Composition and method for producing same, battery including said composition and method for producing same, and vehicle equipped with said battery

Abstract

The present invention pertains to: [1] a composition containing an ether compound (A) represented by general formula (1), and an isocyanate compound (B) having two or more structures of at least one type selected from the group consisting of structures represented by formula (2-1) and formula (2-2), wherein a mass ratio ([A] / [B]) of a content [A] of the ether compound (A) represented by general formula (1) to a content [B] of the isocyanate compound (B) is 0.00010 to 0.15000; [2] a method for producing the composition; [3] a battery provided with a positive electrode, a negative electrode, and the composition; [4] a method for producing the battery; and [5] a vehicle on which the battery is mounted.

Description

A composition and a method for manufacturing the same, a battery containing the composition and a method for manufacturing the same, and a vehicle equipped with the battery.

[0001] The present invention relates to a composition and a method for manufacturing the same, a battery containing the composition and a method for manufacturing the same, and a vehicle equipped with the battery.

[0002] Lithium-ion rechargeable batteries, among others, are widely used in applications such as power supplies for small devices like mobile phones and laptops, and power supplies for vehicles like electric cars. Therefore, numerous studies have been conducted on various battery components, including the positive electrode, negative electrode, and electrolyte, as means of improving battery characteristics.

[0003] In the case of electrolytes, numerous studies have been conducted on the components of the electrolyte, such as additives, electrolytes, and solvents, with the aim of improving battery characteristics.

[0004] In recent years, the demand for higher performance in batteries has been increasing, and there is a need to achieve high levels of battery capacity. Adding ether compounds to the electrolyte is one method used to increase the capacity of batteries. For example, Patent Document 1 describes a non-aqueous electrolyte mainly consisting of an electrolyte and a non-aqueous solvent for dissolving it, which is liquid at 25°C, contains a compound having a dielectric constant and viscosity and a backbone group containing a specific heteroatom, and further contains monofluorophosphate and / or lithium difluorophosphate, and is a non-aqueous electrolyte for secondary batteries that is excellent in high capacity, high-temperature storage characteristics, continuous charging characteristics and cycle characteristics. Patent Document 2 describes an electrolyte for lithium-ion secondary batteries containing a glyme complex consisting of a glyme mixture of methyl triglyme and methyl tetraglyme and lithium ions, which is resistant to oxidative decomposition.

[0005] Japanese Patent Publication No. 2008-277002 Japanese Patent Publication No. 2010-287481

[0006] The non-aqueous electrolyte secondary battery disclosed in Patent Document 1, and the lithium-ion secondary battery having an electrolyte for lithium-ion secondary batteries disclosed in Patent Document 2, had room for improvement in their capacity recovery rate after storage.

[0007] This invention has been made in view of the above problems, and aims to provide a new composition that can exhibit good effects when used as an electrolyte for a battery. Specifically, the object of this invention is to provide a composition that exhibits excellent capacity recovery rate after storage of a battery when used as an electrolyte for a battery, a method for manufacturing the same, a battery containing the composition and a method for manufacturing the same, and a vehicle equipped with the battery.

[0008] As a result of diligent research to solve the above problems, the inventors of the present invention have found that by using a composition containing a specific ether compound and a specific isocyanate compound in a specific mass ratio as an electrolyte, the battery containing the composition exhibits excellent capacity recovery after storage, and have completed the present invention.

[0009] In other words, the gist of the present invention is as follows: [1] A composition comprising an ether compound (A) represented by the following general formula (1), and an isocyanate compound (B) having at least two structures selected from the group consisting of structures represented by the following formulas (2-1) and (2-2), wherein the mass ratio ([A] / [B]) of the content of the ether compound (A) represented by the general formula (1) [A] to the content of the isocyanate compound (B) [B] is 0.00010 to 0.15000. (In formula (1), R １ and R ２ Each of these independently represents a saturated hydrocarbon group with 1 to 4 carbon atoms, and n is an integer between 0 and 3. (In formula (2-2), the nitrogen atom may be bonded to the same atom by a double bond, or to two different atoms by a single bond.) [2] The composition according to [1], wherein in the general formula (1), n ​​is 1 or 2. [3] In the general formula (1), R １ and R ２The composition according to [1] or [2], wherein each is independently a methyl group or an ethyl group. [4] The composition according to any one of [1] to [3], wherein the isocyanate compound (B) is a compound containing a ring structure. [5] The composition according to [4], wherein the compound containing the ring structure is the following compound B-18 or the following compound B-31. [6] A composition according to any one of [1] to [5], further comprising an electrolyte and a non-aqueous solvent, used as an electrolyte. [7] The composition according to [6], wherein the content of the ether compound (A) represented by the general formula (1) is 0.00010 to 1.00000% by mass. [8] The composition according to [6] or [7], wherein the content of the isocyanate compound (B) is 0.05000 to 5.00000% by mass. [9] A method for producing the composition according to any one of [6] to [8], comprising the step of dissolving the ether compound (A) represented by the general formula (1), the isocyanate compound (B), and the electrolyte in the non-aqueous solvent.

[10] A battery comprising a positive electrode, a negative electrode, and the composition according to any one of [6] to [8].

[11] The battery according to

[10] , wherein the positive electrode comprises a positive electrode active material, and the positive electrode active material is a lithium transition metal compound.

[12] The battery according to

[10] or

[11] , wherein the negative electrode comprises a negative electrode active material, the negative electrode active material being selected from the group consisting of carbon-based materials, metallic materials, and mixtures of carbon-based materials and metallic materials.

[13] A method for manufacturing a battery, comprising the steps of housing a positive electrode and a negative electrode in an outer casing, and injecting the composition according to any one of [6] to [8] into the outer casing.

[14] A vehicle equipped with the battery according to any one of

[10] to

[12] .

[0010] The composition according to this embodiment provides a composition that exhibits excellent capacity recovery rate after storage of a battery when used as an electrolyte, a method for manufacturing the same, a battery containing the composition, a method for manufacturing the same, and a vehicle equipped with the battery.

[0011] The following describes in detail embodiments for carrying out the present invention, but the following description is merely one example of an embodiment of the present invention, and the present invention is not limited to these. Furthermore, the present invention can be modified and implemented as such without departing from its essence. In this specification, "~" means that the numerical values ​​described before and after it are included as the lower limit and upper limit.

[0012] [1. Composition] The composition according to this embodiment comprises an ether compound (A) represented by the following general formula (1), and an isocyanate compound (B) having at least two structures selected from the group consisting of structures represented by the following formulas (2-1) and (2-2).

[0013]

[0014] (In formula (1), R １ and R ２ Each of these independently represents a saturated hydrocarbon group with 1 to 4 carbon atoms, and n is an integer between 0 and 3.

[0015]

[0016] (In equation (2-2), the nitrogen in =N-C=O may be bonded to the same atom by a double bond, or to two different atoms by single bonds.)

[0017] Furthermore, the mass ratio ([A] / [B]) of the content of the ether compound (A) represented by general formula (1) in the composition to the content of the isocyanate compound (B) in the composition is 0 for a range of 0.00010 to 0.1500. Note that the mass ratio ([A] / [B]) of the content of the ether compound (A) represented by general formula (1) in the composition to the content of the isocyanate compound (B) in the composition is the same as the ratio of the content (mass%) of the ether compound (A) represented by general formula (1) in the composition to the content (mass%) of the isocyanate compound (B) in the composition (content of ether compound (A) represented by general formula (1) / content of isocyanate compound (B)).

[0018] When added to the electrolyte of a battery or used as an electrolyte by further containing an electrolyte or the like, the composition according to the present embodiment is excellent in the capacity recovery rate after storage of the battery. Regarding the reason for obtaining this effect, the present inventors consider it as follows. However, the reason for obtaining the effect of the present invention is not limited to the content described below.

[0019] Conventionally, by adding an ether compound to an electrolyte, the viscosity of the electrolyte and the solubility of a salt in the electrolyte are adjusted. However, since the ether compound competes with the insertion and desorption of lithium ions into the negative electrode, it also acts as a component that deteriorates the battery. The composition according to the present embodiment contains a specific ether compound (A) and a specific isocyanate compound (B) in a specific ratio, and when used as an electrolyte of a battery, forms a protective film on the negative electrode, thereby suppressing the insertion of the ether compound into the negative electrode, and is considered to have an excellent capacity recovery rate even after storage of the battery. Further, when the mass ratio ([A] / [B]) of the content [A] of the specific ether compound (A) and the content [B] of the specific isocyanate compound (B) is 0.00010 to 0.15000, a protective film on the negative electrode is sufficiently formed, and the insertion of the ether compound (A) into the negative electrode is suppressed, so that it is considered to have an excellent capacity recovery rate even after storage of the battery.

[0020] [1-1. Ether compound (A) represented by general formula (1)] The composition in the present embodiment contains an ether compound (A) represented by the following general formula (1) (hereinafter, also simply referred to as "ether compound (A)").

[0021]

[0022] In formula (1), R １ and R ２ each independently represent a saturated hydrocarbon group having 1 or more and 4 or less carbon atoms, and n is an integer of 0 or more and 3 or less. Among them, from the viewpoint of obtaining an excellent capacity recovery rate after storage, examples of R １ and R ２ include a methyl group, an ethyl group, a propyl group, a butyl group, and an isobutyl group. Among these, a group selected from a methyl group, an ethyl group, and a propyl group is preferable, and a methyl group or an ethyl group is more preferable.

[0023] n represents the number of repeating ethylene oxide molecules in the ether compound (A) represented by general formula (1), and from the viewpoint of obtaining an excellent volume recovery rate after storage, any of 1 to 3 is preferred, with 1 or 2 being more preferred.

[0024] Examples of ether compounds (A) include the following compounds A-1 to A-20. However, the examples are not limited to these compounds.

[0025]

[0026] Among the above compounds, compound A-6 (1,2-dimethoxyethane) and compound A-12 (diethylene glycol diethyl ether) are preferred as ether compounds (A) because they have particularly high stability with respect to lithium, promote the insertion and removal of lithium from the electrodes, and suppress the increase in resistance within the battery, thereby resulting in a better recovery rate of battery capacity after storage at high temperatures.

[0027] [1-2. Isocyanate Compounds (B)] Isocyanate compounds (B) are compounds having two or more structures selected from the group consisting of structures represented by the following formulas (2-1) and (2-2). In formula (2-2), the nitrogen atom may be bonded to the same atom by a double bond, or it may be bonded to two different atoms by a single bond.

[0028] The isocyanate compound (B) typically has 2 to 6 structures represented by formulas (2-1) and (2-2), preferably 2 to 4, and more preferably 2 to 3.

[0029] Examples of isocyanate compounds (B) include compounds in which at least one structure selected from the group consisting of structures represented by formulas (2-1) and (2-2) is substituted on an alkane having 1 to 12 carbon atoms; isocyanates in which two or more structures represented by formula (2-1) are substituted on an alicyclic hydrocarbon either directly or via a methylene group; isocyanurates consisting of a ring structure formed by the structure represented by formula (2-2); and isocyanurates in which a hydrocarbon group having 1 to 4 carbon atoms is substituted on a nitrogen atom derived from the structure represented by formula (2-2) of the isocyanurate.

[0030] Examples of alkanes having 1 to 12 carbon atoms include straight-chain alkanes such as methane, ethane, n-propane, n-butane, n-pentane, and n-hexane, and branched alkanes such as isobutane, 2-methylbutane, and 2,2-dimethylbutane. From the viewpoint of further improving the volume recovery rate after storage, it is preferable that two or more structures represented by formulas (2-1) and / or (2-2) are not substituted on the same carbon atom (except when the alkane is methane), and it is more preferable that the structures represented by formulas (2-1) and / or (2-2) are substituted on the terminal carbon of the alkane. Examples of alicyclic hydrocarbons include monocyclic alicyclic hydrocarbons such as cyclopropane, cyclobutane, cyclopropane, cyclohexane, cycloheptane, and cyclooctane, and bicyclic alicyclic hydrocarbons such as norbornane and adamantane. Examples of ring structures formed by the structure represented by formula (2-2) include ring structures formed by two or three structures represented by formula (2-2). Examples of hydrocarbon groups having 1 to 4 carbon atoms substituted for nitrogen atoms derived from the structure represented by formula (2-2) include alkyl groups such as methyl, ethyl, propyl, and butyl groups, alkenyl groups such as vinyl and allyl groups, and alkynyl groups such as ethynyl, 1-propynyl, and 2-propynyl (propargyl) groups.

[0031] In particular, as isocyanate compound (B), it is preferable that it is a compound containing a ring structure from the viewpoint of further improving the volume recovery rate after storage. As isocyanate compound (B) containing a ring structure, isocyanates in which two or more structures represented by formula (2-1) are substituted directly or via methylene groups on an alicyclic hydrocarbon, uretdiones and isocyanurates in which hydrocarbon groups having 1 to 4 carbon atoms are substituted on a ring structure formed by the structure represented by formula (2-2), and isocyanurates in which two or more structures represented by formula (2-1) are substituted directly or via methylene groups on a cyclohexyl group, and hydrocarbon groups having 1 to 4 carbon atoms are substituted on a 6-membered ring structure formed by three structures represented by formula (2-2).

[0032] Examples of isocyanate compounds (B) include the following compounds B-1 to B-35. However, the examples are not limited to these compounds.

[0033]

[0034]

[0035] Among the above compounds, for isocyanate compound (B), from the viewpoint of achieving a better recovery rate of battery capacity after high-temperature storage by forming a film on the electrode surface through adhesion or crosslinking, it is preferable that one or more compounds selected from compounds B-14 to B-35 containing a ring structure be selected, more preferably one or more compounds selected from compounds B-15 to B-35 containing a six-membered ring structure, and even more preferably one or more compounds selected from compounds B-18 and B-31.

