Nonaqueous electrolyte and nonaqueous electrolyte battery

Abstract

Provided is a nonaqueous electrolyte that, when used in a nonaqueous electrolyte battery, is capable of exhibiting excellent normal-temperature cycle properties and low-temperature input properties after cycle testing. Also provided is a nonaqueous electrolyte battery.　The nonaqueous electrolyte contains: (I) at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by general formula (1) in the description, and salts represented by general formula (2) in the description; (II) a solvent; (III) a nonaqueous organic solvent; and (IV) a compound represented by general formula (3) in the description. The nonaqueous electrolyte battery contains this nonaqueous electrolyte.

Description

Non-aqueous electrolyte and non-aqueous electrolyte battery

[0001] The present disclosure relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery.

[0002] In recent years, there has been a rapid increase in demand for high-capacity, high-power, and high-energy-density batteries that can be installed as auxiliary power sources for electric vehicles, hybrid vehicles, and fuel cell vehicles, as well as for energy storage systems for small, high-energy-density applications such as information-related devices and communication devices, i.e., personal computers, video cameras, digital cameras, mobile phones, and smartphones. There is also a growing demand for batteries that can be used for long periods of time in energy storage systems for large, power applications such as power storage. Non-aqueous electrolyte batteries, such as lithium-ion batteries, have been actively developed as candidates for these various energy storage systems. Non-aqueous electrolyte batteries typically include a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte.

[0003] To date, optimization of various battery components, including the active materials of the positive and negative electrodes, has been investigated as a means of improving the cycle characteristics, high-temperature storage characteristics, and durability of non-aqueous electrolyte batteries. Non-aqueous electrolyte-related technologies are no exception, and various additives have been proposed to suppress degradation caused by decomposition of the non-aqueous electrolyte on the surfaces of the active positive and negative electrodes.

[0004] Patent Document 1 describes that storage characteristics are improved by using a non-aqueous electrolyte containing lithium monofluorophosphate or lithium difluorophosphate. Patent Document 2 describes that a non-aqueous electrolyte containing LiPF as a main electrolyte is used. ６and fluorosulfonate, with the ratio of the two in a predetermined range, is used to improve initial charge / discharge capacity, input / output characteristics, and impedance characteristics. Patent Document 3 discloses a nonaqueous electrolyte containing phosphorus and boron complexes, such as lithium difluorooxalatoborate. Patent Document 4 discloses an electrolyte that contains both difluoro(bisoxalato)phosphate and tetrafluoro(oxalato)phosphate, thereby improving cycle characteristics, high-temperature storage characteristics, and low-temperature characteristics at 0°C or below. Patent Document 5 discloses that by using a nonaqueous electrolyte containing an imide salt having a specific fluorophosphoryl structure and / or fluorosulfonyl structure together with a silane compound of a predetermined structure, a high average discharge voltage at -30°C or below and excellent low-temperature output characteristics are achieved, as well as excellent cycle characteristics and storage characteristics at high temperatures of 50°C or above. Patent Document 6 discloses a nonaqueous electrolyte containing a P-F bond and / or P-NH ２ It is described that by using a non-aqueous electrolyte containing a phosphine oxide compound having a bond, the electrolyte and the battery have an excellent combustion suppression effect. ２ NH ２ It is described that by using a non-aqueous electrolyte containing a small amount of the compound, the compound functions as a resistance reducer for the battery.

[0005] Japanese Patent Application Publication No. 11-067270 Japanese Patent Application Publication No. 2013-152956 Japanese Patent Application Publication No. 2002-110235 Japanese Patent Application Publication No. 2011-222193 Japanese Patent Application Publication No. 2016-157679 International Publication No. 2005 / 104289 Japanese Patent Application Publication No. 2020-087825

[0006] However, as a result of investigations by the present inventors, it was found that there is room for improvement in room temperature cycle characteristics when using a nonaqueous electrolyte containing the additives shown in Patent Documents 1 to 3 and 5 to 7. It was also found that there is room for improvement in low temperature input characteristics after cycle testing when using a nonaqueous electrolyte containing the additive shown in Patent Document 4.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide a nonaqueous electrolyte and a nonaqueous electrolyte battery that, when used in a nonaqueous electrolyte battery, can exhibit excellent room-temperature cycle characteristics and low-temperature input characteristics after a cycle test.

[0008] As a result of extensive research to solve these problems, the present inventors have found that by adding a specific salt and a fluorine-containing compound having a specific structure to a nonaqueous electrolyte solution for a nonaqueous electrolyte battery, which contains a nonaqueous organic solvent and a solute, when the electrolyte is used in a nonaqueous electrolyte battery, excellent room-temperature cycle characteristics and low-temperature input characteristics after a cycle test can be achieved, and have arrived at the present invention. Specifically, the above problems can be solved by the following configuration.

[0009] [1] A non-aqueous electrolyte solution containing: (I) at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by the following general formula (1), and salts represented by the following general formula (2); (II) a solute; (III) a non-aqueous organic solvent; and (IV) a compound represented by the following general formula (3):

[0010]

[0011] In general formula (1), W １ represents a boron atom, a phosphorus atom, or a silicon atom, n1 is 1 to 3, n2 is 0 to 4, and p is 0 or 1. １１ represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure. When n1 is 2 or more, n1 R １１ may be bonded to each other), and R １２ represents a halogen atom, and Y １ and Y ２ each independently represents an oxygen atom or a sulfur atom; Y ３ represents a carbon atom or a sulfur atom. ３ The carbon atom or sulfur atom represented by is bonded with q oxo groups (=O). ３is 1 when it is a carbon atom, and 1 or 2 when it is a sulfur atom. ａ＋ represents an alkali metal cation, an alkaline earth metal cation, or an onium cation, a represents the valence of the corresponding cation, and a to d are 1 or 2, and a×b=c×d is satisfied.

[0012]

[0013] In general formula (2), M ｎ＋ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and n is an integer equal to the valence of the corresponding cation. X is a sulfur atom or a phosphorus atom, and when X is a sulfur atom, m is 2, and R ４ is absent, and when X is a phosphorus atom, m is 1, and R １ , R ２ , R ３ and R ４ are each independently an organic group selected from a fluorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, or an unsaturated bond.

[0014]

[0015] In the general formula (3), W is a phosphorus atom or a sulfur atom, and y is 1 when W is a phosphorus atom, and y is 2 when W is a sulfur atom.

[0016] [2] The nonaqueous electrolyte solution according to [1], wherein (IV) / {(I)+(IV)}, which is the mass ratio of the content of (IV) to the total amount of (I) and (IV), is 0.00019 to 0.99.

[0017] [3] The nonaqueous electrolyte solution according to [1] or [2], wherein the salt represented by the general formula (1) is at least one selected from the group consisting of bis(oxalato)borate, difluoro(oxalato)borate, tris(oxalato)phosphate, difluorobis(oxalato)phosphate, and tetrafluoro(oxalato)phosphate.

[0018] [4] The non-aqueous electrolyte solution according to any one of [1] to [3], wherein the salt represented by the general formula (2) has at least one P-F bond or S-F bond. [5] The non-aqueous electrolyte solution according to any one of [1] to [4], wherein the cation of the salt represented by the formula (I) is a lithium ion, a sodium ion, a potassium ion, or a tetraalkylammonium ion.

[0019] [6] The (II) is LiPF ６ , LiBF ４ , LiSbF ６ , LiAsF ６ , LiClO ４ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiN(SO ２ F) ２ , LiAlO ２ , LiAlCl ４ , LiCl, and LiI, or NaPF ６ , NaBF ４ , NaSbF ６ , NaAsF ６ , NaClO ４ , NaCF ３ SO ３ , NaC ４ F ９ SO ３ , NaN(SO ２ F) ２ , NaAlO ２ , NaAlCl ４ , NaCl, and NaI.

