present in the positive electrode. Furthermore, compound (A) has an SO2 structure in its molecule, so it can more strongly coordinate with the transition metal in the positive electrode. This prevents other electrolyte components from coming into contact with the positive electrode surface, thereby suppressing the oxidative decomposition reaction of the electrolyte. On the other hand, since the compound (A) has a noble reduction potential, it is more susceptible to reductive decomposition at the negative electrode than to its action on the positive electrode. Therefore, even if only the compound (A) is added to the electrolyte, it will hardly act properly on the positive electrode, and gas generation in the battery will not be effectively suppressed.

[0019] On the other hand, the anion (B) represented by general formula (2) has an electron-withdrawing group, so it undergoes a nucleophilic substitution reaction in the presence of a nucleophile. Since the surface functional groups and anionic compounds generated by the reductive decomposition of the electrolyte are present on the negative electrode surface, these undergo a nucleophilic substitution reaction with the anion (B) to form a bond. As a result, the resulting negative electrode coating component is in a very stable form, preventing continued decomposition of the electrolyte. Therefore, when the compound (A) and the anion (B) are used in combination, the compound (A) is prevented from being reduced and decomposed at the negative electrode and consumed, and can effectively act on the positive electrode, which is presumably why gas generation in a high-temperature environment can be suppressed.

[0020] Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited to the following embodiment, and can be implemented by modifying it as desired within the scope that does not deviate from the gist of the present invention. In this specification, when the expression "to" is used, it is intended to be used as an expression that includes the numerical values ​​or physical property values ​​before and after it. In addition, in this specification, the term "independently" used when describing two or more objects together means that the two or more objects may be the same or different.

[0021] [1-1. Compound (A) represented by general formula (1) and anion (B) represented by general formula (2)] The non-aqueous electrolyte solution of the present invention (hereinafter also simply referred to as "non-aqueous electrolyte solution") contains a compound (A) represented by general formula (1) and an anion (B) represented by general formula (2). The non-aqueous electrolytic solution may contain an electrolyte and a non-aqueous solvent that dissolves the electrolyte, as in a general non-aqueous electrolytic solution.

[0022] [1-1-1. Compound (A) represented by general formula (1)] [ka]

[0023] X in general formula (1) 1 and X 2 X each independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. 1 and X 2 are each independently preferably an aliphatic hydrocarbon group having 1 to 2 carbon atoms which may be substituted with a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom, from the viewpoint of reducing steric hindrance around the alkyne moiety and facilitating action on the positive electrode. Examples of the aliphatic hydrocarbon group having 1 to 3 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, and isopropyl; alkenyl groups such as ethenyl and propenyl; and cycloalkyl groups such as cyclopropyl. Among these, from the viewpoint of suppressing reactivity at the negative electrode, an alkyl group is preferred, a methyl group or an ethyl group is more preferred, and a methyl group is even more preferred.

[0024] Y in general formula (1) 1 is a divalent atomic group selected from the group of structures represented by the following formula (1-1).

[0025] [ka] (The * in formula (1-1) indicates the bonding site to the oxygen atom in formula (1).)

[0026] In the above formula (1-1), a divalent atomic group selected from the group of structures represented by the following formula (1-2) is preferred from the viewpoint of suppressing excessive oxidative decomposition at the positive electrode. [ka] (The * in formula (1-2) indicates the bonding site with the oxygen atom in formula (1).)

[0027] In the above formula (1-2), the structure represented by the following formula (1-3) is more preferred from the viewpoint of further suppressing decomposition at the negative electrode. [ka] (The * in formula (1-3) indicates the bonding site with the oxygen atom in formula (1).)

[0028] Z in general formula (1) 1 represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-4).

[0029] [ka] [In formula (1-4), Z2 represents an alkyl group or alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms which may be substituted with a halogen atom. 3 and X 4 each independently represents a hydrogen atom or a halogen atom, and n represents an integer of 1 or more and 5 or less. Note that ** in formula (1-4) represents Y in formula (1). 1 The bond position is shown.

[0030] Z 1 Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an n-pentyl group, and examples of the alkenyl group having 2 to 5 carbon atoms include an ethenyl group, a propenyl group, a butenyl group, and a pentenyl group. 1 The alkyl group having 1 to 5 carbon atoms represented by the formula (I) may be substituted with a halogen atom. Among these, from the viewpoint of suppressing excessive oxidative decomposition, an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 or 3 carbon atoms is preferred, a methyl group, an ethyl group, an n-propyl group, an ethenyl group, or a propenyl group is more preferred, and a methyl group is particularly preferred.

[0031] Z in the above formula (1-4) 2 represents an alkyl group or alkoxy group having 1 to 3 carbon atoms, which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms. Z 2 Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group, examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group, and examples of the alkoxyalkyl group having 2 to 6 carbon atoms include a methoxymethyl group, an ethoxymethyl group, an n-propoxymethyl group, and an isopropoxymethyl group, etc. Among these, an alkoxy group having 1 to 3 carbon atoms is preferred, a methoxy group or an ethoxy group is more preferred, and an ethoxy group is even more preferred. X in the above formula (1-4) 3 and X 4 is preferably a hydrogen atom, and n is preferably 1 or 2, more preferably 1. Examples of the compound (A) represented by the general formula (1) include the following compounds.

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] Among the above compounds, the following compounds are preferred: [ka]

[0036] [ka]

[0037] Among the above compounds, the following compounds are more preferred. [ka]

[0038] Among the above compounds, the following compounds are more preferred. [ka]

[0039] Among the above compounds, the following compounds are more preferred. [ka]

[0040] Among the above compounds, 2-propynyl methyl carbonate represented by the following formula (1-5) is particularly preferred. [ka]

[0041] The compound (A) represented by general formula (1) can be used alone or in any combination of two or more kinds in any ratio. When the non-aqueous electrolyte solution contains two or more kinds of compound (A), the total amount of the compounds is the content of the compound. The content of compound (A) is not particularly limited and can be any amount as long as it does not impair the effects of the present invention.

[0042] The content of the compound (A) represented by general formula (1) in 100% by mass of the nonaqueous electrolyte solution is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2.5% by mass or less, still more preferably 2% by mass or less, and particularly preferably 1% by mass or less. The content of the compound (A) represented by general formula (1) in 100% by mass of the nonaqueous electrolyte solution is usually 0.001% by mass or more and 10% by mass or less, preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.001% by mass or more and 2% by mass or less, more preferably 0.001% by mass or more and 1% by mass or less, and more preferably 0.01% by mass or more and 1% by mass or less. The identification and content of compound (A) can be measured by nuclear magnetic resonance (NMR) spectroscopy.

