Non-aqueous electrolyte solution and non-aqueous electrolyte secondary battery

Abstract

Provided are: a non-aqueous electrolyte solution comprising a carbodiimide compound that is represented by formula (I) and a sulfonyl compound that is represented by a specific formula; and a non-aqueous electrolyte secondary battery.　[In formula (I), each R11 independently represents a C1-12 hydrocarbon group or a C3-18 trialkylsilyl group.]

Description

Non-aqueous electrolyte and non-aqueous electrolyte secondary battery

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

[0002] In recent years, power storage devices such as lithium-ion secondary batteries, which are small, lightweight, and have high output, have become increasingly sophisticated. As a result, these batteries are increasingly being used not only in small electrical appliances but also in large products such as automobiles. Lithium-ion secondary batteries are required to meet specific requirements for various characteristics, such as output characteristics, charge / discharge characteristics, and gas generation. For example, a very important evaluation item is the small reduction in output power that occurs when stored for a long period of time in a high-temperature environment. Patent Document 1 discloses a nonaqueous electrolyte containing lithium trifluoromethanesulfonate (TFMSLi), lithium difluorophosphate (LiDFP), and lithium bis(oxalato)borate (LiBOB), and reports that the use of this nonaqueous electrolyte reduces the resistance at −10° C. after storage at 60° C. for five days.

[0003] Patent Document 1: International Publication No. 2018 / 181369

[0004] There are cases where conventional nonaqueous electrolyte solutions for batteries and nonaqueous electrolyte secondary batteries are required to have a further reduced battery resistance after storage. Therefore, an object of one embodiment of the present disclosure is to provide a nonaqueous electrolyte solution and a nonaqueous electrolyte secondary battery that can suppress an increase in resistance after high-temperature storage of a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery.

[0005] <1> A nonaqueous electrolyte solution containing a carbodiimide compound represented by the following formula (I) and a sulfonyl compound represented by the following formula (II-1), (II-2), (II-3), or (II-4).

[0006]

[0007] [In formula (I), R １１ each independently represents a hydrocarbon group having 1 to 12 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.

[0008]

[0009]

[0010] [In formulas (II-1) to (II-4), (L3), (L4), and (L5), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; L ２１ represents a linking group represented by any one of formulas (L1) to (L4) or a single bond (-); L ２２ represents a linking group represented by any one of formulas (L1) to (L3) and (L5) or a single bond (-); L ２３ represents an oxa group (—O—) or a single bond (−), and R ２１１ , R ２２１ , R ２３１ , and R ２４１ each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ , R ２２２ , and R ２３２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３represents a cyano group (-H), a cyano group (-CN), or an isocyanate group (-NCO). ２１２ If two R ２１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R ２２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

[0011] <2> The non-aqueous electrolyte solution according to <1>, wherein the content of the carbodiimide compound is 0.001% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte solution.

[0012] <3> The non-aqueous electrolyte solution according to <1> or <2>, wherein the content of the sulfonyl compound is 0.01% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte solution.

[0013] <4> The nonaqueous electrolyte solution according to any one of <1> to <3>, wherein the sulfonyl compound includes at least one selected from the group consisting of sulfonyl compounds represented by the following formula (II-1-L1) and sulfonyl compounds represented by the following formula (II-4A):

[0014]

[0015] [In formula (II-1-L1), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; R ２１１ represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ The substituents include fluoro (-F), chloro (-Cl), bromo (-Br), oxa (-O-), carbonyl (>C=O), carboxyl (-COOH), and sulfonyl (>S(=O) ２ ), a fluorosulfonyl group (—SO ２F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ <5> A nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte solution, and a separator, wherein the nonaqueous electrolyte solution is the nonaqueous electrolyte solution according to any one of <1> to <4>.

[0016] According to one aspect of the present disclosure, there are provided a nonaqueous electrolyte and a nonaqueous electrolyte secondary battery that suppress an increase in resistance after high-temperature storage of a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery.

[0017] Fig. 1 is a schematic cross-sectional view showing a laminated lithium ion secondary battery precursor, which is an example of a lithium ion secondary battery precursor. Fig. 2 is a schematic cross-sectional view showing a coin-type lithium ion secondary battery precursor, which is another example of a lithium ion secondary battery precursor.

