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

Abstract

To provide a non-aqueous electrolyte for a lithium secondary battery, which can reduce a low-temperature resistance increase rate during high-temperature storage of the lithium secondary battery.SOLUTION: This non-aqueous electrolyte for a lithium secondary battery contains a compound (I) represented by Formula (I). R11 denotes a hydrogen atom or -SO2RY group, R12 denotes a bivalent group of a carbon number of 1-10, which is one selected from a group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or a bivalent group of a carbon number of 1-10, which is formed by connecting two or more selected from the group A, and RX and RY are independently replaceable aryl groups or replaceable benzyl groups.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a non-aqueous electrolyte for a lithium secondary battery, a lithium secondary battery precursor, a method for manufacturing a lithium secondary battery, a lithium secondary battery, and an additive for a non-aqueous electrolyte for a lithium secondary battery. [Background technology]

[0002] In recent years, various studies have been conducted on non-aqueous electrolytes for batteries such as lithium secondary batteries. For example, Patent Document 1 discloses a nonaqueous electrolyte containing a specific compound having a urea structure, a solute, and a nonaqueous organic solvent as a nonaqueous electrolyte used in a nonaqueous electrolyte battery with a low initial resistance value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 015264 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are cases where it is required to further reduce the rate of increase in low-temperature resistance of a lithium secondary battery when stored at high temperatures (hereinafter also referred to as "rate of increase in low-temperature resistance of a lithium secondary battery when stored at high temperatures"). An object of one aspect of the present disclosure is to provide a nonaqueous electrolyte solution for a lithium secondary battery, a lithium secondary battery precursor, a method for manufacturing a lithium secondary battery, a lithium secondary battery, and an additive for a nonaqueous electrolyte solution for a lithium secondary battery, which are capable of reducing the low-temperature resistance increase rate during high-temperature storage of the lithium secondary battery. [Means for solving the problem]

[0005] The means for solving the above problems include the following embodiments.

[0006] <1> A non-aqueous electrolyte solution for a lithium secondary battery, comprising a compound (I) represented by the following formula (I):

[0007] [ka]

[0008] In formula (I), R 11 is a hydrogen atom or -SO2R Y It is the basis, R 12 teeth, It is a divalent group having 1 to 10 carbon atoms, which is one type selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or a divalent group having 1 to 10 carbon atoms formed by linking two or more types selected from Group A. R X and R Y are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

[0009] <2> R 12 is an alkylene group having 2 carbon atoms or an alkenylene group having 2 carbon atoms, R X and the R Y are each independently an optionally substituted aryl group; <1> The nonaqueous electrolyte for a lithium secondary battery according to claim 1. <3> The compound (I) is at least one selected from the group consisting of the following compounds (I-1) to (I-6): <1> or <2> The nonaqueous electrolyte for a lithium secondary battery according to claim 1.

[0010] [ka]

[0011] <4> The content of the compound (I) is 0.01% by mass or more and 5.0% by mass or less with respect to the total amount of the nonaqueous electrolyte solution for a battery. <1> ~ <3> 10. The nonaqueous electrolyte solution for a lithium secondary battery according to claim 9. <5> The composition further contains at least one additive X selected from the group consisting of compound (II) which is at least one of lithium monofluorophosphate and lithium difluorophosphate, compound (III) represented by the following formula (III), compound (IV) represented by the following formula (IV), and compound (V) represented by the following formula (V): <1> ~ <4> 10. The nonaqueous electrolyte solution for a lithium secondary battery according to claim 9.

[0012] [ka]

[0013] In formula (III), M is an alkali metal; Y is a transition element, an element in Group 13, 14, or 15 of the periodic table; b is an integer from 1 to 3, m is an integer from 1 to 4, n is an integer from 0 to 8, q is 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; Q 1and Q 2 are each independently an oxygen atom or a carbon atom. In formula (IV), R 41 represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, or an alkenylene group having 2 to 6 carbon atoms, R 42 represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (iv-1), or a group represented by formula (iv-2), * is the bond position, In formula (iv-1), R 43 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, In formula (iv-2), R 44 is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms. In formula (V), R 51 and R 52 each independently represents a hydrogen atom, a methyl group, an ethyl group, or a propyl group.

[0014] <6> The content of the additive X is 0.01 mass % or more and 5.0 mass % or less with respect to the total amount of the nonaqueous electrolyte solution for a battery. <5> The nonaqueous electrolyte for a lithium secondary battery according to claim 1. <7> Case and a positive electrode, a negative electrode, a separator, and an electrolyte solution housed in the case; Equipped with the positive electrode is a positive electrode capable of absorbing and desorbing lithium ions, the negative electrode is capable of absorbing and desorbing lithium ions, The electrolyte solution is <1> ~ <6> 1. A lithium secondary battery precursor, which is the nonaqueous electrolyte solution for a lithium secondary battery according to any one of claims 1 to 9. <8> The positive electrode contains, as a positive electrode active material, a lithium-containing composite oxide represented by the following formula (P1): <7> The lithium secondary battery precursor according to claim 1. LiNi a Co b Mn c O2… Formula (P1) [In formula (P1), a, b, and c each independently represent a number greater than 0 and less than 1, and the sum of a, b, and c represents a number greater than or equal to 0.99 and less than or equal to 1.00.] <9> <7> or <8> preparing a lithium secondary battery precursor according to the present invention; charging and discharging the lithium secondary battery precursor; A method for producing a lithium secondary battery, comprising: <10> <7> ~ <9> 1. A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to any one of the above items. <11> An additive for a non-aqueous electrolyte solution of a lithium secondary battery, comprising a compound (I) represented by the following formula (I):

[0015] [ka]

[0016] In formula (I), R 11 is a hydrogen atom or -SO2R Y It is the basis, R 12 is a divalent group having 1 to 10 carbon atoms, which is one group selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or is a divalent group having 1 to 10 carbon atoms formed by linking two or more groups selected from Group A, R X and R Y are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

[0017] <12> R 12 is an alkylene group having 2 carbon atoms, R X and the R Y are each independently an optionally substituted aryl group; <11> The additive for the non-aqueous electrolyte of the lithium secondary battery according to claim 1. <13> The compound (I) is at least one selected from the group consisting of the following compounds (I-1) to (I-4): <11> or <12> The additive for the non-aqueous electrolyte of the lithium secondary battery according to claim 1.