[0020] [7] The nonaqueous electrolyte solution according to any one of [1] to [6], wherein (III) comprises at least one selected from the group consisting of a cyclic ester, a chain ester, a cyclic ether, a chain ether, a sulfone compound, a sulfoxide compound, and an ionic liquid. [8] The nonaqueous electrolyte solution according to [7], wherein the cyclic ester comprises a cyclic carbonate. [9] The nonaqueous electrolyte solution according to [8], wherein the cyclic carbonate comprises at least one selected from the group consisting of ethylene carbonate and propylene carbonate.

[0021]

[10] The nonaqueous electrolyte solution according to [7], wherein the chain ester comprises a chain carbonate.

[11] The nonaqueous electrolyte solution according to

[10] , wherein the chain carbonate comprises at least one selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and methyl propyl carbonate.

[0022]

[12] Further, vinylene carbonate, fluoroethylene carbonate, nitrate, 1,3-propene sultone, 1,3-propane sultone, 1,6-diisocyanatohexane, dimethyl dicarbonate, ethynylethylene carbonate, trans-difluoroethylene carbonate, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl-1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanedisulfonic anhydride, methanesulfonic anhydride, methanesulfonyl fluoride, 1,4-dioxane-2,6-dione, tripropargyl fluoride The nonaqueous electrolyte solution according to any one of [1] to

[11] , containing at least one selected from the group consisting of tetrafluoroisopropyl ether, tetramethylsilane, tetravinylsilane, tetramethyl ...

[0023] According to the present disclosure, it is possible to provide a nonaqueous electrolyte and a nonaqueous electrolyte battery that, when used in a nonaqueous electrolyte battery, can exhibit excellent room temperature cycle characteristics and low temperature input characteristics after a cycle test.

[0024] In this specification, the word "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0025] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific contents.

[0026] 1. Regarding the Non-Aqueous Electrolyte The non-aqueous electrolyte of the present disclosure is a non-aqueous electrolyte containing: (I) at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by the above general formula (1), and salts represented by the above general formula (2); (II) a solute; (III) a non-aqueous organic solvent; and (IV) a compound represented by the following general formula (3):

[0027] When a nonaqueous electrolyte containing both component (I) and component (IV) is used in a nonaqueous electrolyte battery (e.g., a lithium-ion battery or a sodium-ion battery), components (I) and (IV) decompose on at least one of the positive electrode and the negative electrode, forming a coating with good cation conductivity on the surface of at least one of the positive electrode and the negative electrode. This coating is thought to suppress direct contact between the nonaqueous organic solvent or solute and the electrode active material, thereby reducing the cation dissociation energy of the solute. The inventors believe that this results in the nonaqueous electrolyte battery exhibiting excellent room-temperature cycle characteristics and low-temperature input characteristics after cycle testing.

[0028] <(I) At least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by general formula (1), and salts represented by general formula (2)> The nonaqueous electrolyte solution of the present disclosure contains, as component (I), at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by general formula (1), and salts represented by general formula (2).

[0029] (Monofluorophosphate, difluorophosphate, and monofluorosulfonate) The cations (M) possessed by monofluorophosphate, difluorophosphate, and monofluorosulfonate are １ ｎ＋ The cations may be alkali metal cations, alkaline earth metal cations, or onium cations. The type of cation is not particularly limited as long as it does not impair the performance of the nonaqueous electrolyte and the nonaqueous electrolyte battery of the present disclosure, and various cations may be selected from the above.

[0030] M １ｎ＋ When M represents an alkali metal cation, examples of the alkali metal cation include lithium ion, sodium ion, potassium ion, rubidium ion, and cesium ion. １ ｎ＋ When M represents an alkaline earth metal cation, examples of the alkaline earth metal cation include magnesium ion, calcium ion, and barium ion. １ ｎ＋ When represents an onium cation, examples of the onium cation include onium cations such as tetraalkylammonium, tetraalkylphosphonium, and imidazolium derivatives. n represents the valence of the corresponding cation and may be 1 to 3, or may be 1 or 2.

[0031] M １ ｎ＋ In particular, from the viewpoint of helping ion conduction in a non-aqueous electrolyte battery, M is preferably a lithium ion, a sodium ion, a potassium ion, a tetraalkylammonium ion such as a tetramethylammonium ion or a tetraethylammonium ion, or a tetrabutylphosphonium ion, and more preferably a lithium ion, a sodium ion, a potassium ion, or a tetraalkylammonium ion. １ ｎ＋ When used in a lithium ion battery, the charge is more preferably a lithium ion, and when used in a sodium ion battery, the charge is more preferably a sodium ion.

[0032] (Salt represented by general formula (1))

[0033]

[0034] In general formula (1), W １ represents a boron atom, a phosphorus atom, or a silicon atom, n1 is 1 to 3, n2 is 0 to 4, and p is 0 or 1. １１represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure. When n1 is 2 or more, n1 R １１ may be bonded to each other), and R １２ represents a halogen atom, and Y １ and Y ２ each independently represents an oxygen atom or a sulfur atom; Y ３ represents a carbon atom or a sulfur atom. ３ The carbon atom or sulfur atom represented by is bonded with q oxo groups (=O). ３ is 1 when it is a carbon atom, and 1 or 2 when it is a sulfur atom. ａ＋ represents an alkali metal cation, an alkaline earth metal cation, or an onium cation, a represents the valence of the corresponding cation, and a to d are 1 or 2, and a×b=c×d is satisfied.

[0035] W １ represents a boron atom, a phosphorus atom or a silicon atom, and is preferably a boron atom or a phosphorus atom.

[0036] R １１ The alkylene group represented by the formula (R) may be linear or branched. Examples of the alkylene group include alkylene groups having 1 to 10 carbon atoms, such as methylene, ethylene, n-propylene, isopropylene, n-butylene, and n-hexylene. １１ Examples of the halogenated alkylene group having 1 to 10 carbon atoms represented by the formula (R) include groups in which any hydrogen atom in the alkylene group has been substituted with a halogen atom. １１ Examples of the arylene group having 6 to 20 carbon atoms represented by the formula (R) include a phenylene group and a naphthylene group. １１ Examples of the halogenated arylene group having 6 to 20 carbon atoms represented by the formula (I) include groups in which any hydrogen atom of the above arylene group has been substituted with a halogen atom.

[0037] R １１As the alkyl group, a methylene group, an ethylene group, an n-propylene group, a difluoromethylene group, a tetrafluoroethylene group, or a hexafluoropropylene group is preferred, and a methylene group is more preferred.

[0038] R １２ Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, and an iodine atom, with a fluorine atom being preferred.

[0039] Y １ and Y ２ each independently represents an oxygen atom or a sulfur atom, and it is preferable that all of them are oxygen atoms.

[0040] Y ３ represents a carbon atom or a sulfur atom, and is preferably a carbon atom.

[0041] M ａ＋ Examples of the alkali metal cation, alkaline earth metal cation and onium cation represented by the formula (I) include the above-mentioned M １ ｎ＋ Examples of the cations include the alkali metal cations, alkaline earth metal cations and onium cations listed above, and specific examples and preferred examples are also the same.

[0042] Examples of the compound represented by general formula (1) include bis(oxalato)borate, difluoro(oxalato)borate, tris(oxalato)phosphate, difluorobis(oxalato)phosphate, tetrafluoro(oxalato)phosphate, tris(oxalato)silicate, difluorobis(oxalato)silicate, difluoro(malonato)borate, tetrafluoro(malonato)phosphate, difluoro(sulfoacetato)borate, difluoro(maleato)borate, and difluoro(fumarato)borate.

[0043] The salt represented by general formula (1) is preferably at least one selected from the group consisting of bis(oxalato)borate, difluoro(oxalato)borate, tris(oxalato)phosphate, difluorobis(oxalato)phosphate, and tetrafluoro(oxalato)phosphate, and more preferably at least one selected from the group consisting of lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium tris(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate.

