Compound, battery additive, non-aqueous electrolyte for batteries, lithium secondary battery precursor, lithium secondary battery, and method for manufacturing lithium secondary battery

Abstract

To provide a non-aqueous electrolyte for batteries that can reduce battery resistance during storage of the batteries.SOLUTION: The invention provides a compound represented by a formula (I) in the figure. In the formula (I), M1 and M2 each independently represent a hydrogen atom, a lithium atom, a sodium atom or a potassium atom, and n represents a value from 0 to 10.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In recent years, various studies have been conducted on non-aqueous electrolytes for batteries. For example, Patent Document 1 discloses a lithium (N-carbonyl)sulfonamide compound, an additive for a lithium secondary battery, a nonaqueous electrolyte for a lithium secondary battery, a lithium secondary battery precursor, a lithium secondary battery, and a method for producing a lithium secondary battery, which are capable of suppressing an increase in DC resistance and a decrease in discharge capacity even when the lithium secondary battery is stored in a high-temperature environment. The lithium (N-carbonyl)sulfonamide compound has a specific structure, and as a lithium secondary battery additive containing this lithium (N-carbonyl)sulfonamide compound, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 196230 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are cases where it is desired to use a compound other than the compound described in Patent Document 1 to reduce the battery resistance after storage of the battery while maintaining the battery capacity after storage of the battery.

[0005] An object of one aspect of the present disclosure is to provide a compound, a battery additive, a nonaqueous electrolyte solution for a battery, a lithium secondary battery precursor, a lithium secondary battery, and a method for manufacturing a lithium secondary battery, which are capable of reducing the battery resistance after storage of a battery while maintaining the battery capacity after storage of the battery. [Means for solving the problem]

[0006] Means for solving the above problems include the following aspects. <1> A compound represented by the following formula (I):

[0007] [ka]

[0008] In formula (I), M 1 and M 2 each independently represents a hydrogen atom, a lithium atom, a sodium atom, or a potassium atom; and n represents 0 to 10.

[0009] <2> <1> A battery additive comprising compound (I), which is a compound according to claim 1. <3> <1> A non-aqueous electrolyte for a battery, comprising compound (I) according to the above item (1). <4> Further, the composition contains a compound (A), The compound (A) is at least one selected from the group consisting of compound (II) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, compound (III) represented by the following formula (III), and compound (IV) represented by the following formula (IV): <3> The non-aqueous electrolyte for a battery according to claim 1.

[0010] [ka]

[0011] In formula (III), M is an alkali metal; Y is a transition element, an element of 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 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), * 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.

[0012] <5> The content of the compound (A) is 0.01% by mass to 5.0% by mass based on the total amount of the nonaqueous electrolyte for a battery. <4> The non-aqueous electrolyte for a battery according to claim 1. <6> The content of the compound (I) is 0.01% by mass to 5.0% by mass based on the total amount of the nonaqueous electrolyte for a battery. <3> or <4> The non-aqueous electrolyte for a battery according to claim 1. <7> Case and a positive electrode, a negative electrode, a separator, and an electrolyte solution contained in the case; Equipped with 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 solution is <3> ~ <6> The nonaqueous electrolyte solution for a battery according to any one of claims 1 to 5, Lithium secondary battery precursor. <8> The positive electrode contains a lithium-containing composite oxide represented by the following formula (C1) as a positive electrode active material: <7> The lithium secondary battery precursor according to claim 1. LiNi a Co b Mn c O2… Formula (C1) (In formula (C1), 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> or <8> 2. A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to claim 1. Effect of the Invention

[0013] According to one aspect of the present disclosure, there are provided a compound, a battery additive, a nonaqueous electrolyte solution for a battery, a lithium secondary battery precursor, a lithium secondary battery, and a method for manufacturing a lithium secondary battery, which are capable of reducing the battery resistance after storage of a battery while maintaining the battery capacity after storage of the battery. [Brief description of the drawings]

[0014] [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. [Diagram 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 PREFERRED EMBODIMENTS

[0015] 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, when a plurality of substances corresponding to each component are present in the composition, the total amount of the plurality of substances present in the composition, unless otherwise specified. In this specification, the term "process" refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.

[0016] [Compound represented by formula (I)] The compound of the present disclosure is a compound represented by the following formula (I) (hereinafter also referred to as "compound (I)").

[0017] [ka]

[0018] In formula (I), M 1 and M 2 each independently represents a hydrogen atom, a lithium atom, a sodium atom, or a potassium atom; and n represents 0 to 10.

[0019] When compound (I) (i.e., the compound of the present disclosure) is used as a battery additive (e.g., an additive for a non-aqueous electrolyte of a battery), it can reduce the battery resistance after storage of the battery while maintaining the battery capacity after storage of the battery. The reason why such an effect is exhibited is unclear, but it is considered that when compound (I) is used as a battery additive, a high-quality coating of compound (I) is formed on the surface of the electrodes (positive electrode and / or negative electrode) of the battery, and this coating suppresses dissolution of the electrodes and / or decomposition of the non-aqueous electrolyte during storage of the battery.

[0020] In formula (I), M 1 and M 2 each independently represents a hydrogen atom, a lithium atom, a sodium atom, or a potassium atom. M 1 and M 2 are each preferably independently a hydrogen atom or a lithium atom.