[0018] [ka] [Effects of the Invention]

[0019] According to the present disclosure, there are provided a non-aqueous electrolyte for a lithium secondary battery, a lithium secondary battery precursor, a method for manufacturing a lithium secondary battery, a lithium secondary battery, and an additive for a non-aqueous electrolyte for a lithium secondary battery. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a laminated battery, which is an example of a lithium secondary battery precursor according to the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a coin-type battery, which is another example of a lithium secondary battery precursor according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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, the amount of each component in a composition means the total amount of the multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component are present in the composition. 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.

[0022] [Non-aqueous electrolyte for lithium secondary batteries] The non-aqueous electrolyte for lithium secondary batteries of the present disclosure (hereinafter also simply referred to as "nonaqueous electrolyte") contains a compound (I) represented by the following formula (I).

[0023] [ka]

[0024] In formula (I), R 11 is a hydrogen atom or -SO2R Y It is the basis, R 12 is a divalent group having 1 to 10 carbon atoms, which is one group selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or is a divalent group having 1 to 10 carbon atoms, which is formed by linking two or more groups selected from Group A, R X and R Y are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

[0025] The nonaqueous electrolyte solution of the present disclosure can reduce the rate of increase in low-temperature resistance during high-temperature storage of a lithium secondary battery. In the present disclosure, low temperature resistance means resistance under low temperature conditions (for example, conditions of -10°C). In the present disclosure, the rate of increase in low-temperature resistance of a lithium secondary battery when stored at high temperature means the rate of increase in low-temperature resistance of the lithium secondary battery when stored at high temperature. The rate of increase in low-temperature resistance of a lithium secondary battery during high-temperature storage in the present disclosure is calculated as the ratio of the low-temperature resistance of the lithium secondary battery after high-temperature storage to the low-temperature resistance of the lithium secondary battery before high-temperature storage (i.e., ratio [low-temperature resistance of lithium secondary battery after high-temperature storage / low-temperature resistance of lithium secondary battery before high-temperature storage]).

[0026] The above-described effects of the nonaqueous electrolyte solution of the present disclosure are believed to be effects brought about by the combination of the aryl group or benzyl group, the sulfonyl group, and the cyclic urea structure in the compound (I) contained in the nonaqueous electrolyte solution. The reason why the above-mentioned effects are exhibited is thought to be that the combination of the aryl group or benzyl group, the sulfonyl group, and the cyclic urea structure in compound (I) efficiently forms a coating on the electrodes (i.e., the positive electrode and / or the negative electrode) in the lithium secondary battery, and this coating suppresses side reactions such as decomposition of the electrolyte or non-aqueous solvent in the non-aqueous electrolyte solution during charge and discharge.

[0027] <Compound (I)> The non-aqueous electrolyte solution of the present disclosure contains a compound (I) represented by the following formula (I). The non-aqueous electrolyte solution of the present disclosure may contain only one type of compound (I), or may contain two or more types.

[0028] [ka]

[0029] In formula (I), R 11 is a hydrogen atom or -SO2R Y It is the basis, R 12 is a divalent group having 1 to 10 carbon atoms, which is one group selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or is a divalent group having 1 to 10 carbon atoms, which is formed by linking two or more groups selected from Group A, R X and R Y are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

[0030] In formula (I), R 12The alkylene group, fluorinated alkylene group, alkenylene group, and fluorinated alkenylene group in the above may each be a group having a linear structure or a group having a branched structure.

[0031] In formula (I), R 12 teeth, Preferably, it is an alkylene group having 1 to 10 carbon atoms, a fluorinated alkylene group having 1 to 10 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, or a fluorinated alkenylene group having 2 to 10 carbon atoms, More preferably, it is an alkylene group having 1 to 10 carbon atoms or an alkenylene group having 2 to 10 carbon atoms. More preferably, it is an alkylene group having 1 to 4 carbon atoms or an alkenylene group having 2 to 4 carbon atoms. More preferably, it is an alkylene group having 2 carbon atoms or an alkenylene group having 2 carbon atoms.

[0032] In formula (I), R X or R Y The aryl group in the optionally substituted aryl group represented by the formula (I) is preferably a phenyl group, a naphthyl group, or a biphenyl group, and more preferably a phenyl group.

[0033] In formula (I), R X or R Y There are no particular limitations on the substituents that may be contained in the optionally substituted aryl group represented by the following formula: Examples of the substituent that may be contained in the optionally substituted aryl group include: fluorine atoms, A linear or branched alkyl group having 1 to 10 carbon atoms, a linear or branched alkoxy group having 1 to 10 carbon atoms; an alkenyl group having 2 to 10 carbon atoms; an alkenyloxy group having 2 to 10 carbon atoms; an alkynyl group having 2 to 10 carbon atoms; an alkynyloxy group having 2 to 10 carbon atoms; a cycloalkyl group having 3 to 10 carbon atoms; a cycloalkoxy group having 3 to 10 carbon atoms; a cycloalkenyl group having 3 to 10 carbon atoms; a cycloalkenyloxy group having 3 to 10 carbon atoms; an aryl group having 6 to 10 carbon atoms, and an aryloxy group having 6 to 10 carbon atoms; etc. The above-mentioned substituent is preferably a fluorine atom or a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a fluorine atom, a methyl group, or an ethyl group, and even more preferably a fluorine atom or a methyl group.

[0034] In formula (I), R X or R Y There are no particular limitations on the substituents that may be contained in the optionally substituted benzyl group represented by the following formula: Substituents that may be contained in the optionally substituted benzyl group include the same as the substituents that may be contained in the above-mentioned optionally substituted aryl group.

