Non-aqueous electrolyte solution for batteries, lithium secondary battery precursor, lithium secondary battery, and method for producing lithium secondary battery

Abstract

A non-aqueous electrolyte solution for batteries according to the present disclosure contains a compound (A) and a compound (B). The compound (A) is at least one selected from the group consisting of compounds (1) to (8). The compound (B) is at least one selected from the group consisting of compounds (9) to (11). R11 denotes formula (i-1), formula (i-2), formula (i-3), or the like. Formula (i-3) denotes formula (i-4), etc. * denotes a bonding position. R12, R15, R31, R81, Q1, and Q2 denote divalent groups. R13, R14, R32, R41, R42, R51 to R54, R61, R62, R71, R82, R 91, R92, R101 to R103, and R111 to R113 denote monovalent groups. M in formula (3), M in formula (6), and M in formula (11) denote alkali metals. b is 1 to 3. m is 1 to 4. n is 0 to 8. q is 0 or 1. L1 and L2 each denote a single bond or -O-.

Description

Nonaqueous electrolyte for battery, lithium secondary battery precursor, lithium secondary battery, and method for manufacturing lithium secondary battery

[0001] The present disclosure relates to a nonaqueous electrolyte for a battery, a lithium secondary battery precursor, a lithium secondary battery, and a method for manufacturing a lithium secondary battery.

[0002] In recent years, various studies have been conducted on non-aqueous electrolytes for batteries. For example, Patent Document 1 discloses a battery including a positive electrode active material containing lithium iron phosphate.

[0003] Patent Document 1: Patent No. 5317390

[0004] In recent years, evaluation items for lithium-ion secondary batteries have become more diverse. For example, the resistance value and capacity retention rate after storage in a high-temperature environment, and the resistance value in a medium or lower state of charge (SOC) range (e.g., a 50% SOC range; the same applies hereinafter) are important evaluation items that still have room for improvement.

[0005] An object of one aspect of the present disclosure is to provide a nonaqueous electrolyte solution that can improve various characteristics of a lithium ion secondary battery, more specifically, that can improve the capacity retention rate after high-temperature storage or reduce the battery resistance in a region where the SOC is medium or lower.An object of another aspect of the present disclosure is to provide a lithium secondary battery that includes a nonaqueous electrolyte solution for a battery, the lithium secondary battery having an improved capacity retention rate after high-temperature storage or reduced battery resistance in a region where the SOC is medium or lower, as well as a method for producing a lithium secondary battery and a lithium secondary battery precursor that can produce this lithium secondary battery.

[0006] Means for solving the above problems include the following aspects: <1> A nonaqueous electrolyte solution for a battery, comprising a compound (A) and a compound (B), wherein the compound (A) is at least one selected from the group consisting of a compound (1) represented by the following formula (1), a compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, a compound (3) represented by the following formula (3), a compound (4) represented by the following formula (4), a compound (5) represented by the following formula (5), a compound (6) represented by the following formula (6), a compound (7) represented by the following formula (7), and a compound (8) represented by the following formula (8), and the compound (B) is at least one selected from the group consisting of a compound (9) represented by the following formula (9), a compound (10) represented by the following formula (10), and a compound (11) represented by the following formula (11).

[0007]

[0008] [In formula (1), R １１ represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (i-1), a group represented by formula (i-2), or a group represented by formula (i-3), and in formula (i-1), R １２ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, * represents a bonding position, and in formula (i-2), R １３ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a hydrogen atom, * represents a bonding position, and in formula (i-3), R １４ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by formula (i-4), * represents a bonding position, and in formula (i-4), R １５ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, and * represents a bonding position. In formula (3), M represents an alkali metal, b represents an integer of 1 to 3, m represents an integer of 1 to 4, n represents an integer of 0 to 8, q represents 0 or 1, and R ３１represents 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, and when q is 1 and m is 2 to 4, m R ３１ may be bonded to each other; ３２ represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure, and when n is 2 to 8, n R ３２ may be bonded to each other to form a ring; １ and Q ２ are each independently —O— or —CH ２ In formula (4), R ４１ and R ４２ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms. ５１ ~R ５４ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms, and the double line consisting of a solid line and a dotted line represents a single bond or a double bond. ６１ each independently represents a fluorine atom or a fluorohydrocarbon group having 1 to 6 carbon atoms, and M represents an alkali metal. ７１ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms. ８１ represents an alkylene group having 1 to 10 carbon atoms or a halogenated alkylene group having 1 to 10 carbon atoms; R ８２ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a halogenated hydrocarbon group having 1 to 10 carbon atoms (provided that two R ８２ may be linked together to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms). In formula (9), R ９１ and R ９２each independently represents an alkyl group having 1 to 10 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), an alkenyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkenyl group may be substituted with a halogen atom), an alkynyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkynyl group may be substituted with a halogen atom), an aryl group (at least one hydrogen atom of the aryl group may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms), or a halogen atom; １ and L ２ each independently represents a single bond or —O—. １０１ ~R １０３ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. １１１ represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorohydrocarbon group having 1 to 10 carbon atoms; R １１２ and R １１３ each independently represents a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms (provided that R １１２ and R １１３at least one of which is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group; and M represents an alkali metal. <2> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) consists of the compound (2) and at least one selected from the group consisting of the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8); and the compound (B) consists of the compound (9). <3> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) consists of the compound (1) and at least one selected from the group consisting of the compound (2), the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8); and the compound (B) consists of the compound (9). <4> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) is the compound (1), and the compound (B) is the compound (9) and at least one selected from the group consisting of the compound (10) and the compound (11). <5> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) includes the compound (5). <6> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) includes the compound (7). <7> The nonaqueous electrolyte solution for a battery according to <1>, wherein the compound (A) includes the compound (8). <8> The nonaqueous electrolyte solution for a battery according to <1>, which is used for a lithium secondary battery including a positive electrode active material containing lithium metal phosphate. <9> The nonaqueous electrolyte solution for a battery according to <8>, wherein the compound (A) is at least one selected from the group consisting of the compound (1), the compound (2), the compound (3), and the compound (4), and the compound (B) is at least one selected from the group consisting of the compound (9) and the compound (10). <10> A lithium secondary battery precursor, comprising: a case; and a positive electrode, a negative electrode, a separator, and an electrolyte housed in the case, wherein the positive electrode contains a positive electrode active material containing lithium metal phosphate, and the electrolyte is the nonaqueous electrolyte solution for a battery according to any one of <1> to <9>.<11> A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to <10>. <12> A method for producing a lithium secondary battery, comprising: preparing the lithium secondary battery precursor according to <10>; and charging and discharging the lithium secondary battery precursor.

[0009] According to one aspect of the present disclosure, there is provided a non-aqueous electrolyte for a battery that can improve the capacity retention rate during storage of a battery that includes a positive electrode active material containing lithium metal phosphate. According to another aspect of the present disclosure, there is provided a lithium secondary battery that includes a positive electrode that includes a positive electrode active material containing lithium metal phosphate and a non-aqueous electrolyte for a battery, the lithium secondary battery having an improved capacity retention rate during storage, as well as a method for manufacturing the lithium secondary battery and a lithium secondary battery precursor that can manufacture the lithium secondary battery.

[0010] 1 is a schematic cross-sectional view showing a laminated battery as an example of a lithium secondary battery precursor according to the present disclosure, and FIG. 2 is a schematic cross-sectional view showing a coin battery as another example of a lithium secondary battery precursor according to the present disclosure.

[0011] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, when a composition contains multiple substances corresponding to each component, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. In this specification, the term "process" includes not only an independent process, but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0012] [Non-aqueous Electrolyte for Battery] The non-aqueous electrolyte for battery of the present disclosure (hereinafter also simply referred to as "nonaqueous electrolyte") contains compound (A) and compound (B). Compound (A) is at least one selected from the group consisting of compound (1) represented by formula (1) described below, compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, compound (3) represented by formula (3) described below, compound (4) represented by formula (4) described below, compound (5) represented by formula (5) described below, compound (6) represented by formula (6), compound (7) represented by formula (7), and compound (8) represented by formula (8). Compound (B) is at least one selected from the group consisting of compound (9) represented by formula (9) described below, compound (10) represented by formula (10) described below, and compound (11) represented by formula (11) described below. The non-aqueous electrolyte solution is preferably used in a lithium secondary battery that includes a positive electrode active material containing lithium metal phosphate (for example, the lithium secondary battery of the present disclosure described below).

[0013] As described above, the inventors' investigations have revealed that there is room for reducing the capacity retention rate of a lithium secondary battery after high-temperature storage or the resistance in a medium or lower SOC (State of Charge) range (e.g., a 50% SOC range; the same applies hereinafter). The nonaqueous electrolyte solution of the present disclosure can improve the capacity retention rate after high-temperature storage or reduce the resistance of the battery in a medium or lower SOC range. This is thought to be because the nonaqueous electrolyte solution of the present disclosure contains compound (A) and compound (B), which allows a coating with excellent electrode protection effect or a coating with low resistance in a medium or lower SOC range to be formed on the electrode surface.

[0014] <Compound (A)> The nonaqueous electrolyte solution of the present disclosure contains compound (A). Compound (A) is at least one selected from the group consisting of compound (1) represented by formula (1) described below, compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, compound (3) represented by formula (3) described below, compound (4) represented by formula (4) described below, compound (5) represented by formula (5) described below, compound (6) represented by formula (6) described below, compound (7) represented by formula (7) described below, and compound (8) represented by formula (8) described below.

[0015] The content of compound (A) (total content when two or more types are used) is preferably 0.01 mass % to 5.0 mass %, more preferably 0.05 mass % to 3.0 mass %, even more preferably 0.10 mass % to 2.5 mass %, and still more preferably 0.10 mass % to 2.0 mass %, relative to the total amount of the nonaqueous electrolyte.

[0016] In addition, when the non-aqueous electrolyte solution collected by disassembling the lithium secondary battery is actually analyzed, the amount of compound (A) may be reduced compared to the amount added to the non-aqueous electrolyte solution. Even in this case, if even a small amount of compound (A) is detected in the non-aqueous electrolyte solution removed from the lithium secondary battery, the electrolyte solution of the lithium secondary battery is included in the scope of the non-aqueous electrolyte solution of the present disclosure. The same applies to compound (B) described below.