[0044] (Salt represented by general formula (2))

[0045]

[0046] In general formula (2), M ｎ＋ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and n is an integer equal to the valence of the corresponding cation. X is a sulfur atom or a phosphorus atom, and when X is a sulfur atom, m is 2, and R ４ is absent, and when X is a phosphorus atom, m is 1, and R １ , R ２ , R ３ and R ４ are each independently an organic group selected from a fluorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, or an unsaturated bond.

[0047] In general formula (2), M ｎ＋ is the aforementioned M １ ｎ＋ The same applies to specific examples and preferred examples.

[0048] In general formula (2), R １ ~R ４ are each independently an organic group selected from a fluorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and the organic group may also contain a fluorine atom, an oxygen atom, or an unsaturated bond. The organic group may contain a substituent within its structure.

[0049] R １ ~R ４ The alkyl group represented by the formula (I) may be linear or branched, and examples thereof include alkyl groups having 1 to 10 carbon atoms and fluorine-containing alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a trifluoromethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 2,2,3,3-tetrafluoropropyl group, and a 1,1,1,3,3,3-hexafluoroisopropyl group. １ ~R ４ The alkoxy group represented by the formula (I) may be linear or branched, and examples thereof include alkoxy groups having 1 to 10 carbon atoms and fluorine-containing alkoxy groups, such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a trifluoromethoxy group, a 2,2-difluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 2,2,3,3-tetrafluoropropoxy group, a 1,1,1-trifluoroisopropoxy group, and a 1,1,1,3,3,3-hexafluoroisopropoxy group.

[0050] R １ ~R ４The alkenyl group represented by R may be linear or branched, and examples thereof include alkenyl groups having 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 2-butenyl, 3-butenyl, and 1,3-butadienyl, as well as fluorine-containing alkenyl groups. １ ~R ４ The alkenyloxy group represented by the formula (I) may be linear or branched, and examples thereof include alkenyloxy groups having 2 to 10 carbon atoms, such as a vinyloxy group, a 1-propenyloxy group, a 2-propenyloxy group, an isopropenyloxy group, a 2-butenyloxy group, a 3-butenyloxy group, and a 1,3-butadienyloxy group, and fluorine-containing alkenyloxy groups.

[0051] R １ ~R ４ The alkynyl group represented by the formula (R) may be linear or branched, and examples thereof include alkynyl groups having 2 to 10 carbon atoms, such as ethynyl, 2-propynyl, and 1,1-dimethyl-2-propynyl, and fluorine-containing alkynyl groups. １ ~R ４ The alkynyloxy group represented by the formula (I) may be linear or branched, and examples thereof include alkynyloxy groups having 2 to 10 carbon atoms, such as an ethynyloxy group, a 2-propynyloxy group, and a 1,1-dimethyl-2-propynyloxy group, and fluorine-containing alkynyloxy groups.

[0052] R １ ~R ４ Examples of the cycloalkyl group represented by the formula (R) include cycloalkyl groups having 3 to 10 carbon atoms, such as a cyclopentyl group and a cyclohexyl group, and fluorine-containing cycloalkyl groups. １ ~R ４ Examples of the cycloalkoxy group represented by the formula (I) include cycloalkoxy groups having 3 to 10 carbon atoms, such as a cyclopentyloxy group and a cyclohexyloxy group, and fluorine-containing cycloalkoxy groups.

[0053] R １ ~R ４Examples of the cycloalkenyl group represented by the formula (R) include cycloalkenyl groups having 3 to 10 carbon atoms, such as a cyclopentenyl group and a cyclohexenyl group, and fluorine-containing cycloalkenyl groups. １ ~R ４ Examples of the cycloalkenyloxy group represented by the formula (I) include cycloalkenyloxy groups having 3 to 10 carbon atoms, such as a cyclopentenyloxy group and a cyclohexenyloxy group, and fluorine-containing cycloalkenyloxy groups.

[0054] R １ ~R ４ Examples of the aryl group represented by R include aryl groups having 6 to 10 carbon atoms, such as a phenyl group, a tolyl group, and a xylyl group, and fluorine-containing aryl groups. １ ~R ４ Examples of the aryloxy group represented by the formula (I) include aryloxy groups having 6 to 10 carbon atoms, such as a phenyloxy group, a tolyloxy group, and a xylyloxy group, and fluorine-containing aryloxy groups.

[0055] R １ ~R ４ It is preferable that at least one of represents a fluorine atom. That is, it is preferable that the salt represented by general formula (2) has at least one P—F bond or S—F bond.

[0056] R １ ~R ４ are each independently a fluorine atom or an alkyl group containing a fluorine atom, since the degree of ionic dissociation is improved due to its strong electron-withdrawing property, thereby increasing the ionic conductivity in a solution or a composition. Furthermore, a fluorine atom is even more preferable, since the anion size is reduced, thereby improving the mobility, thereby significantly increasing the ionic conductivity in a solution or a composition. １ ~R ４When the number of carbon atoms is 6 or less, the ionic conductivity tends to be relatively high, so it is preferable, the number of carbon atoms is more preferably 1 to 4, and the number of carbon atoms is still more preferably 1 to 3. Specific examples include a trifluoromethyl group and a pentafluoroethyl group, and a trifluoromethyl group having a small anion size is particularly preferable.

[0057] Specific examples of the anion structure of the salt represented by formula (2) are shown below, but the invention is not limited to these.

[0058]

[0059]

[0060] The salt represented by general formula (2) is preferably at least one compound selected from the group consisting of (fluorosulfonyl)(difluorophosphoryl)imide salts and bis(difluorophosphoryl)imide salts, and more preferably (fluorosulfonyl)(difluorophosphoryl)imide lithium or bis(difluorophosphoryl)imide lithium.

[0061] As shown for each of the monofluorophosphate, difluorophosphate, monofluorosulfonate, salt represented by the above general formula (1), and salt represented by the above general formula (2), the cation of these salts, i.e., the cation of the salt represented by (I), is preferably a lithium ion, a sodium ion, a potassium ion, or a tetraalkylammonium ion.

[0062] In the nonaqueous electrolyte solution of the present disclosure, one type of compound may be used alone as (I), or two or more types of compounds may be mixed in any combination and ratio depending on the application.

[0063] In the nonaqueous electrolyte solution of the present disclosure, the content of (I) (also referred to as the "concentration of (I)") relative to the total amount of the nonaqueous electrolyte solution may be 0.01% by mass or more and 10% by mass or less. The lower limit of the concentration of (I) may be 0.08% by mass or more, 0.1% by mass or more, 0.15% by mass or more, 0.3% by mass or more, 0.45% by mass or more, 0.5% by mass or more, 0.7% by mass or more, or 0.8% by mass or more. The upper limit of the concentration of (I) may be 8% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, or 1.5% by mass or less.

[0064] <Regarding (II) Solute> The solute (II) (also referred to as "(II)") contained in the nonaqueous electrolyte solution of the present disclosure will be described. The solute (II) is not particularly limited, and may be, for example, LiPF ６ , LiBF ４ , LiSbF ６ , LiAsF ６ , LiClO ４ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiN(SO ２ F) ２ , LiAlO ２ , LiAlCl ４ , LiCl and LiI, or NaPF ６ , NaBF ４ , NaSbF ６ , NaAsF ６ , NaClO ４ , NaCF ３ SO ３ , NaC ４ F ９ SO ３ , NaN(SO ２ F) ２ , NaAlO ２ , NaAlCl ４ , NaCl, and NaI.

[0065] In the nonaqueous electrolyte solution of the present disclosure, one type of compound may be used alone as (II), or two or more types of compounds may be mixed in any combination and ratio depending on the application.