[0035] In formula (I), R X or R Y As for An optionally substituted aryl group is preferred, An optionally substituted phenyl group is more preferred, A phenyl group or an alkylphenyl group having 7 to 11 carbon atoms is more preferred, A phenyl group or a methylphenyl group is more preferred, A phenyl group or a 4-methylphenyl group is more preferred.

[0036] As an example of a preferred embodiment of compound (I), R 12 is an alkylene group having 2 carbon atoms or an alkenylene group having 2 carbon atoms, and R X and R Y are each independently an optionally substituted aryl group. However, compound (I) is not limited to this preferred embodiment.

[0037] Exemplary compounds of Compound (I) (Compound (I-1) to Compound (I-36)) are shown below, but Compound (I) is not limited to the following exemplary compounds.

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] Among the above exemplary compounds, at least one selected from the group consisting of compounds (I-1) to (I-6) is preferred.

[0042] The content of Compound (I) relative to the total amount of the nonaqueous electrolyte solution of the present disclosure is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 3.0% by mass or less, and even more preferably 0.2% by mass or more and 2.0% by mass or less.

[0043] In addition, when a lithium secondary battery is actually disassembled and the collected non-aqueous electrolyte solution is analyzed, the amount of compound (I) may be found to be reduced compared to the amount added to the non-aqueous electrolyte solution. Even in this case, if even a small amount of compound (I) is detected in the non-aqueous electrolyte solution collected from the battery, the non-aqueous electrolyte solution of the battery is included in the scope of the non-aqueous electrolyte solution of the present disclosure. The same applies to other compounds (additive X and others) described below.

[0044] <Additive X> The nonaqueous electrolyte solution of the present disclosure may further contain an additive X which is at least one selected from the group consisting of compound (II) which is at least one of lithium monofluorophosphate and lithium difluorophosphate, compound (III) represented by formula (III) below, compound (IV) represented by formula (IV) below, and compound (V) represented by formula (V) below.

[0045] When the nonaqueous electrolyte solution of the present disclosure contains additive X, the content of additive X relative to the total amount of the nonaqueous electrolyte solution of the present disclosure is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 3.0% by mass or less, and even more preferably 0.2% by mass or more and 2.0% by mass or less, from the viewpoint of more effectively exerting the effects of the nonaqueous electrolyte solution of the present disclosure.

[0046] From the viewpoint of more effectively achieving the effects of the nonaqueous electrolyte solution of the present disclosure, in the nonaqueous electrolyte solution of the present disclosure, the mass ratio of the content of additive X to the content of compound (I) (hereinafter also referred to as "content mass ratio [additive X / compound (I)]") is preferably 0.1 to 10, more preferably 0.2 to 5.0.

[0047] (Compound (II)) Compound (II) is at least one of lithium monofluorophosphate and lithium difluorophosphate. Here, lithium difluorophosphate is the following compound (II-1), and lithium monofluorophosphate is the following compound (II-2).

[0048] [ka]

[0049] Compound (II) may be either lithium monofluorophosphate or lithium difluorophosphate, or may be both lithium monofluorophosphate and lithium difluorophosphate.

[0050] When the non-aqueous electrolyte solution of the present disclosure contains compound (II), the content of compound (II) is preferably 0.001 mass % or more and 5.0 mass % or less, and more preferably 0.01 mass % or more and 5.0 mass % or less, relative to the total amount of the non-aqueous electrolyte solution. The upper limit of the content of the compound (II) is more preferably 3.0% by mass, and even more preferably 2.0% by mass. The lower limit of the content of the compound (II) is more preferably 0.05% by mass, and even more preferably 0.1% by mass.

[0051] (Compound (III)) Compound (III) is a compound represented by the following formula (III).

[0052] [ka]

[0053] In formula (III), M is an alkali metal; Y is a transition element, an element in Group 13, 14, or 15 of the periodic table; b is an integer from 1 to 3, m is an integer from 1 to 4, n is an integer from 0 to 8, q is 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 32may be bonded to each other to form a ring; Q 1 , and Q 2 are each independently an oxygen atom or a carbon atom.

[0054] M is an alkali metal. Examples of the alkali metal include lithium, sodium, and potassium. Among these, M is preferably lithium. Y is a transition element, or an element in Group 13, 14, or 15 of the periodic table. Y is preferably Al, B, V, Ti, Si, Zr, Ge, Sn, Cu, Y, Zn, Ga, Nb, Ta, Bi, P, As, Sc, Hf, or Sb, and more preferably Al, B, or P. When Y is Al, B, or P, the synthesis of the anion compound becomes relatively easy, and production costs can be reduced. b represents the valence of the anion and the number of cations, and is an integer of 1 to 3, preferably 1. When b is 3 or less, the salt of the anionic compound is easily dissolved in the mixed organic solvent. Each of m and n is a value related to the number of ligands. Each of m and n is determined depending on 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 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 alkylene groups, halogenated alkylene groups, arylene groups, or halogenated arylene groups may contain a substituent or a heteroatom in their structure. Specifically, R 31may contain a substituent in place of the hydrogen atom of these groups. 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. R 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 the group, an electron-withdrawing group is preferred, and a fluorine atom is particularly preferred. Q 1 and Q 2 each independently represents O or C. In other words, the ligand bonds to Y via these hetero atoms.

[0055] Specific examples of the compound (III) include the following compound (III-1) and compound (III-2).

[0056] [ka]

[0057] When the non-aqueous electrolyte solution of the present disclosure contains compound (III), the content of compound (III) is preferably 0.001 mass % or more and 5.0 mass % or less, and more preferably 0.01 mass % or more and 5.0 mass % or less, relative to the total amount of the non-aqueous electrolyte solution. The upper limit of the content of the compound (II) is more preferably 3.0% by mass, and even more preferably 2.0% by mass. The lower limit of the content of the compound (II) is more preferably 0.05% by mass, and even more preferably 0.1% by mass.

[0058] (Compound (IV)) Compound (IV) is a compound represented by the following formula (IV).