[0017] In the nonaqueous electrolyte solution of the present disclosure, the ratio of the mass content of compound (A) to the mass content of compound (B) (hereinafter also referred to as the "mass content ratio [compound (A) / compound (B)]") is preferably 0.10 to 10, more preferably 0.10 to 5.0, even more preferably 0.10 to 2.0, still more preferably 0.10 to 1.5, still more preferably 0.10 or more and less than 1.0, and still more preferably 0.10 to 0.90.

[0018] Compounds (1) to (8), which are alternatives to compound (A), will be explained below.

[0019] (Compound (1) Represented by Formula (1)) In the nonaqueous electrolyte solution of the present disclosure, compound (1), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (1):

[0020]

[0021] In formula (1), R １１ represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (i-1), a group represented by formula (i-2), or a group represented by formula (i-3), * represents a bonding position, and in formula (i-1), R １２ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, * represents a bonding position, and in formula (i-2), R １３ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a hydrogen atom, * represents a bonding position, and in formula (i-3), R １４ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by formula (i-4), * represents a bonding position, and in formula (i-4), R １５ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, and * represents the bonding position.

[0022] In formula (1), R １１ is preferably a group represented by formula (i-1) or a group represented by formula (i-2).

[0023] In formula (i-1), R １２ is preferably an alkylene group having 1 to 3 carbon atoms, an alkenylene group having 1 to 3 carbon atoms, or an oxymethylene group, and more preferably an oxymethylene group. １３ is preferably an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 to 3 carbon atoms, and more preferably a propyl group.

[0024] Specific examples of the compound (1) include the following compound (1)-1, compound (1)-2, and compound (1)-3, with the following compound (1)-1 being particularly preferred.

[0025]

[0026] When compound (A) contains compound (1), the content of compound (1) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0027] Compound (A) preferably includes compound (1). Specifically, compound (A) preferably consists of compound (1), or consists of compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), and compound (5). Compound (A) more preferably consists of compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), and compound (5).

[0028] The proportion of compound (1) in compound (A) is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 70% by mass to 90% by mass.

[0029] (Compound (2) Represented by Formula (2)) In the nonaqueous electrolyte solution of the present disclosure, compound (2), which is one of the options for compound (A), is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate. In the examples described later, "compound (2)-1" is lithium difluorophosphate.

[0030] When compound (A) contains compound (2), the content of compound (2) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0031] (Compound (3) Represented by Formula (3)) Compound (3), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (3):

[0032]

[0033] In formula (3), M represents an alkali metal, b represents an integer of 1 to 3, m represents an integer of 1 to 4, n represents an integer of 0 to 8, q represents 0 or 1, and R ３１ 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, and when q is 1 and m is 2 to 4, m R ３１ may be bonded to each other; ３２ represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure, and when n is 2 to 8, n R ３２ may be bonded to each other to form a ring; １ and Q ２ are each independently —O— or —CH ２ Represents -.

[0034] M is an alkali metal. Examples of alkali metals include lithium, sodium, and potassium. Among these, M is preferably lithium. b represents the valence of the anion and the number of cations. b is an integer of 1 to 3, and is preferably 1. When b is 3 or less, the salt of the anionic compound is easily dissolved in the mixed organic solvent. m and n each represent a value related to the number of ligands. m and n each represent a value determined by the type of M. m is an integer of 1 to 4. n is an integer of 0 to 8. q is 0 or 1. When q is 0, the chelate ring is a five-membered ring, and when q is 1, the chelate ring is a six-membered ring. R ３１represents 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 alkylene groups, halogenated alkylene groups, arylene groups, or halogenated arylene groups may contain a substituent or a heteroatom in their structure. Specifically, these groups may contain a substituent in place of a hydrogen atom. Examples of the substituent include a halogen atom, a linear or cyclic alkyl group, an aryl group, an alkenyl group, an alkoxy group, an aryloxy group, a sulfonyl group, an amino group, a cyano group, a carbonyl group, an acyl group, an amide group, or a hydroxyl group. The carbon element of these groups may be replaced by a nitrogen atom, a sulfur atom, or an oxygen atom. When q is 1 and m is 2 to 4, m R ３１ may be bonded to each other. An example of such a ligand is ethylenediaminetetraacetic acid. ３２ represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms. These alkyl groups, halogenated alkyl groups, aryl groups, and halogenated aryl groups are represented by R ３１ Similarly, the structure may contain a substituent or a heteroatom, and when n is 2 to 8, n R ３２ may be bonded to each other to form a ring. ３２ As Q, an electron-withdrawing group is preferred, and a fluorine atom is particularly preferred. １ and Q ２ are each independently —O— or —CH ２ -. In other words, the ligand is one of these Q １ and Q ２ It bonds to B (boron atom) via

[0035] Specific examples of the compound (3) include the following compound (3)-1 and compound (3)-2, with the following compound (3)-1 being particularly preferred.

[0036]

[0037] When compound (A) contains compound (3), the content of compound (3) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0038] (Compound (4) Represented by Formula (4)) Compound (4), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (4):

[0039]

[0040] In formula (4), R ４１ and R ４２ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms.

[0041] In formula (4), R ４１ and R ４２ The hydrocarbon group having 1 to 6 carbon atoms represented by the formula (R) may be a linear hydrocarbon group or may have a branched and / or cyclic structure. ４１ and R ４２ The hydrocarbon group having 1 to 6 carbon atoms represented by R is preferably an alkyl group or an aryl group, and more preferably an alkyl group. ４１ and R ４２ The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by the formula (I) is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

[0042] In formula (4), R ５１ or R ５２ The fluorohydrocarbon group having 1 to 6 carbon atoms represented by the formula (I) may be a linear fluorohydrocarbon group or a fluorohydrocarbon group having a branched and / or cyclic structure. ５１ or R ５２ The number of carbon atoms in the fluorohydrocarbon group having 1 to 6 carbon atoms represented by the formula (I) is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

[0043] Specific examples of compound (4) include the compounds described in paragraph 0062 of WO 2020 / 121850. As compound (4), the following compound (4)-1 is particularly preferred.

[0044]

[0045] When compound (A) contains compound (4), the content of compound (4) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0046] (Compound (5) Represented by Formula (5)) Compound (5), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (5):

[0047]

[0048] In formula (5), R ５１ ~R ５４ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms, and the double line consisting of a solid line and a dotted line represents a single bond or a double bond.

[0049] In formula (5), R ５１ ~R ５４ The hydrocarbon group having 1 to 3 carbon atoms represented by the formula (R) may be a linear hydrocarbon group or a hydrocarbon group having a branched structure. ５１ ~R ５４ The hydrocarbon group having 1 to 3 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom.

[0050] In formula (5), R ５１ ~R ５４ The fluorohydrocarbon group having 1 to 3 carbon atoms represented by the formula (I) may be a linear fluorohydrocarbon group or a branched fluorohydrocarbon group. ５１ ~R ５４The fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by the formula (I) is preferably a fluorinated alkyl group having 1 to 3 carbon atoms, more preferably a fluorinated alkyl group having 1 or 2 carbon atoms, and even more preferably a fluorinated alkyl group having 1 carbon atom.

[0051] Specific examples of compound (5) include the compounds described in paragraph 0085 of WO 2020 / 121850. As compound (5), the following compound (5)-1 or the following compound (5)-2 is particularly preferred.

[0052]

[0053] When compound (A) contains compound (5), the content of compound (5) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0054] (Compound (6) Represented by Formula (6)) Compound (6), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (6):

[0055]

[0056] In formula (6), R ６１ each independently represents a fluorine atom or a fluorohydrocarbon group having 1 to 6 carbon atoms, and M represents an alkali metal.

[0057] In formula (6), R ６１ The fluorohydrocarbon group having 1 to 3 carbon atoms represented by the formula (I) may be a linear fluorohydrocarbon group or a branched fluorohydrocarbon group. ６１ Examples of the fluoro group include a fluorine atom (fluoro group, -F), a trifluoromethyl group (-CF ３ ), a pentafluoroethyl group (—CF ２ CF ３ ) is more preferred.

[0058] M is an alkali metal, and examples of the alkali metal include lithium, sodium, potassium, etc. Among these, M is preferably lithium.

[0059] As the compound (6), the following compounds (6)-1 and (6)-2 are particularly preferred.

[0060]

[0061] When compound (A) contains compound (6), the content of compound (6) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0062] (Compound (7) Represented by Formula (7)) Compound (7), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (7):

[0063]

[0064] In formula (7), R ７１ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.

[0065] In formula (7), R ７１ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (R) may be a straight-chain hydrocarbon group, a hydrocarbon group having a branched structure, or a hydrocarbon group having a cyclic structure. ７１ As the hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I), an alkyl group having 1 to 8 carbon atoms is preferred.

[0066] In formula (7), R ７１ The trialkylsilyl group having 3 to 18 carbon atoms represented by the formula (I) is a trimethylsilyl group (—Si(CH ３ ) ３ ), triethylsilyl group (—Si(C ２ H ５ ) ３ ), tri-t-butylsilyl group (—Si(tC ４ H ９ )３ ), triphenylsilyl group (—Si(C ６ H ５ ) ３ ) is preferred.

[0067] As the compound (7), the following compound (7)-1, compound (7)-2, and compound (7)-3 are particularly preferred.

[0068]

[0069] When compound (A) contains compound (7), the content of compound (7) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0070] (Compound (8) Represented by Formula (8)) Compound (8), which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (8):

[0071]

[0072] In formula (8), R ８１ represents an alkylene group having 1 to 10 carbon atoms or a halogenated alkylene group having 1 to 10 carbon atoms; R ８２ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a halogenated hydrocarbon group having 1 to 10 carbon atoms (provided that two R ８２ may be linked to each other to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms).

[0073] In formula (8), R ８１ The alkylene group having 1 to 10 carbon atoms represented by the formula (I) may be a linear alkylene group or an alkylene group having a branched structure. ８１ The alkylene group having 1 to 10 carbon atoms represented by the formula (I) is preferably an alkylene group having 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and particularly preferably a methylene group.

[0074] In formula (8), R ８１The halogenated alkylene group having 1 to 10 carbon atoms represented by the formula (I) may be a linear halogenated alkylene group or a branched alkylene group. ８１ The halogenated alkylene group having 1 to 10 carbon atoms represented by the formula (I) is preferably a halogenated alkylene group having 1 to 3 carbon atoms, more preferably a halogenated alkylene group having 1 or 2 carbon atoms, and particularly preferably a difluoromethylene group.