[0066] The concentration of (II) relative to the total amount of the nonaqueous electrolyte is not particularly limited. For example, the lower limit of the concentration of (II) may be 0.5 mol / L or more, 0.7 mol / L or more, or 0.9 mol / L or more. The upper limit of the concentration of (II) may be 5 mol / L or less, 4 mol / L or less, or 2 mol / L or less.

[0067] The liquid temperature when (II) is dissolved in (III) the nonaqueous organic solvent is not particularly limited, but may be from -20 to 80°C or from 0 to 60°C.

[0068] <Regarding (III) Non-aqueous Organic Solvent> The (III) non-aqueous organic solvent (also referred to as "(III)") contained in the non-aqueous electrolyte solution of the present disclosure will be described. The type of (III) non-aqueous organic solvent is not particularly limited, and any non-aqueous organic solvent can be used. Specific examples of the (III) non-aqueous organic solvent include the following non-aqueous organic solvents. Examples of cyclic esters include cyclic carbonates such as propylene carbonate (hereinafter sometimes referred to as "PC"), ethylene carbonate (hereinafter sometimes referred to as "EC"), and butylene carbonate, as well as γ-butyrolactone and γ-valerolactone. Examples of chain esters include chain carbonates such as diethyl carbonate (hereinafter sometimes referred to as "DEC"), dimethyl carbonate (hereinafter sometimes referred to as "DMC"), ethyl methyl carbonate (hereinafter sometimes referred to as "EMC"), and methyl propyl carbonate, as well as methyl acetate, methyl propionate, and ethyl propionate (hereinafter sometimes referred to as "EP"). Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, and dioxane. Examples of chain ethers include dimethoxyethane and diethyl ether. Other examples include sulfone compounds and sulfoxide compounds such as dimethyl sulfoxide and sulfolane. Ionic liquids and the like can also be used.

[0069] (III) The nonaqueous organic solvent may contain at least one selected from the group consisting of cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids.

[0070] The cyclic ester may include a cyclic carbonate, and the cyclic carbonate may include at least one selected from the group consisting of ethylene carbonate and propylene carbonate.

[0071] The chain ester may include a chain carbonate, and the chain carbonate may include at least one selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and methyl propyl carbonate.

[0072] In the nonaqueous electrolyte solution of the present disclosure, as (III), one type of compound may be used alone, or two or more types of compounds may be mixed in any combination and ratio depending on the application.

[0073] The content of the cyclic carbonate is not particularly limited and may be any content as long as it does not significantly impair the effects of the present disclosure. However, when one type is used alone, the content may be 3 vol% or more, more preferably 5 vol% or more, based on 100 vol% of the nonaqueous organic solvent. By setting the content within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the nonaqueous electrolyte can be avoided, and the large-current discharge characteristics, stability with respect to the negative electrode, and cycle characteristics of the nonaqueous electrolyte battery can be easily maintained within good ranges. The content may also be 90 vol% or less, preferably 85 vol% or less, and more preferably 80 vol% or less. Setting the content within this range allows the viscosity of the nonaqueous electrolyte to be within an appropriate range, suppresses a decrease in ionic conductivity, and ultimately facilitates the load characteristics of the nonaqueous electrolyte battery to be easily maintained within good ranges.

[0074] Additionally, any combination of two or more cyclic carbonates can be used. One preferred combination is a combination of ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99:1 to 40:60, and particularly preferably 95:5 to 50:50. Furthermore, the amount of propylene carbonate relative to the total nonaqueous organic solvent is not particularly limited and may be any amount as long as it does not significantly impair the effects of the present disclosure. However, it may be 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, or 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less. The inclusion of propylene carbonate within this range is preferred because it maintains the properties of the combination of ethylene carbonate and dialkyl carbonates while providing even more excellent low-temperature properties.

[0075] The chain ester may be used alone or in any combination and ratio of two or more. The content of the chain ester is not particularly limited, but may be 15% by volume or more, preferably 20% by volume or more, and more preferably 25% by volume or more, based on 100% by volume of the nonaqueous organic solvent. It may also be 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting the content of the chain ester within the above range, the viscosity of the nonaqueous electrolyte can be set to an appropriate range, a decrease in ionic conductivity can be suppressed, and the input / output characteristics and charge / discharge rate characteristics of the nonaqueous electrolyte battery can be easily set to good ranges. Furthermore, a decrease in electrical conductivity due to a decrease in the dielectric constant of the nonaqueous electrolyte can be avoided, and the input / output characteristics and charge / discharge rate characteristics of the nonaqueous electrolyte battery can be easily set to good ranges. Furthermore, by combining a specific chain ester with a specific amount of ethylene carbonate, battery performance can be significantly improved.

[0076] For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain esters, the content of ethylene carbonate is not particularly limited and may be any content as long as it does not significantly impair the effects of the present disclosure, but may be 5% by volume or more, preferably 10% by volume or more, and 45% by volume or less, preferably 40% by volume or less. The content of dimethyl carbonate may be 20% by volume or more, preferably 30% by volume or more, and 50% by volume or less, preferably 45% by volume or less. The content of ethyl methyl carbonate may be 20% by volume or more, preferably 30% by volume or more, and 50% by volume or less, preferably 45% by volume or less. By setting the content within the above range, the low-temperature deposition temperature of the electrolyte is lowered, while also reducing the viscosity of the nonaqueous electrolyte, improving ionic conductivity and making it easier to obtain high input / output even at low temperatures.

[0077] The content of the chain ether is not particularly limited and may be any content as long as it does not significantly impair the effects of the present disclosure. It may be 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, or 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less, based on 100% by volume of the nonaqueous organic solvent. If the content of the chain ether is within the above range, for example, in the case of a lithium-ion battery in which the cation is mainly lithium, it is easy to ensure the effect of improving the degree of lithium ion dissociation of the chain ether and improving ionic conductivity due to reduced viscosity. Furthermore, when the negative electrode active material is a carbonaceous material, the phenomenon of co-intercalation of the chain ether with lithium ions can be suppressed, making it easier to maintain the input / output characteristics and charge / discharge rate characteristics within appropriate ranges.

[0078] The content of the sulfone compound is not particularly limited and may be any content as long as it does not significantly impair the effects of the present disclosure, but may be 0.3 vol% or more, preferably 0.5 vol% or more, more preferably 1 vol% or more, and may be 40 vol% or less, preferably 35 vol% or less, more preferably 30 vol% or less, relative to 100 vol% of the nonaqueous organic solvent. If the content of the sulfone compound is within the above range, it is easy to obtain an effect of improving durability such as cycle characteristics and storage characteristics, and it is also possible to keep the viscosity of the nonaqueous electrolyte within an appropriate range, avoid a decrease in electrical conductivity, and make it easy to keep the input / output characteristics and charge / discharge rate characteristics of the nonaqueous electrolyte battery within appropriate ranges.

[0079] <(IV) Compound Represented by General Formula (3)> The nonaqueous electrolyte solution of the present disclosure further contains (IV) a compound represented by general formula (3) (also referred to as "(IV)").

[0080]

[0081] In the general formula (3), W is a phosphorus atom or a sulfur atom, and y is 1 when W is a phosphorus atom, and y is 2 when W is a sulfur atom.

[0082] In the nonaqueous electrolyte solution of the present disclosure, one type of compound may be used alone as (IV), or two types of compounds may be mixed in any ratio depending on the application.

[0083] In the nonaqueous electrolyte solution of the present disclosure, the content of (IV) (also referred to as the "concentration of (IV)") relative to the total amount of the nonaqueous electrolyte solution may be 0.001% by mass or more and 5% by mass or less. The lower limit of the concentration of (IV) may be 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.08% by mass or more, or 0.1% by mass or more. The upper limit of the concentration of (IV) may be 3% by mass or less, 2% by mass or less, 1% by mass or less, or 0.8% by mass or less.