[0036] [1-3. Mass ratio of ether compound (A) and isocyanate compound (B) represented by formula (1)] The mass ratio ([A] / [B]) of the content of ether compound (A) represented by formula (1) [A] to the content of isocyanate compound (B) [B] is 0.00010 to 0.15000 from the viewpoint of obtaining an excellent volume recovery rate after storage. Here, from the viewpoint of obtaining an excellent volume recovery rate after storage, the above mass ratio is 0.00010 or more, preferably 0.00015 or more, and more preferably 0.00020 or more. Also, from the viewpoint of obtaining an excellent volume recovery rate after storage, the above content is 0.15000 or less, preferably 0.10000 or less, and more preferably 0.05000 or less. And, from the same viewpoint, the mass ratio ([A] / [B]) is preferably 0.00015 to 0.10000, and more preferably 0.00020 to 0.05000. Here, if the ether compound (A) or isocyanate compound (B) contains two or more compounds, the above percentages refer to the total percentage of those compounds.

[0037] [1-4. Applications] The composition according to this embodiment may contain other components in addition to the ether compound (A) and the isocyanate compound (B). Examples of other components include solvents. The solvent is not particularly limited as long as it dissolves the ether compound (A) and the isocyanate compound (B).

[0038] Furthermore, the composition according to this embodiment may be used as an electrolyte, or as an additive to an electrolyte containing an electrolyte and a non-aqueous solvent, by further comprising, for example, an electrolyte and a non-aqueous solvent, as described later, in addition to the ether compound (A) and the isocyanate compound (B).

[0039] [1-5. Method for Producing the Composition] The method for producing the composition according to this embodiment includes the step of mixing an ether compound (A) and an isocyanate compound (B). In the above mixing, the ether compound (A) and the isocyanate compound (B) may be mixed by dissolving them in a solvent.

[0040] The method for dissolving the ether compound (A) and the isocyanate compound (B) in the solvent is not particularly limited. For example, the ether compound (A) and the isocyanate compound (B) may be dissolved sequentially in the solvent, or they may be dissolved simultaneously. Furthermore, the mixture may be diluted or concentrated after dissolution. In addition, other components may be added to the solvent.

[0041] [2. Electrolyte] The composition according to this embodiment may contain, in addition to the ether compound (A) and the isocyanate compound (B), an electrolyte and a non-aqueous solvent, and optionally other compounds. When the composition according to this embodiment contains the ether compound (A), the isocyanate compound (B), the electrolyte, a non-aqueous solvent, and optionally other compounds, the composition may be used as an electrolyte as is, or the composition may be further adjusted in concentration before being used as an electrolyte. Furthermore, when the composition according to this embodiment is added to an electrolyte, the electrolyte to which the composition is added may contain an electrolyte, a non-aqueous solvent, and other compounds. The electrolyte to which the composition according to this embodiment is added is also the composition according to this embodiment.

[0042] When the composition according to this embodiment is used as an electrolyte, one type of ether compound (A) may be used alone, or two or more types may be used in any combination and ratio. There are no restrictions on the content of ether compound (A) in the composition of the present invention, and it is arbitrary as long as it does not significantly impair the effects of the present invention. However, from the viewpoint of further improving the volume recovery rate after storage, 0.00010% by mass or more is preferred, 0.00020% by mass or more is more preferred, 0.00030% by mass or more is even more preferred, and 0.00050% by mass or more is even more preferred. Furthermore, from the viewpoint of further improving the volume recovery rate after storage, the above content is preferably 1.00000% by mass or less, more preferably 0.50000% by mass or less, even more preferably 0.20000% by mass or less, even more preferably 0.10000% by mass or less, even more preferably 0.05000% by mass or less, and even more preferably 0.01000% by mass or less. From a similar viewpoint, the above content is preferably 0.00010 to 1.00000% by mass, more preferably 0.00020 to 0.50000% by mass, even more preferably 0.00030 to 0.20000% by mass, even more preferably 0.00050 to 0.10000% by mass, even more preferably 0.00050 to 0.05000% by mass, and even more preferably 0.00050 to 0.01000% by mass. Here, if two or more ether compounds (A) are included, the above content refers to the total content of those compounds.

[0043] When the composition according to this embodiment is used as an electrolyte, one isocyanate compound (B) may be used alone, or two or more may be used in any combination and ratio. There are no restrictions on the content of isocyanate compound (B) in the composition of the present invention, and it is arbitrary as long as it does not significantly impair the effects of the present invention. However, from the viewpoint of further improving the volume recovery rate after storage, 0.05000% by mass or more is preferred, 0.10000% by mass or more is more preferred, 0.30000% by mass or more is even more preferred, and 0.50000% by mass or more is even more preferred. Furthermore, from the viewpoint of further improving the volume recovery rate after storage, the above content is preferably 5.00000% by mass or less, more preferably 3.00000% by mass or less, even more preferably 2.50000% by mass or less, and even more preferably 2.00000% by mass or less. From a similar viewpoint, the above content is preferably 0.05000 to 5.00000% by mass, more preferably 0.10000 to 3.00000% by mass, even more preferably 0.30000 to 2.50000% by mass, and still more preferably 0.50000 to 2.00000% by mass. Here, if two or more isocyanate compounds (B) are included, the above content refers to the total content of those compounds.

[0044] In this specification, the identification of ether compound (A) and isocyanate compound (B), and the content of ether compound (A) and isocyanate compound (B), are measured by nuclear magnetic resonance (NMR) analysis. If the identification of ether compound (A) and isocyanate compound (B), and the measurement of their content are difficult with nuclear magnetic resonance (NMR) analysis alone, other analyses such as infrared spectroscopy (IR) analysis and gas chromatography-mass spectroscopy (GC-MS) may be used in combination.

[0045] [2-1. Electrolyte] The electrolyte in this embodiment is not particularly limited as long as it can dissociate into cations and anions when dissolved in a solvent. From the viewpoint of increasing solubility, alkali metal salts are preferred, lithium salts, sodium salts, and potassium salts are more preferred, and from the viewpoint of improving cycle characteristics, lithium salts are even more preferred. When the electrolyte according to this embodiment is used in a lithium-ion battery, the counter cation of the electrolyte is preferably a lithium cation. When the electrolyte according to this embodiment is used in a sodium-ion battery, the counter cation of the electrolyte is preferably a sodium cation. When the electrolyte according to this embodiment is used in a potassium-ion battery, the counter cation of the electrolyte is preferably a potassium cation.

[0046] Examples of lithium salts include lithium fluoroborate, lithium fluorophosphate, lithium tungstate, lithium carboxylate, lithium sulfonate, lithium imide, lithium methide, lithium oxalate, and fluorine-containing organic lithium salts. A single lithium salt may be used, or two or more may be used in any ratio and combination.

[0047] Lithium salts are used as lithium fluoroborate salts (LiBF) from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics. ４ ; LiPF as lithium fluorophosphate salt ６ Li ２ PO ３ F, LiPO ２ F ２ ; LiFSO as lithium sulfonate salt ３ ,CH ３ SO ３ Li, CF ３ SO ３ Li; as lithium sulfate salt CH ３ SO ４ Li, CF ３ SO ４ Li, C ２ H ５ SO ４ Li, C ２ F ５ SO４ Li, C ３ H ５ SO ４ Li, C ３ H ３ SO ４ Li; as lithium imide salt, LiN(FSO) ２ ) ２ , LiN (FSO ２ ) (CF ３ SO ２ ), LiN (CF ３ SO ２ ) ２ ,LiN(C ２ F ５ SO ２ ) ２ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide; LiC(FSO) as lithium methide salt ２ ) ３ LiC (CF ３ SO ２ ) ３ LiC(C ２ F ５ SO ２ ) ３ Lithium difluorooxalate borate, lithium bis(oxalate) borate, lithium tetrafluorooxalate phosphate, lithium difluorobis(oxalate) phosphate, and lithium tris(oxalate) phosphate are preferred as lithium oxalate salts, and LiBF is preferred from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics. ４ LiPF ６ LiPO ２ F ２ , LiN (FSO ２ ) ２ Lithium bis(oxalate) borate, LiFSO ３ ,CH ３ SO ４ Li, C ２ H ５ SO ４Li is more preferable. From the viewpoint of further improving the low-temperature output characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, LiPF ６ is even more preferable.

[0048] Examples of the sodium salt include sodium fluoroborate salts, sodium fluorophosphate salts, sodium tungstate salts, sodium carboxylate salts, sodium sulfonate salts, sodium imide salts, sodium methide salts, sodium oxalate salts, fluorine-containing organic sodium salts, and the like. The sodium salt may be used alone or in combination of two or more thereof in any ratio and combination.

[0049] From the viewpoint of improving the low-temperature output characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the sodium salt is NaBF as a sodium fluoroborate salt ４ ; NaPF as a sodium fluorophosphate salt ６ , Na ２ PO ３ F, NaPO ２ F ２ ; NaFSO as a sodium sulfonate salt ３ , CH ３ SO ３ Na, CF ３ SO ３ Na; CH as a sodium sulfate salt ３ SO ４ Na, CF ３ SO ４ Na, C ２ H ５ SO ４ Na, C ２ F ５ SO ４ Na, C ３ H ５ SO ４ Na, C ３ H ３ SO ４ [[ID=​​​​​​​​​​３ SO ２ ) ２ NaN(C) ２ F ５ SO ２ ) ２ , sodium cyclic 1,2-perfluoroethanedisulfonylimide, sodium cyclic 1,3-perfluoropropanedisulfonylimide; as sodium methide salt, NaC(FSO ２ ) ３ NaC(CF ３ SO ２ ) ３ NaC(C ２ F ５ SO ２ ) ３ ;Sodium difluorooxalate borate, sodium bis(oxalate) borate, sodium tetrafluorooxalate phosphate, sodium difluorobis(oxalate) phosphate, and sodium tris(oxalate) phosphate are preferred as sodium oxalate salts, and from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, NaBF ４ NaPF ６ NaPO ２ F ２ NaN(FSO) ２ ) ２ Sodium bis(oxalate) borate, NaFSO ３ ,CH ３ SO ４ Na, C ２ H ５ SO ４ Na is more preferred, and from the viewpoint of further improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, NaPF ６ That is even more preferable.

[0050] Examples of potassium salts include potassium fluoroborate, potassium fluorophosphate, potassium tungstate, potassium carboxylate, potassium sulfonate, potassium imide, potassium methide, potassium oxalate, and fluorine-containing organic potassium salts. Potassium salts may be used individually or in any ratio and combination of two or more types.

[0051] Potassium salts are used as potassium fluoroborate (KBF) from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics. ４ ; as potassium fluorophosphate KPF ６ _K ２ PO ３ F, KPO ２ F ２ ; as potassium sulfonate, KFSO ３ ,CH ３ SO ３ K, CF ３ SO ３ K; as potassium sulfate, CH ３ SO ４ K, CF ３ SO ４ K, C ２ H ５ SO ４ K, C ２ F ５ SO ４ K, C ３ H ５ SO ４ K, C ３ H ３ SO ４ K; as potassium imide salt, KN (FSO ２ ) ２ , KN (FSO ２ ) (CF ３ SO ２ ), KN (CF ３ SO ２ ) ２ , KN (C ２ F ５ SO ２ ) ２, potassium cyclic 1,2-perfluoroethanedisulfonylimide, potassium cyclic 1,3-perfluoropropanedisulfonylimide; potassium methide salt KC (FSO ２ ) ３ , KC (CF ３ SO ２ ) ３ , KC (C ２ F ５ SO ２ ) ３ Potassium difluorooxalate borate, potassium bis(oxalate) borate, potassium tetrafluorooxalate phosphate, potassium difluorobis(oxalate) phosphate, and potassium tris(oxalate) phosphate are preferred as potassium oxalate salts, and from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, KBF ４ KPF ６ , KPO ２ F ２ , KN (FSO ２ ) ２ Potassium bis(oxalate) borate, KFSO ３ ,CH ３ SO ４ K, C ２ H ５ SO ４ K is more preferable, and from the viewpoint of further improving low-temperature output characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, KPF ６ That is even more preferable.

[0052] The electrolyte content in the composition according to this embodiment, which is the electrolyte solution, is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 9% by mass or more, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics. Furthermore, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the above content is preferably 20% by mass or less, more preferably 18% by mass or less, and even more preferably 16% by mass or less. And, from the same viewpoint, the above content is preferably 5 to 20% by mass, more preferably 7 to 18% by mass, and even more preferably 9 to 16% by mass. Here, if two or more electrolytes are included, the above content refers to the total content of those electrolytes. In this specification, the identification of electrolytes and the electrolyte content are measured by nuclear magnetic resonance (NMR) analysis. If it is difficult to identify electrolytes or measure the electrolyte content by nuclear magnetic resonance (NMR) analysis alone, other analyses such as infrared spectroscopy (IR) analysis and gas chromatography-mass (GC-MS) analysis may be used in combination.

[0053] When using two or more electrolytes, it is preferable to combine a first electrolyte and a second electrolyte from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics.

[0054] The first electrolyte is preferably an electrolyte with a high degree of ion dissociation and primarily responsible for carrier transport between electrodes, such as LiBF. ４ LiPF ６ , LiN (FSO ２ ) ２ More preferably, LiPF ６ , LiN (FSO ２ ) ２ More preferably, LiPF ６ The second electrolyte is preferably one with a low degree of ion dissociation and which is mainly responsible for roles other than carrier transport between electrodes, such as film formation on the electrode active material, such as LiPO ２ F ２ Lithium bis(oxalate) borate, LiFSO ３ ,CH ３ SO ４ Li, C ２H ５ SO ４ Li is more preferable, LiPO ２ F ２ LiFSO ３ ,CH ３ SO ４ Li, C ２ H ５ SO ４ Li is even more preferable, LiPO ２ F ２ LiFSO ３ That is particularly preferable.