[0075] In formula (8), R ８２ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (R) may be a linear hydrocarbon group or a hydrocarbon group having a branched structure. ８２ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) is preferably a hydrocarbon group having 1 to 3 carbon atoms, more preferably a hydrocarbon group having 1 or 2 carbon atoms, and particularly preferably a methyl group.

[0076] In formula (8), R ８２ The halogenated hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) may be a linear halogenated hydrocarbon group or a branched halogenated hydrocarbon group. ８２ The halogenated hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) is preferably a halogenated hydrocarbon group having 1 to 3 carbon atoms, more preferably a halogenated hydrocarbon group having 1 or 2 carbon atoms, and particularly preferably a trifluoromethyl group.

[0077] In formula (8), two R ８２ are linked to each other to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms, the divalent hydrocarbon group having 1 to 10 carbon atoms or the divalent halogenated hydrocarbon group having 1 to 10 carbon atoms sandwiched between the two oxa groups (-O-) may be a linear hydrocarbon group or halogenated hydrocarbon group, or a hydrocarbon group or halogenated hydrocarbon group having a branched structure.

[0078] In formula (8), two R ８２are linked to each other to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms, the divalent hydrocarbon group having 1 to 10 carbon atoms or the divalent halogenated hydrocarbon group having 1 to 10 carbon atoms sandwiched between the two oxa groups (—O—) is preferably a methylene group, a difluoromethylene group, an ethylene group, or a tetrafluoroethylene group.

[0079] Specific examples of the compound (8) include the following compounds (8)-1 to (8)-13, with the following compound (8)-1 being particularly preferred.

[0080]

[0081] When compound (A) contains compound (8), the content of compound (8) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and still more preferably 0.10% by mass to 1.0% by mass.

[0082] <Compound (B)> The nonaqueous electrolyte solution of the present disclosure contains compound (B). Compound (B) is at least one selected from the group consisting of compound (9) represented by formula (9) described below, compound (10) represented by formula (10) described below, and compound (11) represented by formula (11) described below.

[0083] The content of compound (B) (total content when two or more types are used) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, relative to the total amount of the nonaqueous electrolyte. The preferred range of the content mass ratio [compound (A) / compound (B)] is as described above.

[0084] Compounds (9) to (11), which are alternatives to compound (B), will be described below.

[0085] (Compound (9) Represented by Formula (9)) Compound (9), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (9). Compound (9) is included in lithium (N-carbonyl)sulfonamide compounds.

[0086]

[0087] In formula (9), R ９１ and R ９２ each independently represents an alkyl group having 1 to 10 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), an alkenyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkenyl group may be substituted with a halogen atom), an alkynyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkynyl group may be substituted with a halogen atom), an aryl group (at least one hydrogen atom of the aryl group may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms), or a halogen atom; １ and L ２ each independently represents a single bond or —O—.

[0088] In formula (9), R ９１ and R ９２The "C1-10 alkyl group" represented by each of the above is a straight-chain or branched-chain alkyl group having from 1 to 10 carbon atoms. Examples of the "C1-10 alkyl group" include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a 2-methylbutyl group, a 1-methylpentyl group, a neopentyl group, a 1-ethylpropyl group, a hexyl group, a 3,3-dimethylbutyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Among these, the "C1-10 alkyl group" is preferably an alkyl group having from 1 to 6 carbon atoms, and more preferably an alkyl group having from 1 to 3 carbon atoms. At least one hydrogen atom of the "C1-10 alkyl group" may be substituted with a halogen atom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, still more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom. In the "alkyl group having 1 to 10 carbon atoms," the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkyl group, with 1 to 7 being preferred.

[0089] In formula (9), R ９１ and R ９２The "alkenyl group having 2 to 10 carbon atoms" represented by each of the above formulas is a straight-chain or branched-chain alkenyl group having from 2 to 10 carbon atoms. Examples of the "alkenyl group having 2 to 10 carbon atoms" include a vinyl group, a 2-propenyl group, a 2-butenyl group, a 3-butenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-pentenyl group, and a 5-hexenyl group. Among these, the "alkenyl group having 2 to 10 carbon atoms" is preferably an alkenyl group having 2 to 6 carbon atoms, and more preferably an alkenyl group having 2 to 3 carbon atoms. At least one hydrogen atom of the "alkenyl group having 2 to 10 carbon atoms" may be substituted with a halogen atom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, even more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom. In the "alkenyl group having 2 to 10 carbon atoms", the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkenyl group, with 1 to 7 being preferred.

[0090] In formula (9), R ９１ and R ９２ The "alkynyl group having 2 to 10 carbon atoms" represented by each of the above formulas is a straight-chain or branched-chain alkynyl group having from 2 to 10 carbon atoms. Examples of the "alkynyl group having 2 to 10 carbon atoms" include an ethynyl group, a propargyl group (2-propynyl group), a 2-butynyl group, a 3-butynyl group, a 2-pentynyl group, a 3-pentynyl group, a 4-pentynyl group, and a 5-hexynyl group. Among these, the "alkynyl group having 2 to 10 carbon atoms" is preferably an alkynyl group having from 2 to 6 carbon atoms, and more preferably an alkynyl group having from 2 to 3 carbon atoms. At least one hydrogen atom of the "alkynyl group having 2 to 10 carbon atoms" may be substituted with a halogen atom. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, even more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom. In the "alkynyl group having 2 to 10 carbon atoms", the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkynyl group, with 1 to 7 being preferred.

[0091] In formula (9), R ９１ and R ９２ The "aryl group" represented by each of the above may be a phenyl group or a naphthyl group, with a phenyl group being preferred.

[0092] In formula (9), R ９１ and R ９２ At least one hydrogen atom in the "aryl group" represented by each of the formulas may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. The halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, even more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom. In the "aryl group," the number of hydrogen atoms substituted with halogen atoms is not particularly limited, and is preferably 1 to 5. The alkyl group in the alkoxy group having 1 to 6 carbon atoms may be linear, branched, or cyclic. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a t-butoxy group, and a pentyloxy group. Among these, the alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 3 carbon atoms, and more preferably a methoxy group or an ethoxy group. In the "aryl group", the number of hydrogen atoms substituted by the alkoxy group having 1 to 6 carbon atoms is not particularly limited, and 1 to 3 is preferable. The alkyl group having 1 to 6 carbon atoms may be linear, branched, or cyclic. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, and a cyclohexyl group. Among these, the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 3 carbon atoms, and a methyl group and an ethyl group are more preferable. In the "aryl group", the number of hydrogen atoms substituted by the alkyl group having 1 to 6 carbon atoms is not particularly limited, and 1 to 3 is preferable.

[0093] In formula (9), R ９１ and R ９２The "halogen atom" represented by each of the above is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, still more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.

[0094] In formula (9), L １ and L ２ each independently represents a single bond or —O—.

[0095] In formula (9), L １ and L ２ As a combination of １ is -O- and L ２ is a single bond or —O—, or ２ is -O- and L １ is a single bond or —O—, and more preferably, L ２ is -O- and L １ is a single bond or —O—, and particularly preferably, L ２ is -O- and L １ is a single bond.

[0096] In formula (9), R ９２ and L ２ As a combination of ９２ is an alkyl group having 1 to 3 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), and L ２ is a combination where:

[0097] In formula (9), R ９１ and L １ As a combination of ９１ is a halogen atom, and L １ is a single bond, and more preferably, R ９１ is a fluorine atom, and L １ is a single bond.

[0098] Specific examples of compound (9) include the compounds described in paragraphs 0206 to 0418 of WO 2022 / 196230.

[0099] As the compound (9), the following compound (9)-1 is particularly preferred. For the synthesis method of compound (9)-1, reference can be made to paragraphs

[0389] to

[0391] of WO 2022 / 196230 (the description of "Lithium fluorosulfonylmethoxycarbonylamide [Synthetic compound (I-42)]" in Synthesis Example 42).

[0100]

[0101] When compound (B) contains compound (9), the content of compound (9) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, relative to the total amount of the nonaqueous electrolyte.

[0102] Compound (B) preferably includes compound (9). Specifically, compound (B) preferably consists of compound (9), or consists of compound (9) and at least one selected from the group consisting of compound (10) and compound (11). Compound (A) more preferably consists of compound (9) and at least one selected from the group consisting of compound (10) and compound (11).

[0103] The proportion of compound (9) in compound (B) is preferably 10% by mass to 100% by mass, more preferably 20% by mass to 100% by mass, even more preferably 30% by mass to 100% by mass, and still more preferably 40% by mass to 90% by mass.

[0104] (Compound (10) Represented by Formula (10)) Compound (10), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (10):

[0105]

[0106] In formula (10), R １０１ ~R １０３ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.

[0107] R １０１ ~R１０３ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (R) may be a linear hydrocarbon group or a hydrocarbon group having a branched structure. １０１ ~R １０３ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).

[0108] R １０１ ~R １０３ are each independently a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group)).

[0109] As the compound (10), the following compound (10)-1 is particularly preferred.

[0110]

[0111] When compound (B) contains compound (10), the content of compound (10) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, relative to the total amount of the nonaqueous electrolyte.

[0112] (Compound (11) Represented by Formula (11)) Compound (11), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (11):

[0113]

[0114] In formula (11), R １１１ represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorohydrocarbon group having 1 to 10 carbon atoms; R １１２ and R １１３each independently represents a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms (provided that R １１２ and R １１３ At least one of R is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group; M represents an alkali metal; １１１ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (R) may be a linear hydrocarbon group or a hydrocarbon group having a branched structure. １１１ The hydrocarbon group having 1 to 10 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).

[0115] R １１１ The fluorinated hydrocarbon group having 1 to 10 carbon atoms represented by the formula (R) is a group having a structure in which at least one hydrogen atom in a hydrocarbon group having 1 to 10 carbon atoms is replaced with a fluorine atom. １１１ A preferred embodiment of the hydrocarbon group having 1 to 10 carbon atoms, which is the base of the fluorinated hydrocarbon group having 1 to 10 carbon atoms, is the aforementioned R １１１ The preferred embodiments are the same as those of the hydrocarbon group having 1 to 10 carbon atoms represented by the following formula:

[0116] R １１１ is preferably a fluorinated hydrocarbon group having 1 to 10 carbon atoms (preferably a fluorinated alkyl group having 1 to 10 carbon atoms, more preferably a fluorinated alkyl group having 1 to 6 carbon atoms, even more preferably a fluorinated alkyl group having 1 to 3 carbon atoms, even more preferably a fluorinated alkyl group having 1 or 2 carbon atoms, even more preferably an alkyl group having 1 carbon atom, and even more preferably a trifluoromethyl group).