[0018] The present disclosure will be described below. However, the present disclosure is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the object of the present disclosure.

[0019] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In numerical ranges described in stages in the present disclosure, the upper or lower limit described in one numerical range may be replaced with the upper or lower limit of another staged numerical range. Furthermore, in numerical ranges described in the present disclosure, the upper or lower limit of that numerical range may be replaced with a value shown in the examples. In the present disclosure, when multiple substances corresponding to each component are present in the composition, the amount of each component refers to the total amount of those multiple substances present in the composition, unless otherwise specified. In the present disclosure, "mass" and "weight" are synonymous, and "mass%" and "wt%" are synonymous. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the description of a group (atomic group) in the present disclosure, a description that does not specify whether it is substituted or unsubstituted includes both those that do not contain a substituent and those that contain a substituent. In the present disclosure, 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.

[0020] <Non-aqueous Electrolyte> A non-aqueous electrolyte (hereinafter may be abbreviated as "nonaqueous electrolyte") according to one embodiment of the present disclosure is characterized in that it contains a non-aqueous electrolyte containing a carbodiimide compound represented by formula (I) (hereinafter may be abbreviated as "carbodiimide compound") and a sulfonyl compound represented by formula (II-1), (II-2), (II-3), or (II-4) below (hereinafter may be abbreviated as "sulfonyl compound").

[0021] The carbodiimide compound and the sulfonyl compound are additives in the non-aqueous electrolyte solution.

[0022]

[0023] [In formula (I), R １１ each independently represents a hydrocarbon group having 1 to 12 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.

[0024]

[0025]

[0026] [In formulas (II-1) to (II-4), (L3), (L4), and (L5), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; L ２１ represents a linking group represented by any one of formulas (L1) to (L4) or a single bond (-); L ２２ represents a linking group represented by any one of formulas (L1) to (L3) and (L5) or a single bond (-); L ２３ represents an oxa group (—O—) or a single bond (−), and R ２１１ , R ２２１ , R ２３１ , and R ２４１ each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ , R ２２２ , and R ２３２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF３ ), sulfo group (—SO ３ represents a cyano group (-H), a cyano group (-CN), or an isocyanate group (-NCO). ２１２ If two R ２１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R ２２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

[0027] The present inventors conducted extensive research to provide a nonaqueous electrolyte solution capable of suppressing an increase in resistance of a lithium ion secondary battery after high-temperature storage. As a result, they discovered that the use of a nonaqueous electrolyte solution containing a carbodiimide compound represented by formula (I) and a sulfonyl compound represented by formula (II-1), formula (II-2), formula (II-3), or formula (II-4) can effectively suppress an increase in resistance of a lithium ion secondary battery after high-temperature storage. The present inventors also discovered that this nonaqueous electrolyte solution also tends to have a low initial low-temperature resistance value. Therefore, the nonaqueous electrolyte solution according to one embodiment of the present disclosure can be said to be excellent, particularly in terms of reducing low-temperature resistance value. Hereinafter, the "carbodiimide compound represented by formula (I)," "sulfonyl compound represented by formula (II-1)," "sulfonyl compound represented by formula (II-2)," "sulfonyl compound represented by formula (II-3)," "sulfonyl compound represented by formula (II-4)," and the like will be described in detail.

[0028] (Carbodiimide Compound Represented by Formula (I)) The carbodiimide compound is represented by the following general formula (I).

[0029]

[0030] [In formula (I), R １１ each independently represents a hydrocarbon group having 1 to 12 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.

[0031] R １１each independently represent a "hydrocarbon group having 1 to 20 carbon atoms" or a "trialkylsilyl group having 3 to 18 carbon atoms", but the "hydrocarbon group" is not limited to an aliphatic hydrocarbon group having a straight-chain structure, and may be a hydrocarbon group having at least one structure selected from the group consisting of a branched structure, a cyclic structure, and a carbon-carbon unsaturated bond structure (a carbon-carbon double bond structure and a carbon-carbon triple bond structure), and the number of these structures is not limited. Therefore, (acyclic) aliphatic hydrocarbon groups, monocyclic aliphatic hydrocarbon groups, polycyclic aliphatic hydrocarbon groups, monocyclic aromatic hydrocarbon groups, polycyclic aromatic hydrocarbon groups, etc. are all included in the "hydrocarbon group". Furthermore, naturally, alkyl groups, alkenyl groups, alkynyl groups, aryl groups, etc. are all included in the "hydrocarbon group". Furthermore, when two R １１ may each independently represent a different type of substituent. ３ As represented by the formula: Figure imgf000012_0001, it is a group in which three hydrocarbon groups are bonded to a silicon atom, and the number of carbon atoms represents the total number of carbon atoms in the three hydrocarbon groups.