[0055] The combination of the first and second electrolytes can be appropriately selected based on the degree of ionization and effects of the electrolytes, for example, LiPF ６ and LiPO ２ F ２ LiPF ６ and lithium bis(oxalate) borate, LiPF ６ and LiFSO ３ LiPF ６ and CH ３ SO ４ Li, LiPF ６ and C ２ H ５ SO ４ Li, LiN (FSO ２ ) ２ and LiPO ２ F ２ , LiN (FSO ２ ) ２ and lithium bis(oxalate) borate, LiN(FSO) ２ ) ２ and LiFSO ３ , LiN (FSO ２ ) ２ and CH ３ SO ４ Li, LiN (FSO ２ ) ２ and C ２ H ５ SO ４ Li is one example. The combination of the first and second electrolytes is LiPFF, from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics. ６ and LiPO ２ F２ LiPF ６ and LiFSO ３ LiPF ６ and CH ３ SO ４ Li, LiPF ６ and C ２ H ５ SO ４ Li, LiN (FSO ２ ) ２ and LiPO ２ F ２ , LiN (FSO ２ ) ２ and LiFSO ３ , LiN (FSO ２ ) ２ and CH ３ SO ４ Li, LiN (FSO ２ ) ２ and C ２ H ５ SO ４ Li is preferred, LiPF ６ and LiPO ２ F ２ LiPF ６ and LiFSO ３ , LiN (FSO ２ ) ２ and LiPO ２ F ２ , LiN (FSO ２ ) ２ and LiFSO ３ This is preferable.

[0056] From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the content of the first electrolyte in the composition according to this embodiment is preferably 4% by mass or more, more preferably 6% by mass or more, and even more preferably 8% by mass or more. Furthermore, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the above content is preferably 19% by mass or less, more preferably 17% by mass or less, and even more preferably 15% by mass or less. And, from the same viewpoint, the above content is preferably 4 to 19% by mass, more preferably 6 to 17% by mass, and even more preferably 8 to 15% by mass. Here, if two or more types of the first electrolyte are included, the above content refers to the total content of those electrolytes.

[0057] From the viewpoint of improving the DC resistance maintenance rate after high-temperature storage and the gas generation suppression effect after high-temperature storage, the content of the second electrolyte in the composition according to this embodiment is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. Furthermore, from the viewpoint of improving the DC resistance maintenance rate after high-temperature storage and the gas generation suppression effect after high-temperature storage, the above content is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 3% by mass or less. And, from the same viewpoint, the above content is preferably 0.001 to 5% by mass, more preferably 0.01 to 4% by mass, and even more preferably 0.1 to 3% by mass. Here, if two or more types of second electrolytes are included, the above content refers to the total content of those electrolytes.

[0058] The mass ratio of the first electrolyte to the second electrolyte (content of the second electrolyte (mass%) / content of the first electrolyte (mass%)) is preferably 0.0001 or higher, more preferably 0.001 or higher, and even more preferably 0.01 or higher, from the viewpoint of improving the DC resistance maintenance rate after high-temperature storage and the gas generation suppression effect after high-temperature storage. Furthermore, from the viewpoint of improving the DC resistance maintenance rate after high-temperature storage and the gas generation suppression effect after high-temperature storage, the above mass ratio is preferably 0.5 or lower, more preferably 0.4 or lower, and even more preferably 0.3 or lower. And, from the same viewpoint, the above mass ratio is preferably 0.0001 to 0.5, more preferably 0.001 to 0.4, and even more preferably 0.01 to 0.3. Note that the above ratio can be appropriately determined depending on the application of the composition according to this embodiment and the operating environment of the battery. Here, if the first electrolyte or the second electrolyte contains two or more compounds, the above content rates refer to the total content of those compounds.

[0059] [2-2. Non-aqueous solvents] The non-aqueous solvent in this embodiment is not particularly limited as long as it is a non-aqueous solvent that dissolves the ether compound (A), the isocyanate compound (B), and the electrolyte. From the viewpoint of suppressing oxidation-reduction decomposition in the battery, organic solvents are preferred as the non-aqueous solvent.

[0060] Examples of non-aqueous solvents include saturated cyclic carbonates, linear carbonates, linear carboxylic acid esters, cyclic carboxylic acid esters, and sulfone compounds. One non-aqueous solvent may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of suppressing oxidation-reduction decomposition in the battery, saturated cyclic carbonates, linear carbonates, linear carboxylic acid esters, cyclic carboxylic acid esters, and sulfone compounds are preferred as non-aqueous solvents, and saturated cyclic carbonates, linear carbonates, and linear carboxylic acid esters are more preferred.

[0061] Examples of combinations of two or more non-aqueous solvents include combinations of saturated cyclic carbonate and linear carbonate, saturated cyclic carbonate and linear carboxylic acid ester, saturated cyclic carbonate and cyclic carboxylic acid ester, linear carbonate and linear carboxylic acid ester, and saturated cyclic carbonate, linear carbonate and linear carboxylic acid ester. From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, combinations of saturated cyclic carbonate and linear carbonate, and saturated cyclic carbonate, linear carbonate and linear carboxylic acid ester are preferred.

[0062] From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the content of the non-aqueous solvent in the electrolyte composition according to this embodiment is preferably 80% by mass or more, more preferably 83% by mass or more, and even more preferably 85% by mass or more. Furthermore, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the above content is preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 91% by mass or less. And, from the same viewpoint, the above content is preferably 80 to 95% by mass, more preferably 83 to 93% by mass, and even more preferably 85 to 91% by mass. Here, if two or more non-aqueous solvents are included, the above content refers to the total content of those solvents. In this specification, the identification of non-aqueous solvents and the content of non-aqueous solvents are measured by nuclear magnetic resonance (NMR) analysis. If identifying non-aqueous solvents or measuring their content is difficult using nuclear magnetic resonance (NMR) analysis alone, other analyses such as infrared spectroscopy (IR) and gas chromatography-mass (GC-MS) analysis may be used in combination.

[0063] [2-2-1. Saturated Cyclic Carbonates] Examples of saturated cyclic carbonates that serve as non-aqueous solvents in this embodiment include ethylene carbonate, propylene carbonate, butylene carbonate, and erythritol bis(carbonate). One type of saturated cyclic carbonate may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of improving the degree of alkali metal ion dissociation, ethylene carbonate and propylene carbonate are preferred, and ethylene carbonate is more preferred.

[0064] When saturated cyclic carbonate is used as a non-aqueous solvent, the content of saturated cyclic carbonate relative to the total non-aqueous solvent is preferably 3 vol% or more, more preferably 5 vol% or more, and even more preferably 10 vol% or more, from the viewpoint of suppressing the decrease in electrical conductivity due to the decrease in dielectric constant of the electrolyte and improving high-current discharge characteristics, stability to the negative electrode, cycle characteristics, oxidation-reduction resistance of the electrolyte, and high-temperature storage characteristics. Furthermore, from the viewpoint of suppressing the decrease in electrical conductivity due to the decrease in dielectric constant of the electrolyte and improving high-current discharge characteristics, stability to the negative electrode, cycle characteristics, oxidation-reduction resistance of the electrolyte, and high-temperature storage characteristics, the above content is preferably 90 vol% or less, more preferably 85 vol% or less, and even more preferably 80 vol% or less. And, from the same viewpoint, the above content is preferably 3 to 90 vol%, more preferably 5 to 85 vol%, and even more preferably 10 to 80 vol%. Here, if two or more saturated cyclic carbonates are included, the above content refers to the total content of those two or more saturated cyclic carbonates. In this specification, volume percent means the percentage of volume at 25°C and 1 atmosphere.

[0065] [2-2-2. Chain-like carbonates] Examples of chain-like carbonates that serve as non-aqueous solvents in this embodiment include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, methylphenyl carbonate, and methyl-2,2,2-trifluoroethyl carbonate. One type of chain-like carbonate may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of suppressing an increase in the viscosity of the electrolyte, chain-like carbonates having 3 to 5 carbon atoms are preferred, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are more preferred.

[0066] When a linear carbonate is used as a non-aqueous solvent, the content of the linear carbonate relative to the total non-aqueous solvent is preferably 15% by volume or more, more preferably 20% by volume or more, and even more preferably 25% by volume or more, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range. Furthermore, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range, the above content is preferably 90% by volume or less, more preferably 85% by volume or less, and even more preferably 80% by volume or less. And, from the same viewpoint, the above content is preferably 15 to 90% by volume, more preferably 20 to 85% by volume, and even more preferably 25 to 80% by volume. Here, if two or more types of linear carbonates are included, the above content refers to the total content of those types.

[0067] In this embodiment, the non-aqueous solvent is preferably a combination of ethylene carbonate and a chain carbonate, and more preferably a combination of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, from the viewpoint of suppressing the increase in viscosity of the electrolyte and improving electrical conductivity.

[0068] When ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are used as non-aqueous solvents, the content of ethylene carbonate relative to the total non-aqueous solvent is preferably 15% by volume or more, and more preferably 20% by volume or more, from the viewpoint of improving rate characteristics derived from improved ion dissociation. Furthermore, from the viewpoint of improving rate characteristics derived from improved ion dissociation, the above content is preferably 45% by volume or less, and more preferably 40% by volume or less. And, from the same viewpoint, the above content is preferably 15 to 45% by volume, and more preferably 20 to 40% by volume.

[0069] When ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are used as non-aqueous solvents, the content of dimethyl carbonate relative to the total non-aqueous solvent is preferably 20 to 50% by volume. Here, from the viewpoint of suppressing an increase in the viscosity of the electrolyte, the above content is preferably 20% by volume or more, and more preferably 30% by volume or more. Furthermore, from the viewpoint of improving the low-temperature characteristics of the battery, the above content is preferably 50% by volume or less, and more preferably 45% by volume or less. And, from the viewpoint of suppressing an increase in the viscosity of the electrolyte and improving the low-temperature characteristics of the battery, the above content is preferably 20 to 50% by volume, and more preferably 30 to 45% by volume.

[0070] When ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate are used as non-aqueous solvents, the content of ethyl methyl carbonate relative to the total non-aqueous solvents is preferably 20% by volume or more, and more preferably 30% by volume or more, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range. Furthermore, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range, the above content is preferably 50% by volume or less, and more preferably 45% by volume or less. And, from the same viewpoint, the above content is preferably 20 to 50% by volume, and more preferably 30 to 45% by volume.

[0071] [2-2-3. Chain-like Carboxylic Acid Esters] Examples of chain-like carboxylic acid esters that serve as non-aqueous solvents in this embodiment 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. One type of chain-like carboxylic acid ester may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl propionate are preferred, and methyl acetate, ethyl acetate, and methyl propionate are more preferred.

[0072] The above-mentioned linear carboxylic acid ester may be a linear carboxylic acid ester in which some of the hydrogen atoms are replaced with fluorine atoms. Examples of fluorine-substituted linear carboxylic acid esters include methyl trifluoroacetate, ethyl trifluoroacetate, 2,2-difluoroethyl acetate, and 2,2,2-trifluoroethyl acetate. One type of fluorine-substituted linear carboxylic acid ester may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of suppressing the increase in viscosity of the electrolyte, methyl trifluoroacetate and ethyl trifluoroacetate are preferred as the fluorine-substituted linear carboxylic acid ester, and methyl trifluoroacetate is more preferred.

[0073] When a linear carboxylic acid ester is used as the non-aqueous solvent, the content of the linear carboxylic acid ester relative to the total non-aqueous solvent is preferably 1 vol% or more, more preferably 5 vol% or more, and even more preferably 15 vol% or more, from the viewpoint of improving the electrical conductivity of the electrolyte and enhancing the high-current discharge characteristics of the battery. Furthermore, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, suppressing the decrease in electrical conductivity, suppressing the increase in negative electrode resistance, and ensuring that the high-current discharge characteristics of the battery are within a good range, the above content is preferably 70 vol% or less, more preferably 50 vol% or less, and even more preferably 40 vol% or less. Similarly, from the same viewpoint, the above content is preferably 1 to 70 vol%, more preferably 5 to 50 vol%, and even more preferably 15 to 40 vol%. Here, if two or more linear carboxylic acid esters are included, the above content refers to the total content of those esters.

[0074] [2-2-4. Cyclic Carboxylic Acid Esters] Examples of cyclic carboxylic acid esters that serve as non-aqueous solvents in this embodiment include γ-butyrolactone and γ-valerolactone. One type of cyclic carboxylic acid ester may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of improving electrical conductivity, γ-butyrolactone is preferred as the cyclic carboxylic acid ester.

[0075] The above-mentioned cyclic carboxylic acid ester may be a cyclic carboxylic acid ester in which some of the hydrogen atoms are replaced with fluorine atoms. Examples of fluorine-substituted cyclic carboxylic acid esters include 3-fluorotetrahydrofuran-2-one and 4-fluorotetrahydrofuran-2-one. A single fluorine-substituted cyclic carboxylic acid ester may be used, or two or more may be used in any ratio and combination. From the viewpoint of improving oxidation resistance, 3-fluorotetrahydrofuran-2-one is preferred as the fluorine-substituted cyclic carboxylic acid ester.

[0076] When a cyclic carboxylic acid ester is used as a non-aqueous solvent, the content of the cyclic carboxylic acid ester relative to the total non-aqueous solvent is preferably 1 vol% or more, more preferably 5 vol% or more, and even more preferably 15 vol% or more, from the viewpoint of improving the electrical conductivity of the electrolyte and enhancing the high-current discharge characteristics of the battery. Here, from the viewpoint of ensuring the viscosity of the electrolyte is within an appropriate range, suppressing the decrease in electrical conductivity, suppressing the increase in negative electrode resistance, and ensuring that the high-current discharge characteristics of the battery are within a good range, the above content is preferably 70 vol% or less, more preferably 50 vol% or less, and even more preferably 40 vol% or less. Furthermore, from the viewpoint of improving the electrical conductivity of the electrolyte, enhancing the high-current discharge characteristics of the battery, ensuring the viscosity of the electrolyte is within an appropriate range, suppressing the decrease in electrical conductivity, suppressing the increase in negative electrode resistance, and ensuring that the high-current discharge characteristics of the battery are within a good range, the above content is preferably 1 to 70 vol%, more preferably 5 to 50 vol%, and even more preferably 15 to 40 vol%. Here, if two or more cyclic carboxylic acid esters are included, the above content refers to the total content of those esters.