[0117] R １１２ and R １１３ each independently represents a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms. １１２ and R １１３At least one of the groups is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group.

[0118] R １１２ and R １１３ The hydrocarbon group having 1 to 6 carbon atoms represented by each of the formulas may be a linear hydrocarbon group or a hydrocarbon group having a branched structure. １１２ and R １１３ The hydrocarbon group having 1 to 6 carbon atoms represented by each of the formulas above is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and still more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).

[0119] R １１２ and R １１３ The hydrocarbon group having 1 to 6 carbon atoms and having a cyano group represented by each of the following formulas is a group in which at least one hydrogen atom (preferably one hydrogen atom) in the hydrocarbon group having 1 to 6 carbon atoms is replaced with a cyano group. １１２ and R １１３ A preferred embodiment of the hydrocarbon group having 1 to 6 carbon atoms that serves as the base for the hydrocarbon group having 1 to 6 carbon atoms and a cyano group represented by each of the following is R １１２ and R １１３ The preferred embodiments are the same as those of the hydrocarbon group having 1 to 6 carbon atoms represented by each of the following.

[0120] R １１２ and R １１３ The halogenated hydrocarbon group having 1 to 6 carbon atoms represented by each of the following formulas is a group in which at least one hydrogen atom (preferably one hydrogen atom) in a hydrocarbon group having 1 to 6 carbon atoms is replaced with a halogen atom. １１２ and R １１３ A preferred embodiment of the hydrocarbon group having 1 to 6 carbon atoms that serves as the base of the halogenated hydrocarbon group represented by each of the following is R １１２ and R １１３ The preferred embodiments are the same as those of the hydrocarbon group having 1 to 6 carbon atoms represented by each of the following. １１２ and R １１３The halogen atom in the halogenated hydrocarbon group represented by each of the following is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, even more preferably a fluorine atom or a chlorine atom, and still more preferably a fluorine atom.

[0121] R １１２ and R １１３ At least one of R is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group. １１２ and R １１３ A preferred embodiment of R １１２ and R １１３ are each independently a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, and R １１２ and R １１３ A more preferred embodiment of R １１２ and R １１３ and (iii) are cyano groups.

[0122] M is an alkali metal. Examples of the alkali metal include lithium, sodium, and potassium. Among these, M is preferably lithium.

[0123] As the compound (11), the following compound (11)-1 is particularly preferred.

[0124]

[0125] When compound (B) contains compound (8), the content of compound (8) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, relative to the total amount of the nonaqueous electrolyte.

[0126] The combination of compound (A) of compounds (1) to (8) and compound (B) of compounds (9) to (11) is not particularly limited, but preferred combinations are exemplified below.

[0127] Preferably, compound (A) comprises compound (2) and at least one selected from the group consisting of compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8), and compound (B) comprises compound (9). Specifically, the non-aqueous electrolyte may contain compound (2), compound (3), and compound (9). The non-aqueous electrolyte may contain compound (2), compound (4), and compound (9). The non-aqueous electrolyte may contain compound (2), compound (5), and compound (9). The non-aqueous electrolyte may contain compound (2), compound (6), and compound (9). The non-aqueous electrolyte may contain compound (2), compound (7), and compound (9). The non-aqueous electrolyte may contain compound (2), compound (8), and compound (9).

[0128] Preferably, compound (A) comprises compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8), and compound (B) comprises compound (9). Specifically, the non-aqueous electrolyte may contain compound (1), compound (2), and compound (9). The non-aqueous electrolyte may contain compound (1), compound (3), and compound (9). The non-aqueous electrolyte may contain compound (1), compound (4), and compound (9). The non-aqueous electrolyte may contain compound (1), compound (5), and compound (9). The non-aqueous electrolyte may contain compound (1), compound (6), and compound (9). The non-aqueous electrolyte may contain compound (1), compound (7), and compound (9).

[0129] It is preferable that compound (A) is compound (1), and compound (B) is compound (9) and at least one selected from the group consisting of compound (10) and compound (11). Specifically, the non-aqueous electrolyte may contain compound (1), compound (9), and compound (10). The non-aqueous electrolyte may contain compound (1), compound (9), and compound (11).

[0130] The nonaqueous electrolyte preferably contains the compound (5) as the compound (A). Specifically, the nonaqueous electrolyte may contain the compound (5) and the compound (9). The nonaqueous electrolyte may contain the compound (5) and the compound (10). The nonaqueous electrolyte may contain the compound (5) and the compound (11).

[0131] It is preferable that the compound (A) contains the compound (7). Specifically, the non-aqueous electrolyte may contain the compound (7) and the compound (9). The non-aqueous electrolyte may contain the compound (7) and the compound (10). The non-aqueous electrolyte may contain the compound (7) and the compound (11).

[0132] It is preferable that the compound (A) contains the compound (8). Specifically, the non-aqueous electrolyte may contain the compound (8) and the compound (9). The non-aqueous electrolyte may contain the compound (8) and the compound (10). The non-aqueous electrolyte may contain the compound (8) and the compound (11).

[0133] It is preferably used in a lithium secondary battery containing a positive electrode active material containing lithium metal phosphate.

[0134] When used in a lithium secondary battery containing a positive electrode active material containing lithium metal phosphate, the non-aqueous electrolyte preferably contains compound (A) consisting of at least one selected from the group consisting of compound (1), compound (2), compound (3), and compound (4), and compound (B) consisting of at least one selected from the group consisting of compound (9) and compound (10). Specifically, the non-aqueous electrolyte may contain compound (1) and compound (9). The non-aqueous electrolyte may contain compound (2) and compound (9). The non-aqueous electrolyte may contain compound (3) and compound (9). The non-aqueous electrolyte may contain compound (4) and compound (9). The non-aqueous electrolyte may contain compound (1) and compound (10). The non-aqueous electrolyte may contain compound (2) and compound (10). The non-aqueous electrolyte may contain the compound (3) and the compound (10). The non-aqueous electrolyte may contain the compound (4) and the compound (10).

[0135] <Non-aqueous Solvent> The non-aqueous electrolyte generally contains a non-aqueous solvent. Various known non-aqueous solvents can be appropriately selected as the non-aqueous solvent. The non-aqueous solvent may be one type only or two or more types.

[0136] Examples of non-aqueous solvents include cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, fluorine-containing chain carbonates, aliphatic carboxylic acid esters, fluorine-containing aliphatic carboxylic acid esters, γ-lactones, fluorine-containing γ-lactones, cyclic ethers, fluorine-containing cyclic ethers, chain ethers, fluorine-containing chain ethers, nitriles, amides, lactams, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, dimethyl sulfoxide phosphate, etc. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Examples of fluorine-containing cyclic carbonates include fluoroethylene carbonate (FEC), etc. Examples of chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), and dipropyl carbonate (DPC). Examples of aliphatic carboxylic acid esters include methyl formate, methyl acetate, methyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylbutyrate, ethyl formate, ethyl acetate, ethyl propionate, ethyl butyrate, ethyl isobutyrate, and ethyl trimethylbutyrate. Examples of γ-lactones include γ-butyrolactone and γ-valerolactone. Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, and 1,4-dioxane. Examples of chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, 1,2-dimethoxyethane, 1,2-dibutoxyethane, etc. Examples of nitriles include acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, etc. Examples of amides include N,N-dimethylformamide, etc.Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, and N,N'-dimethylimidazolidinone.

[0137] The non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, and fluorine-containing chain carbonates. In this case, the total proportion of the cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, and fluorine-containing chain carbonates is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the non-aqueous solvent.

[0138] The non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates and chain carbonates. In this case, the total proportion of the cyclic carbonates and chain carbonates in the non-aqueous solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the non-aqueous solvent.

[0139] The lower limit of the content of the nonaqueous solvent is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total amount of the nonaqueous electrolyte. The upper limit of the content of the nonaqueous solvent is preferably 99% by mass, more preferably 97% by mass, and even more preferably 90% by mass, based on the total amount of the nonaqueous electrolyte.

[0140] <Electrolyte> The non-aqueous electrolyte generally contains an electrolyte.

[0141] The electrolyte preferably contains at least one of a fluorine-containing lithium salt (hereinafter sometimes referred to as a "fluorine-containing lithium salt") and a fluorine-free lithium salt.

[0142] Examples of the fluorine-containing lithium salt include inorganic acid anion salts and organic acid anion salts. Examples of the inorganic acid anion salt include lithium hexafluorophosphate (LiPF ６), lithium tetrafluoroborate (LiBF ４ ), lithium hexafluoroarsenate (LiAsF ６ ), lithium hexafluorotantalate (LiTaF ６ Examples of organic acid anion salts include lithium trifluoromethanesulfonate (LiCF ３ SO ３ ), lithium bis(trifluoromethanesulfonyl)imide (Li(CF ３ SO ２ ) ２ N), lithium bis(pentafluoroethanesulfonyl)imide (Li(C ２ F ５ SO ２ ) ２ Among them, examples of fluorine-containing lithium salts include lithium hexafluorophosphate (LiPF ６ ) is more preferred.

[0143] Examples of fluorine-free lithium salts include lithium perchlorate (LiClO ４ ), lithium aluminum tetrachloride (LiAlCl ４ ), lithium decachlorodecaborate (Li ２ B １０ Cl １０ ) etc.

[0144] When the electrolyte contains a fluorine-containing lithium salt, the content of the fluorine-containing lithium salt is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the electrolyte. ６ ), lithium hexafluorophosphate (LiPF ６ The content of the component (I) is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the electrolyte.

[0145] When the non-aqueous electrolyte solution contains an electrolyte, the concentration of the electrolyte in the non-aqueous electrolyte solution is preferably 0.1 mol / L or more and 3 mol / L or less, more preferably 0.2 mol / L or more and 2 mol / L or less, and even more preferably 0.5 mol / L or more and 2 mol / L or less.