[0032] R １１ When R is a hydrocarbon group, the number of carbon atoms is preferably 2 or more, more preferably 3 or more, and is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. １１ When is a trialkylsilyl group, it preferably has 12 or less carbon atoms, more preferably 9 or less, even more preferably 6 or less, and particularly preferably 4 or less.

[0033] R １１ The hydrocarbon group is a methyl group (-CH ３ ), ethyl group (-CH ２ CH ３ ), vinyl group (-CH=CH ２ ), n-propyl group (—CH ２ CH ２ CH ３ ), i-propyl group (—CH(CH ３ ) ２ ), n-butyl group (—CH ２ CH ２ CH ２ CH ３), s-butyl group (—CH ２ CH (CH ３ ) ２ ), t-butyl group (—C(CH ３ ) ２ ), a cyclohexyl group (-C ６ H １１ ), a phenyl group (-C ６ H ５ ), trimethylsilyl group (—Si(CH ３ ) ３ ), triethylsilyl group (—Si(CH ２ CH ３ ) ３ ), and the like, but an i-propyl group (—CH(CH ３ ) ２ ), a cyclohexyl group (-C ６ H １１ ), trimethylsilyl group (—Si(CH ３ ) ３ ) is particularly preferred.

[0034] Examples of the carbodiimide compound represented by formula (I) include N,N'-di-i-propylcarbodiimide represented by formula (IA) below, N,N'-dicyclohexylcarbodiimide represented by formula (IB) below, and N,N'-bis(trimethylsilyl)carbodiimide represented by formula (IC) below. The non-aqueous electrolyte may contain two or more types of carbodiimide compounds represented by formula (I).

[0035]

[0036] The carbodiimide compound is preferably contained in an amount of 0.001% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte solution. When two or more types of carbodiimide compounds are contained in the non-aqueous electrolyte solution, the total amount of the various carbodiimide compounds is defined as the content of the carbodiimide compounds in the non-aqueous electrolyte solution.

[0037] The carbodiimide compound may be added to the non-aqueous electrolyte solution in two ways: normal addition and trace addition. In the case of "normal addition," the content of the carbodiimide compound in the non-aqueous electrolyte solution is typically 0.01% by mass or more and 5.0% by mass or less, with the lower limit being preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, and the upper limit being preferably 4.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and particularly preferably 1.5% by mass or less, relative to the total amount of the non-aqueous electrolyte solution (assuming the total amount of the non-aqueous electrolyte solution is 100% by mass). On the other hand, in the case of "trace addition", the content of the carbodiimide compound in the non-aqueous electrolyte is usually 0.001% by mass or more and 1.0% by mass or less, with respect to the total amount of the non-aqueous electrolyte (when the total amount of the non-aqueous electrolyte is 100% by mass), with the lower limit preferably being 0.005% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.03% by mass or more, and the upper limit preferably being 0.5% by mass or less, more preferably 0.3% by mass or less, even more preferably 0.2% by mass or less, particularly preferably 0.1% by mass or less. When the content of the carbodiimide compound is within the above range, the initial low-temperature resistance value and the low-temperature resistance value after high-temperature storage are easily reduced. In the case of "trace addition", in addition to the above, the capacity maintenance effect is excellent.

[0038] (Sulfonyl Compound Represented by Formula (II-1)) One type of sulfonyl compound is represented by the following general formula (II-1).