[0043] [1-1-2. Anion (B) represented by general formula (2)] [ka]

[0044] In general formula (2), Z3 represents an alkyl or alkoxy group having from 1 to 4 carbon atoms which may be substituted with a fluorine atom or a halogen atom, or an alkenyl or alkenyloxy group having from 2 to 4 carbon atoms which may be substituted with a halogen atom. Z 3 From the viewpoint of enhancing the reactivity at the negative electrode, is preferably a fluorine atom, or an alkoxy group or alkenyloxy group which may be substituted with a halogen atom, more preferably a fluorine atom, an unsubstituted alkyl group having from 2 to 4 carbon atoms, or an unsubstituted alkoxy group having from 2 to 4 carbon atoms, and more preferably a fluorine atom, or an unsubstituted alkoxy group having from 2 to 4 carbon atoms. As the alkyl group and alkenyl group which may be substituted with a halogen atom, from the viewpoint of oxidation resistance, an alkyl group having 1 to 3 carbon atoms and an alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom are preferred, an alkyl group having 1 to 2 carbon atoms and an alkenyl group having 2 to 3 carbon atoms which may be substituted with a halogen atom are more preferred, a methyl group and an ethyl group which may be substituted with a halogen atom are even more preferred, an unsubstituted methyl group and an unsubstituted ethyl group are even more preferred, and an unsubstituted methyl group is particularly preferred.

[0045] The compound containing the anion represented by general formula (2) is usually an acid or a salt. The compound containing the anion represented by general formula (2) is preferably a salt, and the counter cation is preferably an alkali metal cation such as a lithium cation, a sodium cation, or a potassium cation, and more preferably a lithium cation.

[0046] Specific examples of the anion (B) represented by general formula (2) include sulfate anions such as methyl sulfate anion, ethyl sulfate anion, and n-propyl sulfate anion; and sulfonate anions such as fluorosulfonate anion, methanesulfonate anion, ethanesulfonate anion, and n-propanesulfonate anion. Among these, sulfonate anions are preferred, with one or more selected from fluorosulfonate anion, methyl sulfate anion, ethyl sulfate anion, and n-propyl sulfate anion being more preferred, with one or more selected from fluorosulfonate anion and methyl sulfate anion being even more preferred, and fluorosulfonate anion being particularly preferred. The anion (B) represented by general formula (2) can be used alone or in combination of two or more in any ratio.

[0047] The content of the anion (B) represented by general formula (2) is not particularly limited and may be any content as long as it does not impair the effects of the present invention. The content is usually 0.001% by mass or more, preferably 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1.5% by mass or less, based on the total amount (100% by mass) of the nonaqueous electrolyte solution. The content of the compound (B) represented by general formula (2) in 100% by mass of the nonaqueous electrolyte solution is usually 0.001% by mass or more and 10% by mass or less, preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.001% by mass or more and 2% by mass or less, more preferably 0.001% by mass or more and 1.5% by mass or less, and more preferably 0.01% by mass or more and 1.5% by mass or less. In the nonaqueous electrolyte solution, the mass ratio [(A) / (B)] of the content of the compound (A) represented by the general formula (1) to the content of the anion (B) represented by the general formula (2) is 0.01 or more, preferably 0.05 or more, more preferably 0.1 or more, even more preferably 0.15 or more, still more preferably 0.2 or more, and is 1.2 or less, preferably 1.0 or less, more preferably 0.9 or less, even more preferably 0.8 or less, still more preferably 0.7 or less, from the viewpoint of achieving a sufficient effect of improving the cycle characteristics of the nonaqueous electrolyte battery, suppressing an increase in resistance, and improving the discharge power capacity. The mass ratio [(A) / (B)] of the content of the compound (A) represented by the general formula (1) to the content of the anion (B) represented by the general formula (2) is 0.01 or more and 2.0 or less, preferably 0.01 or more and 1.9 or less, more preferably 0.01 or more and 1.8 or less, more preferably 0.01 or more and 1.7 or less, and more preferably 0.01 or more and 1.6 or less. The anion (B) can be identified and its content measured by nuclear magnetic resonance (NMR) spectroscopy.

[0048] [1-2. Electrolytes] <Lithium salt> A lithium salt is usually used as the electrolyte in the non-aqueous electrolyte solution. There are no particular limitations on the lithium salt, and any lithium salt can be used. However, lithium salts corresponding to [1-1-2. Anion (B) represented by general formula (2)] are excluded. Specific examples thereof include lithium fluoroborates, lithium fluorophosphates, lithium tungstates, lithium carboxylates, lithium imide salts, lithium methide salts, lithium oxalate salts, and fluorine-containing organic lithium salts.

[0049] Among these, from the viewpoint of improving low-temperature output characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, cycle characteristics, etc., lithium fluoroborates such as LiBF4; lithium fluorophosphates such as LiPF6, Li2PO3F, and LiPO2F2; lithium imide salts such as LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, and LiN(C2F5SO2)2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, and lithium cyclic 1,3-perfluoropropanedisulfonylimide; Preferred lithium methide salts include LiC(FSO2)3, LiC(CF3SO2)3, and LiC(C2F5SO2)3; and preferred lithium oxalate salts include lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, and lithium tris(oxalato)phosphate, with one or more selected from LiPF6, LiN(FSO2)2, and lithium bis(oxalato)borate being more preferred, and LiPF6 being particularly preferred.

[0050] The above electrolyte salts can be used alone or in combination of two or more kinds in any ratio. The combination of two or more electrolyte salts is not particularly limited, and examples include a combination of LiPF6 and LiN(FSO2)2, a combination of LiPF6 and LiBF4, a combination of LiPF6 and LiN(CF3SO2)2, a combination of LiBF4 and LiN(FSO2)2, a combination of LiBF4, LiPF6 and LiN(FSO2)2, etc. Among these, the combination of LiPF6 and LiN(FSO2)2, the combination of LiPF6 and LiBF4, and the combination of LiBF4, LiPF6 and LiN(FSO2)2 are preferred.

[0051] The total concentration of the electrolyte is not particularly limited, but from the viewpoint of ensuring that the electrical conductivity ensures proper battery operation and sufficient output characteristics, it is usually 8 mass% or more, preferably 8.5 mass% or more, and more preferably 9 mass% or more, relative to the total amount of the nonaqueous electrolyte solution, and is usually 18 mass% or less, preferably 17 mass% or less, and more preferably 16 mass% or less.

[0052] [1-3. Non-aqueous solvents] The non-aqueous electrolyte solution, like a general non-aqueous electrolyte solution, usually contains a non-aqueous solvent that dissolves the above-mentioned electrolyte as its main component. The non-aqueous solvent used is not particularly limited as long as it can dissolve the above-mentioned electrolyte, and known organic solvents can be used. Examples of the organic solvent include saturated cyclic carbonates, chain carbonates, chain carboxylic acid esters, cyclic carboxylic acid esters, ether-based compounds, and sulfone-based compounds, and are not particularly limited thereto. However, it is preferable that the organic solvent contains a chain carboxylic acid ester.

[0053] The organic solvents can be used alone or in combination of two or more kinds in any ratio. The combination of two or more organic solvents is not particularly limited, and examples thereof include a combination of a saturated cyclic carbonate and a chain carboxylic acid ester, a combination of a cyclic carboxylic acid ester and a chain carbonate, and a combination of a saturated cyclic carbonate, a chain carbonate and a chain carboxylic acid ester, etc. Among these, a combination of a saturated cyclic carbonate and a chain carbonate, and a combination of a saturated cyclic carbonate, a chain carbonate and a chain carboxylic acid ester are preferred.