[0146] The non-aqueous electrolyte is lithium hexafluorophosphate (LiPF ６ ), the non-aqueous electrolyte contains lithium hexafluorophosphate (LiPF ６ The concentration of the HCl HCl salt is preferably 0.1 mol / L or more and 3 mol / L or less, more preferably 0.2 mol / L or more and 2 mol / L or less, and even more preferably 0.5 mol / L or more and 2 mol / L or less.

[0147] <Other Components> The non-aqueous electrolyte may contain other components as needed, such as acid anhydrides.

[0148] [Lithium Secondary Battery Precursor] The lithium secondary battery precursor of the present disclosure includes a case, and a positive electrode, a negative electrode, a separator, and an electrolyte solution housed in the case. Here, the positive electrode includes a positive electrode active material including lithium metal phosphate. The electrolyte solution is the nonaqueous electrolyte solution of the present disclosure.

[0149] In the present disclosure, a lithium secondary battery precursor refers to a lithium secondary battery before being charged and discharged.

[0150] The lithium secondary battery precursor of the present disclosure can produce a lithium secondary battery having an improved capacity retention rate after high-temperature storage or reduced resistance in a region where the SOC is medium or lower. Such effects are brought about by the combination of compound (A) and compound (B) in the nonaqueous electrolyte.

[0151] <Case> The shape of the case is not particularly limited and may be appropriately selected depending on the application of the lithium secondary battery precursor of the present disclosure, etc. Examples of the case include a case including a laminate film and a case consisting of a battery can and a battery can lid.

[0152] <Positive Electrode> The positive electrode preferably contains a positive electrode active material. Examples of the positive electrode active material include MoS２ , TiS ２ , MnO ２ , V ２ O ５ transition metal oxides or transition metal sulfides such as LiCoO ２ , LiMnO ２ , LiMn ２ O ４ , LiNiO ２ , LiNi Ｘ Co （１－Ｘ） O ２ (0<X<1), LiNi ｘ Co ｙ Mn ｚ O ２ (x, y, and z are each independently greater than 0 and less than 1.00, and the sum of x, y, and z is 0.99 to 1.00) (so-called "NCM"; e.g., LiNi ０．３３ Co ０．３３ 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 , LiNi ０．６ Co ０．２ Mn ０．２ O ２ , LiNi ０．８ Co ０．１ Mn ０．１ O ２ Lithium and transition metal composite oxides such as Li ｔ Ni １－ｘ－ｙ Co ｘ Al ｙ O ２ (t is 0.95 or more and 1.15 or less, x is 0 or more and 0.3 or less, y is 0.1 or more and 0.2 or less, and the sum of x and y is less than 0.5) (so-called "NCA"; for example, LiNi ０．８ Co ０．１５ Al ０．０５ O ２composite oxides comprising lithium, a transition metal, and a typical metal, such as lithium phosphate (LiFePO); conductive polymer materials, such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiadiazole, and polyaniline composites; lithium iron phosphate (LiFePO ４ ), lithium manganese phosphate (LiMnPO ４ ), lithium manganese iron phosphate (LiMn ｘ Fe １－ｘ P.O. ４ ; 0<x<1), lithium cobalt phosphate (LiCoPO ４ ), lithium nickel phosphate (LiNiPO ４ lithium metal phosphates such as ammonium phosphate;

[0153] The positive electrode active material preferably contains lithium metal phosphate. The nonaqueous electrolyte of the present disclosure can improve the capacity retention rate after high-temperature storage or reduce the resistance of the battery in a region where the SOC is medium or lower, and is particularly effective in improving the capacity retention rate during storage of a battery containing a positive electrode active material containing lithium metal phosphate (e.g., lithium iron phosphate). One possible reason for this is that metal elutes from the lithium metal phosphate as the positive electrode active material and deposits on the negative electrode during battery storage. In this regard, the nonaqueous electrolyte of the present disclosure can improve the capacity retention rate during storage of a battery containing a positive electrode active material containing lithium metal phosphate (e.g., lithium iron phosphate). The reason for this effect is not clear, but is presumed to be as follows. One possible cause of the decrease in the capacity retention rate during storage of the lithium secondary battery is that metal elutes from the positive electrode active material containing lithium metal phosphate and deposits on the negative electrode during battery storage. Examples of lithium metal phosphate include lithium iron phosphate (LiFePO ). ４ ), lithium manganese phosphate (LiMnPO ４ ), lithium manganese iron phosphate (LiMn ｘ Fe １－ｘ P.O. ４ ; 0<x<1), lithium cobalt phosphate (LiCoPO ４ ), lithium nickel phosphate (LiNiPO ４ ), etc.

[0154] The positive electrode active material preferably contains lithium iron phosphate.

[0155] When the positive electrode active material contains lithium metal phosphate, the positive electrode active material may contain a component other than lithium metal phosphate. The component other than lithium metal phosphate may be: MoS ２ , TiS ２ , MnO ２ , V ２ O ５ transition metal oxides or transition metal sulfides such as LiCoO ２ , LiMnO ２ , LiMn ２ O ４ , LiNiO ２ , LiNi Ｘ Co （１－Ｘ） O ２ [0<X<1], LiNi ｘ Co ｙ Mn ｚ O ２ [x, y, and z are each independently greater than 0 and less than 1.00, and the sum of x, y, and z is 0.99 to 1.00.] (So-called "NCM"; e.g., LiNi ０．３３ Co ０．３３ 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 , LiNi ０．６ Co ０．２ Mn ０．２ O ２ , LiNi ０．８ Co ０．１ Mn ０．１ O ２ Lithium and transition metal composite oxides such as Li ｔ Ni １－ｘ－ｙ Co ｘ Al ｙ O ２[t is 0.95 or more and 1.15 or less, x is 0 or more and 0.3 or less, y is 0.01 or more and 0.2 or less, and the sum of x and y is less than 0.5.] (So-called "NCA"; for example, LiNi ０．８ Co ０．１５ Al ０．０５ O ２ composite oxides comprising lithium, a transition metal and a typical metal, such as lithium nitrite, ...

[0156] When the positive electrode active material contains lithium metal phosphate, the proportion of lithium metal phosphate in the positive electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. When the positive electrode active material contains lithium metal phosphate, the proportion of lithium metal phosphate in the positive electrode active material may be 100% by mass or less.

[0157] When the positive electrode active material contains lithium metal phosphate, the proportion of lithium iron phosphate in the positive electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. When the positive electrode active material contains lithium metal phosphate, the proportion of lithium iron phosphate in the positive electrode active material may be 100% by mass or less.

[0158] The positive electrode preferably includes a positive electrode composite layer containing a positive electrode active material. The positive electrode composite layer may contain components other than the positive electrode active material. Examples of the components other than the positive electrode active material include a conductive additive, a binder, etc. Examples of the conductive additive include carbon materials such as carbon black (e.g., acetylene black), amorphous whiskers, and graphite. Examples of the binder include polyvinylidene fluoride.

[0159] The positive electrode composite layer can be formed by applying a positive electrode composite slurry containing a positive electrode active material and a solvent onto a positive electrode current collector (described later) and drying the slurry. The positive electrode composite slurry may contain components other than the positive electrode active material (e.g., a conductive additive, a binder, etc.). Examples of the solvent in the positive electrode composite slurry include organic solvents such as N-methylpyrrolidone.

[0160] The proportion of the positive electrode active material in the total solid content of the positive electrode mixture layer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The proportion of the positive electrode active material in the total solid content of the positive electrode mixture layer may be 100% by mass. Here, the total solid content of the positive electrode mixture layer means the total amount excluding the solvent from the positive electrode mixture layer when a solvent remains in the positive electrode mixture layer, or means the total amount of the positive electrode mixture layer when no solvent remains in the positive electrode mixture layer.

[0161] The proportion of lithium metal phosphate in the total solid content of the positive electrode mixture layer is preferably 70 mass% or more, more preferably 80 mass% or more, and even more preferably 90 mass% or more. The proportion of lithium metal phosphate in the total solid content of the positive electrode mixture layer may be 100 mass% or less.

[0162] The proportion of lithium iron phosphate in the total solid content of the positive electrode mixture layer is preferably 70 mass% or more, more preferably 80 mass% or more, and even more preferably 90 mass% or more. The proportion of lithium iron phosphate in the total solid content of the positive electrode mixture layer may be 100 mass% or less.

[0163] The positive electrode preferably includes a positive electrode current collector. There are no particular limitations on the material of the positive electrode current collector, and any known material can be used. Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloys, stainless steel, nickel, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper; and the like.

[0164] <Negative Electrode> The negative electrode preferably contains a negative electrode active material. Examples of the negative electrode active material include at least one selected from the group consisting of metallic lithium, lithium-containing alloys, metals or alloys capable of alloying with lithium, oxides capable of doping / dedoping with lithium ions, transition metal nitrides capable of doping / dedoping with lithium ions, and carbon materials capable of doping / dedoping with lithium ions. Examples of metals or alloys capable of alloying with lithium (or lithium ions) include silicon, silicon alloys, tin, and tin alloys. Examples of the negative electrode active material include lithium titanate. Among these, carbon materials capable of doping / dedoping with lithium ions are preferred. Examples of such carbon materials include carbon black, activated carbon, graphite materials (artificial graphite, natural graphite), amorphous carbon materials, and the like. The carbon materials may be in the form of fibers, spheres, potatoes, or flakes.

[0165] Specific examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) calcined at 1500°C or less, and mesophase pitch carbon fiber (MCF). Examples of the graphite material include natural graphite and artificial graphite. Examples of the artificial graphite include graphitized MCMB and graphitized MCF. Examples of the graphite material that can be used include those containing boron. Examples of the graphite material that can be used include those coated with metals such as gold, platinum, silver, copper, and tin, those coated with amorphous carbon, and those that are a mixture of amorphous carbon and graphite.

[0166] These carbon materials may be used alone or in combination of two or more. As the carbon material, a carbon material having a lattice spacing d(002) of the (002) plane measured by X-ray analysis of 0.340 nm or less is particularly preferred. As the carbon material, a carbon material having a true density of 1.70 g / cm ３ Graphite or a highly crystalline carbon material having properties similar to those of graphite is also preferred. The use of such carbon materials can further increase the energy density of the battery.