[0084] In the nonaqueous electrolyte solution of the present disclosure, the mass ratio of the content of (IV) to the total amount of (I) and (IV), (IV) / {(I)+(IV)}, is preferably 0.00019 to 0.99. The lower limit of this ratio may be 0.0002 or more, 0.0005 or more, 0.0010 or more, 0.0100 or more, or 0.0500 or more. The upper limit of this ratio may be 0.8, 0.6, 0.4, or 0.2.

[0085] <Regarding Other Components That May Be Included> The above is a description of the basic configuration of the nonaqueous electrolyte solution of the present disclosure, but the nonaqueous electrolyte solution of the present disclosure may contain the components described below (hereinafter also referred to as "other components that may be included" or "other components") in any combination and ratio, as long as the gist of the present disclosure is not impaired. As the other components, for example, additives commonly used in this technical field may be added in any ratio.

[0086] Specific examples of other components include vinylene carbonate, fluoroethylene carbonate, nitrates, 1,3-propene sultone, 1,3-propane sultone, 1,6-diisocyanatohexane, dimethyl dicarbonate, ethynylethylene carbonate, trans-difluoroethylene carbonate, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl-1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethanedisulfonic anhydride, methanesulfonic anhydride, methanesulfonyl fluoride, 1,4-dioxane-2,6-dione, thiazolin ... Examples of suitable electrolytes include tripropargyl phosphate, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, N,N'-carbonylbis(N-methylsulfamoyl fluoride), tetravinylsilane, trivinylmethylsilane, t-butylbenzene, t-amylbenzene, fluorobenzene, and cyclohexylbenzene, and it is preferable to contain at least one selected from these. By including the above-mentioned other components in the nonaqueous electrolyte solution of the present disclosure, at least one of the overcharge prevention effect, the negative electrode film formation effect, and the positive electrode protection effect may be enhanced.

[0087] When the non-aqueous electrolyte solution of the present disclosure contains other components, the content of the other components may be 0.01% by mass or more and 10% by mass or less relative to the total amount of the non-aqueous electrolyte solution. Among the other components, the content of fluoroethylene carbonate may be 0.01% by mass or more and 55% by mass or less relative to the total amount of the non-aqueous electrolyte solution.

[0088] The nonaqueous electrolyte of the present disclosure is suitable for use in nonaqueous electrolyte batteries (preferably nonaqueous electrolyte secondary batteries).

[0089] 2. Regarding the Non-Aqueous Electrolyte Battery The non-aqueous electrolyte battery of the present disclosure includes at least the non-aqueous electrolyte of the present disclosure, a negative electrode, and a positive electrode. It may also include a separator, an exterior body, and the like. The non-aqueous electrolyte battery of the present disclosure preferably includes at least a positive electrode, a negative electrode, a separator, and the non-aqueous electrolyte of the present disclosure. The non-aqueous electrolyte battery of the present disclosure is preferably a non-aqueous electrolyte secondary battery.

[0090] The negative electrode is not particularly limited, but may be made of a material that allows reversible insertion and desorption of alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions.

[0091] For example, in the case of a lithium-ion battery in which the cation is mainly lithium, the negative electrode active material constituting the negative electrode is capable of doping and dedoping lithium ions. For example, carbon materials having a d value of the (002) lattice plane in X-ray diffraction of 0.340 nm or less, carbon materials having a d value of the (002) lattice plane in X-ray diffraction of more than 0.340 nm, oxides of one or more metals selected from Si, Sn, and Al, alloys containing one or more metals selected from Si, Sn, and Al, or alloys of these metals or alloys with lithium, and lithium titanium oxide. These negative electrode active materials can be used alone or in combination of two or more. Lithium metal, metal nitrides, tin compounds, conductive polymers, etc. may also be used.

[0092] For example, in the case of a sodium-ion battery in which the cation is primarily sodium, the negative electrode active material constituting the negative electrode may be sodium metal, an alloy of sodium metal with other metals such as tin, an intermetallic compound of sodium metal with other metals, various carbon materials such as hard carbon, metal oxides such as titanium oxide, metal nitrides, tin (element), tin compounds, activated carbon, conductive polymers, etc. In addition to these, phosphorus (element) such as red phosphorus or black phosphorus, phosphorus compounds such as Co—P, Cu—P, Sn—P, Ge—P, or Mo—P, antimony (element), or antimony compounds such as Sb / C or Bi—Sb, etc. may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0093] The positive electrode is not particularly limited, but may be made of a material that allows reversible insertion and desorption of alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions.

[0094] For example, when the cation is lithium, the positive electrode material (positive electrode active material) is LiCoO ２ , LiNiO ２ , LiMnO ２ , LiMn ２ O ４ Lithium-containing transition metal composite oxides such as those described above, in which a plurality of transition metals such as Co, Mn, and Ni are mixed, those in which a part of the transition metal in the lithium-containing transition metal composite oxide is replaced with a metal other than the transition metal, and LiFePO , which is called olivine. ４ , LiCoPO ４ , LiMnPO ４ transition metal phosphate compounds such as TiO ２ , V ２ O ５ , MoO ３ oxides such as TiS ２ , sulfides such as FeS, conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, activated carbon, radical-generating polymers, carbon materials, etc. may also be used. １／３ Mn １／３ Co １／３ ]O２ , Li[Ni ０．４５ Mn ０．３５ Co ０．２ ]O ２ , Li[Ni ０．５ Mn ０．３ Co ０．２ ]O ２ , Li[Ni ０．６ Mn ０．２ Co ０．２ ]O ２ (hereinafter, sometimes referred to as "NCM622"), Li[Ni ０．８ Mn ０．１ Co ０．１ ]O ２ (hereinafter, sometimes referred to as "NCM811"), Li[Ni ０．４９ Mn ０．３ Co ０．２ Zr ０．０１ ]O ２ , Li[Ni ０．４９ Mn ０．３ Co ０．２ Mg ０．０１ ]O ２ , LiNi ０．８ Co ０．２ O ２ , LiNi ０．８５ Co ０．１０ Al ０．０５ O ２ , LiNi ０．８７ Co ０．１０ Al ０．０３ O ２ , LiNi ０．９０ Co ０．０７ Al ０．０３ O ２ , LiNi ０．６ Co ０．３ Al ０．１ O ２、 LiMn １．５ Ni ０．５ O ４ etc.

[0095] For example, when the cation is sodium, the positive electrode material (positive electrode active material) is NaCrO ２ , NaFe ０．５ Co ０．５ O ２ , NaFe ０．４ Mn ０．３ Ni ０．３ O２ , NaNi ０．５ Ti ０．３ Mn ０．２ O ２ , NaNi １／３ Ti １／３ Mn １／３ O ２ , NaNi ０．３３ Ti ０．３３ Mn ０．１６ Mg ０．１７ O ２ , Na ２／３ Ni １／３ Ti １／６ Mn １／２ O ２ , Na ２／３ Ni １／３ Mn ２／３ O ２ sodium-containing transition metal composite oxides such as those described above, in which a plurality of transition metals such as Co, Mn, and Ni are mixed, sodium-containing transition metal composite oxides in which a part of the transition metal is replaced with a metal other than the transition metal, NaFePO ４ , NaVPO ４ F, Na ３ V ２ (P.O. ４ ) ３ , Na ２ Fe ２ (SO ４ ) ３ Polyanion type compounds such as those of the formula Na ａ M ｂ [Fe(CN) ６ ] ｃ (M=Cr, Mn, Fe, Co, Ni, Cu, or Zn, and 0≦a≦2, 0.5≦b≦1.5, 0.5≦c≦1.5), TiO ２ , V ２ O ５ , MoO ３ oxides such as TiS ２ Alternatively, sulfides such as FeS, conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, activated carbon, radical-generating polymers, carbon materials, and the like may be used.