[0054] [1-3-1. Saturated cyclic carbonates] Examples of saturated cyclic carbonates include those having an alkylene group having 2 to 4 carbon atoms, and from the viewpoint of improving battery characteristics resulting from an improved degree of lithium ion dissociation, saturated cyclic carbonates having 2 to 3 carbon atoms are preferred. Specific examples of saturated cyclic carbonates include ethylene carbonate, propylene carbonate, butylene carbonate, etc. Among these, ethylene carbonate or propylene carbonate is preferred, and ethylene carbonate, which is less susceptible to oxidation and reduction, is more preferred. The saturated cyclic carbonates can be used alone or in combination of two or more in any ratio.

[0055] The content of the saturated cyclic carbonate is not particularly limited and may be any content as long as it does not impair the effects of the present invention. The content of the saturated cyclic carbonate is usually 3% by volume or more, preferably 5% by volume or more, based on the total amount of the nonaqueous solvent, and is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting the content within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the nonaqueous electrolyte solution can be avoided, and the large-current discharge characteristics, stability with respect to the negative electrode, and cycle characteristics of the nonaqueous electrolyte secondary battery tend to be in good ranges, and the oxidation / reduction resistance of the nonaqueous electrolyte solution and stability during high-temperature storage tend to be improved. In this specification, "volume %" refers to volume % at 25°C and 1 atmosphere.

[0056] [1-3-2. Chain carbonate] As the chain carbonate, for example, one having 3 to 7 carbon atoms is usually used, and in order to adjust the viscosity of the electrolyte solution within an appropriate range, a chain carbonate having 3 to 5 carbon atoms is preferably used. Specific examples of chain carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, etc., and preferably one or more selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Furthermore, chain carbonates having fluorine atoms (hereinafter also referred to as "fluorinated chain carbonates") can also be suitably used. The number of fluorine atoms in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has multiple fluorine atoms, the multiple fluorine atoms may be bonded to the same carbon or different carbons. Examples of the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives such as fluoromethyl methyl carbonate; fluorinated ethyl methyl carbonate derivatives such as 2-fluoroethyl methyl carbonate; and fluorinated diethyl carbonate derivatives such as ethyl-(2-fluoroethyl) carbonate. The chain carbonates can be used alone or in combination of two or more kinds in any ratio.

[0057] The content of the chain carbonate is not particularly limited, but from the viewpoint of keeping the viscosity of the nonaqueous electrolyte solution within an appropriate range, suppressing a decrease in ionic conductivity, and ultimately improving the output characteristics of the nonaqueous electrolyte secondary battery, the content is usually 15% by volume or more, preferably 20% by volume or more, and more preferably 25% by volume or more, relative to the total amount of the nonaqueous solvent in the nonaqueous electrolyte solution, and is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. Furthermore, by combining a specific chain carbonate with ethylene carbonate in a specific content, the battery performance can be significantly improved. For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonates, the content of ethylene carbonate is arbitrary as long as it does not impair the effects of the present invention, but from the viewpoint of improving high-temperature stability and suppressing gas generation, the content of ethylene carbonate is usually 15% by volume or more, preferably 20% by volume or more, and usually 45% by volume or less, preferably 40% by volume or less, based on the total amount of solvent in the non-aqueous electrolyte solution. The content of dimethyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, based on the total amount of non-aqueous solvent in the non-aqueous electrolyte solution. The content of ethyl methyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, based on the total amount of non-aqueous solvent in the non-aqueous electrolyte solution.

[0058] [1-3-3. Chain carboxylic acid esters] Examples of chain carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, methyl valerate, methyl isobutyrate, ethyl isobutyrate, and methyl pivalate. Among these, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate are preferred from the viewpoint of improving battery characteristics. Chain carboxylic acid esters in which some of the hydrogen atoms of the above compounds are substituted with fluorine atoms (e.g., methyl trifluoroacetate, ethyl trifluoroacetate, etc.) can also be suitably used. The amount of the chain carboxylic acid ester is usually 1% by volume or more, preferably 5% by volume or more, and more preferably 15% by volume or more, based on the total amount of the nonaqueous solvent, from the viewpoints of improving the electrical conductivity of the nonaqueous electrolyte and enhancing the large-current discharge characteristics of the nonaqueous electrolyte battery. The upper limit of the amount is usually 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoints of maintaining an appropriate viscosity of the nonaqueous electrolyte, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and ensuring good large-current discharge characteristics of the nonaqueous electrolyte secondary battery.

[0059] [1-3-4. Cyclic carboxylic acid esters] Examples of cyclic carboxylic acid esters include γ-butyrolactone and γ-valerolactone. Among these, γ-butyrolactone is more preferred. Cyclic carboxylic acid esters in which some of the hydrogen atoms in the above-mentioned compounds are substituted with fluorine atoms can also be used suitably. The amount of the cyclic carboxylic acid ester is usually 1% by volume or more, preferably 5% by volume or more, and more preferably 15% by volume or more, based on the total amount of the nonaqueous solvent, from the viewpoints of improving the electrical conductivity of the nonaqueous electrolyte and enhancing the large-current discharge characteristics of the nonaqueous electrolyte battery. The upper limit of the amount is usually 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoints of maintaining an appropriate viscosity of the nonaqueous electrolyte, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and ensuring good large-current discharge characteristics of the nonaqueous electrolyte secondary battery.

[0060] [1-3-5. Ether compounds] Preferred ether compounds are chain ethers having 3 to 10 carbon atoms, such as dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether, and cyclic ethers having 3 to 6 carbon atoms, such as tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, and 1,4-dioxane. Some hydrogen atoms in the ether compounds may be substituted with fluorine atoms. Among these, as the chain ethers having 3 to 10 carbon atoms, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferred from the viewpoints of providing a high solvation ability for lithium ions, improving ionic dissociation, low viscosity, and high ionic conductivity, and as the cyclic ethers having 3 to 6 carbon atoms, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, and the like are preferred from the viewpoints of providing high ionic conductivity.

[0061] The content of the ether-based compound is arbitrary as long as it does not impair the effects of the present invention, but is usually 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less, based on the total amount of nonaqueous solvent in the nonaqueous electrolyte. If the content of the ether-based compound is within the above range, it is easy to ensure the effect of improving the degree of lithium ion dissociation by the ether-based compound and improving ionic conductivity due to the reduced viscosity of the nonaqueous electrolyte. Furthermore, when the negative electrode active material is a carbon-based material, the phenomenon of co-insertion of chain ethers with lithium ions can be suppressed, thereby allowing the input / output characteristics and charge / discharge rate characteristics to be within appropriate ranges.