[0167] The proportion of the carbon material (preferably graphite material) in the negative electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The proportion of the carbon material (preferably graphite material) in the negative electrode active material may be 100% by mass or less.

[0168] The negative electrode preferably includes a negative electrode composite layer containing a negative electrode active material. The negative electrode composite layer may contain components other than the negative electrode active material. Examples of the components other than the negative electrode active material include a conductive additive and a binder. Examples of the conductive additive include the same conductive additives as those exemplified as the conductive additives that can be contained in the positive electrode composite layer. Examples of the binder include carboxymethyl cellulose, SBR latex, etc.

[0169] The negative electrode composite layer can be formed by applying a negative electrode composite slurry containing a negative electrode active material and a solvent onto a negative electrode current collector (described later) and drying the slurry. The negative electrode composite slurry may contain components other than the negative electrode active material (e.g., a conductive additive, a binder, etc.). Examples of the solvent in the negative electrode composite slurry include water.

[0170] The proportion of the negative electrode active material in the total solid content of the negative electrode mixture layer is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The proportion of the negative electrode active material in the total solid content of the negative electrode mixture layer may be 100% by mass. Here, the total solid content of the negative electrode mixture layer means the total amount excluding the solvent from the negative electrode mixture layer when a solvent remains in the negative electrode mixture layer, or means the total amount of the negative electrode mixture layer when no solvent remains in the negative electrode mixture layer.

[0171] The proportion of the carbon material (preferably graphite material) in the total solid content of the negative electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more. The proportion of the carbon material (preferably graphite material) in the total solid content of the negative electrode mixture layer may be 100 mass %.

[0172] The negative electrode preferably includes a negative electrode current collector. There are no particular restrictions on the material of the negative electrode current collector, and any known material can be used. Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, and nickel-plated steel. Among these, copper is particularly preferred from the viewpoint of ease of processing.

[0173] <Separator> An example of the separator is a porous resin flat plate. Examples of materials for the porous resin flat plate include resins and nonwoven fabrics containing such resins. Examples of resins include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, and polyamide. Among these, the separator is preferably a porous resin sheet having a single layer or multilayer structure. The material of the porous resin sheet is mainly composed of one or more polyolefin resins. The thickness of the separator is preferably 5 μm or more and 30 μm or less. The separator is preferably disposed between the positive electrode and the negative electrode.

[0174] <Specific Example of Lithium Secondary Battery Precursor> FIG. 1 is a schematic cross-sectional view showing a laminated lithium secondary battery precursor, which is an example of the lithium secondary battery precursor of the present disclosure.

[0175] As shown in Fig. 1, the lithium secondary battery precursor 1 is a laminated battery precursor. Specifically, in the lithium secondary battery precursor 1, a battery element 10 is enclosed inside an exterior body 30. The exterior body 30 is formed of a laminate film. A positive electrode lead 21 and a negative electrode lead 22 are attached to the battery element 10. The positive electrode lead 21 and the negative electrode lead 22 are led out in opposite directions, from the inside to the outside of the exterior body 30.

[0176] As shown in Fig. 1, the battery element 10 is formed by stacking a positive electrode 11, a separator 13, and a negative electrode 12. The positive electrode 11 is formed by forming a positive electrode composite layer 11B on both main surfaces of a positive electrode current collector 11A. The negative electrode 12 is formed by forming a negative electrode composite layer 12B on both main surfaces of a negative electrode current collector 12A. The positive electrode composite layer 11B formed on one main surface of the positive electrode current collector 11A of the positive electrode 11 and the negative electrode composite layer 12B formed on one main surface of the negative electrode current collector 12A of the negative electrode 12 adjacent to the positive electrode 11 face each other with the separator 13 interposed therebetween.

[0177] The nonaqueous electrolyte solution of the present disclosure is poured into the interior of the exterior housing 30 of the lithium secondary battery precursor 1. The nonaqueous electrolyte solution of the present disclosure permeates the positive electrode composite layer 11B, the separator 13, and the negative electrode composite layer 12B. In the lithium secondary battery precursor 1, one unit cell layer 14 is formed by adjacent positive electrode composite layer 11B, separator 13, and negative electrode composite layer 12B. Note that the positive electrode and the negative electrode may each have a composite layer formed on one side of each current collector.

[0178] Although the lithium secondary battery precursor 1 is a stacked-type lithium secondary battery precursor, the lithium secondary battery precursor of the present disclosure is not limited thereto and may be, for example, a wound-type lithium secondary battery precursor. A wound-type lithium secondary battery precursor is formed by stacking a positive electrode, a separator, a negative electrode, and a separator in this order and winding them into a layered configuration. Wound-type lithium secondary battery precursors include cylindrical lithium secondary battery precursors and prismatic lithium secondary battery precursors.

[0179] 1 , in the lithium secondary battery precursor 1, the directions in which the positive electrode lead and the negative electrode lead protrude from the inside to the outside of the exterior body 30 are opposite directions relative to the exterior body 30, but the present disclosure is not limited thereto. For example, the directions in which the positive electrode lead and the negative electrode lead protrude from the inside to the outside of the exterior body 30 may be the same direction relative to the exterior body 30.

[0180] An example of the lithium secondary battery of the present disclosure, which will be described later, is a lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor 1.

[0181] FIG. 2 is a schematic cross-sectional view showing a coin-type lithium secondary battery precursor, which is another example of the lithium secondary battery precursor of the present disclosure.

[0182] 2 , a disc-shaped negative electrode 42, a separator 45 filled with a nonaqueous electrolyte solution, a disc-shaped positive electrode 41, and, as needed, spacer plates 47, 48 made of stainless steel, aluminum, or the like are stacked in this order and housed between a positive electrode can 43 (hereinafter also referred to as a "battery can") and a sealing plate 44 (hereinafter also referred to as a "battery can lid"). The positive electrode can 43 and the sealing plate 44 are crimped and sealed via a gasket 46. In this example, the nonaqueous electrolyte solution of the present disclosure is used as the nonaqueous electrolyte solution filled in the separator 45.

[0183] An example of the lithium secondary battery of the present disclosure, which will be described later, is a lithium secondary battery obtained by charging and discharging the coin-type lithium secondary battery precursor shown in FIG. 2 .

[0184] [Lithium secondary battery and manufacturing method thereof] A manufacturing method of a lithium secondary battery according to the present disclosure includes the steps of: preparing the lithium secondary battery precursor according to the present disclosure described above (hereinafter also referred to as the "preparation step"); and charging and discharging the lithium secondary battery precursor. The lithium secondary battery according to the present disclosure is a lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to the present disclosure described above.

[0185] According to the lithium secondary battery and the method for producing the same of the present disclosure, the capacity retention rate of the lithium secondary battery during storage can be improved.

[0186] The preparation step may be a step of simply preparing a previously manufactured lithium secondary battery precursor of the present disclosure for a step of charging and discharging, or may be a step of manufacturing a lithium secondary battery precursor of the present disclosure. The lithium secondary battery precursor is as described above.

[0187] In the step of charging and discharging, the charging and discharging of the lithium secondary battery precursor can be carried out according to a known method. In this step, the charging and discharging cycle may be repeated multiple times for the lithium secondary battery precursor. As described above, this charging and discharging preferably forms an SEI (Solid Electrolyte Interface) film on the surface of the positive electrode (particularly the positive electrode active material) and / or the negative electrode (particularly the negative electrode active material) in the lithium secondary battery precursor.

[0188] In the step of charging and discharging, the lithium secondary battery precursor is preferably subjected to a combination of charging and discharging at least once in an environment of 25°C to 70°C.

[0189] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0190] Example 1-1 Preparation of Non-Aqueous Electrolyte Solution Ethylene carbonate (hereinafter referred to as "EC"), dimethyl carbonate (hereinafter referred to as "DMC"), and ethyl methyl carbonate (hereinafter referred to as "EMC") were mixed. The volume ratio (EC:DMC:EMC) was 30:35:35. This resulted in a mixed solvent as a non-aqueous solvent. LiPF as an electrolyte was added to the obtained mixed solvent. ６ was dissolved so that the concentration in the finally obtained non-aqueous electrolyte solution was 1.2 mol / L, thereby obtaining an electrolyte solution (hereinafter also referred to as "basic electrolyte solution"). To the obtained basic electrolyte solution, a compound shown in Table 1 was added so that the content relative to the total amount of the finally obtained non-aqueous electrolyte solution was the content (mass %) shown in Table 1, thereby obtaining a non-aqueous electrolyte solution. In Table 1, compound (2)-1 (i.e., lithium difluorophosphate) is a specific example of compound (2). Compound (3)-1 is a specific example of compound (3). Compound (9)-1 is a specific example of compound (9).

[0191] <Preparation of Positive Electrode> LiNi as Positive Electrode Active Material ０．５ Co ０．２ Mn ０．３ O ２A mixture was obtained by mixing 90% by mass of cellulose acetate (C10), 2.5% by mass of carbon black and 2.5% by mass of graphite (as conductive additives), and 5% by mass of polyvinylidene fluoride (PVdF) as a binder. The resulting mixture was dispersed in an N-methylpyrrolidone solvent to obtain a positive electrode composite slurry. A 20 μm thick aluminum foil was prepared as a positive electrode current collector. The resulting positive electrode composite slurry was applied to aluminum foil, dried, and then rolled in a press to obtain a sheet-shaped positive electrode. The positive electrode consisted of a positive electrode current collector and a positive electrode composite layer.

[0192] <Preparation of Negative Electrode> Graphite (96% by mass) was used as the negative electrode active material, carbon black (1% by mass) was used as a conductive additive, 1% by mass of sodium carboxymethyl cellulose dispersed in pure water as a thickener (solid content), and 2% by mass of styrene-butadiene rubber (SBR) dispersed in pure water as a binder (solid content) were mixed to obtain a negative electrode composite slurry. A 10 μm-thick copper foil was prepared as a negative electrode current collector. The obtained negative electrode composite slurry was applied to copper foil, dried, and then rolled in a press to obtain a sheet-shaped negative electrode. The negative electrode consisted of a negative electrode current collector and a negative electrode composite layer.

[0193] <Preparation of Separator> A porous polyethylene film was prepared as a separator.