[0021] In the formula (I), n represents 0 to 10. From the viewpoint of further reducing the battery resistance after storage of the battery, n is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and still more preferably 2 or less. From the viewpoint of ease of synthesis of compound (I), n is preferably 1 or more.

[0022] Specific examples (exemplary compounds) of compound (I) include the following compounds (I-1) to (I-7). Examples of the synthesis of these exemplary compounds will be described later.

[0023] [ka]

[0024] Among the compounds (I), M 1 and M 2 The compound in which each of the groups is a hydrogen atom can be synthesized, for example, by reacting chlorosulfonyl isocyanate with a linear alkanediol to obtain intermediate A, and then reacting the obtained intermediate A with potassium hydrogen difluoride (see Synthesis Examples 1 to 5 described later). Among the compounds (I), M 1 and M 2 The compound in which at least one of the groups is a lithium atom is, for example, 1 and M 2are hydrogen atoms with a lithium-containing compound (see Synthesis Examples 6 to 7 described later). Examples of the lithium-containing compound include lithium bis(trimethylsilyl)amide, lithium chloride, lithium carbonate, lithium hydroxide, lithium methoxide, lithium ethoxide, and lithium-t-butoxide. Among them, the lithium-containing compound is preferably lithium bis(trimethylsilyl)amide, lithium chloride, lithium carbonate, or lithium hydroxide, and more preferably lithium bis(trimethylsilyl)amide. Among the compounds (I), M 1 and M 2 Similarly, the compound in which at least one of is a sodium atom is also 1 and M 2 are hydrogen atoms with a sodium-containing compound (eg, sodium carbonate, sodium bis(trimethylsilyl)amide, etc.). Among the compounds (I), M 1 and M 2 Similarly, compounds in which at least one of the groups is a potassium atom are also described above as M 1 and M 2 are hydrogen atoms with a potassium-containing compound (for example, potassium carbonate, potassium bis(trimethylsilyl)amide, etc.). As for the reaction conditions for producing compound (I), known reaction conditions such as the reaction conditions in WO 2022 / 196230 can be appropriately applied.

[0025] [Battery Additives] The battery additive of the present disclosure contains at least one of the above-mentioned compounds (I). According to the battery additive of the present disclosure, the same effects as those achieved by the above-mentioned compound (I) can be obtained. The battery additive of the present disclosure is preferably an additive for a non-aqueous electrolyte of a battery, and more preferably an additive for a non-aqueous electrolyte of a lithium secondary battery.

[0026] [Nonaqueous electrolyte for batteries] The nonaqueous electrolyte for a battery according to the present disclosure (hereinafter also simply referred to as "nonaqueous electrolyte") contains at least one of the above-mentioned compounds (I). According to the nonaqueous electrolyte of the present disclosure, the same effects as those achieved by the above-mentioned compound (I) can be obtained.

[0027] <Compound (I)> Compound (I) is as already described as a compound of the present disclosure.

[0028] The content of compound (I) relative to the total amount of the nonaqueous electrolyte is preferably 0.01 mass % to 5.0 mass %, more preferably 0.01 mass % to 3.0 mass %, even more preferably 0.1 mass % to 2.0 mass %, and still more preferably 0.2 mass % to 1.5 mass %.

[0029] In addition, when the non-aqueous electrolyte solution collected by disassembling the lithium secondary battery is actually analyzed, the amount of compound (I) 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 (I) is detected in the non-aqueous electrolyte solution taken out of 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 the compound (A) described below.

[0030] <Compound (A)> The nonaqueous electrolyte solution of the present disclosure preferably further contains the following compound (A). This further reduces the battery resistance after storage of the battery, and further improves the battery capacity after storage of the battery. Compound (A) is Compound (II) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate; A compound (III) represented by formula (III) described below, A compound (IV) represented by formula (IV) described below, At least one selected from the group consisting of:

[0031] When the non-aqueous electrolyte solution of the present disclosure contains compound (A), from the viewpoint of more effectively obtaining the effect of reducing battery resistance after storage, the content of compound (A) relative to the total amount of the non-aqueous electrolyte solution of the present disclosure is preferably 0.01 mass% to 5.0 mass%, more preferably 0.05 mass% to 3.0 mass%, even more preferably 0.1 mass% to 2.0 mass%, and still more preferably 0.2 mass% to 1.5 mass%.

[0032] When the nonaqueous electrolyte solution of the present disclosure contains compound (A), from the viewpoint of more effectively obtaining the effect of reducing the battery resistance after storage, in the nonaqueous electrolyte solution of the present disclosure, the ratio of the mass content of compound (A) to the mass content of compound (I) (hereinafter, also referred to as "mass ratio [compound (A) / compound (I)]") is 0.1 to 5.0, and more preferably 0.1 to 2.0.

[0033] Compounds (II) to (IV), which are alternatives to compound (A), will be described below.

[0034] (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).

[0035] [ka]

[0036] Compound (II) may be either lithium monofluorophosphate or lithium difluorophosphate, or may be both lithium monofluorophosphate and lithium difluorophosphate.

[0037] 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 0.01% by mass, and even more preferably 0.1% by mass.

[0038] (Compound (III)) Compound (III) is a compound represented by the following formula (III).