[0039]

[0040]

[0041] [In formula (II-1), formula (L3), and formula (L4), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; L ２１ represents a linking group represented by any one of formulas (L1) to (L4) or a single bond (-), R ２１１represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ represents a cyano group (-H), a cyano group (-CN), or an isocyanate group (-NCO). ２１２ If two R ２１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

[0042] M ＋ represents an "alkali metal ion," an "alkaline earth metal ion," an "ammonium ion," an "imidazolium ion," a "pyridinium ion," a "pyrrolidinium ion," a "piperidinium ion," or a "phosphonium ion." The alkali metal ion includes a lithium ion (Li ＋ ), sodium ions (Na ＋ ), potassium ions (K ＋ ), and examples of alkaline earth metal ions include magnesium ions (Mg ２＋ ), calcium ions (Ca ２＋) Examples of the ammonium ion include an ion represented by the following formula (C1), examples of the imidazolium ion include an ion represented by the following formula (C2), examples of the pyridinium ion include an ion represented by the following formula (C3), examples of the pyrrolidinium ion include an ion represented by the following formula (C4), examples of the piperidinium ion include an ion represented by the following formula (C5), and examples of the phosphonium ion include an ion represented by the following formula (C6):

[0043]

[0044] In formulas (C1) to (C6), R' is independently a hydrogen atom (-H), or a substituent such as a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), or a sulfonyl group (>S(=O) ２ represents a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a primary amino group (-NH-), a secondary amino group (-NH-), and a tertiary amino group (-N<). ＋ As the lithium ion (Li ＋ ) is particularly preferred.

[0045] L ２１ represents "a linking group represented by any one of formulas (L1) to (L4)" or "a single bond (-)", ２１ is a linking group represented by formula (L1), the sulfonyl compound represented by formula (II-1) is a sulfonyl compound represented by the following formula (II-1-L1), ２１ is a linking group represented by formula (L2), the sulfonyl compound represented by formula (II-1) is a sulfonyl compound represented by the following formula (II-1-L2), ２１ is a linking group represented by formula (L3), the sulfonyl compound represented by formula (II-1) is a sulfonyl compound represented by the following formula (II-1-L3), ２１ is a linking group represented by formula (L4), the sulfonyl compound represented by formula (II-1) is a sulfonyl compound represented by the following formula (II-1-L4), ２１is a single bond (-), it means that the sulfonyl compound represented by formula (II-1) is a sulfonyl compound represented by the following formula (II-1-L6). That is, the tip of the wavy line on the left side of formulas (L1) to (L4) is the -N in formula (II-1). － (M ＋ ) group, and the end of the wavy line on the right side of formula (L1) to formula (L4) is R ２１２ It means that it is bonded to the group.

[0046]

[0047] R ２１１ represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent. R ２１２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ represents a hydroxyl group (-H), a cyano group (-CN), or an isocyanate group (-NCO).

[0048] R ２１１represents a "fluoro group (-F)", a "chloro group (-Cl)", a "bromo group (-Br)", an "iodine group (-I)", a "fluorocarbon group having 1 to 20 carbon atoms", or a "hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent", and R ２１２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (-H), a cyano group (-CN), and an isocyanate group (-NCO); a fluorosulfonyl group (-SO ２ F), trifluoromethylsulfonyl group (-SO ２ CF ３ ) and sulfo group (-SO ３ The "hydrocarbon group" represents an aliphatic hydrocarbon group (-H), a cyano group (-CN), or an isocyanate group (-NCO), but the "hydrocarbon group" has the same meaning as above, and is not limited to an aliphatic hydrocarbon group having a straight-chain structure, and may be a hydrocarbon group having at least one structure selected from the group consisting of a branched structure, a cyclic structure, and a carbon-carbon unsaturated bond structure (a carbon-carbon double bond structure and a carbon-carbon triple bond structure).