[0062] [1-3-6. Sulfone compounds] The sulfone compound is not particularly limited and may be a cyclic sulfone or a chain sulfone. In the case of a cyclic sulfone, the carbon number is usually 3 to 6, preferably 3 to 5, and in the case of a chain sulfone, the carbon number is usually 2 to 6, preferably 2 to 5. In addition, the number of sulfonyl groups in one molecule of the sulfone compound is not particularly limited, but is usually 1 or 2. Examples of cyclic sulfones include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones, and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. Among these, from the viewpoints of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferred, and tetramethylene sulfones (sulfolanes) are even more preferred. Preferred sulfolanes are sulfolane and sulfolane derivatives, and preferred sulfolane derivatives are those in which one or more hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring are substituted with a fluorine atom, an alkyl group, or a fluorine-substituted alkyl group. Among these, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, and the like are preferred because they have high ionic conductivity and high input / output.

[0063] Examples of the chain sulfone include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, pentafluoroethyl methyl sulfone, etc. Among these, dimethyl sulfone, ethyl methyl sulfone, and monofluoromethyl methyl sulfone are preferred in terms of improving the high-temperature storage stability of the electrolyte solution. The content of the sulfone-based compound is arbitrary as long as it does not impair the effects of the present invention. From the viewpoint of improving high-temperature storage stability, the content is usually 0.3 vol% or more, preferably 0.5 vol% or more, more preferably 1 vol% or more, relative to the total amount of the nonaqueous solvent in the nonaqueous electrolyte solution, and is usually 40 vol% or less, preferably 35 vol% or less, more preferably 30 vol% or less.

[0064] [1-4. Auxiliaries] The non-aqueous electrolyte solution of the present invention may contain various auxiliary agents within the range that does not impair the effects of the present invention. As the auxiliary agent, any conventionally known agent can be used. The auxiliary agent can be used alone or in combination of two or more in any ratio. Examples of the auxiliary include cyclic carbonates having a carbon-carbon unsaturated bond, fluorine-containing cyclic carbonates, compounds having an isocyanate group, compounds having an isocyanuric acid skeleton, compounds having a cyano group, sulfur-containing organic compounds, phosphorus-containing organic compounds, silicon-containing compounds, aromatic compounds, fluorine-free carboxylic acid esters, cyclic compounds having an ether bond, carboxylic acid anhydrides, borates, oxalates, monofluorophosphates, difluorophosphates, etc. Examples include compounds described in WO 2015 / 111676. The content of the auxiliary agent is not particularly limited and may be any amount as long as it does not impair the effects of the present invention, but is usually 0.001% by mass or more, preferably 0.01% by mass or more, and more preferably 0.1% by mass or more, relative to the total amount of the nonaqueous electrolyte solution, and is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably less than 1% by mass.

[0065] The cyclic compound having an ether bond can be used as an auxiliary agent in a non-aqueous electrolyte solution, and some of them can also be used as a non-aqueous solvent as described in [1-3. Non-aqueous solvent]. When a cyclic compound having an ether bond is used as an auxiliary agent, it is preferably used in an amount of less than 4% by mass. Borates, oxalates, monofluorophosphates, and difluorophosphates can be used as auxiliary agents in non-aqueous electrolyte solutions, and as described in [1-2. Electrolyte], some of these compounds can also be used as electrolytes. When these compounds are used as auxiliary agents, it is preferably used in an amount of less than 3% by mass. Among these, fluorine-containing cyclic carbonates and cyclic carbonates having a carbon-carbon unsaturated bond are preferred, and fluorine-containing cyclic carbonates are more preferred from the viewpoint of easily forming a stable interface protective coating.

[0066] [1-4-1. Fluorine-containing cyclic carbonates] The fluorine-containing cyclic carbonate is not particularly limited as long as it has a cyclic carbonate structure and contains a fluorine atom. Examples of fluorine-containing cyclic carbonates include fluorinated cyclic carbonates having an alkylene group with 2 to 6 carbon atoms, and derivatives thereof, such as fluorinated ethylene carbonate (hereinafter also referred to as "fluorinated ethylene carbonate") and derivatives thereof. Examples of derivatives of fluorinated ethylene carbonate include fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group with 1 to 4 carbon atoms). Among these, fluorinated ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferred.

[0067] Examples of fluorinated ethylene carbonates having 1 to 8 fluorine atoms and derivatives thereof include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, and 4,4-difluoro-5,5-dimethylethylene carbonate. Among these, from the viewpoint of imparting high ionic conductivity to the electrolyte and facilitating the formation of a stable interface protective coating, one or more selected from monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate are preferred. The fluorine-containing cyclic carbonates can be used alone or in combination of two or more kinds in any ratio.

[0068] The content of the fluorine-containing cyclic carbonate (total amount when two or more types are used) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 0.8% by mass or more, relative to 100% by mass of the nonaqueous electrolyte solution, and is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less. When the fluorine-containing cyclic carbonate is used as the non-aqueous solvent, the content thereof is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more, and is preferably 50% by volume or less, more preferably 35% by volume or less, and even more preferably 25% by volume or less, based on 100% by volume of the non-aqueous solvent.

[0069] When the non-aqueous electrolyte solution contains LiPF6, the mass ratio of the total content of fluorine-containing cyclic carbonate to the content of LiPF6 (fluorine-containing cyclic carbonate / LiPF6) is usually 0.00005 or more, preferably 0.001 or more, more preferably 0.01 or more, even more preferably 0.02 or more, and even more preferably 0.025 or more, from the viewpoint of improving the energy device characteristics, particularly durability characteristics, and minimizing the decomposition side reaction of LiPF6 within the energy device system, and is also usually 0.5 or less, preferably 0.45 or less, more preferably 0.4 or less, and even more preferably 0.35 or less.

[0070] [2.Nonaqueous electrolyte battery] The nonaqueous electrolyte battery of the present invention is a nonaqueous electrolyte battery, preferably a lithium battery, that includes a positive electrode having a positive electrode active material capable of absorbing and releasing metal ions, a negative electrode, and the nonaqueous electrolyte of the present invention. Note that, within the scope of the present invention, other nonaqueous electrolytes may be mixed with the nonaqueous electrolyte of the present invention.

[0071] [2-1. Lithium battery] The lithium battery according to the present invention comprises a positive electrode having a current collector and a positive electrode active material layer provided on the current collector, a negative electrode having a current collector and a negative electrode active material layer provided on the current collector and capable of absorbing and releasing lithium ions, and the nonaqueous electrolyte solution according to the present invention. In the present invention, the term "lithium battery" is a general term for lithium ion primary batteries and lithium ion secondary batteries. The lithium battery has the same configuration as conventionally known lithium batteries except for the non-aqueous electrolyte solution of the present invention. Typically, the lithium battery has a configuration in which a positive electrode and a negative electrode are stacked via a porous membrane (separator) impregnated with a non-aqueous electrolyte solution, and these are housed in a case (exterior body).

[0072] [2-2. Positive electrode] The positive electrode has a positive electrode active material capable of absorbing and desorbing lithium ions on at least a portion of the surface of a current collector. The positive electrode active material preferably contains a lithium transition metal compound. [2-2-1. Positive electrode active material]

[0073] [2-2-1-1. Lithium transition metal compounds] The lithium transition metal compound is a compound having a structure capable of desorbing and inserting lithium ions, and examples thereof include sulfides, phosphate compounds, silicate compounds, borate compounds, lithium transition metal composite oxides, etc. Among these, phosphate compounds and lithium transition metal composite oxides are preferred, and lithium transition metal composite oxides are more preferred. Examples of lithium transition metal composite oxides include those having a spinel structure that allows three-dimensional diffusion and those having a layered structure that allows two-dimensional diffusion of lithium ions.