[0039] [ka]

[0040] In formula (III), M is an alkali metal; Y is a transition element, an element of 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 1 , and Q 2 are each independently an oxygen atom or a carbon atom.

[0041] 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, a group 13 element, a group 14 element, or a group 15 element 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 the production cost can be reduced. b represents the valence of the anion and the number of cations, and is an integer of 1 to 3, and is preferably 1. When b is 3 or less, the salt of the anion 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 the structure. Specifically, R 31 may contain a substituent instead 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. R32 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 preferable, and a fluorine atom is particularly preferable. Q 1 and Q 2 each independently represents O or C. That is, the ligand bonds to Y via these heteroatoms.

[0042] Specific examples of compound (III) include the following compound (III-1) and compound (III-2).

[0043] [ka]

[0044] 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, based on 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 0.01% by mass, and even more preferably 0.1% by mass.

[0045] (Compound (IV)) Compound (IV) is a compound represented by the following formula (IV).

[0046] [ka]

[0047] 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.

[0048] 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.

[0049] Specific examples of compound (IV) include the following compounds (IV-1) to (IV-8).

[0050] [ka]

[0051] In formula (IV), R 41 may be an oxygen atom or an alkylene group having 1 to 6 carbon atoms. Among the above specific examples, in formula (IV), R 41Specific examples of when is an oxygen atom or an alkylene group having 1 to 6 carbon atoms include compounds (IV-1) to (IV-3) and compounds (IV-5) to (IV-8).

[0052] When the non-aqueous electrolyte solution of the present disclosure contains compound (IV), the content of compound (IV) 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 (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 0.01% by mass, and even more preferably 0.1% by mass.

[0053] <Non-aqueous solvent> The non-aqueous electrolyte generally contains a non-aqueous solvent. As the non-aqueous solvent, various known ones can be appropriately selected, and the non-aqueous solvent may be one kind or two or more kinds.

[0054] 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 carboxylate 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. The amides include, for example, N,N-dimethylformamide. Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, and N,N'-dimethylimidazolidinone.

[0055] 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 cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, and fluorine-containing chain carbonates is preferably 50 mass% or more and 100 mass% or less, more preferably 60 mass% or more and 100 mass% or less, and even more preferably 80 mass% or more and 100 mass% or less, based on the total amount of the non-aqueous solvent.

[0056] 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.

[0057] The lower limit of the content of the nonaqueous solvent is preferably 60 mass % or more, and more preferably 70 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 mass %, more preferably 97 mass %, and further preferably 90 mass %, based on the total amount of the nonaqueous electrolyte.

[0058] <Electrolytes> The non-aqueous electrolyte generally contains an electrolyte.

[0059] 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.

[0060] 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 them, lithium hexafluorophosphate (LiPF6) is more preferable as the fluorine-containing lithium salt.

[0061] Fluorine-free lithium salts include lithium perchlorate (LiClO4), lithium aluminium tetrachloride (LiAlCl4), and lithium decachlorodecaborate (Li2B 10 Cl 10 ) etc.

[0062] When the electrolyte contains a fluorine-containing lithium salt, the content of the fluorine-containing lithium salt is preferably 50 mass % or more and 100 mass % or less, more preferably 60 mass % or more and 100 mass % or less, and even more preferably 80 mass % or more and 100 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 mass% or more and 100 mass% or less, more preferably 60 mass% or more and 100 mass% or less, and even more preferably 80 mass% or more and 100 mass% or less, based on the total amount of the electrolyte.

[0063] When the non-aqueous electrolyte contains an electrolyte, the concentration of the electrolyte in the non-aqueous electrolyte is preferably 0.1 mol / L to 3 mol / L, more preferably 0.2 mol / L to 2 mol / L, and even more preferably 0.5 mol / L to 2 mol / L.

[0064] 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 0.2 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.

[0065] <Other ingredients> The non-aqueous electrolyte may contain other components as necessary. Other components include acid anhydrides.

[0066] [Lithium secondary battery precursor] The lithium secondary battery precursor of the present disclosure is Case and A positive electrode, a negative electrode, a separator, and an electrolyte solution, all of which are housed in a case; Equipped with. Here, the positive electrode is a positive electrode capable of absorbing and releasing lithium ions, the negative electrode is a negative electrode capable of absorbing and releasing lithium ions, and the electrolyte is the nonaqueous electrolyte of the present disclosure.

[0067] In the present disclosure, a lithium secondary battery precursor refers to a lithium secondary battery before being charged and discharged.

[0068] The lithium secondary battery precursor of the present disclosure contains the nonaqueous electrolyte solution of the present disclosure, and therefore exhibits effects similar to those of the nonaqueous electrolyte solution of the present disclosure.

[0069] <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. Examples of the case include a case including a laminate film, and a case consisting of a battery can and a battery can lid.

[0070] <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 releasing lithium ions.

[0071] The positive electrode preferably includes a positive electrode current collector and a positive electrode mixture layer. The positive electrode mixture layer is provided on at least a portion of the surface of the positive electrode current collector.

[0072] Examples of the material of the positive electrode current collector include metals and alloys. More specifically, examples of the material of the positive electrode current collector include aluminum, nickel, stainless steel (SUS), and copper. Among them, aluminum is preferred from the viewpoint of the balance between high conductivity and cost. Here, "aluminum" means pure aluminum or an aluminum alloy. As the positive electrode current collector, aluminum foil is preferred. The material of the aluminum foil is not particularly limited, and examples thereof include A1085 material, A3003 material, and the like.