[0049] R ２１１In the above, "may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent" means that a hydrogen atom of the hydrocarbon group may be substituted with a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), etc., and also that a carbon atom of the hydrocarbon group may be substituted with an oxa group (-O-), etc. ２１２ In the above, "substituents include fluoro (-F), chloro (-Cl), bromo (-Br), oxa (-O-), carbonyl (>C=O), carboxyl (-COOH), sulfonyl (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ The phrase "may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), a carboxyl group (-COOH), a fluorosulfonyl group (-SO), a cyano group (-CN), and an isocyanate group (-NCO)" means that the hydrogen atom of the hydrocarbon group may be replaced with a functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), a carboxyl group (-COOH), a fluorosulfonyl group (-SO), a fluoroisopropyl ... ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ It also means that the carbon atom of the hydrocarbon group may be substituted with an oxa group (-O-), a carbonyl group (>C=O), a sulfonyl group (>S(=O) ２ ) or the like. In addition, since the number of substituents (functional groups) in the hydrocarbon group is not limited, an oxa group (—O—) and a carbonyl group (>C═O) may be adjacent to each other in the hydrocarbon group to form an oxycarbonyl group (—O—C(═O)—) or the like. In addition, "two R ２１２ If two R ２１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, but "two R ２１２"The case where R ２１２ The phrase "the hydrocarbon groups bond to each other to form a cyclic structure" means that the resulting structure is similar to that of the compounds of the following formulae (II-1-L4A), (II-1-L4B), and (II-1-L4C). When hydrocarbon groups bond to each other to form a cyclic structure, the number of carbon atoms in the cyclic structure is calculated as the sum of the carbon atoms in the two hydrocarbon groups and is 3 to 40. In addition, when a carboxyl group (-COOH) and a sulfo group (-SO ３ Since H) is an acidic functional group, the hydrogen ion may be exchanged with an alkali metal ion, an alkaline earth metal ion, an ammonium ion, or the like to form a salt.

[0050]

[0051] R ２１１ or R ２１２ When is a hydrocarbon group, the hydrocarbon group preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less carbon atoms.

[0052] R ２１１ Specific examples of the fluorocarbon group include a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), and an iodo group (-I) (specific examples of a fluorocarbon group having 1 to 20 carbon atoms), and (specific examples of a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent).

[0053] R ２１２ Specific examples of the fluorosulfonyl group include fluorosulfonyl groups (-SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ H), cyano group (-CN), isocyanate group (-NCO), methyl group (-CH ３ ), ethyl group (-CH ２ CH ３), vinyl group (-CH=CH ２ ), n-propyl group (—CH ２ CH ２ CH ３ ), i-propyl group (—CH(CH ３ ) ２ ), n-butyl group (—CH ２ CH ２ CH ２ CH ３ ), s-butyl group (—CH ２ CH (CH ３ ) ２ ), t-butyl group (—C(CH ３ ) ２ ), a cyclohexyl group (-C ６ H １１ ), a phenyl group (-C ６ H ５ ), 1-(ethoxycarbonyl)ethyl group (—CH(COOCH ２ CH ３ ) CH ３ ), 1-sulfomethyl group (—CH ２ SO ３ H(Li)), 2-sulfoethyl group (—CH ２ CH ２ SO ３ H(Li)), 3-sulfo-n-propyl group (—CH ２ CH ２ CH ２ SO ３ H(Li)) and the like.

[0054] Specific examples of the sulfonyl compound represented by formula (II-1) include sulfonyl compounds represented by the following formulas (II-1A) to (II-1Q). The nonaqueous electrolyte may contain two or more types of sulfonyl compounds represented by formula (II-1).

[0055]

[0056]

[0057]

[0058] (Sulfonyl Compound Represented by Formula (II-2)) One type of sulfonyl compound is represented by the following general formula (II-2).

[0059]

[0060]

[0061] [In formula (II-2), formula (L3), and formula (L5), M ＋ is an alkali metal ion, an alkaline earth metal ion, or an ammonium ion, ２２ represents a linking group represented by any one of formulas (L1) to (L3) and (L5) or a single bond (-); R ２２１ represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２２２ are each independently a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ represents a cyano group (—H), a cyano group (—CN), or an isocyanate group (—NCO), provided that two or more R ２２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

[0062] L ２２ represents "a linking group represented by any one of formulas (L1) to (L3) and formula (L5)" or "a single bond (-)",２２ is a linking group represented by formula (L1), the sulfonyl compound represented by formula (II-2) is a sulfonyl compound represented by the following formula (II-2-L1), ２２ is a linking group represented by formula (L2), the sulfonyl compound represented by formula (II-2) is a sulfonyl compound represented by the following formula (II-2-L2), ２２ is a linking group represented by formula (L3), the sulfonyl compound represented by formula (II-2) is a sulfonyl compound represented by the following formula (II-2-L3), ２２ is a linking group represented by formula (L5), the sulfonyl compound represented by formula (II-2) is a sulfonyl compound represented by the following formula (II-2-L5), ２２ is a single bond (-), it means that the sulfonyl compound represented by formula (II-2) is a sulfonyl compound represented by the following formula (II-2-L6). That is, the tip of the wavy line on the left side of formulas (L1) to (L3) and (L5) is the -N(R ２２２ ) group, and the end of the wavy line on the right side of formula (L1) to formula (L3) and formula (L5) is R ２２２ It means that it is bonded to the group.