[0059] [ka]

[0060] In formula (IV), R 41 represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, or an alkenylene group having 2 to 6 carbon atoms, R 42 represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (iv-1), or a group represented by formula (iv-2), * is the bond position, In formula (iv-1), R 43 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, In formula (iv-2), R 44 is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms.

[0061] In formula (IV), R 42 is preferably a group represented by formula (iv-1) or a group represented by formula (iv-2). In formula (iv-1), R 43 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. In formula (iv-2), R 44 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.

[0062] Specific examples of the compound (IV) include the following compounds (IV-1) to (IV-8).

[0063] [ka]

[0064] When the non-aqueous electrolyte solution of the present disclosure contains compound (IV), the content of compound (IV) is preferably 0.001% by mass or more and 5.0% by mass or less, and more preferably 0.01% by mass or more and 5.0% by mass or less, relative to the total amount of the non-aqueous electrolyte solution. The upper limit of the content of the compound (IV) is more preferably 3.0% by mass, and even more preferably 2.0% by mass. The lower limit of the content of the compound (IV) is more preferably 0.05% by mass, and even more preferably 0.1% by mass.

[0065] (Compound (V)) The compound (V) is a compound represented by the following formula (V).

[0066] [ka]

[0067] In formula (V), R 51 and R 52 each independently represents a hydrogen atom, a methyl group, an ethyl group, or a propyl group.

[0068] In formula (V), R 51 and R 52 are each independently preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. Examples of the compound (V) represented by formula (V) include vinylene carbonate (hereinafter also referred to as "VC"), methyl vinylene carbonate, and dimethyl vinylene carbonate, with vinylene carbonate being particularly preferred.

[0069] When the non-aqueous electrolyte solution of the present disclosure contains compound (V), the content of compound (V) is preferably 0.001 mass % or more and 5.0 mass % or less, and more preferably 0.01 mass % or more and 5.0 mass % or less, relative to the total amount of the non-aqueous electrolyte solution. The upper limit of the content of the compound (V) is more preferably 3.0% by mass, and even more preferably 2.0% by mass. The lower limit of the content of the compound (V) is more preferably 0.05% by mass, and even more preferably 0.1% by mass.

[0070] <Other additives> The nonaqueous electrolyte of the present disclosure may contain other additives. The other additives are not particularly limited, and any known additives can be used. As other additives, for example, additives described in paragraphs 0042 to 0055 of JP-A-2019-153443 can be used.

[0071] <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.

[0072] 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, and dimethyl sulfoxide phosphate. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). Examples of fluorine-containing cyclic carbonates include fluoroethylene carbonate (FEC). 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, and 1,2-dibutoxyethane. Examples of nitriles include acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, and 3-methoxypropionitrile. Examples of amides include N,N-dimethylformamide. Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, and N,N'-dimethylimidazolidinone.

[0073] 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.

[0074] 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 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.

[0075] The lower limit of the content of the non-aqueous solvent is preferably 60% by mass or more, and more preferably 70% by mass or more, based on the total amount of the non-aqueous electrolyte. The upper limit of the content of the non-aqueous solvent is preferably 99 mass %, more preferably 97 mass %, and even more preferably 90 mass %, relative to the total amount of the non-aqueous electrolyte. An example of the range of the content of the non-aqueous solvent is 60% by mass or more and 99% by mass or less.

[0076] The intrinsic viscosity of the non-aqueous solvent is preferably 10.0 mPa·s or less at 25° C., from the viewpoint of further improving the dissociation property of the electrolyte and the mobility of ions.

[0077] <Electrolyte> The non-aqueous electrolyte generally contains an electrolyte.

[0078] 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.

[0079] Examples of the fluorine-containing lithium salt include inorganic acid anion salts and organic acid anion salts. Examples of inorganic acid anion salts include lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), and lithium hexafluorotantalate (LiTaF6). Examples of organic acid anion salts include lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (Li(CF3SO2)2N), and lithium bis(pentafluoroethanesulfonyl)imide (Li(C2F5SO2)2N). Among these, lithium hexafluorophosphate (LiPF6) is more preferable as the fluorine-containing lithium salt.

[0080] Fluorine-free lithium salts include lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), and lithium decachlorodecaborate (Li2B 10 Cl 10 ) etc.

[0081] 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. When the fluorine-containing lithium salt contains lithium hexafluorophosphate (LiPF6), the content of lithium hexafluorophosphate (LiPF6) 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.

[0082] When the non-aqueous electrolyte contains an electrolyte, the concentration of the electrolyte in the non-aqueous electrolyte is preferably 0.1 mol / L or more and 3 mol / L or less, and more preferably 0.5 mol / L or more and 2 mol / L or less.

[0083] When the non-aqueous electrolyte contains lithium hexafluorophosphate (LiPF6), the concentration of lithium hexafluorophosphate (LiPF6) in the non-aqueous electrolyte is preferably 0.1 mol / L or more and 3 mol / L or less, more preferably 0.5 mol / L or more and 2 mol / L or less.

[0084] <Other ingredients> The non-aqueous electrolyte may contain other components as needed. Other components include acid anhydrides.

[0085] [Lithium secondary battery precursor] The lithium secondary battery precursor of the present disclosure comprises: Case and a positive electrode, a negative electrode, a separator, and an electrolyte solution housed in a case; Equipped with. where: The positive electrode is a positive electrode capable of absorbing and releasing lithium ions, The negative electrode is capable of absorbing and releasing lithium ions, The electrolyte is a non-aqueous electrolyte of the present disclosure.

[0086] In the present disclosure, a lithium secondary battery precursor refers to a lithium secondary battery before being charged and discharged.

[0087] According to the lithium secondary battery precursor of the present disclosure, in a lithium secondary battery obtained by charging and discharging this lithium secondary battery precursor, the rate of increase in low-temperature resistance during high-temperature storage can be reduced.

[0088] <Case> The shape of the case is not particularly limited and may be appropriately selected depending on the intended use of the lithium secondary battery precursor of the present disclosure. Examples of the case include a case including a laminate film, and a case consisting of a battery can and a battery can lid.