[0073] The positive electrode mixture layer contains a positive electrode active material and a binder.

[0074] The positive electrode active material is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions, and can be appropriately adjusted depending on the application of the lithium secondary battery precursor, etc.

[0075] Examples of the positive electrode active material include a first oxide and a second oxide. The first oxide includes lithium (Li) and nickel (Ni) as constituent metal elements. The second oxide includes Li, Ni, and at least one metal element other than Li and Ni as constituent metal elements. Examples of the metal elements other than Li and Ni include transition metal elements and typical metal elements. The second oxide preferably includes the metal elements other than Li and Ni at a ratio equal to or less than Ni in terms of atomic number. The metal elements other than Li and Ni may be 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 a mixture of two or more.

[0076] The positive electrode active material preferably contains a lithium-containing composite oxide (hereinafter, sometimes referred to as "NCM") represented by the following formula (C1). The lithium-containing composite oxide (C1) has the advantages of high energy density per unit volume and excellent thermal stability. LiNia Co b Mn c O2… Formula (C1) In formula (C1), a, b and c each independently represent more than 0 and less than 1, and the sum of a, b and c is 0.99 or greater and 1.00 or less. 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.

[0077] The positive electrode active material may contain a lithium-containing composite oxide (hereinafter sometimes referred to as "NCA") represented by the following formula (C2). Li t Ni 1-x-y Co x Al y O2… Formula (C2) In formula (C2), 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. A specific example of NCA is LiNi 0.8 Co 0.15 Al 0.05 Examples include O2.

[0078] When the positive electrode in the lithium secondary battery precursor of the present disclosure includes a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the content of the positive electrode active material in the positive electrode mixture layer is preferably 10 mass% to 99.9 mass%, more preferably 30 mass% to 99.0 mass%, still more preferably 50 mass% to 99.0 mass%, and particularly preferably 70 mass% to 99.0 mass%, relative to the total amount of the positive electrode mixture layer.

[0079] Examples of the binder include polyvinyl acetate, polymethyl methacrylate, nitrocellulose, fluororesin, and rubber particles. Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and vinylidene fluoride-hexafluoropropylene copolymer. Examples of the 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 necessary. 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 with respect to the total amount of the positive electrode mixture layer, from the viewpoint of balancing the physical properties of the positive electrode mixture layer (e.g., electrolyte permeability, peel strength, etc.) and battery performance. When the content of the binder is 0.1% by mass or more, the adhesion of the positive electrode mixture layer to the positive electrode current collector and the binding of the positive electrode active materials themselves are further improved. When the content of the binder is 4% by mass or less, the amount of the positive electrode active material in the positive electrode mixture layer can be increased, and thus the discharge capacity is further improved.

[0080] The positive electrode mixture layer preferably contains a conductive assistant. As the material of the conductive assistant, a known conductive assistant can be used. As the known conductive assistant, a conductive carbon material is preferable. As the conductive carbon material, graphite, carbon black, conductive carbon fiber, fullerene, etc. can be mentioned. These can be used alone or in combination of two or more kinds. As the conductive carbon fiber, carbon nanotube, carbon nanofiber, carbon fiber, etc. can be mentioned. As the graphite, for example, artificial graphite, natural graphite, etc. can be mentioned. As the natural graphite, for example, flake graphite, lump graphite, earthy graphite, etc. can be mentioned. The conductive additive may be a commercially available product. Examples of commercially available carbon black products 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, 5000ULTRAIII, 5000ULTRA, etc., Conductex SC ULTRA, Conductex 975ULTRA, etc., 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 of such blacks include LITX-50, LITX-200 (furnace black, manufactured by Cabot Corporation), Ensaco 250G, Ensaco 260G, Ensaco 350G, Super-P (manufactured by TIMCAL Corporation), Ketjen Black EC-300J, EC-600JD (manufactured by Akzo Corporation), Denka Black, Denka Black HS-100, FX-35 (acetylene black, manufactured by Denka Corporation).

[0081] The positive electrode mixture layer may contain other components such as a thickener, a surfactant, a dispersant, a wetting agent, and a defoamer.

[0082] <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 releasing lithium ions.

[0083] More preferably, the negative electrode includes a negative electrode current collector and a negative electrode mixture layer. The negative electrode mixture layer is provided on at least a portion of the surface of the negative electrode current collector.

[0084] The material of the negative electrode current collector is not particularly limited and can be any known material, for example, metal or alloy. More 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 preferable as the material of the negative electrode current collector from the viewpoint of workability. Copper foil is preferable as the negative electrode current collector.

[0085] The negative electrode mixture layer contains a negative electrode active material and a binder.

[0086] 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 selected from the group consisting of, for example, 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 referred to as "carbon material").

[0087] 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 thereof include fibrous, spherical, potato, and flake 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) 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. The graphite material may contain boron. The graphite material may be coated with a metal or amorphous carbon. Examples of the metal material that coats the graphite material include gold, platinum, silver, copper, and tin. The graphite material may be a mixture of amorphous carbon and graphite.