[0074] A lithium transition metal composite oxide having a spinel structure is generally represented by the following formula (11). Li x M2O4(11) [In formula (11), x is 1≦x≦1.5, and M represents one or more transition metal elements.] Specific examples of the oxide represented by formula (11) include LiMn2O4, LiCoMnO4, and LiNi 0.5 Mn 1.5 O4, LiCoVO4, etc.

[0075] A lithium transition metal composite oxide having a layered structure is generally represented by the following composition formula (12). Li 1+x MO2(12) (In formula (12), x is −0.1≦x≦0.5, and M represents one or more transition metal elements.) Specific examples of oxides represented by formula (12) include LiCoO2, LiNiO2, and LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.80 Co 0.15 Al 0.05 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, Li 1.05 Ni 0.33 Co 0.33 Mn 0.33 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.91 Co 0.06 Mn 0.03 O2, LiNi 0.91 Co 0.06 Al 0.03 O2, LiNi 0.90 Co 0.03 Al 0.07 Examples include O2.

[0076] Among these, from the viewpoint of improving battery capacity, lithium transition metal composite oxides having a layered structure are preferred, and lithium transition metal composite oxides represented by the following formula (13) are more preferred. Li a1 Ni b1 M c1 O2(13) [In formula (13), a1, b1, and c1 are 0.90≦a1≦1.10, 0.40≦b1≦0.98, and 0≦c1≦0.20, respectively, and b1+c1=1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.] From the viewpoint of suppressing the amount of gas stored at a battery voltage of 4.3 V or higher, b1 in formula (13) is preferably 0.40≦b1≦0.80, more preferably 0.40≦b1≦0.75, and even more preferably 0.40≦b1≦0.55.

[0077] In particular, from the viewpoint of the structural stability of the lithium transition metal composite oxide, a lithium transition metal composite oxide represented by the following formula (14) is preferred. Li a2 Ni b2 Co c2 M d2 O2(14) [In formula (14), a2, b2, c2, and d2 are 0.90≦a2≦1.10, 0.40≦b2≦0.98, 0.01≦c2≦0.06, and 0.01≦d2≦0.04, respectively, and b2+c2+d2=1. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.] From the viewpoint of suppressing the amount of gas stored at a battery voltage of 4.3 V or higher, b2 in formula (14) is preferably 0.40≦b2≦0.80, more preferably 0.40≦b2≦0.75, and still more preferably 0.40≦b2≦0.55. The lithium transition metal composite oxide represented by the above formula (14) is LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.80 Co 0.15 Al 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.91 Co 0.06 Mn 0.03 O2, LiNi 0.91 Co 0.06 Al0.03 O2, LiNi 0.90 Co 0.03 Al 0.07 O2 etc. is preferred, LiNi 0.80 Co 0.15 Al 0.05 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2 is more preferable, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2 is more preferable, LiNi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2 and the like are more preferred. In the above formulas (11) to (13), from the viewpoint of increasing the structural stability of the lithium transition metal oxide and suppressing structural deterioration during repeated charge and discharge, M preferably contains Mn or Al, and more preferably contains Mn. In the above formula (14), M preferably contains Mn or Al, from the viewpoint of increasing the structural stability of the lithium transition metal oxide and suppressing structural deterioration during repeated charge and discharge. The positive electrode active material is identified by wet decomposition of the sample followed by ICP emission spectroscopy.

[0078] [2-2-1-2. Introduction of different elements] The lithium transition metal composite oxide may also contain elements (foreign elements) other than the elements contained in any of the above formulas (11) to (14).

[0079] [2-2-1-3. Surface coating] The positive electrode may be one in which a substance (surface-adhering substance) having a different composition from the positive electrode active material is attached to the surface of the positive electrode active material. Examples of the surface-attaching substance include oxides such as aluminum oxide, sulfates such as lithium sulfate, carbonates such as lithium carbonate, etc. These surface-attaching substances can be attached to the surface of the positive electrode active material by, for example, dissolving or suspending them in a solvent, adding them to the positive electrode active material by impregnation, and drying them. The amount of the surface-adhering substance is preferably 1 μmol / g or more, more preferably 10 μmol / g or more, and usually preferably 1 mmol / g or less, relative to the positive electrode active material. In this specification, a positive electrode active material having the above-mentioned surface-adhering substance attached to its surface is also referred to as a "positive electrode active material."

[0080] [2-2-1-4. Blend] The positive electrode active material may be used alone or in combination of two or more kinds in any ratio. do.

[0081] [2-2-2. Positive electrode structure and manufacturing method] The positive electrode using the positive electrode active material can be manufactured by a conventional method. That is, the positive electrode active material and a binder, and optionally a conductive material and a thickener, are mixed in a dry state to form a sheet, which is then pressed onto the positive electrode current collector, or these materials are dissolved or dispersed in a liquid medium such as an aqueous solvent or an organic solvent to form a slurry, which is then applied to the positive electrode current collector and dried to form a positive electrode active material layer on the current collector. A positive electrode can also be obtained by a coating method. For example, the above-mentioned positive electrode active material may be roll-molded into a sheet electrode, or may be compression-molded into a pellet electrode. Hereinafter, the case where the slurry is sequentially applied to the positive electrode current collector and then dried will be described.

[0082] [2-2-2-1. Content of positive electrode active material] The content of the positive electrode active material in the positive electrode active material layer is usually 80% by mass or more and 99.5% by mass or less.

[0083] [2-2-2-2. Electrode density] The positive electrode active material layer obtained by coating and drying is preferably compacted by a hand press, a roller press, or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer present on the current collector is usually 1.5 g / cm. 3 More preferably, it is 2.0 g / cm or more. 3 More preferably, it is 3.0 g / cm 3 or more, usually 4.5 g / cm 3 More preferably, it is 4.0 g / cm or less. 3 or less, and particularly preferably 3.5 g / cm 3 The following is the result. The density of the positive electrode active material layer is measured by measuring the thickness and weight of the positive electrode active material layer.

[0084] [2-2-2-3.Conductive materials] Any known conductive material can be used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; and carbon-based materials such as amorphous carbon such as needle coke. The conductive material can be used alone or in combination of two or more types in any ratio. The conductive material is typically used so that it is contained in the positive electrode active material layer in an amount of 0.01% by mass to 50% by mass.

[0085] [2-2-2-4. Binder] When forming the positive electrode active material layer by a coating method, the binder used in producing the positive electrode active material layer is not particularly limited as long as it is a material that can be dissolved or dispersed in a liquid medium for the slurry. For example, in view of weather resistance, chemical resistance, heat resistance, flame retardancy, etc., fluorine-based resins such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, etc.; CN group-containing polymers such as polyacrylonitrile, polyvinylidene cyanide, etc. are preferred. Also usable are mixtures, modified products, derivatives, random copolymers, alternating copolymers, graft copolymers, block copolymers, etc. The binder may be used alone or in combination of two or more kinds in any ratio. Furthermore, when a resin is used as a binder, the weight-average molecular weight of the resin is optional as long as it does not impair the effects of the present invention, and is usually from 10,000 to 3,000,000. When the molecular weight is in this range, the strength of the electrode is improved, and the electrode can be suitably formed. The proportion of the binder in the positive electrode active material layer is usually 0.1 mass % or more and 80 mass % or less.