[0063]

[0064] R ２２１ is the aforementioned R ２１１ It is synonymous with R ２２２ is the aforementioned R ２１２ and "two R in formula (II-2)" ２２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, but ２２２ The phrase "the hydrocarbon groups are bonded to each other to form a cyclic structure" means that the resulting structure is like that of each of the compounds of formula (II-2-L1A) to formula (II-2-L3A), formula (II-2-L5A), and formula (II-2-L6A) below.

[0065]

[0066] R ２２１ or R ２２２When is a hydrocarbon group, the hydrocarbon group preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less carbon atoms.

[0067] R ２２１ Specific examples of R include a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), (specific examples of a fluorocarbon group having 1 to 20 carbon atoms), or (specific examples of a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent). ２２２ Specific examples of the fluorosulfonyl group include fluorosulfonyl groups (-SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), methyl group (-CH ３ ), ethyl group (-CH ２ CH ３ ), ethylene group (-CH ２ CH ２ -), vinyl group (-CH=CH ２ ), n-propyl group (—CH ２ CH ２ CH ３ ), n-propylene group (—CH ２ CH ２ CH ２ -), i-propyl group (-CH(CH ３ ) ２ ), n-butyl group (—CH ２ CH ２ CH ２ CH ３ ), n-butylene group (—CH ２ CH ２ CH ２ CH ２ -), s-butyl group (-CH ２ CH (CH ３ ) ２ ), t-butyl group (—C(CH ３ ) ２ ), n-heptyl group (—CH ２ CH ２ CH ２CH ２ CH ３ ), n-heptylene group (—CH ２ CH ２ CH ２ CH ２ CH ２ -), cyclohexyl group (-C ６ H １１ ), a phenyl group (-C ６ H ５ ) etc.

[0068] Specific examples of the sulfonyl compound represented by formula (II-2) include sulfonyl compounds represented by the following formulas (II-2A) to (II-2I). The nonaqueous electrolyte may contain two or more sulfonyl compounds represented by formula (II-2).

[0069]

[0070] (Sulfonyl Compound Represented by Formula (II-3)) One type of sulfonyl compound is represented by the following general formula (II-3).

[0071]

[0072] [In formula (II-3), L ２３ represents an oxa group (—O—) or a single bond (−), and R ２３１ represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２３２ The substituents include fluoro (-F), chloro (-Cl), bromo (-Br), oxa (-O-), carbonyl (>C=O), carboxyl (-COOH), and sulfonyl (>S(=O) ２ ), a fluorosulfonyl group (—SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (—H), a cyano group (—CN), and an isocyanate group (—NCO); a fluorosulfonyl group (—SO ２ F), trifluoromethylsulfonyl group (—SO ２ CF ３ ), sulfo group (—SO ３ represents a cyano group (—H), a cyano group (—CN), or an isocyanate group (—NCO).

[0073] R ２３１ is the aforementioned R ２１１ is synonymous with R ２３２ is the aforementioned R ２１２ is synonymous with.

[0074] L ２３ represents an "oxa group (-O-)" or a "single bond (-)", ２３ is an oxa group (—O—), the —S(═O) of formula (II-3) ２ R ２３１ The group is joined to -R via an oxa group (-O-). ２３２ The bond to the group is represented by L ２３ is a single bond (-), the -S(=O) of formula (II-3) ２ R ２３１ The group is directly -R ２３２ It means that it is bonded to the group.

[0075] R ２３１ or R ２３２ When is a hydrocarbon group, the hydrocarbon group preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less carbon atoms.