[0088] The negative electrode mixture layer preferably contains a conductive assistant. Examples of the conductive assistant include the same conductive assistants as those exemplified as the conductive assistants that can be contained in the positive electrode mixture layer.

[0089] 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 a defoamer.

[0090] <separator> The separator may be, for example, a porous resin plate. The material of the porous resin plate may be a resin, a nonwoven fabric containing the resin, etc. The resin may be polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, polyamide, etc. In particular, the separator is preferably a porous resin sheet having a single layer or a multilayer structure. The material of 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.

[0091] <Specific examples of lithium secondary battery precursors> FIG. 1 is a schematic cross-sectional view showing a laminated type lithium secondary battery precursor, which is an example of the lithium secondary battery precursor of the present disclosure.

[0092] 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.

[0093] As shown in Fig. 1, the battery element 10 is formed by laminating a positive electrode 11, a separator 13, and a negative electrode 12. The positive electrode 11 is formed by forming a positive electrode mixture layer 11B on both main surfaces of a positive electrode current collector 11A. The negative electrode 12 is formed by forming a negative electrode mixture layer 12B on both main surfaces of a negative electrode current collector 12A. The positive electrode mixture layer 11B formed on one main surface of the positive electrode current collector 11A of the positive electrode 11 and the negative electrode mixture 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 via the separator 13.

[0094] The nonaqueous electrolyte solution of the present disclosure is injected into the interior of the exterior body 30 of the lithium secondary battery precursor 1. The nonaqueous electrolyte solution of the present disclosure permeates the positive electrode mixture layer 11B, the separator 13, and the negative electrode mixture layer 12B. In the lithium secondary battery precursor 1, one single cell layer 14 is formed by the adjacent positive electrode mixture layer 11B, the separator 13, and the negative electrode mixture layer 12B. Note that the positive electrode and the negative electrode may each have a mixture layer formed on one side of each current collector.

[0095] The lithium secondary battery precursor 1 is a laminated type lithium secondary battery precursor, but 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. The 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 shape. The wound type lithium secondary battery precursor includes a cylindrical lithium secondary battery precursor and a prismatic lithium secondary battery precursor.

[0096] 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 of the exterior body 30 to the outside are opposite directions with respect 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 each protrude from the inside of the exterior body 30 to the outside may be the same direction with respect to the exterior body 30.

[0097] An example of the lithium secondary battery of the present disclosure described below is a lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor 1.

[0098] 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.

[0099] 2, a disk-shaped negative electrode 42, a separator 45 filled with a non-aqueous electrolyte, a disk-shaped positive electrode 41, and, if necessary, 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 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 .

[0100] An example of the lithium secondary battery of the present disclosure described below is a lithium secondary battery obtained by charging and discharging a coin-type lithium secondary battery precursor shown in FIG.

[0101] [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 described above (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-mentioned lithium secondary battery precursor of the present disclosure.

[0102] According to the lithium secondary battery and the manufacturing method thereof disclosed herein, it is possible to reduce the battery resistance of the lithium secondary battery during storage while maintaining the battery capacity of the lithium secondary battery after storage.

[0103] 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.

[0104] 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 the negative electrode (particularly the negative electrode active material) in the lithium secondary battery precursor.

[0105] 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. EXAMPLES

[0106] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples. Hereinafter, "room temperature" means 25°C.

[0107] [Synthesis Example 1] Hexane-1,6-diyl bis((fluorosulfonyl)carbamate) [compound (I-1)] represented by the following structural formula was synthesized as follows.

[0108] [ka]

[0109] Chlorosulfonyl isocyanate (7.91 g, 55.9 mmol) and acetonitrile (100 mL) as a solvent were placed in a 100 mL four-neck flask connected to a nitrogen-purged Dimroth condenser and cooled to 0°C. 1,6-hexanediol (3.00 g, 25.4 mmol) was added thereto and reacted with stirring at room temperature for 1 hour, after which potassium hydrogen difluoride (4.76 g, 60.9 mmol) was added and further reacted with stirring. After 2 hours, the reaction was stopped. The reaction product was then washed with water. That is, 100 mL of distilled water was added to the reaction solution, and 100 mL of hexane / ethyl acetate was added, followed by extraction and washing in a separatory funnel. The above water washing was repeated twice, and the organic phase after the two water washings was washed with saturated saline (20 mL). After washing with saturated saline, the organic phase was dried by adding magnesium sulfate, and then concentrated under reduced pressure to obtain a crude product. The obtained crude product was separated and purified by flash column chromatography using a hexane / ethyl acetate solvent. The hexane / ethyl acetate solvent is composed of hexane and ethyl acetate. The obtained solid was washed with hexane and methylene chloride. As a result of the above, hexane-1,6-diyl bis((fluorosulfonyl)carbamate) (7.95 g, 21.6 mmol, yield 85%) was obtained as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.29-1.34(m,4H), 1.51-1.54(m,4H), 3.90(t,J=6.6Hz,4H), 9.74(brs,2H)

[0110] As described above, in Synthesis Example 1, hexane-1,6-diyl bis((fluorosulfonyl)carbamate) [compound (I-1)] was obtained according to the following reaction scheme.

[0111] [ka]

[0112] [Synthesis Example 2] Pentane-1,5-diyl bis((fluorosulfonyl)carbamate) [compound (I-2)] represented by the following structural formula was synthesized as follows.