[0086] [2-2-2-5. Current collector] The material of the positive electrode current collector is not particularly limited, and any known material can be used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, with aluminum being preferred. The current collector may be in the form of a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punched metal, a foamed metal, or the like. Among these, a metal foil or a metal thin film is preferred. The metal thin film may be suitably formed into a mesh shape. When the current collector of the positive electrode is in the form of a plate or film, the thickness of the current collector is optional, but is usually 1 μm or more and 1 mm or less.

[0087] [2-2-2-6. Thickness of the positive electrode plate] The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the positive electrode active material layer obtained by subtracting the thickness of the current collector from the thickness of the positive electrode plate is usually 10 μm or more and 500 μm or less on one side of the current collector.

[0088] [2-2-2-7. Surface coating of positive electrode plate] The positive electrode plate may have a substance of a different composition from the positive electrode plate attached to its surface, and the substance may be the same as the surface-attached substance that may be attached to the surface of the positive electrode active material.

[0089] [2-3. Negative electrode] The negative electrode has a negative electrode active material on at least a portion of the surface of a current collector. [2-3-1. Negative electrode active material] The negative electrode active material used in the negative electrode is not particularly limited as long as it can electrochemically absorb and release metal ions. Specific examples include (i) carbon-based materials, (ii) particles containing a metal that can be alloyed with Li, (iii) lithium-containing metal composite oxide materials, and (iv) mixtures thereof. Among these, (i) carbon-based materials, (ii) particles containing a metal that can be alloyed with Li, and (v) mixtures of particles containing a metal that can be alloyed with Li and graphite particles are preferred because of their excellent cycle characteristics and safety, as well as excellent continuous charge characteristics. It is preferable to do so. These may be used alone or in combination of two or more in any ratio. The negative electrode active material is identified and its content is measured by alkali fusion of the sample and then ICP emission spectroscopy.

[0090] [2-3-1-1. Carbon-based materials] (i) Examples of carbonaceous materials include natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, and resin-coated graphite. Of these, natural graphite is preferred. The carbonaceous materials can be used alone or in combination of two or more in any ratio. Examples of natural graphite include scaly graphite, flake graphite, and / or graphite particles obtained by subjecting such graphite to treatment such as spheroidization or densification. Among these, spherical or ellipsoidal graphite particles that have been subjected to spheroidization treatment are preferred from the viewpoint of particle packing properties or charge / discharge rate characteristics. The average particle size (d50) of the graphite particles is usually 1 μm or more and 100 μm or less.

[0091] [2-3-1-2. Physical properties of carbon-based materials] The carbonaceous material as the negative electrode active material preferably satisfies at least one of the characteristics such as physical properties and shape shown in the following items (1) to (4), and more preferably satisfies several items at the same time. (1) X-ray diffraction parameters The d value (interlayer distance) of the lattice plane (002 plane) of carbon-based materials determined by X-ray diffraction using the Gakushin method is usually 0.335 nm or more and 0.360 nm or less. Also, the crystallite size (Lc) of carbon-based materials determined by X-ray diffraction using the Gakushin method is 1.0 nm or more. (2) Volume-based average particle size The volume-based average particle size of the carbon-based material is the volume-based average particle size (median diameter) determined by a laser diffraction / scattering method, and is usually 1 μm or more and 100 μm or less. (3) Raman R value, Raman half-width The Raman R value of a carbon-based material is a value measured using argon ion laser Raman spectroscopy, and is usually 0.01 or more and 1.5 or less. In addition, the 1580 cm -1 The Raman half-width in the vicinity is not particularly limited, but is usually 10 cm -1 More than 100cm -1 The following is the result. (4) BET specific surface area The BET specific surface area of ​​a carbon-based material is the value of the specific surface area measured using the BET method, and is usually 0.1 m 2 ·g -1 More than 100m 2 ·g -1 The following is the result. The negative electrode active material may contain two or more carbonaceous materials with different properties, where the properties refer to one or more characteristics selected from the group consisting of X-ray diffraction parameters, volume-based average particle size, Raman R value, Raman half-width, and BET specific surface area. Examples of containing two or more types of carbon-based materials with different properties include cases where the volume-based particle size distribution is not symmetric about the median diameter, cases where two or more types of carbon-based materials with different Raman R values are contained, and cases where X-ray diffraction parameters are different, etc.

[0092] [Particles Containing a Metal Capable of Alloying with Li] (ii) Any of the conventionally known particles containing a metal capable of alloying with Li can be used, but from the viewpoints of capacity and cycle life, for example, particles of a metal or its compound selected from the group consisting of Sb, Si, Sn, Al, As, and Zn are preferable. Further, when the particles containing a metal capable of alloying with Li contain two or more types of metals, the particles may be alloy particles composed of an alloy of these metals. Examples of the compound of a metal capable of alloying with Li include metal oxides, metal nitrides, metal carbides, etc. The compound may contain two or more types of metals capable of alloying with Li. Among these, metal Si (hereinafter also referred to as "Si") or a Si-containing inorganic compound is preferable in terms of increasing the capacity. Also, the compound of a metal capable of alloying with Li may already be alloyed with Li during the production of the negative electrode described later, and as the compound, Si or a Si-containing inorganic compound is preferable in terms of increasing the capacity. In this specification, Si or a Si-containing inorganic compound is collectively referred to as a Si compound. Examples of the Si compound include SiO x (0 ≦ x ≦ 2), etc. Examples of the metal compound alloyed with Li include Li y Si (0 < y ≦ 4.4), Li<…>​​​​​​​50 ) is usually 0.01 μm or more and 10 μm or less from the viewpoint of cycle life.

[0093] [2-3-1-4. Mixture of particles containing metals capable of alloying with Li and graphite particles] (v) The mixture of particles containing a metal capable of being alloyed with Li and graphite particles is prepared by the method of (ii) above. The material may be a mixture in which particles containing a metal capable of being alloyed with Li and the graphite particles are mixed together in the state of independent particles, or a composite in which particles containing a metal capable of being alloyed with Li are present on the surface or inside of graphite particles. The content of the particles containing a metal capable of being alloyed with Li relative to the total of the particles containing a metal capable of being alloyed with Li and the graphite particles is usually 1% by mass or more and 99% by mass or less.