[0096] The positive electrode material and the negative electrode material may contain, as a conductive material, acetylene black, ketjen black, carbon fiber, or graphite, and as a binder, polytetrafluoroethylene, polyvinylidene fluoride, SBR resin, or the like, and may further contain an electrode sheet formed into a sheet.

[0097] As a separator for preventing contact between the positive electrode and the negative electrode, a nonwoven fabric or porous sheet made of polypropylene, polyethylene, paper, glass fiber, or the like may be used.

[0098] The above elements are assembled into an electrochemical device having a coin-like, cylindrical, rectangular, aluminum laminate sheet, or other shape.

[0099] In the present specification, in preparing a nonaqueous electrolyte solution, by setting the scale of each component to an appropriate amount and using a balance with appropriate accuracy, the value of (IV) / {(I)+(IV)}, which is the mass ratio of the content of (IV) to the total amount of (I) and (IV), can be calculated to five decimal places.

[0100] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to such examples.

[0101] [Preparation of Nonaqueous Electrolyte Solution] Example 1-1 (Preparation of Nonaqueous Electrolyte Solution 1-1) A mixed solvent of EC:DMC:EMC=3:3:4 (volume ratio) was used as a nonaqueous organic solvent, and lithium hexafluorophosphate (hereinafter, "LiPF 6") was added as a solute to the solvent. ６ ") to a concentration of 1.0 mol / L, lithium difluorophosphate (hereinafter also referred to as "DFP") as component (I) to a concentration of 1.0 mass% relative to the total amount of the non-aqueous electrolyte, and FSO 4 as component (IV). ２ NH ２ was dissolved in the non-aqueous electrolyte solution to a concentration of 0.1% by mass relative to the total amount of the non-aqueous electrolyte solution, to prepare non-aqueous electrolyte solution 1-1. The above preparation was carried out while maintaining the solution temperature at 25°C.

[0102] Examples 1-2 to 1-18 (Preparation of Nonaqueous Electrolytes 1-2 to 1-18) Non-aqueous electrolytes 1-2 to 1-18 were prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte 1-1, except that the type and concentration of component (I) and the concentration of component (IV) were changed as shown in Table 1. In addition, "FS" means lithium fluorosulfonate, "BOB" means lithium bis(oxalato)borate, "DFOB" means lithium difluorooxalatoborate, "DFBOP" means lithium difluorobis(oxalato)phosphate, "TFOP" means lithium tetrafluorooxalatophosphate, "TOP" means lithium tris(oxalato)phosphate, "DFPFSI" means lithium (difluorophosphoryl)(fluorosulfonyl)imide, and "DFPI" means lithium bis(difluorophosphoryl)imide.

[0103] Comparative Example 1-0-1 (Preparation of Comparative Non-Aqueous Electrolyte Solution 1-0-1) Comparative non-aqueous electrolyte solution 1-0-1 was prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte solution 1-1, except that component (I) and component (IV) were not added.

[0104] Comparative Example 1-0-2 (Preparation of Comparative Non-Aqueous Electrolyte 1-0-2) Comparative non-aqueous electrolyte 1-0-2 was prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte 1-1, except that component (I) was not added.

[0105] Comparative Examples 1-1 to 1-20 (Preparation of Comparative Non-Aqueous Electrolytes 1-1 to 1-20) Comparative non-aqueous electrolytes 1-1 to 1-18 were prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte 1-1, except that the type and concentration of component (I) were changed as shown in Table 1 and that component (IV) was not added. Furthermore, comparative non-aqueous electrolytes 1-19 to 1-20 were prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte 1-1, except that the types and concentrations of component (I) and component (IV) were changed as shown in Table 1.

[0106] Examples 2-1 to 2-18 (Preparation of Non-Aqueous Electrolyte Solutions 2-1 to 2-18) Non-aqueous electrolyte solutions 2-1 to 2-18 were prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte solution 1-1, except that the types and concentrations of component (I) and component (IV) were changed as shown in Table 2.

[0107] Comparative Example 1-0-3 (Preparation of Comparative Non-Aqueous Electrolyte 1-0-3) F as Component (IV) ２ PONH ２ Comparative non-aqueous electrolyte solution 1-0-3 was prepared by dissolving in the same manner as in the preparation of comparative non-aqueous electrolyte solution 1-0-2, except that the following was used:

[0108] Comparative Examples 2-1 to 2-8 (Preparation of Comparative Non-Aqueous Electrolytes 2-1 to 2-8) Comparative non-aqueous electrolytes 2-1 to 2-8 were prepared by dissolving in the same manner as in the preparation of non-aqueous electrolyte 1-1, except that the type and concentration of component (I) were changed as shown in Table 2 and component (IV) was not added.

[0109] Examples 3-1 to 3-18, Comparative Examples 3-0-1 to 3-20 to Examples 4-1 to 4-18, Comparative Examples 4-1 to 4-8 EC, DMC, and EMC were used as nonaqueous organic solvents, and FEC was used as another component. These were mixed and dissolved in a volume ratio of EC:FEC:DMC:EMC = 3:0.2:3:3.8, and then LiPF was added as a solute. ６ and lithium bis(fluorosulfonyl)imide (hereinafter also referred to as "LiFSI") were dissolved to concentrations of 1.0 mol / L and 0.1 mol / L, respectively, and the types and concentrations of component (I) and component (IV) were changed as shown in Tables 3 and 4. Except for this, the nonaqueous electrolyte solutions and comparative nonaqueous electrolyte solutions shown in each table were prepared in the same manner as in the preparation of the electrolyte solutions shown in Tables 1 and 2.

[0110] Examples 5-1 to 5-17, Comparative Examples 5-0-1 to 5-19 to Examples 6-1 to 6-17, Comparative Examples 6-1 to 6-8 EC, PC, and EMC were used as non-aqueous organic solvents, and FEC was used as another component. These were mixed and dissolved in a volume ratio of EC:PC:FEC:EMC=2:1:0.2:6.8, and then sodium hexafluorophosphate (hereinafter "NaPF") was added as a solute. ６ ") was dissolved to a concentration of 1.0 mol / L, and the types and concentrations of component (I) and component (IV) were changed as shown in Tables 5 and 6. The same dissolution procedures as in the preparation of the electrolyte solutions shown in Tables 1 and 2 were carried out to prepare non-aqueous electrolyte solutions and comparative non-aqueous electrolyte solutions shown in each table.

[0111] [Preparation of non-aqueous electrolyte battery] (Preparation of NCM622 positive electrode) LiNi ０．６ Co ０．２ Mn ０．２ O ２ 90.0% by mass of the powder was mixed with 5.0% by mass of polyvinylidene fluoride (hereinafter also referred to as "PVDF") as a binder and 5.0% by mass of acetylene black as a conductive material, and N-methyl-2-pyrrolidone (hereinafter also referred to as "NMP") was further added to prepare a positive electrode composite paste. This paste was applied to both sides of aluminum foil (A1085), dried, pressed, and then punched out to a 4 cm x 5 cm piece to obtain a test NCM622 positive electrode.

[0112] (Preparation of NCM811 positive electrode) LiNi ０．８ Mn ０．１ Co ０．１ O ２ A positive electrode composite paste was prepared by mixing 92.0% by mass of the powder with 3.5% by mass of PVDF as a binder and 4.5% by mass of acetylene black as a conductive material, followed by addition of NMP. This paste was applied to both sides of aluminum foil (A1085), dried, pressed, and then punched out to a 4 cm x 5 cm piece to obtain a test NCM811 positive electrode.