[0113] [ka]

[0114] Chlorosulfonyl isocyanate (7.91 g, 55.9 mmol) was changed to chlorosulfonyl isocyanate (8.97 g, 63.3 mmol); Potassium hydrogen difluoride (4.76 g, 60.9 mmol) was changed to potassium hydrogen difluoride (5.40 g, 69.1 mmol); 1,6-Hexanediol (3.00g, 25.4mmol) was changed to 1,5-pentanediol (3.00g, 28.8mmol). By carrying out the same procedure as in Synthesis Example 1 except for the above, pentane-1,5-diyl bis((fluorosulfonyl)carbamate) (7.53 g, 21.3 mmol, 74% yield) was obtained as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.31-1.38(m,2H), 1.53-1.60(m,4H), 3.96(t,J=6.6Hz,4H), 10.68(brs,2H)

[0115] [Synthesis Example 3] Butane-1,4-diyl bis((fluorosulfonyl)carbamate) [compound (I-3)] represented by the following structural formula was synthesized as follows.

[0116] [ka]

[0117] Chlorosulfonyl isocyanate (7.91 g, 55.9 mmol) was changed to chlorosulfonyl isocyanate (10.4 g, 73.3 mmol); Potassium hydrogen difluoride (4.76 g, 60.9 mmol) was changed to potassium hydrogen difluoride (6.24 g, 79.9 mmol); 1,6-Hexanediol (3.00g, 25.4mmol) was changed to 1,4-butanediol (3.00g, 33.3mmol). Except for this, the same procedure as in Synthesis Example 1 was carried out to obtain butane-1,4-diyl bis((fluorosulfonyl)carbamate) (9.44 g, 27.7 mmol, yield 80%) as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.56-1.62(m,4H), 3.94-3.99(m,4H), 12.10(brs,2H)

[0118] [Synthesis Example 4] Propane-1,3-diyl bis((fluorosulfonyl)carbamate) [compound (I-4)] represented by the following structural formula was synthesized as follows.

[0119] [ka]

[0120] Chlorosulfonyl isocyanate (7.91 g, 55.9 mmol) was changed to chlorosulfonyl isocyanate (10.3 g, 72.4 mmol); Change to potassium hydrogen difluoride (6.17 g, 79.0 mmol) and potassium hydrogen difluoride (6.24 g, 79.9 mmol). Acetonitrile (100 mL) was changed to acetonitrile (150 mL); 1,6-Hexanediol (3.00 g, 25.4 mmol) was replaced with 1,3-propanediol (2.50 g, 32.9 mmol). Except for the above, the same operation as in Synthesis Example 1 was carried out to obtain propane-1,3-diyl bis((fluorosulfonyl)carbamate) (7.83 g, 24.0 mmol, yield 73%) as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.83(m,2H), 3.99(t,J=6.4Hz,4H), 11.00(brs,2H)

[0121] [Synthesis Example 5] Ethan-1,2-diyl bis((fluorosulfonyl)carbamate) [compound (I-5)] represented by the following structural formula was synthesized as follows.

[0122] [ka]

[0123] Chlorosulfonyl isocyanate (7.91 g, 55.9 mmol) was changed to chlorosulfonyl isocyanate (12.5 g, 88.6 mmol); Change to potassium hydrogen difluoride (6.17 g, 79.0 mmol) and potassium hydrogen difluoride (7.55 g, 96.7 mmol). Acetonitrile (100 mL) was changed to acetonitrile (150 mL); 1,6-Hexanediol (3.00 g, 25.4 mmol) was replaced with ethylene glycol (2.50 g, 40.3 mmol). Except for this, the same procedure as in Synthesis Example 1 was carried out to obtain ethane-1,2-diyl bis((fluorosulfonyl)carbamate) (10.1 g, 32.4 mmol, yield 80%) as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ4.06(s,2H), 10.05(brs,2H)

[0124] [Synthesis Example 6] Lithium ((hexane-1,6-diylbis(oxy))bis(carbonyl))bis((fluorosulfonyl)amide) [compound (I-6)] represented by the following structural formula was synthesized as follows.

[0125] [ka]

[0126] In a nitrogen-purged 100 mL four-neck flask, hexane-1,6-diyl bis((fluorosulfonyl)carbamate) [compound (I-1)] (4.00 g) and methanol (40 mL) as a solvent were charged, and lithium carbonate (1.76 g, 23.8 mmol) was added thereto, followed by stirring and reaction for 1 hour. The resulting reaction solution was concentrated under reduced pressure, and ethyl acetate (40 mL) was added to make a suspension. The suspension was filtered through Celite, and the filtrate was concentrated under reduced pressure. Dichloromethane (40 mL) was added to the resulting concentrated solution, and the mixture was stirred at room temperature for 1 hour, resulting in the precipitation of a white solid. The resulting solution was filtered under reduced pressure, and the remaining solvent of the resulting white solid was distilled off under reduced pressure. As a result of the above, lithium ((hexane-1,6-diylbis(oxy))bis(carbonyl))bis((fluorosulfonyl)amide) (2.07 g, 5.44 mmol, yield 50%) was obtained as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.26-1.30(m,4H), 1.46-1.50(m,4H), 3.78(t,J=6.8Hz,4H)

[0127] As described above, in Synthesis Example 6, hexane-1,6-diyl bis((fluorosulfonyl)carbamate) [compound (I-6)] was obtained according to the following reaction scheme.