[0094] [2-3-1-5. Lithium-containing metal composite oxide materials] (iii) The lithium-containing metal composite oxide material is not particularly limited as long as it can absorb and release lithium ions. Specifically, from the viewpoint of high current density charge / discharge characteristics, a lithium-containing metal composite oxide material containing titanium is preferred, a composite oxide of lithium and titanium (hereinafter also referred to as "lithium-titanium composite oxide") is more preferred, and a lithium-titanium composite oxide having a spinel structure is even more preferred because it significantly reduces output resistance. Furthermore, the lithium and / or titanium of the lithium titanium composite oxide may be substituted with another metal element, for example, at least one element selected from the group consisting of Al, Ga, Cu, and Zn. As a lithium titanium composite oxide, Li 4 / 3 Ti 5 / 3 O4, Li1Ti2O4 and Li 4 / 5 Ti 11 / 5 O4 is preferred. In addition, examples of lithium titanium composite oxides in which part of lithium and / or titanium is substituted with other elements include Li 4 / 3 Ti 4 / 3 Al 1 / 3 O4 is also preferred.

[0095] [2-3-2. Negative electrode structure and manufacturing method] The negative electrode may be produced by any known method as long as it does not impair the effects of the present invention. For example, the negative electrode may be produced by adding a binder, a liquid medium such as an aqueous solvent or an organic solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to the negative electrode active material to form a slurry, which is then applied to a current collector, dried, and pressed to form a negative electrode active material layer.

[0096] [2-3-2-1. Content of negative electrode active material] The content of the negative electrode active material in the negative electrode active material layer is usually 80% by mass or more and 99.5% by mass or less.

[0097] [2-3-2-2. Electrode density] The negative electrode active material layer obtained by coating and drying is preferably compacted by a hand press, a roller press or the like in order to increase the packing density of the negative electrode active material. There are no particular restrictions on the electrode structure when the negative electrode active material is made into an electrode, but the density of the negative electrode active material layer on the current collector is usually 1 g cm -3 More than 2.2g cm -3 is less than 1.2 g cm -3 More than 2.0g cm -3 Preferably less than 1.4 g cm -3 More than 1.8g cm -3 The following is more preferred: The density of the negative electrode active material layer is measured by measuring the thickness and weight of the negative electrode active material layer.

[0098] [2-3-2-3. Thickener] Thickeners are usually used to adjust the viscosity of the slurry. Examples of thickeners include, but are not limited to, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, etc. These may be used alone or in combination of two or more in any ratio. When a thickener is used, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more and 5% by mass or less.

[0099] [2-3-2-4. Binder] The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable in the non-aqueous electrolyte solution and the liquid medium used in producing the electrode. Specific examples thereof include rubber-like polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), and ethylene-propylene rubber, as well as fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and tetrafluoroethylene-ethylene copolymers. These may be used alone or in combination of two or more in any ratio. The ratio of the binder to the negative electrode active material is usually 0.1 mass % or more and 20 mass % or less. In particular, when the binder contains a rubber-like polymer such as SBR as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass to 5% by mass, and when the binder contains a fluorine-based polymer such as polyvinylidene fluoride as a main component, the ratio of the binder to the negative electrode active material is usually 1% by mass to 15% by mass.

[0100] [2-3-2-5. Current collector] Any known current collector can be used to support the negative electrode active material. Examples of the negative electrode current collector include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel, but copper is particularly preferred from the standpoints of ease of processing and cost. The negative electrode current collector may be in the form of a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punched metal, a foamed metal, or the like. Among these, a metal foil or a metal thin film is preferred. The metal thin film may be suitably formed into a mesh shape. When the negative electrode current collector is in the form of a plate or film, the thickness of the current collector is not limited, but is usually 1 μm or more and 1 mm or less.

[0101] [2-3-2-6. Thickness of negative electrode plate] The thickness of the negative electrode (negative electrode plate) is designed to match the positive electrode (positive electrode plate) to be used and is not particularly limited, but the thickness of the negative electrode active material layer, obtained by subtracting the thickness of the current collector from the thickness of the negative electrode material, is usually 15 μm or more and 300 μm or less.

[0102] [2-3-2-7. Surface coating of negative electrode plate] The negative electrode plate may have a surface to which a substance (surface-attached substance) having a different composition from the negative electrode active material is attached. Examples of the surface-attached substance include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate.

[0103] [2-4. Separator] A separator is usually interposed between the positive electrode and the negative electrode to prevent short circuits, and in this case, the non-aqueous electrolyte is usually impregnated into the separator before use. There are no particular restrictions on the material or shape of the separator, and any known material can be used as long as it does not impair the effects of the present invention.

[0104] [2-5.Battery design] [2-5-1. Electrode group] The electrode group may have either a laminated structure of the positive electrode plate and the negative electrode plate sandwiched between the separator, or a structure of the positive electrode plate and the negative electrode plate spirally wound with the separator sandwiched between them. The ratio of the volume of the electrode group to the internal volume of the battery (electrode group occupancy rate) is usually 40% to 90%.

[0105] [2-5-2. Current collection structure] When the electrode group has the aforementioned laminated structure, a structure in which the metal core portions of each electrode layer are bundled and welded to a terminal is preferably used. A structure in which multiple terminals are provided within the electrode to reduce resistance is also preferably used. When the electrode group has the aforementioned wound structure, the internal resistance can be reduced by providing multiple lead structures on each of the positive electrode and negative electrode and bundling them to a terminal.

[0106] [2-5-3.Protection elements] The protective element may be a PTC (Positive Temperature Coefficient) element whose resistance increases with heat generation due to excessive current, a thermal fuse, a thermistor, or a valve (current cutoff valve) that cuts off the current flowing in the circuit due to a sudden rise in the internal pressure or temperature of the battery when abnormal heat is generated. It is preferable to select the above protective element so that it will not operate under normal use at high current, and it is even more preferable to design it so that abnormal heat generation or thermal runaway does not occur even without the protective element.

[0107] [2-5-4. Exterior body] A non-aqueous electrolyte battery is generally constructed by housing the non-aqueous electrolyte of the present invention, a negative electrode, a positive electrode, a separator, etc. in an exterior body (exterior case). There are no limitations on this exterior body, and any known exterior body can be used as long as it does not impair the effects of the present invention. The material of the outer case is not particularly limited as long as it is stable against the nonaqueous electrolyte solution used, but from the viewpoints of weight reduction and cost, metals such as iron, aluminum, and aluminum alloys, or laminate films are preferably used. Iron is particularly preferred from the viewpoint of pressure resistance required to operate the current cutoff valve. Examples of exterior cases using the above metals include those in which metals are welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed, airtight structure, and those in which the above metals are used via a resin gasket to form a crimped structure.

[0108] [2-5-5. Shape] The shape of the exterior case may also be arbitrary, and may be, for example, cylindrical, square, laminated, coin-shaped, large, etc. In particular, a cylindrical shape is most preferable from the viewpoint of attaching a current cutoff valve. [Example]

[0109] Below are examples Reference example The present invention will be explained in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

[0110] Example 1 [Preparation of non-aqueous electrolyte] In a dry argon atmosphere, thoroughly dried LiPF6 was dissolved as an electrolyte at a concentration of 1.0 mol / L in a mixed solvent consisting of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (mixing volume ratio 30:30:40), and monofluoroethylene carbonate was further added as an auxiliary agent at 1.0 mass% relative to the total electrolyte solution to prepare a reference electrolyte solution. Furthermore, 1.6 mass % of 2-propynyl methanesulfonate and 1.2 mass % of lithium fluorosulfonate (LiFSO3) were added to the reference electrolyte to prepare a non-aqueous electrolyte.