[0076] R ２３１ Specific examples of R include a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), (specific examples of a fluorocarbon group having 1 to 20 carbon atoms), or (specific examples of a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent). ２３２Specifically, examples of the methyl group (-CH ３ ), ethyl group (-CH ２ CH ３ ), vinyl group (-CH=CH ２ ), n-propyl group (—CH ２ CH ２ CH ３ ), 3-fluorosulfoxyl-n-propyl group (—CH ２ CH ２ CH ２ OSO ２ F), i-propyl group (-CH(CH ３ ) ２ ), n-butyl group (—CH ２ CH ２ CH ２ CH ３ ), 4-fluorosulfoxyl-n-butyl group (—CH ２ CH ２ CH ２ CH ２ OSO ２ F), s-butyl group (—CH ２ CH (CH ３ ) ２ ), t-butyl group (—C(CH ３ ) ２ ), a cyclohexyl group (-C ６ H １１ ), a phenyl group (-C ６ H ５ ), 4-fluorosulfoxylphenyl group (—C ６ H ４ OSO ２ F), 3,5-bis(fluorosulfoxyl)phenyl group (-C ６ H ４ (OSO ２ F) ２ ) etc.

[0077] Specific examples of the sulfonyl compound represented by formula (II-3) include sulfonyl compounds represented by the following formulas (II-3A) to (II-3N). The nonaqueous electrolyte may contain two or more sulfonyl compounds represented by formula (II-3).

[0078]

[0079]

[0080]

[0081] (Sulfonyl Compound Represented by Formula (II-4)) One type of sulfonyl compound is represented by the following general formula (II-4).

[0082]

[0083] [In formula (II-4), R ２４１ each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; M ＋ represents an alkali metal ion, an alkaline earth metal ion, or an ammonium ion.

[0084] R ２４１ is the aforementioned R ２１１ It is synonymous with R ２４１ When is a hydrocarbon group, the hydrocarbon group preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less carbon atoms.

[0085] R ２４１ Specific examples of the fluorocarbon group include a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), and an iodo group (-I) (specific examples of a fluorocarbon group having 1 to 20 carbon atoms), and (specific examples of a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent).

[0086] Specific examples of the sulfonyl compound represented by formula (II-4) include lithium fluorosulfonate and sodium fluorosulfonate represented by the following formula (II-4A). The nonaqueous electrolyte may contain two or more types of sulfonyl compounds represented by formula (II-4).

[0087]

[0088] The content of the sulfonyl compound in the non-aqueous electrolyte is usually 0.01% by mass or more and 5.0% by mass or less, with the lower limit being preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.3% by mass or more, and the upper limit being preferably 4.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and particularly preferably 1.5% by mass or less, relative to the total amount of the non-aqueous electrolyte (assuming the total amount of the non-aqueous electrolyte is 100% by mass). When the total content of the sulfonyl compound is within the above range, the initial low-temperature resistance value and the low-temperature resistance value after high-temperature storage are easily reduced.

[0089] <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.

[0090] Examples of non-aqueous solvents include cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, fluorine-containing chain carbonates, aliphatic carboxylic acid esters, fluorine-containing aliphatic carboxylic acid esters, γ-lactones, fluorine-containing γ-lactones, cyclic ethers, fluorine-containing cyclic ethers, chain ethers, fluorine-containing chain ethers, nitriles, amides, lactams, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, dimethyl sulfoxide phosphate, etc. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Examples of fluorine-containing cyclic carbonates include fluoroethylene carbonate (FEC), etc. Examples of chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), dipropyl carbonate (DPC), etc. Examples of fluorine-containing chain carbonates include methyl-2,2,2-trifluoroethyl carbonate, etc.

[0091] 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 fluorine-containing aliphatic carboxylic acid esters include methyl difluoroacetate, methyl 3,3,3-trifluoropropionate, ethyl difluoroacetate, and 2,2,2-trifluoroethyl acetate. 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 fluorine-containing cyclic ethers include ethyl nonafluorobutyl ether and methyl nonafluorobutyl ether. Examples of the chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, 1,2-dimethoxyethane, 1,2-dibutoxyethane, etc. Examples of the fluorine-containing chain ethers include HCF ２ CF ２ CH ２ OCF ２ CF ２ H, C.F. ３ CF ２ CH ２ OCF ２ CF ２ H, HCF ２ CF ２ CH ２ OCF ２ CFHCF ３ , C.F. ３ CF ２ CH ２ OCF ２ CFHCF ３ , C ６ F １３ OCH ３ , C ６ F １３ O.C. ２ H ５ , C ８ F１７ OCH ３ , C ８ F １７ O.C. ２ H ５ , C.F. ３ CFHCF ２ CH (CH ３ ) OCF ２ CFHCF ３ , HCF ２ CF ２ OCH (C ２ H ５ ) ２ , HCF ２ CF ２ O.C. ４ H ９ , HCF ２ CF ２ OCH ２ CH(C ２ H ５ ) ２ , HCF ２ CF ２ OCH ２ CH (CH ３ ) ２ Examples of nitriles include acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, etc. Examples of amides include N,N-dimethylformamide, etc. Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, N,N'-dimethylimidazolidinone, etc.