[0089] <Positive electrode> The positive electrode is capable of absorbing and releasing lithium ions. The positive electrode preferably contains at least one positive electrode active material capable of absorbing and desorbing lithium ions.

[0090] The positive electrode preferably includes a positive electrode current collector and a positive electrode mixture layer provided on at least a portion of the surface of the positive electrode current collector.

[0091] Examples of the material for the positive electrode current collector include metals and alloys. Specifically, examples of the material for the positive electrode current collector include aluminum, nickel, stainless steel (SUS), and copper. Among these, aluminum is preferred from the viewpoint of the balance between high conductivity and cost. Here, "aluminum" refers to pure aluminum or an aluminum alloy. The positive electrode current collector is preferably aluminum foil. The material for the aluminum foil is not particularly limited, and examples include A1085 and A3003.

[0092] The positive electrode mixture layer contains a positive electrode active material and a binder.

[0093] The positive electrode active material is not particularly limited as long as it is a material that can absorb and release lithium ions, and can be adjusted appropriately depending on the application of the lithium secondary battery precursor.

[0094] Examples of positive electrode active materials include a first oxide and a second oxide. The first oxide contains lithium (Li) and nickel (Ni) as constituent metal elements. The second oxide contains Li, Ni, and at least one metal element other than Li and Ni as constituent metal elements. Examples of metal elements other than Li and Ni include transition metal elements and typical metal elements. The second oxide preferably contains the metal elements other than Li and Ni in an amount equivalent to or less than Ni in atomic number terms. The metal element other than Li and Ni may be, for example, at least one selected from the group consisting of Co, Mn, Al, Cr, Fe, V, Mg, Ca, Na, Ti, Zr, Nb, Mo, W, Cu, Zn, Ga, In, Sn, La, and Ce. These positive electrode active materials may be used alone or in combination.

[0095] The positive electrode active material preferably contains a lithium-containing composite oxide (hereinafter, sometimes referred to as "NCM") represented by the following formula (P1): The lithium-containing composite oxide (P1) has the advantages of high energy density per unit volume and excellent thermal stability. LiNi a Co b Mn c O2… Formula (P1) In formula (P1), a, b, and c each independently represent a number greater than 0 and less than 1, and the sum of a, b, and c represents a number greater than or equal to 0.99 and less than or equal to 1.00. A specific example of NCM is LiNi 0.33 Co 0.33 Mn 0.33 O2, LiNi 0.5 Co 0.3 Mn 0.2 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 Examples include O2.

[0096] The positive electrode active material may contain a lithium-containing composite oxide (hereinafter, sometimes referred to as "NCA") represented by the following formula (P2). Li t Ni 1-x-y Co x Al y O2… Formula (P2) In formula (P2), 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. A specific example of NCA is LiNi 0.8 Co 0.15 Al 0.05 Examples include O2.

[0097] When the positive electrode in the lithium secondary battery precursor of the present disclosure includes a positive electrode current collector and a positive electrode composite layer containing a positive electrode active material and a binder, the content of the positive electrode active material in the positive electrode composite layer is preferably 10% by mass or more and 99.9% by mass or less, more preferably 30% by mass or more and 99.9% by mass or less, even more preferably 50% by mass or more and 99% by mass or less, and particularly preferably 70% by mass or more and 99% by mass or less, relative to the total amount of the positive electrode composite layer.

[0098] Examples of binders include polyvinyl acetate, polymethyl methacrylate, nitrocellulose, fluororesin, and rubber particles. Examples of fluororesin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and vinylidene fluoride-hexafluoropropylene copolymer. Examples of rubber particles include styrene-butadiene rubber particles and acrylonitrile rubber particles. Among these, fluororesin is preferred from the viewpoint of improving the oxidation resistance of the positive electrode mixture layer. One type of binder can be used alone, or two or more types can be used in combination as needed. The content of the binder in the positive electrode mixture layer is preferably 0.1% by mass or more and 4% by mass or less, based on the total amount of the positive electrode mixture layer, from the viewpoint of achieving both the physical properties of the positive electrode mixture layer (e.g., electrolyte permeability, peel strength, etc.) and battery performance. When the binder content is 0.1% by mass or more, the adhesion of the positive electrode mixture layer to the positive electrode current collector and the binding strength between the positive electrode active materials are further improved. When the binder content is 4% by mass or less, the amount of positive electrode active material in the positive electrode mixture layer can be increased, thereby further improving the discharge capacity.

[0099] The positive electrode mixture layer preferably contains a conductive additive. Known conductive additives can be used as the material for the conductive additive. As known conductive additives, conductive carbon materials are preferred. Examples of conductive carbon materials include graphite, carbon black, conductive carbon fiber, and fullerene. These can be used alone or in combination of two or more. Examples of conductive carbon fibers include carbon nanotubes, carbon nanofibers, and carbon fibers. Examples of graphite include artificial graphite and natural graphite. Examples of natural graphite include flake graphite, lump graphite, and amorphous graphite. The material of the conductive additive may be a commercially available product. Examples of commercially available carbon black include Toka Black #4300, #4400, #4500, #5500, etc. (furnace black manufactured by Tokai Carbon Co., Ltd.), Printex L, etc. (furnace black manufactured by Degussa Corporation), Raven 7000, 5750, 5250, 5000ULTRA III, 5000ULTRA, etc., Conductex SC ULTRA, Conductex 975ULTRA, etc., and PUER BLACK100, 115, 205, etc. (Columbian Furnace Black), #2350, #2400B, #2600B, #30050B, #3030B, #3230B, #3350B, #3400B, #5400B, etc. (Mitsubishi Chemical Furnace Black), MONARCH1400, 1300, 900, VulcanXC-72R, BlackPearls2000, Examples include LITX-50, LITX-200 (furnace black, manufactured by Cabot Corporation), Ensaco250G, Ensaco260G, Ensaco350G, Super-P (manufactured by TIMCAL), Ketjenblack EC-300J, EC-600JD (manufactured by Akzo), Denkablack, Denkablack HS-100, FX-35 (acetylene black, manufactured by Denka Co., Ltd.), and the like.