[0113] (Sodium ion battery positive electrode: NaNi ０．５ Ti ０．３ Mn ０．２ O ２ Preparation of positive electrode) NaNi was used as the positive electrode active material. ０．５ Ti ０．３ Mn ０．２ O ２ 90.0 mass% of the above, 5.0 mass% of acetylene black as a conductive agent, and 5.0 mass% of PVDF as a binder were mixed, and NMP was further added as a solvent to prepare a positive electrode composite paste. This paste was applied to both sides of aluminum foil (A1085), dried, pressed, and then punched out to 4 cm x 5 cm to prepare a test NaNi ０．５ Ti ０．３ Mn ０．２ O ２ The positive electrode was obtained.

[0114] (Preparation of Natural Graphite Negative Electrode) 92.0% by mass of natural graphite powder, 3.0% by mass of conductive material (HS-100 manufactured by Denka), 2.0% by mass of carbon nanofiber (VGCF manufactured by Showa Denko), 2.0% by mass of styrene butadiene rubber (hereinafter also referred to as "SBR"), 1.0% by mass of sodium carboxymethyl cellulose (hereinafter also referred to as "CMC"), and water were mixed to prepare a negative electrode composite paste. This paste was applied to copper foil, dried, pressed, and then punched out to 4.5 cm x 5.5 cm to obtain a test natural graphite negative electrode.

[0115] (Preparation of silicon-containing graphite negative electrode) 85.0% by mass of artificial graphite powder, 7.0% by mass of nanosilicon, 3.0% by mass of conductive material (HS-100 manufactured by Denka), 2.0% by mass of carbon nanofiber (VGCF manufactured by Showa Denko), 2.0% by mass of SBR, 1.0% by mass of CMC, and water were mixed to prepare a negative electrode composite paste. This paste was applied to copper foil, dried, pressed, and then punched out to 4.5 cm x 5.5 cm to obtain a silicon-containing graphite negative electrode for testing.

[0116] (Preparation of Hard Carbon Negative Electrode) 90.0% by mass of hard carbon powder (Carbotron P, manufactured by Kureha Corporation) and 10.0% by mass of PVDF as a binder were mixed, and NMP was further added as a solvent to prepare a negative electrode composite paste. This paste was applied to aluminum foil (A1085), dried, pressed, and then punched out to 4.5 cm × 5.5 cm to obtain a test hard carbon negative electrode.

[0117] (Preparation of Nonaqueous Electrolyte Battery) After welding a terminal to the above-mentioned NCM622 positive electrode in an argon atmosphere with a dew point of −50° C. or less, the positive electrode was sandwiched between two polyethylene separators (5 cm × 6 cm). The outer surface of the separator was then sandwiched between two natural graphite negative electrodes with terminals previously welded, with the negative electrode active material facing the positive electrode active material. The resulting assembly was then placed in an aluminum laminate bag with an opening on one side. After vacuum-injecting the nonaqueous electrolyte, the opening was heat-sealed to prepare the aluminum laminate nonaqueous electrolyte batteries according to the examples and comparative examples shown in Tables 1 and 2. In the examples and comparative examples shown in Tables 3 and 4, nonaqueous electrolyte batteries were similarly prepared using NCM811 as the positive electrode and silicon-containing graphite as the negative electrode. In the examples and comparative examples shown in Tables 5 and 6, NaNi was used as the positive electrode. ０．５ Ti ０．３ Mn ０．２ O ２ A non-aqueous electrolyte battery (sodium ion battery) was similarly fabricated using a hard carbon negative electrode as the positive electrode and the negative electrode.

[0118] [Evaluation] <Initial Charge / Discharge Test: Lithium-Ion Battery> First, conditioning was performed using the prepared cell at an ambient temperature of 25° C. under the following conditions. That is, in the initial charge / discharge test, the cell was charged at a constant current and constant voltage of 5 mA at an upper charge voltage of 4.2 V, discharged at a constant current of 10 mA to a discharge cut-off voltage of 2.5 V, and then charged at a constant current and constant voltage of 10 mA at an upper charge voltage of 4.2 V, and discharged at a constant current of 10 mA to a discharge cut-off voltage of 2.5 V. This charge / discharge cycle was repeated three times. The discharge capacity in the third cycle was taken as the initial discharge capacity.

[0119] <Initial Charge / Discharge Test: Sodium-Ion Battery> First, the fabricated cell was conditioned at an ambient temperature of 25° C. under the following conditions. That is, in the initial charge / discharge test, the cell was charged at a constant current and constant voltage of 5 mA at an upper charge voltage of 4.1 V, discharged at a constant current of 10 mA to a discharge cut-off voltage of 1.5 V, and then charged at a constant current and constant voltage of 10 mA at an upper charge voltage of 4.1 V, and discharged at a constant current of 10 mA to a discharge cut-off voltage of 1.5 V. This charge / discharge cycle was repeated three times. The discharge capacity in the third cycle was taken as the initial discharge capacity.

[0120] <Cycle Test (25°C): Lithium-ion Battery> The nonaqueous electrolyte battery after the initial charge / discharge test was subjected to constant-current / constant-voltage charging at 100 mA with an upper limit charge voltage of 4.2 V, and constant-current discharging at 100 mA to a discharge cut-off voltage of 2.5 V. This charge / discharge cycle at 100 mA in a 25°C environment was repeated 1,000 cycles. Thereafter, the battery was subjected to constant-current / constant-voltage charging at 10 mA with an upper limit charge voltage of 4.2 V, and constant-current discharging at 10 mA to a discharge cut-off voltage of 2.5 V, and the discharge capacity was recorded as the discharge capacity after the cycle test.

[0121] <Cycle Test (25° C.): Sodium Ion Battery> The sodium ion battery was evaluated in the same manner as the lithium ion battery, except that the upper limit charge voltage was changed to 4.1 V and the end-of-discharge voltage was changed to 1.5 V.

[0122] <Capacity retention rate after cycle test: lithium ion battery> The capacity retention rate after cycle test was calculated using the following formula. A larger value indicates better cycle characteristics. Capacity retention rate after cycle test (%) = (discharge capacity after cycle test / initial discharge capacity) x 100

[0123] <Capacity retention rate after cycle test: sodium ion battery> Evaluated in the same manner as for lithium ion batteries. A larger value indicates better cycle characteristics.

[0124] <Measurement of low-temperature (-20°C) DC internal resistance after cycle testing: lithium-ion battery> The nonaqueous electrolyte battery subjected to the above cycle testing was charged at a constant current of 10 mA for 150 minutes at an ambient temperature of 25°C, allowed to stand at an ambient temperature of -20°C for 5 hours, and then charged at a constant current of predetermined values ​​(0.5 mA, 1.0 mA, 2.5 mA, 5.0 mA, 10.0 mA) for 10 seconds. The voltage at the 10th second was measured and plotted against the current value. An approximate line was obtained by applying the least squares method to each plot. The slope of the approximate line was taken as the low-temperature DC internal resistance after the cycle testing. A smaller value indicates better low-temperature input characteristics after the cycle testing.

[0125] <Measurement of DC internal resistance at low temperature (-20°C) after cycle test: sodium ion battery> Evaluation was performed in the same manner as for the lithium ion battery. The smaller this value, the better the low-temperature input characteristics after cycle test.

[0126] The evaluation results are shown in the following Tables 1 to 6. In each of the Examples in Tables 1 to 6, the cycle capacity retention rate and the low-temperature DC internal resistance after the cycle test are also shown as relative values ​​when the value of each Comparative Example using a nonaqueous electrolyte solution under the same conditions except that it did not contain component (IV) is set at 100.

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149]

[0150]

[0151] In the comparative nonaqueous electrolytes 1-19 in Table 1, 3-19 in Table 3, and 5-18 in Table 5, SO ２ CH ３ NH ２ Although methanesulfonamide is not included in component (IV), it is listed in the component (IV) column for convenience. In comparative non-aqueous electrolytes 1-20 in Table 1 and comparative non-aqueous electrolytes 3-20 in Table 3, compound 1a(Li) represents the following compound. Although compound 1a(Li) is not included in component (I), it is listed in the component (I) column for convenience.