[0111] [Preparation of positive electrode] Nickel-containing transition metal oxide (LiNi 0.50 Co 0.20 Mn 0.30 97 parts by mass of acetylene black (as a conductive material) and 1.5 parts by mass of polyvinylidene fluoride (as a binder) were mixed in N-methylpyrrolidone solvent using a disperser to form a slurry. This was uniformly applied to both sides of a 21 μm thick aluminum foil, dried, and then the density was 3.0 g / cm. 3 The positive electrode was formed by pressing the electrode so that the positive electrode was in a state of being oriented as follows:

[0112] [Preparation of negative electrode] The negative electrode active material was natural graphite powder, the thickener was an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose: 1% by mass), and the binder was an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber: 50% by mass). These materials were mixed in a disperser to form a slurry. This slurry was uniformly applied to one side of a 12 μm thick copper foil, dried, and then the density was 1.5 g / cm. 3 After drying, the negative electrode was pressed to a mass ratio of natural graphite, sodium carboxymethyl cellulose, and styrene-butadiene rubber of 98:1:1.

[0113] [Manufacturing non-aqueous electrolyte batteries (pouch type)] The above positive electrode, negative electrode, and polypropylene separator were stacked in this order to prepare a battery element. This battery element was inserted into a bag made of a laminate film in which both sides of aluminum (40 μm thick) were coated with a resin layer so that the positive and negative electrode terminals protruded. The nonaqueous electrolyte solution obtained above was then poured into the bag, which was then vacuum-sealed to prepare a pouch-type battery, which was a nonaqueous electrolyte battery.

[0114] < Reference Example 2. Comparative Examples 1 to 6 A nonaqueous electrolyte battery was fabricated in the same manner as in Example 1, except that the conditions in Example 1 were changed to those shown in Table 1.

[0115] <Evaluation of non-aqueous electrolyte batteries> [Stored gas volume] Example Reference example The nonaqueous electrolyte batteries obtained in the Example and Comparative Examples were sandwiched between glass plates to enhance adhesion between the electrodes, and then charged at 25°C for 4 hours at a constant current equivalent to 0.05 C, and then discharged to 2.8 V at a constant current of 0.2 C. Here, 1 C represents the current value at which the battery's reference capacity is discharged in 1 hour, 0.5 C represents a current value that is 1 / 2 times 1 C, and 0.2 C represents a current value that is 1 / 5 of 1 C. Next, the battery was charged to 4.1 V at a constant current equivalent to 0.1 C, discharged to 2.8 V at a constant current of 0.2 C, and then further charged at a constant current and constant voltage at 0.2 C to 4.1 V (cut off at 0.05 C), after which it was discharged to 2.8 V at a constant current of 0.2 C. It was then charged at a constant current and constant voltage at 0.2 C to 4.4 V (cut off at 0.05 C), after which it was discharged to 2.8 V at a constant current of 0.2 C. It was then again charged at a constant current and constant voltage at 0.2 C to 4.4 V (cut off at 0.05 C), after which it was discharged to 2.8 V at a constant current of 1.0 C, and then it was charged at a constant current and constant voltage at 0.2 C to 4.4 V (cut off at 0.05 C). The volume of each non-aqueous electrolyte battery after the pre-test charging and discharging was measured using Archimedes' principle. Reference exampleThe nonaqueous electrolyte batteries obtained in the comparative example and comparative example were again sandwiched between glass plates and stored at 60°C for one week. After removing the glass plates, the volume of each nonaqueous electrolyte battery was measured using Archimedes' principle. The volume change before and after the test was recorded as the amount of stored gas. Table 1 shows the relative values, with the amount of stored gas in Comparative Example 1 set to 100.

[0116] [Table 1]

[0117] From Table 1, Example 1 and Example 2, which are provided with an electrolyte solution containing a compound (A) represented by general formula (1) and an anion (B) represented by general formula (2), are shown. Reference Example The nonaqueous electrolyte battery of Example 2 has a better suppression rate of the amount of gas stored than the nonaqueous electrolyte battery of Comparative Example 1 having an electrolyte solution that does not contain compound (A) and anion (B), the nonaqueous electrolyte battery of Comparative Example 2 having an electrolyte solution that does not contain anion (B), and the battery of Comparative Example 3 having an electrolyte solution that does not contain compound (A), confirming the synergistic effect of compound (A) and anion (B). Reference Example 2 has a better suppression rate of the amount of gas stored than the nonaqueous electrolyte batteries of Comparative Examples 5 and 6, which are equipped with an electrolyte containing 2-propynyl methyl carbonate instead of compound (A). This shows that the effects of the present invention can be achieved by a nonaqueous electrolyte battery equipped with a nonaqueous electrolyte that uses, among triple bond-containing compounds, compound (A) represented by general formula (1) in combination with an anion (B). [Industrial Applicability]

[0118] By using the nonaqueous electrolyte solution of the present invention as the electrolyte of a nonaqueous electrolyte battery, malfunction of the current cutoff valve under normal use conditions can be suppressed and discharge power capacity can be improved. Therefore, the nonaqueous electrolyte solution of the present invention can be suitably used in all fields of electronic devices, such as those using nonaqueous electrolyte batteries. Specific examples of uses of the nonaqueous electrolyte secondary battery of the present invention include laptop computers, pen-input personal computers, mobile personal computers, e-book players, mobile phones, mobile fax machines, mobile copiers, mobile printers, mobile audio players, compact video cameras, headphone stereos, video movie players, LCD televisions, handheld vacuum cleaners, portable CD players, mini-discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting equipment, toys, game equipment, watches, power tools, flash devices, cameras, home backup power supplies, business backup power supplies, load-leveling power supplies, and natural energy storage power supplies.

Claims

1. A non-aqueous electrolyte solution containing a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2): 【Chemistry 1】 [In formula (1), X １ and X ２ each independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may be substituted with a hydrogen atom or a halogen atom. １ is a divalent atomic group selected from the group of structures represented by the following formula (1-2). Z １ represents an alkyl group having 1 to 5 carbon atoms. 【Chemistry 2】 (The * in formula (1-2) indicates the bonding site with the oxygen atom in formula (1).) 【Transformation 3】 [In formula (2), Z ３ represents a fluorine atom.

2. A non-aqueous electrolyte battery comprising: a positive electrode having a positive electrode active material capable of absorbing and releasing lithium ions; a negative electrode; and the non-aqueous electrolyte solution according to claim 1.

3. 3. The nonaqueous electrolyte battery according to claim 2, wherein the positive electrode contains, as a positive electrode active material, a lithium transition metal composite oxide represented by the following general formula (13): Li ａ１ Ni ｂ１ M ｃ１ O ２ (13) [In formula (13), a1, b1, and c1 are 0.90≦a1≦1.10, 0.40≦b1≦0.98, and 0≦c1≦0.20, respectively, and b1+c1=1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.]

4. 4. The nonaqueous electrolyte battery according to claim 3, wherein b1 satisfies the condition 0.40≦b1≦0.80.

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