[0194] <Preparation of Lithium Secondary Battery Precursor> The negative electrode was punched into a disk with a diameter of 14 mm. The positive electrode was punched into a disk with a diameter of 13 mm. The separator was punched into a disk with a diameter of 17 mm. This resulted in a coin-shaped negative electrode, a coin-shaped positive electrode, and a coin-shaped separator. The resulting coin-shaped negative electrode, coin-shaped separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (size: 2032). Next, 20 μL of nonaqueous electrolyte was poured into the battery can, and the separator, positive electrode, and negative electrode were immersed in the nonaqueous electrolyte. Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery can lid was crimped via a polypropylene gasket to seal the battery. As a result, a coin-shaped lithium secondary battery precursor (i.e., a lithium secondary battery before charging and discharging) having the configuration shown in FIG. 2 was obtained. The lithium secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.

[0195] <Fabrication of Lithium Secondary Battery> The lithium secondary battery precursor was charged to 4.2 V and discharged to 2.5 V three times in a temperature range of 25° C. to 70° C. to obtain a lithium secondary battery.

[0196] The following measurements were carried out on the lithium secondary battery obtained above. The results are shown in Table 1. Each result is shown as a relative value, with the value of Reference Example 1-1 described below being set at 100.

[0197] <Battery Resistance (SOC 50%)> The lithium secondary battery obtained above was charged until the SOC (State of Charge) reached 50%. The DCIR (direct current resistance) [Ω] of the charged lithium secondary battery was measured. The obtained result was taken as the battery resistance (SOC 50%). The above operation was carried out in a thermostatic chamber at 25°C.

[0198] <Battery Resistance (SOC 25%)> After measuring the battery resistance (SOC 50%), the lithium secondary battery was discharged until the SOC reached 25%. The DCIR (direct current resistance) [Ω] of the discharged lithium secondary battery was measured. The obtained result was taken as the battery resistance (SOC 25%). The above operation was performed in a thermostatic chamber at 25°C.

[0199] Examples 1-2 to 1-3, Reference Example 1-1 Non-aqueous electrolyte solutions were obtained in the same manner as in Example 1-1, except that the type and content of additives in the non-aqueous electrolyte solution were changed as shown in Table 1. Using the obtained non-aqueous electrolyte solution, the battery resistance (SOC 50%) and battery resistance (SOC 25%) were measured in the same manner as in Example 1-1. The results are shown in Table 1. The additives added to the non-aqueous electrolyte solutions of Examples 1-2 to 1-3 and Reference Example 1-1 are each represented by the following formula, and compound (6)-1 (i.e., bis(fluorosulfonyl)imide) of Reference Example 1-1 is a specific example of compound (6). Each result is shown as a relative value when the value of Reference Example 1-1 is set to 100.

[0200]

[0201]

[0202] As shown in Table 1, the nonaqueous electrolyte solutions for batteries in Examples 1-1 to 1-3 contained compound (A) and compound (B). Compound (A) in Examples 1-1 to 1-3 consisted of compound (2) and compound (3). Compound (B) in Examples 1-1 to 1-3 consisted of compound (9). The nonaqueous electrolyte solution for batteries in Reference Example 1-1 contained compound (A) but did not contain compound (B). Therefore, in the region of moderate or lower SOC (specifically, SOC 50% and SOC 25%), the battery resistances of Examples 1-1 to 1-3 were reduced compared to Reference Example 1-1.

[0203] Examples 2-1 to 2-17, Comparative Example 2-1 Preparation of Non-Aqueous Electrolyte Solutions Non-aqueous electrolyte solutions were obtained in the same manner as in Example 1-1, except that the types and contents of additives in the non-aqueous electrolyte solutions were changed as shown in Table 2.

[0204]

[0205] <Fabrication of Lithium Secondary Battery> A lithium secondary battery was fabricated using the obtained nonaqueous electrolyte solution in the same manner as in Example 1-1.

[0206] The following measurements were carried out on the lithium secondary battery obtained above. The results are shown in Table 2. Each result is shown as a relative value, with the value of Comparative Example 2-1 taken as 100. "-" in Table 2 means that no additive was added. "Not measured" in Table 2 means that no measurement was carried out.

[0207] <Measurement of Initial Discharge Capacity> The lithium secondary battery was charged to 3.5 V at a charge rate of 0.2 C in a thermostatic chamber at 25° C. using CC-CV (Constant Current-Constant Voltage) charging, and then the initial (i.e., before high-temperature storage) discharge capacity (0.2 C) (mAh) was measured at 25° C. and a discharge rate of 0.2 C.

[0208] <High-Temperature Storage> Next, the lithium secondary batteries whose initial discharge capacities (0.2 C) had been measured were CC-CV charged to 4.2 V at a charge rate of 0.2 C at 25° C., and then stored in a temperature environment of 60° C. (hereinafter referred to as "high-temperature storage"). The storage time of this high-temperature storage will be described later.

[0209] <Measurement of recovered discharge capacity after high-temperature storage> Seven days after the start of high-temperature storage (i.e., storage time: 7 days), the recovered discharge capacity after high-temperature storage was measured as follows. The lithium secondary battery after high-temperature storage was CC discharged at a discharge rate of 0.2 C at 25°C until the SOC reached 0%, and then CC-CV charged to 4.2 V at a charge rate of 0.2 C. Next, this lithium secondary battery was CC discharged at a discharge rate of 0.2 C, and the recovered discharge capacity (0.2 C) (mAh) after high-temperature storage was measured.

[0210] <Capacity Retention Rate During Storage> After 7 days of high-temperature storage, the capacity retention rate during storage was calculated using the following formula. Table 2 also shows the initial (i.e., before high-temperature storage) capacity retention rate (i.e., capacity retention rate 100%). Capacity retention rate during storage (%) = [(recovered discharge capacity after high-temperature storage (0.2 C)) / (initial discharge capacity (0.2 C))] × 100

[0211] <Battery Resistance (25°C)> The lithium secondary battery obtained above was charged until the SOC reached 50%. The DCIR (direct current resistance) [Ω] of the charged lithium secondary battery was measured. The obtained result was taken as the battery resistance (SOC 50%). The above operation was carried out in a thermostatic chamber at 25°C.

[0212] <Battery Resistance (-10°C)> The lithium secondary battery obtained above was charged until the SOC reached 50%. The DCIR (direct current resistance) [Ω] of the charged lithium secondary battery was measured. The obtained result was taken as the battery resistance (SOC 50%). The above operation was carried out in a thermostatic bath at -10°C.

[0213]

[0214] As shown in Table 2, the nonaqueous electrolyte solutions of Examples 2-1 to 2-17 contained compound (A) and compound (B). Compound (A) in Examples 2-1 to 2-17 was at least one selected from the group consisting of compound (1), compound (2), compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8). Compound (B) in Examples 2-1 to 2-17 consisted of compound (9). The nonaqueous electrolyte solution of Comparative Example 2-1 contained compound (B) but did not contain compound (A). Compound (B) in Comparative Example 2-1 consisted of compound (9). The capacity retention rates of Examples 2-1 to 2-17 were improved compared to Comparative Example 2-1, and the battery resistances of Examples 2-1 to 2-17 were reduced compared to Comparative Example 2-1 in the medium or lower SOC range (specifically, SOC 50% (25°C) and SOC 50% (-10°C)).

[0215] Example 3-1 Preparation of Non-Aqueous Electrolyte Solution Ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) were mixed to obtain a non-aqueous solvent. The volume ratio (EC:DMC:EMC) was 20:35:45. LiPF as an electrolyte was added to the obtained mixed solvent. ６was dissolved in the non-aqueous electrolyte solution to give an electrolyte concentration of 0.9 mol / L. The following additives were added to the resulting solution to obtain a non-aqueous electrolyte solution. Compound (9)-1, a specific example of compound (9), was added so that its content relative to the total mass of the non-aqueous electrolyte was 1.0 mass%. Furthermore, compound (1)-1, a specific example of compound (1), was added so that its content relative to the total mass of the non-aqueous electrolyte was 0.5 mass%.

[0216] <Preparation of Positive Electrode> Lithium iron phosphate (LiFePO ) was used as the positive electrode active material. ４ (hereinafter also referred to as "LFP") (90 parts by mass), acetylene black (5 parts by mass) as a conductive additive, and polyvinylidene fluoride (5 parts by mass) as a binder were kneaded using N-methylpyrrolidinone as a solvent to prepare a paste-like positive electrode composite slurry. Next, this positive electrode composite slurry was applied to a 20 μm thick strip-shaped aluminum foil positive electrode current collector, dried, and then compressed with a roll press to obtain a sheet-like positive electrode consisting of a positive electrode current collector and a positive electrode composite layer. The coating density of the positive electrode composite layer at this time was 12 mg / cm ２ and the packing density was 2.0 g / mL.

[0217] <Preparation of Negative Electrode> A paste-like negative electrode composite slurry was prepared by kneading natural graphite (98 parts by mass) as a negative electrode active material, carboxymethyl cellulose (1 part by mass) as a binder, and SBR latex (1 part by mass) as a binder with an aqueous solvent. Next, this negative electrode composite slurry was applied to a 10 μm-thick strip-shaped negative electrode current collector made of copper foil, dried, and then compressed with a roll press to obtain a sheet-like negative electrode consisting of the negative electrode current collector and a negative electrode composite layer. The coating density of the negative electrode composite layer at this time was 6.0 mg / cm. ２ and the packing density was 1.5 g / mL.

[0218] <Preparation of Separator> A microporous polyethylene film having a thickness of 20 μm was prepared as a separator.

[0219] <Preparation of Lithium Secondary Battery Precursor> The above-mentioned negative electrode was punched into a disk with a diameter of 14 mm. The above-mentioned positive electrode was punched into a disk with a diameter of 13 mm. A coin-shaped negative electrode and a coin-shaped positive electrode were obtained. The above-mentioned separator was punched into a disk with a diameter of 17 mm to obtain a coin-shaped separator. The obtained coin-shaped negative electrode, coin-shaped separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (2032 size). Next, 18 μL of nonaqueous electrolyte was injected into the battery can and impregnated into the separator, positive electrode, and negative electrode. Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery was sealed by crimping the battery can lid via a polypropylene gasket. As a result, a coin-shaped lithium secondary battery precursor (i.e., a lithium secondary battery before charging and discharging) having the configuration shown in FIG. 2 was obtained. The lithium secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.