[0152]

[0153] Compound 1a(Li) was synthesized by the method described in

[0090] of WO 2021 / 015264.

[0154] In the comparative non-aqueous electrolyte solution 5-19 in Table 5, compound 1a(Na) represents the following compound. Although compound 1a(Na) is not included in component (I), it is listed in the component (I) column for convenience.

[0155]

[0156] Compound 1a(Na) was synthesized according to the method described in

[0090] of WO 2021 / 015264.

[0157] Tables 1 to 6 show that, when compared under identical conditions except for the presence or absence of component (IV), nonaqueous electrolyte batteries containing the nonaqueous electrolytes of Examples containing components (I) and (IV) exhibit superior room-temperature cycle characteristics and low-temperature input characteristics after cycle testing compared to nonaqueous electrolyte batteries containing the nonaqueous electrolytes of Comparative Examples containing component (I) but not component (IV). Furthermore, the Comparative Examples containing component (IV) but not component (I), and the Comparative Examples containing neither component (I) nor (IV), all exhibited inferior room-temperature cycle characteristics and low-temperature input characteristics after cycle testing compared to the nonaqueous electrolyte batteries containing the nonaqueous electrolytes of Examples. Furthermore, the Comparative Examples using compounds 1a(Li) and 1a(Na), which are comparative compounds not corresponding to component (I), all exhibited inferior room-temperature cycle characteristics and low-temperature input characteristics after cycle testing compared to the corresponding Examples using compounds corresponding to component (I). Furthermore, the Comparative Examples using SO , which is a comparative compound not corresponding to component (IV), all exhibited inferior room-temperature cycle characteristics and low-temperature input characteristics after cycle testing compared to the corresponding Examples using compounds corresponding to component (I). ２ CH ３ NH ２ The comparative examples using the compound corresponding to component (IV) were all inferior in room temperature cycle characteristics and low temperature input characteristics after the cycle test.

[0158] According to the present disclosure, it is possible to provide a nonaqueous electrolyte and a nonaqueous electrolyte battery that, when used in a nonaqueous electrolyte battery, can exhibit excellent room temperature cycle characteristics and low temperature input characteristics after a cycle test.

[0159] Although the present disclosure has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present disclosure. This application is based on a Japanese patent application (Patent Application No. 2023-174648) filed on October 6, 2023, the contents of which are incorporated herein by reference.

Claims

1. A non-aqueous electrolyte solution containing: (I) at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, monofluorosulfonates, salts represented by the following general formula (1), and salts represented by the following general formula (2): (II) a solute; (III) a non-aqueous organic solvent; and (IV) a compound represented by the following general formula (3): In general formula (1), W １ represents a boron atom, a phosphorus atom, or a silicon atom, n1 is 1 to 3, n2 is 0 to 4, and p is 0 or 1. １１ represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure. When n1 is 2 or more, n1 R １１ may be bonded to each other), R １２ represents a halogen atom; Y １ and Y ２ each independently represents an oxygen atom or a sulfur atom; Y ３ represents a carbon atom or a sulfur atom. ３ The carbon atom or sulfur atom represented by is bonded with q oxo groups (=O). ３ is 1 when it is a carbon atom, and is 1 or 2 when it is a sulfur atom. ａ＋ represents an alkali metal cation, an alkaline earth metal cation, or an onium cation, a represents the valence of the corresponding cation, and a to d are 1 or 2, and a×b=c×d is satisfied. In general formula (2), M ｎ＋ is an alkali metal cation, an alkaline earth metal cation, or an onium cation, and n is an integer equal to the valence of the corresponding cation. X is a sulfur atom or a phosphorus atom, and when X is a sulfur atom, m is 2; R ４ is absent, when X is a phosphorus atom, m is 1, and R １ , R ２ , R ３ and R ４ are each independently an organic group selected from a fluorine atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkenyloxy group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a cycloalkoxy group having 3 to 10 carbon atoms, a cycloalkenyl group having 3 to 10 carbon atoms, a cycloalkenyloxy group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms, and a fluorine atom, an oxygen atom, or an unsaturated bond may also be present in the organic group. In general formula (3), W is a phosphorus atom or a sulfur atom, and when W is a phosphorus atom, y is 1, and when W is a sulfur atom, y is 2.

2. The nonaqueous electrolyte according to claim 1, wherein the mass ratio of the content of said (IV) to the total amount of said (I) and said (IV), that is, (IV) / {(I)+(IV)}, is 0.00019 to 0.

99.

3. The nonaqueous electrolyte according to claim 1, wherein the salt represented by the general formula (1) is at least one selected from the group consisting of bis(oxalato)borate, difluoro(oxalato)borate, tris(oxalato)phosphate, difluorobis(oxalato)phosphate, and tetrafluoro(oxalato)phosphate.

4. The nonaqueous electrolyte according to claim 1, wherein the salt represented by the general formula (2) has at least one P--F bond or S--F bond.

5. The non-aqueous electrolyte according to claim 1, wherein the cation of the salt shown in (I) is a lithium ion, a sodium ion, a potassium ion, or a tetraalkylammonium ion.

6. The above (II) is LiPF ６ , LiBF ４ , LiSbF ６ , LiAsF ６ , LiClO ４ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiN(SO ２ F) ２ , LiAlO ２ , LiAlCl ４ At least one selected from the group consisting of LiCl, LiI, and NaPF ６ , NaBF ４ , NaSbF ６ , NaAsF ６ , NaClO ４ , NaCF ３ SO ３ , NaC ４ F ９ SO ３ , NaN(SO ２ F) ２ , NaAlO ２ , NaAlCl ４ 2. The nonaqueous electrolyte according to claim 1, which is at least one selected from the group consisting of NaCl, NaI, and NaI.

7. The nonaqueous electrolyte according to claim 1, wherein the (III) contains at least one selected from the group consisting of cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids.

8. The non-aqueous electrolyte according to claim 7, wherein the cyclic ester comprises a cyclic carbonate.

9. The nonaqueous electrolyte according to claim 8, wherein the cyclic carbonate comprises at least one selected from the group consisting of ethylene carbonate and propylene carbonate.

10. The nonaqueous electrolyte according to claim 7, wherein the chain ester comprises a chain carbonate.

11. The nonaqueous electrolyte according to claim 10, wherein the chain carbonate comprises at least one selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and methyl propyl carbonate.

12. In addition, vinylene carbonate, fluoroethylene carbonate, nitrates, 1,3-propene sultone, 1,3-propane sultone, 1,6-diisocyanatohexane, dimethyl dicarbonate, ethynyl ethylene carbonate, trans-difluoroethylene carbonate, 1,3,2-dioxathiolane-2,2-dioxide, 4-propyl-1,3,2-dioxathiolane-2,2-dioxide, methylenemethane disulfonate, 1,2-ethane disulfonic anhydride, methanesulfonic anhydride, methanesulfonyl fluoride, 1,4-dioxane-2,6-dione, triplo The non-aqueous electrolyte solution according to claim 1, which contains at least one selected from the group consisting of pargyl phosphate, tris(trimethylsilyl)borate, (ethoxy)pentafluorocyclotriphosphazene, tetrafluoro(picolinato)phosphate, 1,3-dimethyl-1,3-divinyl-1,3-di(1,1,1,3,3,3-hexafluoroisopropyl)disiloxane, N,N'-carbonylbis(N-methylsulfamoyl fluoride), tetravinylsilane, trivinylmethylsilane, t-butylbenzene, t-amylbenzene, fluorobenzene, and cyclohexylbenzene.

13. A nonaqueous electrolyte battery comprising at least a positive electrode, a negative electrode, a separator, and the nonaqueous electrolyte according to any one of claims 1 to 12.

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