[0077] [2-2-5. Sulfone Compounds] The sulfone compound that serves as the non-aqueous solvent in this embodiment may be a cyclic sulfone or a chain sulfone. One sulfone compound may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving ionic conductivity, the number of sulfonyl groups in the sulfone compound is preferably 1 to 2, and more preferably 1.

[0078] Examples of the above-mentioned cyclic sulfones include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones (sulfolanes), and hexamethylene sulfones; and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. A single cyclic sulfone may be used, or two or more may be used in any ratio and combination. From the viewpoint of suppressing the increase in viscosity of the electrolyte, cyclic sulfones having 3 to 6 carbon atoms are preferred, chain-like sulfones having 3 to 5 carbon atoms are more preferred, and sulfolanes are even more preferred.

[0079] Examples of sulfolanes include sulfolane; sulfolane derivatives such as 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, and 3-trifluoromethylsulfolane. Sulfolanes may be used individually or in any ratio and combination of two or more. From the viewpoint of improving ionic conductivity, sulfolane and sulfolane derivatives are preferred, and sulfolane, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, and 3-trifluoromethylsulfolane are more preferred.

[0080] From the viewpoint of improving oxidation resistance, sulfolane derivatives are preferably sulfolane derivatives in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with fluorine atoms, sulfolane derivatives in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with alkyl groups, and sulfolane derivatives in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with fluorine-substituted alkyl groups. More preferably are 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, and 3-trifluoromethylsulfolane.

[0081] Examples of the above-mentioned chain-like sulfones include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, and pentafluoroethyl methyl sulfone. One type of chain-like sulfone may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of improving the high-temperature storage stability of the electrolyte, chain-like sulfones having 2 to 6 carbon atoms are preferred, chain-like sulfones having 2 to 5 carbon atoms are more preferred, and dimethyl sulfone, ethyl methyl sulfone, and monofluoromethyl methyl sulfone are even more preferred.

[0082] When a sulfone compound is used as a non-aqueous solvent, the content of the sulfone compound relative to the total non-aqueous solvent is preferably 0.3 volume% or more, more preferably 0.5 volume% or more, and even more preferably 1 volume% or more, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range. Furthermore, from the viewpoint of ensuring that the viscosity of the electrolyte is within an appropriate range, that the decrease in ionic conductivity is suppressed, and that the output characteristics of the battery are within a good range, the above content is preferably 40 volume% or less, more preferably 35 volume% or less, and even more preferably 30 volume% or less. And, from the same viewpoint, the above content is preferably 0.3 to 40 volume%, more preferably 0.5 to 35 volume%, and even more preferably 1 to 30 volume%. Here, if two or more sulfone compounds are included, the above content refers to the total content of those compounds.

[0083] [2-3. Other Compounds] The composition according to this embodiment, which serves as the electrolyte, may contain other compounds besides the ether compound (A), the isocyanate compound (B), the electrolyte, and the non-aqueous solvent, as long as the effects of the present invention are not significantly impaired.

[0084] Other compounds include, for example, unsaturated cyclic carbonates, fluorine-containing cyclic carbonates, sulfur-containing organic compounds, phosphorus-containing organic compounds, silicon-containing compounds, aromatic compounds, cyano group-containing organic compounds, acid anhydride compounds, and triple bond-containing compounds. These other compounds may be used individually or in any ratio and combination of two or more. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, unsaturated cyclic carbonates, fluorine-containing cyclic carbonates, sulfur-containing organic compounds, phosphorus-containing organic compounds, silicon-containing compounds, aromatic compounds, cyano group-containing organic compounds, acid anhydride compounds, and triple bond-containing compounds are preferred, unsaturated cyclic carbonates and fluorine-containing cyclic carbonates are more preferred, and unsaturated cyclic carbonates and fluorine-containing cyclic carbonates are even more preferred.

[0085] From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the total content of other compounds in the electrolyte composition according to this embodiment is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.5% by mass or more. Furthermore, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the total content is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. Similarly, from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, the total content is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. And, from the same viewpoint, the total content is preferably 0.1 to 20% by mass, more preferably 0.2 to 15% by mass, and even more preferably 0.5 to 10% by mass. In this specification, the identification of other compounds and the content of other compounds are measured by nuclear magnetic resonance (NMR) analysis. If it is difficult to identify other compounds or measure the content of other compounds by nuclear magnetic resonance (NMR) analysis alone, other analyses such as infrared spectroscopy (IR) analysis and gas chromatography-mass (GC-MS) analysis may be used in combination.

[0086] [2-3-1. Unsaturated Cyclic Carbonates] Examples of unsaturated cyclic carbonates that can be used as other compounds in this embodiment include vinylene carbonates; ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds, or carbon-carbon triple bonds; phenyl carbonates; vinyl carbonates; allyl carbonates; catechol carbonates, etc. Unsaturated cyclic carbonates may be used individually or two or more in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, vinylene carbonates and ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds, or carbon-carbon triple bonds are preferred, and vinylene carbonates are more preferred.

[0087] Examples of vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, and 4,5-diallyl vinylene carbonate. Vinylene carbonates may be used individually or in any ratio and combination of two or more types.

[0088] Examples of ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds, or carbon-carbon triple bonds include vinylethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5-ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4-allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, and 4-methyl-5-allylethylene carbonate. Ethylene carbonates substituted with substituents having aromatic rings, carbon-carbon double bonds, or carbon-carbon triple bonds may be used individually or in any ratio and combination of two or more types.

[0089] From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, vinylene carbonate, vinylethylene carbonate, and ethynylethylene carbonate are preferred as unsaturated cyclic carbonates, vinylene carbonate and vinylethylene carbonate are more preferred, and vinylene carbonate is even more preferred.

[0090] [2-3-2. Fluorine-containing cyclic carbonates] Other fluorine-containing cyclic carbonates that can be used as compounds in this embodiment include, for example, fluorinated cyclic carbonates having alkylene groups with 2 to 6 carbon atoms, such as fluorinated ethylene carbonate; and derivatives of fluorinated cyclic carbonates having alkylene groups with 2 to 6 carbon atoms, such as fluorinated ethylene carbonate substituted with alkyl groups with 1 to 4 carbon atoms. One type of fluorine-containing cyclic carbonate may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, fluoroethylene carbonates with 1 to 4 fluorine atoms, derivatives of fluoroethylene carbonates with 1 to 8 fluorine atoms, and ethylene carbonates having fluorine-containing groups are preferred as fluorine-containing cyclic carbonates.

[0091] Examples of fluoroethylene carbonates having 1 to 4 fluorine atoms, derivatives of fluoroethylene carbonates having 1 to 8 fluorine atoms, and ethylene carbonates having a fluorine-containing group 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, and 4,4-difluoro-5-methylethylene Examples include ethylene 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, 4,4-difluoro-5,5-dimethylethylene carbonate, etc. Fluoroethylene carbonates with 1 to 4 fluorine atoms, derivatives of fluoroethylene carbonates with 1 to 8 fluorine atoms, and ethylene carbonates having a fluorine-containing group may be used individually or in any ratio and combination of two or more types. Of the fluoroethylene carbonates having 1 to 4 fluorine atoms, derivatives of fluoroethylene carbonates having 1 to 8 fluorine atoms, and ethylene carbonates having a fluorine-containing group, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate are preferred from the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics.

[0092] [2-3-3. Sulfur-containing organic compounds] In this embodiment, the sulfur-containing organic compounds that are other compounds are preferably organic compounds having at least one S=O bond, from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, and more preferably linear sulfonic acid esters, cyclic sulfonic acid esters, linear sulfate esters, cyclic sulfate esters, linear sulfite esters, and cyclic sulfite esters.

[0093] Examples of sulfur-containing organic compounds include methyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, propargyl methanesulfonate, busulfan, methyl methanesulfonyloxyacetate, methyl vinylsulfonate, allyl vinylsulfonate, propargyl allylsulfonate, methoxycarbonylmethyl methanedisulfonate, ethoxycarbonylmethyl methanedisulfonate, methoxycarbonylmethyl 1,3-butanedisulfonate, ethoxycarbonylmethyl 1,3-butanedisulfonate, and 1,3-butanedisulfonate. Chain-like sulfonic acid esters such as alkyl disulfonic acid esters like 1-methoxycarbonylethyl phosphate, 1-ethoxycarbonylethyl 1,3-butanedisulfonic acid, and hexafluorophenyl methanesulfonic acid; 1,3-propanesultone, 1-fluoro-1,3-propanesultone, 1-methyl-1,3-propanesultone, 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 1,3-butanesultone, 2, Cyclic sulfonic acid esters such as 4-butanesultone, 1,4-butanesultone, 1,5-pentanesultone, methylenemethanedisulfate, ethylenemethanedisulfate, and 2,2-dioxide-1,2-oxathiolan-4-ylacetate; linear sulfuric acid esters such as dimethyl sulfate, ethylmethyl sulfate, and diethyl sulfate; 1,2-ethylene sulfate, 1,2-propylene sulfate, 1,3-propylene sulfate, 1,2-butylene sulfate, and 2,4,8,10-tetraoxa-3,9-dithia Cyclic sulfuric acid esters such as spiro[5,5]undecane-3,3,9,9-tetraoxide; linear sulfite esters such as dimethyl sulfite, ethyl methyl sulfite, and diethyl sulfite; cyclic sulfite esters such as 1,2-ethylene sulfite, 1,2-propylene sulfite, 1,3-propylene sulfite, and 1,2-butylene sulfite; cyclic sulfones such as 1,1-dioxidetetrahydrothiophene-3-ylmethanesulfonate and 1,1-dioxide-2,3-dihydrothiophene-3-ylmethanesulfonate;Examples include sulfonic acid esters such as butane-2,3-diylmethanesulfonate, butane-1,4-diylmethanesulfonate, and methylenemethanedisulfonate; and vinyl sulfones such as divinylsulfone, 2-bis(vinylsulfonyl)ethane, and bis(2-vinylsulfonylethyl) ether. The sulfur-containing organic compound may be used individually or in any ratio and combination of two or more. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, linear sulfonic acid esters, cyclic sulfonic acid esters, and cyclic sulfite esters are preferred, cyclic sulfonic acid esters and cyclic sulfite esters are more preferred, and 1,3-propanesultone, methylenemethanedisulfonate, and 1,2-ethylenesulfate are even more preferred.

[0094] [2-3-4. Phosphorus-containing organic compounds] Examples of phosphorus-containing organic compounds that can be used as other compounds in this embodiment include trimethyl phosphate, tributyl phosphate, trioctyl phosphate, trippropargyl phosphate, tris(2,2,2-trifluoroethyl) phosphate, ethyl-2-(diethoxyphosphoryl) acetate, 2-propynyl-2-(diethoxyphosphoryl) acetate, methoxypentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, ethoxyheptafluorocyclotetraphosphazene, and the like. A single phosphorus-containing organic compound may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, trimethyl phosphate, tributyl phosphate, and trioctyl phosphate are preferred as phosphorus-containing organic compounds, with trimethyl phosphate being more preferred.

[0095] [2-3-5. Silicon-containing compounds] Other silicon-containing compounds in this embodiment include, for example, borate compounds such as tris(trimethylsilyl) borate, tris(trimethoxysilyl) borate, tris(triethylsilyl) borate, and tris(dimethylvinylsilyl) borate; phosphoric acid compounds such as tris(trimethylsilyl) phosphate, tris(triethylsilyl) phosphate, tris(triphenylsilyl) phosphate, tris(trimethoxysilyl) phosphate, and tris(dimethylvinylsilyl) phosphate; tris(trimethylsilyl) phosphate, tris(triethylsilyl) phosphate, tris(triphenylsilyl) phosphate, tris(trimethoxysilyl) phosphate, and tris(trimethylsilyl) phosphate. Examples include phosphorous acid compounds such as dimethylvinylsilyl; sulfonic acid compounds such as trimethylsilyl methanesulfonate and trimethylsilyl tetrafluoromethanesulfonate; silane compounds such as tetramethylsilane, trimethylvinylsilane, dimethyldivinylsilane, methyltrivinylsilane, and tetravinylsilane; disilane compounds such as hexamethyldisilane, hexaethyldisilane, 1,1,2,2-tetramethyldisilane, and 1,2-diphenyltetramethyldisilane; and disiloxane compounds such as hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, and 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane. Silicon-containing compounds may be used individually or in any ratio and combination of two or more. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, disilane compounds and disiloxane compounds are preferred as silicon-containing compounds, disiloxane compounds are more preferred, hexamethyldisiloxane and 1,3-divinyltetramethyldisiloxane are even more preferred, and 1,3-divinyltetramethyldisiloxane is particularly preferred.

[0096] [2-3-6. Aromatic Compounds] Examples of aromatic compounds that can be used as other compounds in this embodiment include cyclohexylbenzene, tert-butylbenzene, tert-amylbenzene, 1-fluoro-4-tert-butylbenzene, biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, fluorobenzene, methylphenyl carbonate, ethylphenyl carbonate, diphenyl carbonate, and the like. One aromatic compound may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, fluorobenzene, cyclohexylbenzene, tert-butylbenzene, and tert-amylbenzene are preferred, and biphenyl, o-terphenyl, fluorobenzene, cyclohexylbenzene, and tert-amylbenzene are more preferred.

[0097] [2-3-7. [Cyano Group-Containing Organic Compounds] Other cyano group-containing organic compounds in this embodiment include, for example, monocyano compounds such as acetonitrile, propionitrile, butyronitrile, pentanenitrile, hexanenitrile, decanenitrile, undecanenitrile, dodecanenitrile, cyclohexanecarbonitride, acrylonitrile, methacrylonitrile, and crotononitrile; dicyano compounds such as succinonitrile, glutalonitrile, adiponitrile, pimeronitrile, suberonitrile, sebaconitrile, methylmalononitrile, ethylmalononitrile, bicyclohexyl-1,1-dicarbonitride, 1,4-dicyanopentane, and 1,2-didianobenzene; and tricyano compounds such as 1,2,3-propanetricarbonitride, 1,2,3-tris(2-cyanoethoxy)propane, 1,3,6-hexanetricarbonitride, 1,3,5-cyclohexanetricarbonitride, and 1,3,5-benzenetricarbonitride. The cyano group-containing organic compound may be used alone or two or more in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, dicyano compounds are preferred, succinonitrile and adiponitrile are more preferred, and adiponitrile is even more preferred.