[0100] The positive electrode mixture layer may contain other components such as a thickener, a surfactant, a dispersant, a wetting agent, and an antifoaming agent.

[0101] <Negative electrode> The negative electrode is capable of absorbing and releasing lithium ions. The negative electrode preferably contains at least one negative electrode active material capable of absorbing and desorbing lithium ions.

[0102] The negative electrode preferably includes a negative electrode current collector and a negative electrode mixture layer provided on at least a portion of the surface of the negative electrode current collector.

[0103] The material of the negative electrode current collector is not particularly limited and any known material can be used, for example, a metal or alloy. Specifically, the material of the negative electrode current collector can be aluminum, nickel, stainless steel (SUS), nickel-plated steel, copper, etc. Among them, copper is preferred as the material of the negative electrode current collector from the viewpoint of workability. Copper foil is preferred as the negative electrode current collector.

[0104] The negative electrode mixture layer contains a negative electrode active material and a binder.

[0105] The negative electrode active material is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions. The negative electrode active material is preferably at least one material selected from the group consisting of metallic lithium, lithium-containing alloys, metals or alloys capable of alloying with lithium, oxides capable of doping and dedoping lithium ions, transition metal nitrides capable of doping and dedoping lithium ions, and carbon materials capable of doping and dedoping lithium ions. Among these, the negative electrode active material is preferably a carbon material capable of doping and dedoping lithium ions (hereinafter simply referred to as "carbon material").

[0106] Examples of carbon materials include carbon black, activated carbon, graphite materials, and amorphous carbon materials. These carbon materials may be used alone or in combination of two or more. The form of the carbon material is not particularly limited, and examples include fibrous, spherical, potato-like, and flake-like forms. The particle size of the carbon material is not particularly limited, and is preferably 5 μm to 50 μm, more preferably 20 μm to 30 μm. Examples of amorphous carbon materials include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500° C. or less, and mesophase pitch carbon fiber (MCF). Examples of graphite materials include natural graphite and artificial graphite. Examples of artificial graphite include graphitized MCMB and graphitized MCF. The graphite material may contain boron. The graphite material may be coated with a metal or amorphous carbon. Examples of metal materials that coat the graphite material include gold, platinum, silver, copper, and tin. The graphite material may be a mixture of amorphous carbon and graphite.

[0107] The negative electrode mixture layer preferably contains a conductive additive. 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 mixture layer.

[0108] In addition to the above components, the negative electrode mixture layer may contain other components such as a thickener, a surfactant, a dispersant, a wetting agent, and an antifoaming agent.

[0109] <Separator> The separator may be, for example, a porous resin plate. Materials for the porous resin plate include resin and nonwoven fabric containing the resin. Examples of resin include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, and polyamide. In particular, the separator is preferably a porous resin sheet having a single layer or a multilayer structure. The porous resin sheet is mainly made 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.

[0110] <Specific examples of lithium secondary battery precursors> 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.

[0111] As shown in FIG. 1, a lithium secondary battery precursor 1 is a laminated type battery precursor. Specifically, in the lithium secondary battery precursor 1, the 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.

[0112] As shown in FIG. 1 , battery element 10 is formed by laminating positive electrode 11, separator 13, and negative electrode 12. Positive electrode 11 has positive electrode composite layer 11B formed on both main surfaces of positive electrode current collector 11A. Negative electrode 12 has negative electrode composite layer 12B formed on both main surfaces of negative electrode current collector 12A. Positive electrode composite layer 11B formed on one main surface of positive electrode current collector 11A of positive electrode 11 and negative electrode composite layer 12B formed on one main surface of negative electrode current collector 12A of negative electrode 12 adjacent to positive electrode 11 face each other with separator 13 interposed therebetween.

[0113] 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 the adjacent positive electrode composite layer 11B, the separator 13, and the negative electrode composite layer 12B. Note that the positive electrode and the negative electrode may each have an active material layer formed on one side of the respective current collectors.

[0114] Although the lithium secondary battery precursor 1 is a laminated lithium secondary battery precursor, the lithium secondary battery precursor of the present disclosure is not limited thereto and may be, for example, a wound lithium secondary battery precursor. A wound 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 lithium secondary battery precursors include cylindrical lithium secondary battery precursors and prismatic lithium secondary battery precursors.

[0115] 1 , in the lithium secondary battery precursor 1, the directions in which the positive electrode lead and the negative electrode lead each 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 to this. For example, the directions in which the positive electrode lead and the negative electrode lead each protrude from the inside to the outside of the exterior body 30 may be the same direction relative to the exterior body 30.

[0116] 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.

[0117] 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.

[0118] 2, a disc-shaped negative electrode 42, a separator 45 filled with a non-aqueous electrolyte, a disc-shaped positive electrode 41, and, if necessary, spacer plates 47 and 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 with a gasket 46 interposed therebetween. In this example, the nonaqueous electrolyte of the present disclosure is used as the nonaqueous electrolyte injected into separator 45 .

[0119] 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.

[0120] [Lithium secondary battery and manufacturing method thereof] The method for producing a lithium secondary battery according to the present disclosure includes: a step of preparing the lithium secondary battery precursor of the present disclosure (hereinafter also referred to as a "preparation step"); charging and discharging the lithium secondary battery precursor; Includes. The lithium secondary battery of the present disclosure is a lithium secondary battery obtained by charging and discharging the above-described lithium secondary battery precursor of the present disclosure.

[0121] According to the lithium secondary battery and the method for producing the same of the present disclosure, it is possible to reduce the rate of increase in low-temperature resistance of the lithium secondary battery when stored at high temperatures.

[0122] 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.

[0123] In the step of charging and discharging, the lithium secondary battery precursor can be charged and discharged according to a known method. In this step, the lithium secondary battery precursor may be subjected to a cycle of charging and discharging multiple times. 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 negative electrode (particularly the negative electrode active material) in the lithium secondary battery precursor.