[0220] <Preparation of Lithium Secondary Battery (Charge and Discharge of Lithium Secondary Battery Precursor)> The lithium secondary battery precursor was charged to 3.5 V and discharged to 2.0 V three times at 25° C. to obtain a lithium secondary battery.

[0221] <Measurement of Initial Discharge Capacity> The lithium secondary battery was charged to 3.5 V at a charge rate of 0.2 C in a thermostatic chamber at 25° C. using CC-CV (Constant Current-Constant Voltage) charging, and then the initial (i.e., before high-temperature storage) discharge capacity (0.2 C) (mAh) was measured at 25° C. and a discharge rate of 0.2 C.

[0222] <High-Temperature Storage> Next, the lithium secondary batteries whose initial discharge capacities (0.2 C) had been measured were CC-CV charged to 3.5 V at a charge rate of 0.2 C at 25° C., and then stored in a temperature environment of 60° C. (hereinafter referred to as "high-temperature storage"). The storage time of this high-temperature storage will be described later.

[0223] <Measurement of recovered discharge capacity after high-temperature storage> Seven days after the start of high-temperature storage (i.e., storage time 7 days) and 14 days after the start of high-temperature storage, the recovered discharge capacity after high-temperature storage was measured as follows. The lithium secondary battery after high-temperature storage was CC discharged at a discharge rate of 0.2 C at 25°C until the SOC (State of charge) became 0%, and then CC-CV charged to 3.5 V at a charge rate of 0.2 C. Next, this lithium secondary battery was CC discharged at a discharge rate of 0.2 C, and the recovered discharge capacity (0.2 C) (mAh) after high-temperature storage was measured.

[0224] <Capacity Retention Rate During Storage> The capacity retention rate during storage was calculated using the following formula for each of 7 days and 14 days after the start of high-temperature storage. The results are shown in Table 3. Table 3 also shows the initial capacity retention rate (i.e., before high-temperature storage) (i.e., capacity retention rate 100%).

[0225] Capacity retention rate during storage (%)=[(recovered discharge capacity after high-temperature storage (0.2 C)) / (initial discharge capacity (0.2 C))]×100

[0226] Examples 3-2 to 3-14, Comparative Examples 3-1 to 3-3 Non-aqueous electrolyte solutions were obtained in the same manner as in Example 3-1, except that the type and content of the additives used in preparing the non-aqueous electrolyte solution were changed as shown in Table 3. Using the obtained non-aqueous electrolyte solution, the initial capacity retention rate, the capacity retention rate during storage 7 days after the start of high-temperature storage, and the capacity retention rate during storage 14 days after the start of high-temperature storage were measured in the same manner as in Example 3-1. The results are shown in Table 3. The additives added to the non-aqueous electrolyte solutions of Examples 3-1 to 3-14 and Comparative Examples 3-1 to 3-3 are each represented by the following formula. In Table 3, "-" means that no additive was added.

[0227]

[0228]

[0229] As shown in Table 3, the nonaqueous electrolytes of Examples 3-2 to 3-14 contained compound (A) and compound (B). The nonaqueous electrolytes of Comparative Examples 3-1 to 3-3 contained compound (B) but did not contain compound (A). Therefore, the capacity retention rates during storage of the batteries of Examples 3-1 to 3-14 were superior to those of Comparative Examples 3-1 to 3-3. The compound (A) of Examples 3-8 to 3-12 consisted of at least one compound selected from the group consisting of compound (1), compound (2), compound (3), compound (4), and compound (5). The compound (A) of Examples 3-1 to 3-7 consisted of only one compound. Therefore, the capacity retention rates during storage of the batteries of Examples 3-8 to 3-12 were superior to those of Examples 3-1 to 3-7.

[0230] Examples 3-15 to 3-19, Comparative Example 3-4 The same operations as in Example 3-1 were performed except that the type and content of the additive used in preparing the non-aqueous electrolyte solution were changed as shown in Table 4, and furthermore, the lithium ion secondary battery precursor was produced as follows. The results are shown in Table 4. The additives added to the non-aqueous electrolyte solutions of Examples 3-1 to 3-19 and Comparative Example 3-4 are each represented by the following formula. In Table 4, "-" means that no additive was added.

[0231]

[0232] <Preparation of Lithium Secondary Battery Precursor> A sheet-shaped negative electrode similar to the sheet-shaped negative electrode in Example 3-1 was prepared, and a sheet-shaped positive electrode similar to the sheet-shaped positive electrode in Example 3-1 was prepared. The above-mentioned sheet-shaped negative electrode was punched into a rectangular shape measuring 42 mm in length and 31 mm in width. The above-mentioned sheet-shaped positive electrode was punched into a rectangular shape measuring 40 mm in length and 29 mm in width. A rectangular negative electrode and a rectangular positive electrode were obtained. The above-mentioned separator was punched into a rectangular shape measuring 45 mm in length and 35 mm in width to obtain a rectangular separator. The obtained rectangular negative electrode, rectangular separator, and rectangular positive electrode were stacked in this order in a bag-shaped aluminum laminate. Next, 125 μL of nonaqueous electrolyte was injected into this aluminum laminate, impregnating the rectangular separator, rectangular positive electrode, and rectangular negative electrode. Next, the battery was sealed by closing the opening of the bag with a heat sealer. As a result of the above, a laminated lithium secondary battery precursor (that is, a lithium secondary battery before being charged and discharged) having the structure shown in FIG. 1 was obtained.

[0233]

[0234] As shown in Table 4, the nonaqueous electrolytes of Examples 3-15 to 3-19 contained compound (A) and compound (B). The nonaqueous electrolyte of Comparative Example 3-4 contained compound (B) but did not contain compound (A). Therefore, the capacity retention rates during storage of the batteries of Examples 3-15 to 3-19 were superior to those of Comparative Example 4. The compound (B) of Examples 3-16 to 3-19 consisted of at least one selected from the group consisting of compound (6), compound (7), and compound (8). The compound (B) of Example 3-15 consisted of one compound. Therefore, the capacity retention rates during storage of the batteries of Examples 3-16 to 3-19 were superior to those of Example 3-15.

[0235] The disclosures of Japanese Patent Application No. 2023-018744, filed on February 9, 2023, Japanese Patent Application No. 2023-040531, filed on March 15, 2023, and Japanese Patent Application No. 2023-104562, filed on June 26, 2023, are incorporated herein by reference in their entireties. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A non-aqueous electrolyte solution for a battery, comprising a compound (A) and a compound (B), wherein the compound (A) is at least one selected from the group consisting of a compound (1) represented by the following formula (1), a compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, a compound (3) represented by the following formula (3), a compound (4) represented by the following formula (4), a compound (5) represented by the following formula (5), a compound (6) represented by the following formula (6), a compound (7) represented by the following formula (7), and a compound (8) represented by the following formula (8), and the compound (B) is at least one selected from the group consisting of a compound (9) represented by the following formula (9), a compound (10) represented by the following formula (10), and a compound (11) represented by the following formula (11). [In formula (1), R １１ represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (i-1), a group represented by formula (i-2), or a group represented by formula (i-3), １２ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, * represents a bonding position, １３ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a hydrogen atom, * represents a bonding position, and in formula (i-3), R １４ represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by formula (i-4), * represents a bonding position, and in formula (i-4), R １５ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, and * represents a bonding position. In formula (3), M represents an alkali metal, b represents an integer of 1 to 3, m represents an integer of 1 to 4, n represents an integer of 0 to 8, q represents 0 or 1, R ３１ 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, and when q is 1 and m is 2 to 4, m R ３１ may be bonded to each other; R ３２ is a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure, and when n is 2 to 8, n R ３２ may be bonded to each other to form a ring; １ and Q. ２ each independently represents -O- or -CH ２ In formula (4), R ４１ and R ４２ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms. ５１ ~R ５４ each independently represents a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms, and the double line consisting of a solid line and a dotted line represents a single bond or a double bond. ６１ each independently represents a fluorine atom or a fluorohydrocarbon group having 1 to 6 carbon atoms, and M represents an alkali metal. ７１ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms. ８１ represents an alkylene group having 1 to 10 carbon atoms or a halogenated alkylene group having 1 to 10 carbon atoms; R ８２ each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a halogenated hydrocarbon group having 1 to 10 carbon atoms (provided that two R ８２ may be linked together to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms). In formula (9), R ９１ and R ９２ each independently represents an alkyl group having 1 to 10 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), an alkenyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkenyl group may be substituted with a halogen atom), an alkynyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkynyl group may be substituted with a halogen atom), an aryl group (at least one hydrogen atom of the aryl group may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms), or a halogen atom; １ and L ２ Each of R independently represents a single bond or -O-. １０１ ~R １０３ Each of R independently represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms. １１１ R represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorohydrocarbon group having 1 to 10 carbon atoms; １１２ and R １１３ each independently represents a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms (provided that R １１２ and R １１３ At least one of the groups is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group; and M represents an alkali metal.

2. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) consists of the compound (2) and at least one selected from the group consisting of the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8), and the compound (B) consists of the compound (9).

3. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) consists of the compound (1) and at least one selected from the group consisting of the compound (2), the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8), and the compound (B) consists of the compound (9).

4. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) is the compound (1), and the compound (B) is the compound (9) and at least one selected from the group consisting of the compound (10) and the compound (11).

5. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) includes the compound (5).

6. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) includes the compound (7).

7. The nonaqueous electrolyte for a battery according to claim 1, wherein the compound (A) includes the compound (8).

8. The nonaqueous electrolyte for a battery according to claim 1, which is used in a lithium secondary battery containing a positive electrode active material containing lithium metal phosphate.

9. The nonaqueous electrolyte for a battery according to claim 8, wherein the compound (A) is at least one selected from the group consisting of the compound (1), the compound (2), the compound (3), and the compound (4), and the compound (B) is at least one selected from the group consisting of the compound (9) and the compound (10).

10. A lithium secondary battery precursor comprising: a case; and a positive electrode, a negative electrode, a separator, and an electrolyte solution contained in the case; wherein the positive electrode contains a positive electrode active material containing lithium metal phosphate; and the electrolyte solution is the nonaqueous electrolyte solution for batteries according to any one of claims 1 to 9.

11. A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to claim 10.

12. A method for producing a lithium secondary battery, comprising the steps of: preparing a lithium secondary battery precursor according to claim 10; and charging and discharging the lithium secondary battery precursor.

Images