[0098] [2-3-8. Acid Anhydride Compounds] Examples of other acid anhydride compounds in this embodiment include chain-like carboxylic acid anhydrides such as acetic anhydride, acrylic anhydride, methacrylic anhydride, cyclohexanecarboxylic acid anhydride, propic acid anhydride, benzoic acid anhydride, fluoroacetic acid anhydride, 4-fluorobenzoic acid anhydride, and propionic acetate anhydride, as well as succinic anhydride, maleic anhydride, citraconic acid anhydride, glutaric acid anhydride, itaconic acid anhydride, fluorosuccal anhydride, allyl succinic acid anhydride, 1,2-oxathiolan-5-one = 2,2-dioxide, and 1,2,6-oxadithiane = 2,2,6,6-tetraoxide. One acid anhydride compound may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, methacrylic anhydride, succinic anhydride, maleic anhydride, and allyl succinic anhydride are preferred as acid anhydride compounds, with succinic anhydride and allyl succinic anhydride being more preferred.

[0099] [2-3-9. Triple Bond-Containing Compounds] Examples of triple bond-containing compounds that can be used as other compounds in this embodiment include 2-propynylmethyl carbonate, 2-propynyl acetate, 2-propynyl formate, 2-propynyl methacrylate, 2-propynyl methanesulfonic acid, 2-propynyl vinylsulfonic acid, 2-propynyl 2-(methanesulfonyloxy)propionic acid, di(2-propynyl)oxalate, 2-butyne-1,4-diylmethanesulfonate, 2-butyne-1,4-diyldiformate, 1H-imidazole-1-carboxylic acid propargyl, and the like. A single triple bond-containing compound may be used, or two or more may be used in any ratio and combination. From the viewpoint of improving low-temperature power characteristics, high-rate charge-discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, preferred triple-bond-containing compounds are 2-propynylmethyl carbonate, 2-propynyl methacrylate, 2-propynyl methanesulfonic acid, 2-propynyl vinylsulfonic acid, di(2-propynyl)oxalate, and 2-butyne-1,4-diylmethanesulfonate, with 2-propynyl methanesulfonic acid, 2-propynyl vinylsulfonic acid, di(2-propynyl)oxalate, and 2-butyne-1,4-diylmethanesulfonate being more preferred. Note that isocyanate compounds (B) having triple bonds, such as compounds B-32 to B-35 above, are not included in the triple-bond-containing compounds. The same applies to ether compounds (A).

[0100] [2-4. Method for producing the composition used as an electrolyte] The method for producing the composition according to this embodiment used as an electrolyte includes the step of mixing an ether compound (A), an isocyanate compound (B), an electrolyte, a non-aqueous solvent, and optionally another compound. At this time, the composition containing the ether compound (A) and the isocyanate compound (B) may be mixed with the electrolyte dissolved in the non-aqueous solvent and optionally another compound, i.e., the electrolyte.

[0101] The method for dissolving an ether compound (A), an isocyanate compound (B), an electrolyte, and optionally other compounds in a non-aqueous solvent is not particularly limited. A composition may be obtained by sequentially dissolving the ether compound (A), the isocyanate compound (B), the electrolyte, and optionally other compounds in a non-aqueous solvent to form an electrolyte. Alternatively, a composition may be obtained by sequentially mixing a high-concentration ether compound (A), a high-concentration isocyanate compound (B) dissolved in a non-aqueous solvent, an electrolyte dissolved in a non-aqueous solvent at a high concentration, and optionally other compounds dissolved in a non-aqueous solvent at a high concentration, in a non-aqueous solvent to form an electrolyte. A composition may also be obtained by dissolving a high-concentration ether compound (A) and an isocyanate compound (B) in a non-aqueous solvent, and an electrolyte dissolved in a high concentration in a non-aqueous solvent, and optionally other compounds dissolved in a high concentration in a non-aqueous solvent, in a non-aqueous solvent, in a non-aqueous solvent to form an electrolyte.

[0102] [3. Battery] The battery according to this embodiment includes a composition that forms the positive electrode, the negative electrode, and the electrolyte.

[0103] [3-1. Electrolyte] The composition that serves as the electrolyte in this embodiment is the composition described above. Other electrolytes may be used in combination, as long as they do not significantly impair the effects of the present invention.

[0104] [3-2. Positive Electrode] In this embodiment, the positive electrode includes positive electrode active material in at least a portion of the surface of the current collector.

[0105] [3-2-1. Positive Electrode Active Material] The positive electrode active material in this embodiment is not particularly limited as long as it is capable of electrochemically intercalating and releasing metal ions. Examples of positive electrode active materials include lithium transition metal compounds, sodium transition metal compounds, potassium transition metal compounds, etc. The positive electrode active material may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of increasing the energy density of the battery, lithium transition metal compounds, sodium transition metal compounds, and potassium transition metal compounds are preferred as positive electrode active materials, and lithium transition metal compounds are more preferred.

[0106] [3-2-1-1. Lithium Transition Metal Compounds] The lithium transition metal compound that serves as the positive electrode active material in this embodiment is not particularly limited as long as it is a compound having a structure that allows for insertion, removal, and insertion of lithium ions. Examples of lithium transition metal compounds include lithium transition metal sulfides, lithium transition metal phosphate compounds, lithium transition metal silicate compounds, lithium transition metal borate compounds, and lithium transition metal composite oxides. One lithium transition metal compound may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of increasing the energy density of the battery, lithium transition metal phosphate compounds and lithium transition metal composite oxides are preferred, and lithium transition metal composite oxides are more preferred.

[0107] Examples of lithium transition metal composite oxide structures include spinel structures, olivine structures, and layered structures. From the viewpoint of battery capacity and durability, spinel structures, olivine structures, and layered structures are preferred for lithium transition metal composite oxides, and from the viewpoint of increasing battery capacity, layered structures are more preferred.

[0108] Lithium transition metal composite oxides having a spinel structure allow for three-dimensional diffusion of lithium ions and are generally represented by the following compositional formula (I). Li ａ１ M １ ｂ１ O ４ (I) (In the empirical formula (I), 0.8 ≤ a1 ≤ 1.5 and 1.9 ≤ b1 ≤ 2.1, M １ (It includes at least one transition metal element and / or aluminum, and is a metallic element excluding Li.)

[0109] M １ Examples include Ni, Co, Mn, V, Al, etc. １ One type may be used alone, or two or more types may be used in any ratio and combination. １ From the viewpoint of improving the battery's cycle performance, Ni, Co, and Mn are preferred, and Ni and Mn are more preferred.

[0110] Examples of lithium transition metal composite oxides having a spinel structure include LiMn ２ O ４ LiCoMnO ４ LiNi ０．５ Mn １．５ O ４ LiCoVO ４ Examples include LiMn. A lithium transition metal composite oxide having a spinel structure may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving the battery cycle performance, LiMn ２ O ４ LiNi ０．５ Mn １．５ O ４ LiNi ０．５ Mn １．５ O ４ This is preferable.

[0111] Lithium transition metal composite oxides having an olivine structure allow for three-dimensional diffusion of lithium ions and are generally represented by the following compositional formula (II). Li ａ２ M ２ ｂ２ PO ４ (II) (In the composition formula (II), 0.8 ≤ a² ≤ 1.5 and 0.9 ≤ b² ≤ 1.1, M ２ (It includes at least one transition metal element and / or aluminum, and is a metallic element excluding Li.)

[0112] M ２ Examples include Fe, Ni, Co, Mn, Al, etc. ２ One type may be used alone, or two or more types may be used in any ratio and combination. ２ From the viewpoint of improving the battery's cycle performance, Fe, Ni, Co, and Mn are preferred, with Fe and Mn being more preferred.

[0113] Examples of lithium transition metal composite oxides having an olivine structure include LiFePO ４Examples include the following. A lithium transition metal composite oxide having an olivine structure may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of improving the battery cycle performance, the lithium transition metal composite oxide having an olivine structure is LiFePO ４ It is preferable.

[0114] Lithium transition metal composite oxides having a layered structure allow for three-dimensional diffusion of lithium ions and are generally represented by the following compositional formula (III). Li ａ３ M ３ ｂ３ O ２ (III) (In the empirical formula (III), 0.8 ≤ a³ ≤ 1.5 and 0.5 ≤ b³ ≤ 1.1, M ３ (It includes at least one transition metal element and / or aluminum, and is a metallic element excluding Li.)

[0115] M ３ Examples include Ni, Co, Mn, Al, Mg, Zr, Fe, Ti, Er, etc. ３ One type may be used alone, or two or more types may be used in any ratio and combination. ３ From the viewpoint of improving the battery's cycle performance, Ni, Co, Mn, Al, Mg, and Zr are preferred, and Ni, Co, Mn, and Al are more preferred.

[0116] Examples of lithium transition metal composite oxides having a layered structure include LiCoO ２ LiNiO ２ LiNi ０．９ Co ０．０５ Mn ０．０５ O ２ LiNi ０．８５ Co ０．１ Al ０．０５ O ２ LiNi ０．８ Co ０．１５ Al ０．０５ O ２ LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ Li １．０５ Ni ０．３３ Co０．３３ Mn ０．３３ O ２ LiNi ０．５ Co ０．３ Mn ０．２ O ２、 LiNi ０．５ Co ０．２ Mn ０．３ O ２ Li １．０５ Ni ０．５ Co ０．２ Mn ０．３ O ２ LiNi ０．６ Co ０．２ Mn ０．２ O ２ LiNi ０．８ Co ０．１ Mn ０．１ O ２ , Li[Li １／３ Mn ２／３ ]O ２ Examples include solid solutions thereof. A lithium transition metal composite oxide having a layered structure may be used alone, or two or more may be used in any ratio and combination.

[0117] From the viewpoint of increasing battery capacity, a lithium transition metal composite oxide having a layered structure is preferred if it is represented by the following compositional formula (IV), and more preferably if it is represented by the following compositional formula (V). ａ４ Ni ｂ４ M ４ ｃ４ O ２ (IV) (In compositional formula (IV), 0.8≦a4≦1.1, 0.3≦b4≦0.98, 0.0≦c4≦0.7, 0.9≦b ４ +c ４ ≤ 1.1, M ４ (It is at least one metallic element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.) Li ａ５ Ni ｂ５ Co ｃ５ M ５ ｄ５ O ２(V) (In the composition formula (V), 0.8 ≤ a5 ≤ 1.1, 0.3 ≤ b5 ≤ 0.98, 0.01 ≤ c5 ≤ 0.7, 0.01 ≤ d5 ≤ 0.6, and 0.9 ≤ b5 + c5 + d5 ≤ 1.1, M ５ (This is at least one metallic element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er.)

[0118] M in the composition formula (IV) ４ This element is at least one metal element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er. From the viewpoint of improving the structural stability of lithium transition metal oxides and suppressing structural degradation during repeated charging and discharging, Co, Mn, and Al are preferred, and Co and Mn are more preferred.

[0119] In composition formula (IV), b4 is preferably 0.3 or higher from the viewpoint of improving the battery's cycle performance. Furthermore, b4 is 0.98 or lower, and from the viewpoint of battery safety, it is preferably 0.97 or lower, and more preferably 0.96 or lower. And from the viewpoint of improving the battery's cycle performance and battery safety, b4 is preferably 0.3 to 0.98, more preferably 0.3 to 0.97, and even more preferably 0.3 to 0.96.

[0120] Examples of lithium transition metal composite oxides represented by compositional formula (IV) include LiNi ０．９ Co ０．０５ Mn ０．０５ O ２ LiNi ０．８５ Co ０．１ Al ０．０５ O ２ LiNi ０．８ Co ０．１５ Al ０．０５ O ２ LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ LiNi ０．５ Co ０．２ Mn ０．３ O ２ Li １．０５ Ni ０．５ Co ０．２ Mn ０．３ O ２ LiNi０．６ Co ０．２ Mn ０．２ O ２ LiNi ０．８ Co ０．１ Mn ０．１ O ２ LiNi ０．９１ Co ０．０６ Mn ０．０３ O ２ LiNi ０．９１ Co ０．０６ Al ０．０３ O ２ LiNi ０．９ Co ０．０３ Al ０．０７ O ２ LiNi ０．６１ Co ０．２ Mn ０．１９ O ２ Examples include the following. The lithium transition metal composite oxide represented by compositional formula (IV) may be used alone, or two or more may be used in any ratio and combination.

[0121] M in the composition formula (V) ５ This element is at least one metal element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er. From the viewpoint of improving the structural stability of lithium transition metal oxides and suppressing structural degradation during repeated charging and discharging, Mn and Al are preferred, and Mn is more preferred.

[0122] In composition formula (V), b5 is preferably 0.3 or higher from the viewpoint of increasing the energy density of the battery. Furthermore, b5 is 0.98 or lower, and from the viewpoint of battery safety, it is preferably 0.97 or lower, and more preferably 0.96 or lower. And from the viewpoint of increasing the energy density of the battery and battery safety, b5 is preferably 0.3 to 0.98, more preferably 0.3 to 0.97, and even more preferably 0.3 to 0.96.

[0123] In composition formula (V), d5 is 0.01 or greater, and from the viewpoint of battery safety, 0.1 or greater is preferred. Furthermore, from the viewpoint of increasing the energy density of the battery, d5 is preferably 0.4 or less. And from the viewpoint of battery safety and increasing the energy density of the battery, d5 is preferably 0.01 to 0.4, and more preferably 0.1 to 0.4.