[0128] [ka]

[0129] [Synthesis Example 7] Lithium ((pentane-1,5-diylbis(oxy))bis(carbonyl))bis((fluorosulfonyl)amide) [compound (I-7)] represented by the following structural formula was synthesized as follows.

[0130] [ka]

[0131] In a 100 mL four-neck flask purged with nitrogen, butane-1,4-diyl bis((fluorosulfonyl)carbamate) [compound (I-3)] (5.00 g) and tetrahydrofuran (50 mL) as a solvent were charged and kept at -78°C. Lithium bis(trimethylsilyl)amide (1.3 M) tetrahydrofuran solution (21.7 mL, 28.2 mmol) was added thereto, and the mixture was allowed to warm to room temperature and reacted with stirring for 3 hours. The resulting reaction solution was concentrated under reduced pressure and washed with dimethyl carbonate. As a result of the above, lithium ((pentane-1,5-diylbis(oxy))bis(carbonyl))bis((fluorosulfonyl)amide) (4.62 g, 13.1 mmol, yield 89%) was obtained as a white solid. Below 1 The measurement results by H-NMR (DMSO-d6) are shown. 1 H-NMR: δ1.49-1.52(m,4H), 3.78-3.81(m,4H)

[0132] As described above, in Synthesis Example 7, hexane-1,6-diyl bis((fluorosulfonyl)carbamate) [compound (I-7)] was obtained according to the following reaction scheme.

[0133] [ka]

[0134] Example 1 <Preparation of non-aqueous electrolyte> Ethylene carbonate (hereinafter, EC), dimethyl carbonate (hereinafter, DMC), and ethyl methyl carbonate (EMC) were mixed in a volume ratio of EC:DMC:EMC=30:35:35 to obtain a mixed solvent as a non-aqueous solvent. In the resulting mixed solvent, LiPF6 was dissolved as an electrolyte 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, the above-mentioned compound (I-1) as compound (I) 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.

[0135] <Preparation of positive electrode> Li(Ni 0.5 Co 0.2 Mn 0.3 A mixture was obtained by adding 94% by mass of O2, 3% by mass of carbon black as a conductive additive, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder. The mixture was dispersed in an N-methylpyrrolidone solvent to obtain a positive electrode composite slurry. An aluminum foil having a thickness of 20 μm was prepared as a positive electrode current collector. The obtained positive electrode mixture slurry was applied onto an aluminum foil, dried, and then rolled with a press to obtain a sheet-shaped positive electrode. The positive electrode was composed of a positive electrode current collector and a positive electrode active material layer.

[0136] <Preparation of negative electrode> Graphite (96 mass%) was used as the negative electrode active material, carbon black (1 mass%) was used as a conductive additive, 1 mass% of sodium carboxymethylcellulose dispersed in pure water as a thickener (solid content), and 2 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 copper foil having a thickness of 10 μm was prepared as a negative electrode current collector. The obtained negative electrode mixture slurry was applied onto a copper foil, dried, and then rolled with a press to obtain a sheet-shaped negative electrode. The negative electrode was composed of a negative electrode current collector and a negative electrode active material layer.

[0137] <Preparing the separator> As a separator, a porous polyethylene film was prepared.

[0138] <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 into a disk shape with a diameter of 13 mm, and the separator into a disk shape with a diameter of 17 mm, thereby obtaining a coin-shaped negative electrode, a coin-shaped positive electrode, and 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 (size: 2032 size). Next, 20 μL of non-aqueous electrolyte was poured into the battery can to impregnate 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 can 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 charging and discharging) having the configuration shown in Fig. 2 was obtained. The size of the lithium secondary battery precursor was 20 mm in diameter and 3.2 mm in height.

[0139] <Preparation of lithium secondary battery> The lithium secondary battery precursor was charged from 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.

[0140] <Evaluation of initial discharge capacity> The lithium secondary battery obtained above was charged to 4.2 V in a thermostatic chamber at 25° C., and then discharged to 2.5 V, and the discharge capacity [mAh] (hereinafter referred to as “initial discharge capacity”) was measured.

[0141] <Evaluation of initial resistance value (room temperature)> Next, the lithium secondary battery after the initial discharge capacity measurement was charged at 3.7 V, and then in a thermostatic bath at 25° C., the DC resistance [Ω] was measured as the initial resistance value (at room temperature) based on each voltage drop (=voltage before the start of discharge−voltage 10 seconds after the start of discharge) due to “CC10s discharge” at each discharge rate of 0.2 C to 2.0 C and each current value (i.e., each current value corresponding to a discharge rate of 0.2 C to 2.0 C). Here, normal temperature means 25°C.

[0142] <Evaluation of initial resistance value (-10℃)> Next, the lithium secondary battery after the initial resistance (room temperature) measurement was charged at 3.7 V and then cooled to -10°C in a thermostatic chamber. Based on each voltage drop (=voltage before the start of discharge-voltage 10 seconds after the start of discharge) due to "CC10s discharge" at discharge rates of 0.1 C to 0.6 C and each current value (i.e., each current value corresponding to discharge rates of 0.1 C to 0.6 C), the DC resistance [Ω] was measured as the initial resistance value (-10°C).