[0124] 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.

[0125] [Additive for non-aqueous electrolyte of lithium secondary battery] The additive for the non-aqueous electrolyte of the lithium secondary battery of the present disclosure contains the above-mentioned compound (I). The preferred embodiments of compound (I) are as described above. By incorporating the additive for a non-aqueous electrolyte solution of a lithium secondary battery according to the present disclosure into a non-aqueous electrolyte solution for a lithium secondary battery, the same effects as those achieved by the non-aqueous electrolyte solution of the present disclosure described above can be achieved. [Example]

[0126] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples. Hereinafter, "%" means "% by mass" unless otherwise specified.

[0127] Example 1 <Preparation of non-aqueous electrolyte> 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 in a volume ratio of EC:DMC:EMC = 30:35:35, thereby obtaining a mixed solvent as a non-aqueous solvent. LiPF6 as an electrolyte was dissolved in the obtained mixed solvent so that the concentration in the finally obtained non-aqueous electrolyte solution was 1 mol / L, to obtain an electrolyte solution (hereinafter also referred to as "basic electrolyte solution"). To the obtained base electrolyte solution, compound (I-1) was added as compound (I) so that the content relative to the total amount of the finally obtained non-aqueous electrolyte solution would be the content (mass %) shown in Table 1, thereby obtaining a non-aqueous electrolyte solution.

[0128] <Preparation of positive electrode> LiNi as a positive electrode active material 0.5 Co 0.2 Mn 0.3 A mixture of O2 (94% by mass), carbon black (3% by mass) as a conductive additive, and polyvinylidene fluoride (PVdF) (3% by mass) as a binder was obtained, and the resulting mixture was dispersed in N-methylpyrrolidone solvent to obtain a positive electrode composite slurry. An aluminum foil with a thickness of 20 μm was prepared as a positive electrode current collector. The resulting positive electrode mixture slurry was applied to an aluminum foil, dried, and then rolled in a press to obtain a sheet-shaped positive electrode, which was composed of a positive electrode current collector and a positive electrode active material layer.

[0129] <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 in terms of solid content, and 2% by mass of styrene-butadiene rubber (SBR) dispersed in pure water as a binder in terms of solid content were mixed together to obtain a negative electrode composite slurry. A copper foil with a thickness of 10 μm was prepared as a negative electrode current collector. The resulting negative electrode mixture slurry was applied to a copper foil, dried, and then rolled in a press to obtain a sheet-shaped negative electrode, which was composed of a negative electrode current collector and a negative electrode active material layer.

[0130] <Preparing the separator> A porous polyethylene film was prepared as a separator.

[0131] <Preparation of lithium secondary battery precursor> The negative electrode was punched out into a disk shape with a diameter of 14 mm, the positive electrode was punched out into a disk shape with a diameter of 13 mm, and the separator was punched out into a disk shape with a diameter of 17 mm, thereby obtaining a coin-shaped negative electrode, coin-shaped positive electrode, and coin-shaped separator, respectively. 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 (size: 2032). Next, 28 μL of non-aqueous electrolyte was poured into the battery can, and the separator, positive electrode, and negative electrode were immersed in the non-aqueous electrolyte. Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery case lid was crimped via a polypropylene gasket to seal the battery. As a result, a coin-type lithium secondary battery precursor (i.e., a lithium secondary battery before being charged and discharged) was obtained having the configuration shown in Figure 2. The lithium secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.

[0132] <Fabrication of lithium secondary batteries> The lithium secondary battery precursor was charged to 1.5 V to 4.2 V, held for 5 to 50 hours, charged to 4.2 V, and discharged to 2.5 V in this order at a temperature range of 25°C to 70°C to obtain a lithium secondary battery.

[0133] <Measurement of initial low-temperature resistance> The lithium secondary battery was charged at 3.7 V and then cooled to -10°C in a thermostatic chamber. The amount of voltage drop (= voltage before discharge started - voltage 10 seconds after discharge started) due to CC10s discharge at discharge rates of 0.1 C to 0.6 C was measured in a -10°C environment. CC10s discharge refers to discharge at a constant current for 10 seconds. The DC resistance [Ω], which represents the initial low-temperature resistance, was calculated based on the amount of voltage drop and each current value (i.e., each current value corresponding to a discharge rate of 0.1 C to 0.6 C). The DC resistance [Ω] was similarly determined as the initial low-temperature resistance for Comparative Example 1 described below.

[0134] <High temperature storage> Next, the lithium secondary battery after measuring the initial low-temperature resistance was charged to 4.2 V, and the charged lithium secondary battery was stored in a thermostatic chamber at 60° C. for 14 days (hereinafter referred to as "high-temperature storage").

[0135] <Measurement of low-temperature resistance after high-temperature storage> The lithium secondary battery after high-temperature storage was discharged to 2.5 V, and then the low-temperature resistance after high-temperature storage was measured in the same manner as in the measurement of the initial low-temperature resistance. Similarly, for Comparative Example 1 described later, the DC resistance [Ω] was determined as the low-temperature resistance after high-temperature storage.

[0136] <Calculation of the rate of increase in low-temperature resistance during high-temperature storage> The low-temperature resistance increase rate (%) during high-temperature storage was calculated using the following formula. Low-temperature resistance increase rate during high-temperature storage (%) = (low-temperature resistance after high-temperature storage / initial low-temperature resistance) x 100

[0137] Similarly, the rate of increase in low-temperature resistance (%) during high-temperature storage was calculated for Comparative Example 1 described later.

[0138] The low-temperature resistance increase rate (relative value) of Example 1 during high-temperature storage was determined, assuming that the low-temperature resistance increase rate of Comparative Example 1 during high-temperature storage was 100. The results are shown in Table 1.

[0139] In Table 1, the content of each additive indicates the content (mass %) relative to the total amount of the non-aqueous electrolyte, and "-" indicates that the corresponding component is not contained.