[0124] Examples of lithium transition metal composite oxides represented by compositional formula (V) include LiNi ０．９ Co ０．０５ Mn ０．０５ O ２ LiNi ０．８５ Co ０．１ Al ０．０５ O ２ LiNi ０．８ Co ０．１５ Al ０．０５ O ２ LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ LiNi ０．５ Co ０．２ Mn ０．３ O ２ Li １．０５ Ni ０．５ Co ０．２ Mn ０．３ O ２ LiNi ０．６ Co ０．２ Mn ０．２ O ２ LiNi ０．８ Co ０．１ Mn ０．１ O ２ LiNi ０．９１ Co ０．０６ Mn ０．０３ O ２ LiNi ０．９１ Co ０．０６ Al ０．０３ O ２ LiNi ０．９ Co ０．０３ Al ０．０７ O ２ LiNi ０．６１ Co ０．２ Mn ０．１９ O ２ Examples include the following. The lithium transition metal composite oxide represented by compositional formula (V) may be used alone, or two or more may be used in any ratio and combination.

[0125] The lithium transition metal composite oxide may further contain elements other than those included in the aforementioned compositional formulas (I) to (V) (other elements).

[0126] [3-2-1-2. Surface Coating] In this embodiment, the positive electrode active material may be one in which a substance with a different composition from the positive electrode active material (surface-adhered substance) is attached to the surface of the positive electrode active material. Examples of surface-adhered substances include oxides such as aluminum oxide; sulfates such as lithium sulfate; and carbonates such as lithium carbonate. One type of surface-adhered substance may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of battery safety, lithium carbonate is preferred as the surface-adhered substance. The surface-adhered substance can be attached to the surface of the positive electrode active material by dissolving it in a solvent or dispersing it in a dispersion medium and impregnating the positive electrode active material with it.

[0127] From the viewpoint of battery safety, the content of surface-adhered material relative to the total positive electrode active material is preferably 1 μmol / g or more, and more preferably 10 μmol / g or more. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 1 mmol / g or less, and more preferably 0.5 mmol / g or less. And, from the viewpoint of battery safety and increasing the energy density of the battery, the above content is preferably 1 μmol / g to 1 mmol / g, and more preferably 10 μmol / g to 0.5 mmol / g. In this specification, surface-adhered material attached to the surface of the positive electrode active material is also included in the positive electrode active material.

[0128] [3-2-2. Method for Manufacturing the Positive Electrode] Examples of methods for manufacturing the positive electrode in this embodiment include a method of obtaining a positive electrode by forming a positive electrode active material layer on a current collector by pressure bonding, and a method of obtaining a positive electrode by forming a positive electrode active material layer on a current collector by coating. From the viewpoint of a simple manufacturing process and excellent productivity, the method of obtaining a positive electrode by forming a positive electrode active material layer on a current collector by coating is preferred.

[0129] The positive electrode active material layer further includes a conductive material and a thickening agent, in addition to the positive electrode active material and a binder, as necessary.

[0130] In the method of obtaining a positive electrode by forming a positive electrode active material layer on a current collector by pressure bonding, a preferred method is one in which, from the viewpoint of a simple manufacturing process and excellent productivity, a positive electrode active material and binder, as well as conductive material and thickener as needed, are dry-mixed to form a sheet, and then pressure-bonded onto a positive electrode current collector to obtain the positive electrode.

[0131] In the method of obtaining a positive electrode by forming a positive electrode active material layer on a current collector by coating, a method is preferred from the viewpoint of simplicity of the manufacturing process and excellent productivity, in which, in addition to the positive electrode active material and binder, conductive material and thickener are further dissolved in a solvent or dispersed in a dispersion medium as needed, and this mixture is coated onto the positive electrode current collector and dried to obtain the positive electrode.

[0132] [3-2-2-1. Positive Electrode Active Material Layer] From the viewpoint of increasing the energy density of the battery, the content of positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, and more preferably 90% by mass or more. Furthermore, from the viewpoint of improving the handling of the positive electrode, the above content is preferably 99.5% by mass or less, and more preferably 99% by mass or less. And from the viewpoint of increasing the energy density of the battery and improving the handling of the positive electrode, the above content is preferably 80 to 99.5% by mass, and more preferably 90 to 99% by mass. Here, if two or more positive electrode active materials are included, the above content refers to the total content of those materials. In this specification, the identification of positive electrode active materials and the content of positive electrode active materials are measured by high-frequency inductively coupled plasma (ICP) emission spectroscopy after wet decomposition of the sample. If it is difficult to identify the positive electrode active material or determine its content using radiofrequency inductively coupled plasma (ICP) emission spectroscopy alone, other analyses such as X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS) may be used in combination.

[0133] Examples of binders include fluororesins such as polyvinyl fluoride, polyvinylidene fluoride, and polytetrafluoroethylene; cyano group-containing resins such as polyacrylonitrile and polyvinylidene cyanide; and modified versions thereof, derivatives, random copolymers, alternating copolymers, graft copolymers, and block copolymers. One binder may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of weather resistance, chemical resistance, heat resistance, and flame retardancy, fluororesins and cyano group-containing resins are preferred as binders.

[0134] When a resin is used as a binder, the weight-average molecular weight of the resin is preferably 10,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more, from the viewpoint of improving the strength of the positive electrode. Furthermore, from the viewpoint of ease of forming the positive electrode, the weight-average molecular weight is preferably 3,000,000 or less, more preferably 950,000 or less, and even more preferably 900,000 or less. And from the viewpoint of improving the strength of the positive electrode and ease of forming the positive electrode, the weight-average molecular weight is preferably 10,000 to 3,000,000, more preferably 50,000 to 950,000, and even more preferably 100,000 to 900,000.

[0135] From the viewpoint of battery durability, the binder content in the positive electrode active material layer is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 20% by mass or less, and more preferably 10% by mass or less. And from the viewpoint of battery durability and increasing the energy density of the battery, the above content is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass.

[0136] Examples of conductive materials include metallic 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. One type of conductive material may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of enhancing conductivity, carbon black is preferred as the conductive material.

[0137] When the positive electrode active material layer contains a conductive material, the content of the conductive material in the positive electrode active material layer is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more, from the viewpoint of increasing conductivity. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 15% by mass or less, and more preferably 10% by mass or less. And, from the viewpoint of increasing conductivity and increasing the energy density of the battery, the above content is preferably 0.01 to 15% by mass, and more preferably 0.1 to 10% by mass.

[0138] From the viewpoint of increasing the packing density of the positive electrode active material, it is preferable to compact the positive electrode active material layer using a hand press, roller press, or the like. From the viewpoint of increasing the energy density of the battery, the density of the positive electrode active material layer should be 1.5 g / cm³. ３ The above is preferable, specifically 2.0 g / cm³. ３ The above is more preferable. Furthermore, from the viewpoint of impregnating with electrolyte, the density is 4.5 g / cm³. ３ The following is preferable: 4.0 g / cm³ ３ The following is more preferable. Furthermore, from the viewpoint of increasing the energy density of the battery and impregnating it with electrolyte, the above density is 1.5 to 4.5 g / cm³. ３ Preferably, 2.0 to 4.0 g / cm³ ３ This is preferable.

[0139] From the viewpoint of increasing the energy density of the battery, the thickness of the positive electrode active material layer is preferably 10 μm or more, and more preferably 15 μm or more. Furthermore, from the viewpoint of improving the rate characteristics of the battery, the thickness is preferably 500 μm or less, and more preferably 300 μm or less. And from the viewpoint of increasing the energy density of the battery and improving the rate characteristics of the battery, the thickness is preferably 10 to 500 μm, and more preferably 15 to 300 μm. The positive electrode active material layer may be formed on one surface of the current collector, or on both surfaces of the current collector.

[0140] [3-2-2-2. Current Collector] Examples of materials for the current collector include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum. From the viewpoint of increasing the energy density of the battery, aluminum is preferred as the material for the current collector.

[0141] Examples of current collector shapes include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. From the viewpoint of improving the handling of the positive electrode, metal foil and metal thin film are preferred as current collector shapes. The metal thin film may be formed in a mesh shape.

[0142] When the shape of the current collector is plate-shaped or film-shaped, the thickness of the current collector is preferably 1 μm or more, and more preferably 2 μm or more, from the viewpoint of improving the handling of the positive electrode. Furthermore, from the viewpoint of increasing the energy density of the battery, the above thickness is preferably 1 mm or less, and more preferably 0.5 mm or less. And from the viewpoint of improving the handling of the positive electrode and increasing the energy density of the battery, the above thickness is preferably 1 μm to 1 mm, and more preferably 2 μm to 0.5 mm.

[0143] [3-2-3. Surface Coating of the Positive Electrode] The positive electrode may be one in which a substance with a different composition from the positive electrode active material (surface-adhered substance) is attached to the surface of the positive electrode. The same explanation as for the surface-adhered substance in [3-1-1-2. Surface Coating] applies to the surface-adhered substance on the surface of the positive electrode, and the preferred embodiments are also the same. In this specification, the surface-adhered substance attached to the surface of the positive electrode is also included in the positive electrode.

[0144] [3-3. Negative Electrode] In this embodiment, the negative electrode includes a negative electrode active material on at least a portion of the surface of the current collector.

[0145] [3-3-1. Negative Electrode Active Material] The negative electrode active material in this embodiment is not particularly limited as long as it is capable of electrochemically intercalating and releasing metal ions. Examples of negative electrode active materials include carbon-based materials and metal materials. The negative electrode active material may be used alone, or two or more may be used in any ratio and combination. From the viewpoint of cycle characteristics, continuous charging characteristics and safety, the negative electrode active material is preferably selected from carbon-based materials, metal materials, and mixtures of carbon-based materials and metal materials.

[0146] [3-3-1-1. Carbon-based materials] Examples of carbon-based materials that serve as the negative electrode active material in this embodiment include natural graphite such as uncoated natural graphite, amorphous carbon-coated natural graphite, graphite-coated natural graphite, and resin-coated natural graphite; artificial graphite; amorphous carbon, etc. One type of carbon-based material may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of increasing battery capacity, natural graphite is preferred as the carbon-based material.

[0147] Examples of natural graphite include scaly natural graphite, flake-like natural graphite, and natural graphite obtained by treating these graphites with processes such as spheroidization or densification. Natural graphite may be used individually or in any ratio and combination of two or more types. From the viewpoint of packing properties and charge / discharge rate characteristics, spheroidized natural graphite is preferred.

[0148] [3-3-1-2. Physical Properties of Carbon-Based Materials] Theoretically, the d002 value (d value (interlayer distance) of the lattice plane (002 plane)) of carbon-based materials is 0.3354 nm or more, and from the viewpoint of increasing battery capacity, it is preferably 0.3360 nm or less, and more preferably 0.3357 nm or less. Furthermore, from the viewpoint of increasing battery capacity, the above d002 value is preferably 0.3354 to 0.3360 nm, and more preferably 0.3354 to 0.3357 nm. In this specification, the d002 value is measured by X-ray diffraction according to the Japan Society for the Promotion of Science (JSPS) method.

[0149] From the viewpoint of increasing battery capacity, the Lc (crystallite size) of carbon-based materials is preferably 0.9 nm or larger, and more preferably 1.0 nm or larger. There is no particular upper limit to the Lc (crystallite size), but it is usually 500 nm or less. Similarly, from the same viewpoint, the above Lc (crystallite size) is preferably 0.9 to 500 nm, and more preferably 1.0 to 500 nm. In this specification, the Lc value is measured by X-ray diffraction according to the Japan Society for the Promotion of Science (JSPS) method.

[0150] From the viewpoint of increasing battery capacity, the average particle size of carbon-based materials is preferably 1 μm or more, and more preferably 3 μm or more. Furthermore, from the viewpoint of suppressing resistance, the average particle size is preferably 100 μm or less, and more preferably 50 μm or less. And from the viewpoint of increasing battery capacity and suppressing resistance, the average particle size is preferably 1 to 100 μm, and more preferably 3 to 50 μm. In this specification, the average particle size of particles such as carbon-based materials is the average particle size (median diameter) based on volume, and is measured by laser diffraction / scattering.

[0151] From the viewpoint of suppressing resistance, the Raman R value of carbon-based materials is preferably 0.01 or higher, and more preferably 0.1 or higher. Furthermore, from the viewpoint of increasing battery capacity, the Raman R value is preferably 1.5 or lower, and more preferably 1 or lower. And, from the viewpoint of suppressing resistance and increasing battery capacity, the Raman R value is preferably 0.01 to 1.5, and more preferably 0.1 to 1. In this specification, the Raman R value is measured by argon ion laser Raman spectroscopy.

[0152] The Raman full width at half maximum (FWHM) of carbon-based materials is 10 cm, from the perspective of suppressing resistance. －１ The above is preferable, 20 cm －１ The above is preferable. Also, from the viewpoint of increasing battery capacity, the above Raman half-width is 100 cm. －１ The following is preferable: 80 cm －１ The following is more preferable. Furthermore, from the viewpoint of suppressing resistance and increasing battery capacity, the above Raman half-width should be 10 to 100 cm. －１ Preferably, 20-80 cm －１ This is more preferable. In this specification, the Raman full width at half maximum is measured by argon ion laser Raman spectroscopy.

[0153] The specific surface area of ​​carbon-based materials is 0.1 m² from the viewpoint of suppressing resistance. ２ Preferably 0.2 m ２ A value of 100 m² or more is more preferable. Furthermore, from the viewpoint of increasing battery capacity, the above specific surface area should be 100 m². ２ Preferably less than / g, and 50m ２ It is more preferable that the specific surface area is less than or equal to / g. Furthermore, from the viewpoint of suppressing resistance and increasing battery capacity, the specific surface area is 0.1 to 100 m². ２ / g is preferred, and 0.2 to 50 m ２ / g is more preferable. In this specification, the specific surface area is measured by the BET method.

[0154] [3-3-1-3. Metallic Material] The metallic material that serves as the negative electrode active material in this embodiment is a material containing a metallic element and / or a metalloid element that can be alloyed with an alkali metal. Furthermore, the metallic elements constituting the metallic material are metallic elements and / or metalloid elements.

[0155] Examples of metallic materials include metals such as Fe, Co, Sb, Bi, Pb, Ni, Ag, Si, Sn, Al, Zr, Cr, V, Mn, As, Nb, Mo, Cu, Zn, Ge, In, Ti, and W; and compounds of these metals (metallic compounds). The metallic material may be used individually, in any ratio and combination of two or more metals, or as an alloy of two or more metals. Examples of metallic compounds include metal oxides, metal nitrides, and metal carbides. The metallic compound may be an oxide, nitride, or carbide of an alloy of two or more metals.