[0143] <Evaluation of capacity after storage> Next, the lithium secondary battery after measuring the initial resistance value (-10°C) 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"). The discharge capacity [mAh] of the lithium secondary battery after high-temperature storage was measured by discharging the battery to 2.5 V in a thermostatic chamber at 25° C., then charging the battery to 4.2 V, and discharging the battery further to 2.5 V. The discharge capacity [mAh] at the final discharge was determined as the discharge capacity after high-temperature storage. From the above results, the discharge capacity of the lithium secondary battery after high-temperature storage in Example 1 was determined based on the discharge capacity of the lithium secondary battery after high-temperature storage in Comparative Example 1 taken as 100, and this was taken as the "capacity after storage (relative value)". The resulting "capacity after storage (relative value)" is shown in Table 1.

[0144] <Evaluation of resistance after storage (at room temperature)> Next, the resistance value (at room temperature) of the lithium secondary battery after the post-storage capacity measurement was measured in the same manner as for the initial resistance value (at room temperature). Similarly, for Comparative Example 1 described later, the resistance value (at room temperature) of the lithium secondary battery after the post-storage capacity measurement was measured. From the above results, the resistance value (room temperature) (relative value) of the lithium secondary battery after the post-storage capacity measurement in Example 1 was calculated, assuming that the resistance value (room temperature) of the lithium secondary battery after the post-storage capacity measurement in Comparative Example 1 was 100, and this was designated as the "post-storage resistance (room temperature) (relative value)." The obtained “resistance after storage (room temperature) (relative value)” is shown in Table 1.

[0145] <Evaluation of resistance value after storage (-10℃)> Next, the resistance value (-10°C) of the lithium secondary battery after measuring the post-storage resistance (room temperature) was measured in the same manner as for the initial resistance value (-10°C). Similarly, for Comparative Example 1 described later, the resistance value (-10°C) of the lithium secondary battery after the post-storage capacity measurement was measured. From the above results, the resistance value (-10°C) (relative value) of the lithium secondary battery after the post-storage capacity measurement in Example 1 was calculated, assuming that the resistance value (-10°C) of the lithium secondary battery after the post-storage capacity measurement in Comparative Example 1 was 100, and this was designated as the "post-storage resistance (-10°C) (relative value)." The obtained "resistance after storage (-10°C) (relative value)" is shown in Table 1.

[0146] [Examples 2 to 12, Comparative Examples 1 to 3] The same procedure as in Example 1 was carried out except that the types and contents of the additives used in the preparation of the nonaqueous electrolyte were changed as shown in Table 1. The structures of the compound (I) (specifically, the compounds (I-1) to (I-7)) and the compound (A) (specifically, the compound (II-1), the compound (III-1), and the compound (IV-1)) as additives are as described above. The results are shown in Table 1. In Table 1, the structures of the additive compounds (I) (specifically, compounds (I-1) to (I-7)) and (A) (specifically, compounds (II-1), (III-1), and (IV-1)) are as described above.

[0147] [Table 1]

[0148] As shown in Table 1, the lithium secondary batteries of Examples 1 to 11 using a nonaqueous electrolyte solution containing compound (I) had reduced battery resistance after storage compared to the lithium secondary battery of Comparative Example 1 using a nonaqueous electrolyte solution not containing compound (I). Furthermore, compared with the lithium secondary battery of Comparative Example 1, the lithium secondary batteries of Examples 1 to 11 maintained the same or higher battery capacity after storage. Furthermore, as shown in Examples 5 and 7 to 9, in Examples 7 to 9 in which the non-aqueous electrolyte solution contained Compound (I) and Compound (A), the battery resistance after storage was further reduced and the battery capacity after storage was maintained at a higher level. [Explanation of symbols]

[0149] 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 plate

Claims

1. A compound represented by the following formula (I): 【Chemistry 1】 [In formula (I), M １ and M. ２ each independently represents a hydrogen atom, a lithium atom, a sodium atom, or a potassium atom, and n represents an integer from 0 to 10.

2. A battery additive comprising compound (I), which is the compound according to claim 1.

3. A non-aqueous electrolyte for a battery, comprising compound (I) according to claim 1.

4. Further, the composition contains a compound (A), The compound (A) is at least one selected from the group consisting of compound (II), which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, compound (III) represented by the following formula (III), and compound (IV) represented by the following formula (IV): The nonaqueous electrolyte for a battery according to claim 3 . 【Chemistry 2】 [In formula (III), M is an alkali metal; Y is a transition element, an element of 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 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), * indicates 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.

5. The non-aqueous electrolyte solution for a battery according to claim 4, wherein the content of the compound (A) is 0.01% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte solution for a battery.

6. The non-aqueous electrolyte solution for a battery according to claim 3, wherein the content of the compound (I) is 0.01% by mass to 5.0% by mass based on 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 contained in the case; Equipped with 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 the nonaqueous electrolyte for a battery according to any one of claims 3 to 6. Lithium secondary battery precursor.

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 (C1) as a positive electrode active material: LiNi ａ Co ｂ Mn ｃ O ２ ... Formula (C1) [In formula (C1), 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 a 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.

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