[0140] Examples 2 to 16 The same procedure as in Example 1 was carried out, except that the types and contents of additives added to the base electrolyte were changed as shown in Table 1. The results are shown in Table 1. The structures of the additives (compound (I-1) and others) shown in Table 1 are as described above. VC in Example 3 means vinylene carbonate.

[0141] Comparative Example 1 The same procedure as in Example 1 was carried out except that Compound (I) was not added to the basic electrolyte solution. The results are shown in Table 1.

[0142] [Table 1]

[0143] As shown in Table 1, the lithium secondary batteries of Examples 1 to 16, which used non-aqueous electrolyte solutions containing Compound (I) as an additive, had a reduced rate of increase in low-temperature resistance during high-temperature storage, compared to the lithium secondary battery of Comparative Example 1, which used a base electrolyte solution containing no additive. [Explanation of symbols]

[0144] 1. Lithium secondary battery precursor 10 Battery element 11 Positive electrode 11A positive electrode current collector 11B Positive electrode composite layer 12 Negative electrode 12A negative electrode current collector 12B Negative electrode composite layer 13 Separator 14 Cell layer 21 Positive lead 22 Negative lead 30 Exterior body 41 Positive electrode 42 Negative electrode 43 Positive electrode can 44 Sealing plate 45 Separator 46 Gasket 47, 48 Spacer plates

Claims

1. A non-aqueous electrolyte solution for a lithium secondary battery, comprising a compound (I) represented by the following formula (I): 【Chemistry 1】 [In formula (I), R １１ is a hydrogen atom or —SO ２ R Ｙ It is the basis, R １２ teeth, The divalent group is one type of divalent group having 1 to 10 carbon atoms selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or a divalent group having 1 to 10 carbon atoms formed by linking two or more types of divalent groups selected from Group A. R Ｘ and R Ｙ are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

2. The R １２ is an alkylene group having 2 carbon atoms or an alkenylene group having 2 carbon atoms, The R Ｘ and the R Ｙ are each independently an optionally substituted aryl group; The nonaqueous electrolyte for a lithium secondary battery according to claim 1 .

3. The nonaqueous electrolyte solution for a lithium secondary battery according to claim 1, wherein the compound (I) is at least one selected from the group consisting of the following compounds (I-1) to (I-6): 【Chemistry 2】

4. 2. The non-aqueous electrolyte solution for a lithium secondary battery according to claim 1, wherein the content of the compound (I) is 0.01% by mass or more and 5.0% by mass or less based on the total amount of the non-aqueous electrolyte solution for a battery.

5. 2. The nonaqueous electrolyte solution for a lithium secondary battery according to claim 1, further comprising an additive X which is at least one selected from the group consisting of compound (II) which is at least one of lithium monofluorophosphate and lithium difluorophosphate, compound (III) represented by the following formula (III), compound (IV) represented by the following formula (IV), and compound (V) represented by the following formula (V): 【Transformation 3】 [In formula (III), M is an alkali metal; Y is a transition element, a Group 13 element, a Group 14 element, or a Group 15 element of the periodic table; b is an integer from 1 to 3; m is an integer from 1 to 4, n is an integer from 0 to 8, q is 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 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; Q １ and Q ２ are each independently an oxygen atom or a carbon atom. In formula (IV), R ４１ represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, or an alkenylene group having 2 to 6 carbon atoms, R ４２ represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (iv-1), or a group represented by formula (iv-2), * denotes a bond position, In formula (iv-1), R ４３ 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, In formula (iv-2), R ４４ is an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms. In formula (V), R ５１ and R ５２ each independently represents a hydrogen atom, a methyl group, an ethyl group, or a propyl group.

6. 6. The non-aqueous electrolyte solution for a lithium secondary battery according to claim 5, wherein the content of the additive X is 0.01% by mass or more and 5.0% by mass or less with respect to the total amount of the non-aqueous electrolyte solution for a battery.

7. Case and a positive electrode, a negative electrode, a separator, and an electrolyte solution housed in the case; Equipped with the positive electrode is a positive electrode capable of absorbing and desorbing lithium ions, the negative electrode is capable of absorbing and desorbing lithium ions, A lithium secondary battery precursor, wherein the electrolyte solution is the nonaqueous electrolyte solution for lithium secondary batteries according to any one of claims 1 to 6.

8. The lithium secondary battery precursor according to claim 7 , wherein the positive electrode contains a lithium-containing composite oxide represented by the following formula (P1) as a positive electrode active material: LiNi ａ Co ｂ Mn ｃ O ２ … Formula (P1) In formula (P1), a, b, and c each independently represent a number greater than 0 and less than 1, and the sum of a, b, and c represents a number greater than or equal to 0.99 and less than or equal to 1.

00.

9. A step of preparing the lithium secondary battery precursor according to claim 7; charging and discharging the lithium secondary battery precursor; A method for producing a lithium secondary battery, comprising:

10. A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to claim 7.

11. An additive for a non-aqueous electrolyte of a lithium secondary battery, comprising a compound (I) represented by the following formula (I): 【Chemistry 4】 [In formula (I), R １１ is a hydrogen atom or —SO ２ R Ｙ It is the basis, R １２ is a divalent group having 1 to 10 carbon atoms and being one type selected from Group A consisting of an alkylene group, a fluorinated alkylene group, an alkenylene group, a fluorinated alkenylene group, and a carbonyl group, or is a divalent group having 1 to 10 carbon atoms formed by linking two or more types selected from Group A, R Ｘ and R Ｙ are each independently an optionally substituted aryl group or an optionally substituted benzyl group.

12. The R １２ is an alkylene group having 2 carbon atoms, The R Ｘ and the R Ｙ are each independently an optionally substituted aryl group; The additive for a non-aqueous electrolyte of a lithium secondary battery according to claim 11.

13. The compound (I) is at least one selected from the group consisting of the following compounds (I-1) to (I-6): An additive for a non-aqueous electrolyte solution of a lithium secondary battery according to claim 11: 【Transformation 5】

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