[0156] From the viewpoint of capacity and cycle life, the metallic material is preferably at least one metal selected from the group consisting of Si, Sn, As, Sb, Al, Zn, and W, or a compound thereof, and from the viewpoint of high capacity, Si and Si compounds are more preferred. In this specification, Si and Si compounds are collectively referred to as Si-based materials.

[0157] Examples of Si compounds include Si oxides, Si nitrides, Si carbides, oxides of Si nitrides, and oxides of Si carbides (silicon oxycarbide). Si compounds may be used individually or in any ratio and combination of two or more types.

[0158] Si oxides are, for example, SiO ｘ１ It is expressed as, 0 < x １ <2 satisfies. Si nitrides are, for example, Si ３ N ４ SiN ｘ２ It is expressed as, 0 < x ２ The condition ≤ 1.3 is satisfied. Si carbides are, for example, SiC ｘ３ It is expressed as follows, and 0.9 ≤ x ３ The condition ≤ 1.1 is satisfied. Oxides of Si nitrides include, for example, SiN ｙ１ O ｚ１ It is expressed as follows, where 1 ≤ y １ ≤ 10, 0 < z １ The condition ≤ 1 is satisfied. Oxides of Si carbides include, for example, SiC ｙ２ O ｚ２ It is expressed as follows, where 1 ≤ y ２ ≤ 10, 0 < z ２It satisfies ≤ 1.

[0159] Si-based materials include Si, Si oxide, and Si carbide oxides. Si is preferred because it allows for easy movement of alkali metal salts such as lithium ions, enabling high capacity. Si oxide is preferred because it has a larger theoretical capacity compared to graphite. Si carbide oxide is also preferred because it has a larger theoretical capacity compared to graphite.

[0160] When used in batteries that do not require high output performance, metal composite oxides are preferred as metal materials from the viewpoint of battery durability. Examples of metal composite oxides include Li ４／３ Ti ５／３ O ４ Li １ Ti ２ O ４ Li ４／５ Ti １１／５ O ４ Lithium titanium composite oxides such as Li ４／３ Ti ４／３ Al １／３ O ４ Examples include lithium titanium composite oxides in which part of lithium and / or titanium is replaced with other metals (e.g., Al, Ga, Cu, Zn, etc.). Metal composite oxides may be used individually or in any ratio and combination of two or more types. From the viewpoint of high current density charge / discharge characteristics, lithium titanium composite oxides and lithium titanium composite oxides in which part of lithium and / or titanium is replaced with other metals are preferred, and from the viewpoint of reducing output resistance, lithium titanium composite oxides having a spinel structure and lithium titanium composite oxides having a spinel structure in which part of lithium and / or titanium is replaced with other metals are more preferred. ４／３ Ti ５／３ O ４ Li １ Ti ２ O ４ Li ４／５ Ti １１／５ O ４ Li ４／３ Ti ４／３ Al １／３ O ４ That is even more preferable.

[0161] When the metal material is particles, from the perspective of increasing the battery capacity, the average particle size of the metal particles is preferably 0.005 μm or more, more preferably 0.1 μm or more. Also, from the perspective of suppressing resistance, the average particle size is preferably 10 μm or less, more preferably 5 μm or less. And from the perspectives of increasing the battery capacity and suppressing resistance, the average particle size is preferably 0.005 to 10 μm, more preferably 0.1 to 5 μm.

[0162] [3-3-1-4. Mixture of Carbon-Based Material and Metal Material] The mixture of the carbon-based material and the metal material serving as the negative electrode active material in this embodiment may be a mixture in which the carbon-based material and the metal material are mixed in a state independent of each other, or may be a composite in which the metal material exists on the surface or inside of the carbon-based material.

[0163] When using a mixture of a carbon-based material and a metal material as the negative electrode active material, from the perspective of enhancing the conductivity of the negative electrode, the content rate of the carbon-based material with respect to the entire negative electrode active material is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. Also, from the perspective of increasing the energy density of the battery, the content rate is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 80% by mass or less. And from the perspectives of enhancing the conductivity of the negative electrode and increasing the energy density of the battery, the content rate is preferably 1 to 95% by mass, more preferably 5 to 90% by mass, and still more preferably 10 to 80% by mass.

[0164] When using a mixture of a carbon-based material and a metal material as the negative electrode active material, from the perspective of increasing the energy density of the battery, the content rate of the metal material with respect to the entire negative electrode active material is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more. Also, from the perspective of suppressing the capacity loss during battery operation due to the deterioration of the metal material, the content rate is preferably 99% by mass or less, more preferably 95% by mass or less, and still more preferably 80% by mass or less. And from the perspectives of increasing the energy density of the battery and suppressing the capacity loss during battery operation due to the deterioration of the metal material, the content rate is preferably 5 to 99% by mass, more preferably 10 to 95% by mass, and still more preferably 20 to 80% by mass.

[0165] [3-3-2. Method for manufacturing negative electrode] As the method for manufacturing the negative electrode in the present embodiment, for example, a method of obtaining a negative electrode by forming a negative electrode active material layer on a current collector by pressure bonding; a method of obtaining a negative electrode by forming a negative electrode active material layer on a current collector by coating, etc. can be mentioned. From the viewpoint of simplicity of the manufacturing process and excellent productivity, the method of obtaining a negative electrode by forming a negative electrode active material layer on a current collector by coating is preferable.

[0166] The negative electrode active material layer further contains a conductive material, a thickening agent, and a filler as necessary, in addition to the negative electrode active material and the binder.

[0167] From the viewpoint of simplicity of the manufacturing process and excellent productivity, the method of obtaining a negative electrode by forming a negative electrode active material layer on a current collector by pressure bonding is preferably a method of obtaining a negative electrode by pressure bonding a sheet formed by dry-mixing a conductive material, a thickening agent, and a filler, in addition to the negative electrode active material and the binder, as necessary, onto the negative electrode current collector.

[0168] From the viewpoint of simplicity of the manufacturing process and excellent productivity, the method of obtaining a negative electrode by forming a negative electrode active material layer on a current collector by coating is preferably a method of obtaining a negative electrode by coating a slurry in which a conductive material, a thickening agent, and a filler are further dispersed in a dispersion medium onto the negative electrode current collector and drying it.

[0169] [3-3-2-1. Negative electrode active material layer] From the viewpoint of increasing the energy density of the battery, the content of the negative electrode active material in the negative electrode active material layer is preferably 80% by mass or more, more preferably 90% by mass or more. Also, from the viewpoint of improving the handling property of the negative electrode, the above content is preferably 99.5% by mass or less, more preferably 99% by mass or less. Here, when two or more negative electrode active materials are included, the above content means the total content thereof. And from the viewpoints of increasing the energy density of the battery and improving the handling property of the negative electrode, the above content is preferably 80 to 99.5% by mass, more preferably 90 to 99% by mass. In this specification, the identification of the negative electrode active material and the content of the negative electrode active material are measured by high-frequency inductively coupled plasma (ICP) emission spectroscopy after the sample is alkali-melted.

[0170] Examples of binders include rubbery polymers such as styrene-butadiene rubber (SBR), isoprene rubber, butadiene rubber, fluororubber, acrylonitrile-butadiene rubber (NBR), and ethylene-propylene rubber; and fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and tetrafluoroethylene-ethylene copolymer. A single binder may be used, or two or more binders may be used in any ratio and combination. From the viewpoint of battery durability, styrene-butadiene rubber is preferred as the binder.

[0171] From the viewpoint of battery durability, the binder content in the negative electrode active material layer is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 20% by mass or less, and more preferably 10% by mass or less. And from the viewpoint of battery durability and increasing the energy density of the battery, the above content is preferably 0.1 to 20% by mass, and more preferably 0.5 to 10% by mass.

[0172] When a rubbery polymer is used as the main component of the binder, the binder content in the negative electrode active material layer is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more, from the viewpoint of battery durability. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 5% by mass or less, and more preferably 2% by mass or less. And from the viewpoint of battery durability and increasing the energy density of the battery, the above content is preferably 0.1 to 5% by mass, and more preferably 0.5 to 2% by mass.

[0173] When a fluorine-based polymer is used as the main component of the binder, the binder content in the negative electrode active material layer is preferably 1% by mass or more, and more preferably 2% by mass or more, from the viewpoint of battery durability. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 15% by mass or less, and more preferably 10% by mass or less. And from the viewpoint of battery durability and increasing the energy density of the battery, the above content is preferably 1 to 15% by mass, and more preferably 2 to 10% by mass.

[0174] Examples of conductive materials include carbon black such as acetylene black; and carbon-based materials such as amorphous carbon such as needle coke. One type of conductive material may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of enhancing conductivity, carbon black is preferred as the conductive material.

[0175] When the negative electrode active material layer contains a conductive material, the content of the conductive material in the negative electrode active material layer is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more, from the viewpoint of increasing conductivity. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 15% by mass or less, and more preferably 10% by mass or less. And, from the viewpoint of increasing conductivity and increasing the energy density of the battery, the above content is preferably 0.01 to 15% by mass, and more preferably 0.1 to 10% by mass.

[0176] Examples of thickening agents include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, and their salts. A single thickening agent may be used, or two or more may be used in any ratio and combination. From the viewpoint of battery durability, carboxymethylcellulose or its salts are preferred as the thickening agent.

[0177] When the negative electrode active material layer contains a thickening agent, the content of the thickening agent in the negative electrode active material layer is preferably 0.5% by mass or more, and more preferably 1% by mass or more, from the viewpoint of battery durability. Furthermore, from the viewpoint of increasing the energy density of the battery, the above content is preferably 5% by mass or less, and more preferably 2% by mass or less. And, from the viewpoint of battery durability and increasing the energy density of the battery, the above content is preferably 0.5 to 5% by mass, and more preferably 1 to 2% by mass.

[0178] From the viewpoint of increasing the packing density of the negative electrode active material, it is preferable to compact the negative electrode active material layer using a hand press, roller press, etc. From the viewpoint of increasing the energy density of the battery, the density of the negative electrode active material layer should be 1.0 g / cm³. ３ The above is preferable, 1.5 g / cm³ ３ The above is more preferable. Furthermore, from the viewpoint of impregnating with electrolyte, the density is 2.2 g / cm³.３ The following is preferable: 2.0 g / cm³ ３ The following is more preferable. The density is 1.0 to 2.2 g / cm³ from the viewpoint of increasing the energy density of the battery and impregnating it with the electrolyte. ３ Preferably, 1.5 to 2.0 g / cm³ ３ This is preferable.

[0179] From the viewpoint of increasing the energy density of the battery, the thickness of the negative electrode active material layer is preferably 10 μm or more, and more preferably 15 μm or more. Furthermore, from the viewpoint of improving the rate characteristics of the battery, the thickness is preferably 500 μm or less, and more preferably 300 μm or less. And, from the viewpoint of increasing the energy density of the battery and improving the rate characteristics of the battery, the thickness is preferably 10 to 500 μm, and more preferably 15 to 300 μm. The negative electrode active material layer may be formed on one surface of the current collector, or on both surfaces of the current collector.

[0180] [3-3-2-2. Current Collector] Examples of materials for the current collector include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is preferred as the material for the current collector because it does not alloy with alkali metals and is inexpensive.

[0181] Examples of current collector shapes include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. From the viewpoint of improving the handling of the negative electrode, metal foil and metal thin film are preferred as current collector shapes. The metal thin film may be formed in a mesh shape.

[0182] When the shape of the current collector is plate-shaped or film-shaped, the thickness of the current collector is preferably 1 μm or more, and more preferably 2 μm or more, from the viewpoint of improving the handling of the negative electrode. Furthermore, from the viewpoint of increasing the energy density of the battery, the above thickness is preferably 1 mm or less, and more preferably 0.5 mm or less. And, from the viewpoint of improving the handling of the negative electrode and increasing the energy density of the battery, the above thickness is preferably 1 μm to 1 mm, and more preferably 2 μm to 0.5 mm.

[0183] [3-3-3. Surface Coating of the Negative Electrode] The negative electrode may be one in which a substance with a different composition from the negative electrode active material (surface-adhered substance) is attached to the surface of the negative electrode. The surface-adhered substance on the surface of the negative electrode is described in the same way as the surface-adhered substance on the surface of the positive electrode in [3-2-3. Surface Coating of the Positive Electrode], and the preferred embodiments are also the same. In this specification, the surface-adhered substance attached to the surface of the negative electrode is also included in the negative electrode.

[0184] [3-4. Separator] In the battery according to this embodiment, it is preferable to interpose a separator between the positive electrode and the negative electrode to prevent short circuits. It is preferable to use a separator that is impregnated with an electrolyte.

[0185] The separator material can be any known material, as long as it does not significantly impair the effects of the present invention. The separator shape can be any known shape, as long as it does not significantly impair the effects of the present invention.

[0186] [3-5. Battery Design] [3-5-1. Electrode Group] The electrode group in this embodiment may be a stacked structure in which the positive electrode and the negative electrode are stacked with a separator in between, or a wound structure in which the positive electrode and the negative electrode are wound in a spiral shape with a separator in between.

[0187] From the viewpoint of increasing the energy density of the battery, the electrode group occupancy rate, that is, the volume ratio of the electrode group to the internal volume of the battery, is preferably 40% or more, and more preferably 50% or more. Furthermore, from the viewpoint of impregnating with electrolyte, the electrode group occupancy rate is preferably 90% or less, and more preferably 80% or less. And from the viewpoint of increasing the energy density of the battery and impregnating with electrolyte, the electrode group occupancy rate is preferably 40 to 90%, and more preferably 50 to 80%.

[0188] [3-5-2. Current Collection Structure] In this embodiment, when the electrode group has a laminated structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to a terminal, or a structure that reduces resistance by providing multiple terminals within the electrode, is preferably used. Furthermore, when the electrode group has a wound structure, a structure that reduces resistance by providing multiple lead structures on each electrode and bundling them to a terminal is preferably used.

[0189] [3-5-3. Protective Elements] Examples of protective elements include PTC (Positive Temperature Coefficient) elements whose resistance increases with heat generation due to excessive current, thermal fuses, thermistors, and current interruption valves that interrupt the current flowing through the circuit due to a rapid rise in internal pressure or temperature of the battery during abnormal heat generation. One type of protective element may be used alone, or two or more types may be used in any ratio and combination. From the viewpoint of battery safety, protective elements that do not operate under normal high-current use are preferred, but it is even more preferable to design the battery so that abnormal heat generation or thermal runaway does not occur even without protective elements.

[0190] [3-5-4. Outer casing] The battery according to this embodiment is typically constructed by housing the positive electrode, negative electrode, separator, and electrolyte inside an outer casing.

[0191] Examples of materials for the exterior include metals such as iron, aluminum, and aluminum alloys; and laminated films. From the viewpoint of weight reduction and cost, metals and laminated films are preferred as the material for the exterior, and from the viewpoint of pressure resistance for operating the current interruption valve, iron is more preferred.

[0192] When metal is used as the material for the exterior, the structure of the exterior may be a sealed structure formed by welding metals together using laser welding, resistance welding, or ultrasonic welding, or it may be a crimped structure using metal via a resin gasket.

[0193] Examples of exterior shapes include cylindrical, rectangular, laminated, coin-shaped, and large. From the viewpoint of increasing the energy density of the battery, cylindrical, rectangular, and laminated exteriors are preferred.

[0194] [3-6. Method for Manufacturing a Battery] The method for manufacturing a battery according to this embodiment includes the steps of housing the positive electrode and the negative electrode in an outer casing, and injecting the electrolyte composition into the outer casing.

[0195] The step of housing the positive electrode and the negative electrode in the exterior body and the step of injecting the composition, which is the electrolytic solution, into the exterior body may be carried out in either order. However, from the viewpoint of impregnating the electrolytic solution, it is preferable to carry out the step of injecting the electrolytic solution into the exterior body after the step of housing the positive electrode and the negative electrode in the exterior body.

[0196] In the step of housing the positive electrode and the negative electrode in the exterior body, from the viewpoint of having a simple manufacturing process and excellent productivity, it is preferable to house the separator together with the positive electrode and the negative electrode in the exterior body.

[0197] [3 - 7. Applications] From the viewpoint of being repeatedly used for various applications, the battery according to this embodiment is preferably a non-aqueous electrolytic solution secondary battery, more preferably an alkaline ion secondary battery, and even more preferably a lithium ion secondary battery.

[0198] The battery according to this embodiment can be used for various known applications. Specific examples of the applications include, for example, notebook computers, pen input computers, mobile computers, e-book players, mobile phones, mobile faxes, mobile copiers, mobile printers, mobile audio players, small video cameras, headphone stereos, video movies, liquid crystal TVs, handy cleaners, portable CDs, mini discs, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, motorized bicycles, bicycles, lighting fixtures, toys, game devices, watches, power tools, strobes, cameras, household backup power supplies, industrial backup power supplies, load leveling power supplies, natural energy storage power supplies, etc.

[0199] Among them, the battery according to this embodiment is excellent in the effect of suppressing gas generation in an over-discharged state and can be preferably used for vehicles such as automobiles, motorcycles, motorized bicycles, and bicycles from the viewpoint of being safely used, and can be particularly preferably used for automobiles. That is, the present invention also relates to a vehicle equipped with the above battery.

[0200] Hereinafter, the present invention will be described more specifically by way of examples and comparative examples, but the present invention is not limited to these examples.

[0201] [Manufacturing of the positive electrode] Lithium-containing transition metal oxide (LiNi) is used as the positive electrode active material. １／３ Co １／３ Mn １／３ O ２ 97 parts by mass of ) and 1.5 parts by mass of acetylene black as a conductive material and 1.5 parts by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in an N-methylpyrrolidone solvent using a disperser to form a slurry. This slurry was uniformly applied to one side of a 21 μm thick aluminum foil, dried, and then pressed to form the positive electrode.

[0202] [Manufacturing of the negative electrode] Natural graphite powder was used as the negative electrode active material, an aqueous dispersion of sodium carboxymethylcellulose (1% by mass of sodium carboxymethylcellulose) as a thickener, and an aqueous dispersion of styrene-butadiene rubber (50% by mass of styrene-butadiene rubber) as a binder. These 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 pressed to form the negative electrode. The negative electrode was prepared so that the mass ratio of natural graphite:sodium carboxymethylcellulose:styrene-butadiene rubber after drying was 98:1:1.

[0203] [Preparation of Electrolyte] The compositions obtained in Examples 1-1 to 1-8, 2-1 to 2-4, 3-1 to 3-4, and 4-1 to 4-4, as well as in Comparative Examples 1-1 to 1-6, 2-1 to 2-3, 3-1 and 3-2, and 4-1, described later, were used as electrolytes as they were.

[0204] [Battery Manufacturing] The obtained positive electrode and negative electrode were laminated with a polypropylene separator in between to obtain an electrode group. The obtained electrode group was inserted into a laminate film bag made of aluminum (40 μm thick) with both sides coated with a resin layer, so that the terminals of the positive and negative electrodes protruded from the bag. Then, the obtained electrolyte was injected into the bag, and it was vacuum sealed to manufacture a laminate-type battery.

[0205] [Pre-test charging and discharging] Each of the fabricated non-aqueous electrolyte batteries was charged at 25°C for 4 hours with a constant current equivalent to 0.05C while sandwiched between glass plates to improve contact between electrodes, and then discharged to 2.8V with a constant current of 0.2C. Here, 1C represents the current value that discharges the battery's standard capacity in 1 hour, 0.5C represents half that current value, and 0.2C represents one-fifth that current value. Next, the batteries were charged to 4.1V with a constant current equivalent to 0.2C, and after 24 hours at 60°C, they were discharged to 2.8V with a constant current of 0.2C. After that, the charging conditions were standardized to constant current-constant voltage charging (0.05C cut) up to 4.3V at 0.2C, and the 0.2C discharge capacity up to 2.8V was measured. This discharge capacity is considered the pre-storage capacity. After that, the batteries were charged again to 4.3V.

[0206] [Capacity Recovery Rate After Storage] After being left standing at 60°C for one week, the batteries were cooled to 25°C, discharged to 2.8V with a constant current of 0.2C, and charged to 4.3V with a constant current equivalent to 0.2C. The 0.2C discharge capacity up to 2.8V was measured. This capacity was defined as the capacity recovered after storage. Note that the standing period was extended to two weeks for Examples 1-7 and Comparative Example 1-5, and to four weeks for Examples 1-8 and Comparative Example 1-6. The capacity recovery rate after storage was defined as "100 × Capacity recovered after storage / Capacity before storage," and is shown as a relative value with Comparative Example 1-1, which does not contain ether compound (A) and isocyanate compound (B), set as the baseline value of 100% for the capacity recovery rate after storage. Table 1 shows the evaluation results for Examples 1-1 to 1-8, 2-1 to 2-4, 3-1 to 3-4, and 4-1 to 4-4, as well as Comparative Examples 1-1 to 1-6, 2-1 to 2-3, 3-1 and 3-2, and 4-1.

[0207] [Example 1-1] Under a dry argon atmosphere, a mixture of ethylene carbonate (hereinafter referred to as EC), ethyl methyl carbonate (hereinafter referred to as EMC), and dimethyl carbonate (hereinafter referred to as DMC) (volume ratio 3:4:3) was used as a non-aqueous solvent, and a thoroughly dried LiPF was used as the electrolyte. ６The compound was dissolved in an electrolyte solution at a concentration of 1.0 mol / L, and then 1,3-bis(isocyanatemethyl)cyclohexane (compound B-18) was added as isocyanate compound (B) at a concentration of 0.50000% by mass relative to the total composition, and 1,2-dimethoxyethane (compound A-6) was added as ether compound (A) at a concentration of 0.00010% by mass relative to the total composition to prepare the composition of Example 1-1.

[0208] [Examples 1-2 to 1-8 and Comparative Examples 1-1 to 1-6] The compositions of Examples 1-2 to 1-6 and Comparative Examples 1-1 to 1-6 were prepared in the same manner as in Example 1-1, except that the content of compound A-6 and compound B-18 in the composition was set to the content shown in Table 1, respectively. In Table 1, "-" means that the compound is not present.

[0209] [Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-3] In Example 1-1, triallyl isocyanurate (compound B-31) was used instead of compound B-18, and the content of compound A-6 and compound B-31 in the composition was set to the content shown in Table 1, respectively. The compositions of Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-3 were prepared in the same manner.

[0210] [Examples 3-1 to 3-4 and Comparative Examples 3-1 and 3-2] In Example 1-1, diethylene glycol diethyl ether (compound A-12) was used instead of compound A-6, and the content of compound A-12 and compound B-18 in the composition was set to the content shown in Table 1, respectively. The compositions of Examples 3-1 to 3-4 and Comparative Examples 3-1 and 3-2 were prepared in the same manner.

[0211] [Examples 4-1 to 4-4 and Comparative Example 4-1] The compositions of Examples 4-1 to 4-4 and Comparative Example 4-1 were prepared in the same manner as in Example 1-1, except that compound A-12 was used instead of compound A-6, compound B-31 was used instead of compound B-18, and the content of compound A-12 and compound B-31 in the composition was as shown in Table 1.

[0212]

[0213] As shown in Table 1, the compositions of Examples 1-1 to 1-8, 2-1 to 2-4, 3-1 to 3-4, and 4-1 to 4-4 according to this embodiment exhibited excellent post-storage capacity recovery rates when used as electrolytes for batteries. The post-storage capacity recovery rate of Example 1-7 after standing for two weeks was 103.4% when compared to Comparative Example 1-5 after similar standing for two weeks, with the standard post-storage capacity recovery rate set at 100%. Similarly, the post-storage capacity recovery rate of Example 1-7 after standing for four weeks was 105.0% when compared to Comparative Example 1-6 after similar standing for four weeks, with the standard post-storage capacity recovery rate set at 100%. Here, since the compositions of Examples 1-3, 1-7, and 1-8 have the same composition, it can be seen that the compositions according to this embodiment exhibit superior effects as the period of standing (storage) increases, compared to the case where compositions without ether compound (A) and isocyanate compound (B) are used as the electrolyte of a battery. On the other hand, the compositions of Comparative Examples 1-3, 2-1, 3-1, and 4-1, which contain ether compound (A) and isocyanate compound (B) but whose mass ratio ([A] / [B]) is outside the scope of the present invention, the compositions of Comparative Examples 2-2 and 3-2, which do not contain isocyanate compound (B), and Comparative Examples 1-4 and 2-3, which do not contain ether compound (A), all did not show the same effect as the post-storage capacity recovery rate of the compositions of this embodiment when used as the electrolyte of a battery. Furthermore, when the composition of Comparative Example 1-2 was used as the electrolyte of a battery, it was impossible to charge the battery. This is thought to be because the mass ratio ([A] / [B]) of the ether compound (A) content [A] to the isocyanate compound (B) content [B] in the composition was not within the range of 0.00010 to 0.15000, and the isocyanate content was excessive, resulting in a coating that was too thick on the electrode surface, preventing the battery from being charged.

[0214] A battery using the composition according to this embodiment as the electrolyte can be used in various known applications. Specific examples of applications include, for example, notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, portable audio players, mini video cameras, headphone stereos, video camcorders, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, household backup power supplies, business backup power supplies, load leveling power supplies, and natural energy storage power supplies. The above battery has excellent capacity recovery after storage and can be used safely, making it suitable for use in vehicles such as automobiles, motorcycles, mopeds, and bicycles, and particularly suitable for use in automobiles.

Claims

1. A composition comprising an ether compound (A) represented by the following general formula (1), and an isocyanate compound (B) having at least two structures selected from the group consisting of structures represented by the following formulas (2-1) and (2-2), wherein the mass ratio ([A] / [B]) of the content of the ether compound (A) represented by the general formula (1) [A] to the content of the isocyanate compound (B) [B] is 0.00010 to 0.15000. (In formula (1), R １ and R ２ Each of these independently represents a saturated hydrocarbon group with 1 to 4 carbon atoms, and n is an integer between 0 and 3. (In formula (2-2), the nitrogen atom may be bonded to the same atom by a double bond, or to two different atoms by single bonds.) 2. The composition according to claim 1, wherein n is 1 or 2 in the general formula (1).

3. In the above general formula (1), R １ and R ２ The composition according to claim 1, wherein each is independently a methyl group or an ethyl group.

4. The composition according to claim 1, wherein the isocyanate compound (B) is a compound containing a ring structure.

5. The composition according to claim 4, wherein the compound containing the ring structure is compound B-18 or compound B-31.

6. The composition according to any one of claims 1 to 5, further comprising an electrolyte and a non-aqueous solvent, and used as an electrolyte solution.

7. The composition according to claim 6, wherein the content of the ether compound (A) represented by the general formula (1) is 0.00010 to 1.00000% by mass.

8. The composition according to claim 6, wherein the content of the isocyanate compound (B) is 0.05000 to 5.00000% by mass.

9. A method for producing the composition described in claim 6, comprising the step of dissolving the ether compound (A) represented by the general formula (1), the isocyanate compound (B), and the electrolyte in the non-aqueous solvent.

10. A battery comprising a positive electrode, a negative electrode, and the composition described in claim 6.

11. The battery according to claim 10, wherein the positive electrode includes a positive electrode active material, and the positive electrode active material is a lithium transition metal compound.

12. The battery according to claim 10, wherein the negative electrode includes a negative electrode active material, and the negative electrode active material is selected from the group consisting of carbon-based materials, metallic materials, and mixtures of carbon-based materials and metallic materials.

13. A method for manufacturing a battery, comprising the steps of housing a positive electrode and a negative electrode in an outer casing, and injecting the composition described in claim 6 into the outer casing.

14. A vehicle equipped with the battery described in claim 10.

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