[0092] 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.

[0093] The non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates and chain carbonates. In this case, the total proportion of the cyclic carbonates and chain carbonates in the non-aqueous solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the non-aqueous solvent.

[0094] The upper limit of the content of the nonaqueous solvent is preferably 99 mass %, more preferably 97 mass %, and even more preferably 90 mass % relative to the total amount of the nonaqueous electrolyte, and the lower limit of the content of the nonaqueous solvent is preferably 60 mass % or more, and even more preferably 70 mass % or more relative to the total amount of the nonaqueous electrolyte.

[0095] 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.

[0096] <Electrolyte> The non-aqueous electrolyte generally contains an electrolyte.

[0097] 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.

[0098] Examples of the fluorine-containing lithium salt include inorganic acid anion salts and organic acid anion salts. Examples of the inorganic acid anion salt include lithium hexafluorophosphate (LiPF ６ ), lithium tetrafluoroborate (LiBF ４ ), lithium hexafluoroarsenate (LiAsF ６ ), lithium hexafluorotantalate (LiTaF ６ Examples of organic acid anion salts include lithium trifluoromethanesulfonate (LiCF ３ SO ３ ), lithium bis(trifluoromethanesulfonyl)imide (Li(CF ３ SO ２ ) ２N), lithium bis(pentafluoroethanesulfonyl)imide (Li(C ２ F ５ SO ２ ) ２ Among them, examples of fluorine-containing lithium salts include lithium hexafluorophosphate (LiPF ６ ) is more preferred.

[0099] Examples of fluorine-free lithium salts include lithium perchlorate (LiClO ４ ), lithium aluminum tetrachloride (LiAlCl ４ ), lithium decachlorodecaborate (Li ２ B １０ Cl １０ ) etc.

[0100] When the electrolyte contains a fluorine-containing lithium salt, the content of the fluorine-containing lithium salt is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the electrolyte. ６ ), lithium hexafluorophosphate (LiPF ６ The content of the component (I) is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the electrolyte.

[0101] When the non-aqueous electrolyte solution contains an electrolyte, the concentration of the electrolyte in the non-aqueous electrolyte solution is preferably 0.1 mol / L or more and 3 mol / L or less, more preferably 0.5 mol / L or more and 2 mol / L or less.

[0102] The non-aqueous electrolyte is lithium hexafluorophosphate (LiPF ６ ), the non-aqueous electrolyte contains lithium hexafluorophosphate (LiPF ６ The concentration of the HCl HCl 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.

[0103] [Lithium-ion secondary battery precursor] The nonaqueous electrolyte secondary battery of the present disclosure is obtained by charging and discharging a nonaqueous electrolyte secondary battery precursor, which is a nonaqueous electrolyte secondary battery before charging and discharging. The nonaqueous electrolyte secondary battery precursor refers to a nonaqueous electrolyte secondary battery before charging and discharging. A specific example of a nonaqueous electrolyte secondary battery precursor is a lithium-ion secondary battery precursor that charges and discharges by the movement of lithium ions.

[0104] The lithium ion secondary battery precursor includes a case, and a positive electrode, a negative electrode, a separator, and an electrolyte solution housed in the case, wherein the positive electrode is capable of absorbing and desorbing lithium ions, the negative electrode is capable of absorbing and desorbing lithium ions, and the electrolyte solution is the nonaqueous electrolyte solution of the present disclosure.

[0105] According to the lithium ion secondary battery precursor, in a lithium ion secondary battery obtained by charging and discharging this lithium ion secondary battery precursor, the room temperature resistance increase rate during high temperature storage can be reduced.

[0106] <Case> The shape of the case is not particularly limited and may be appropriately selected depending on the application of the lithium ion secondary battery precursor, etc. Examples of the case include a case including a laminate film and a case consisting of a battery can and a battery can lid.

[0107] <Positive Electrode> The positive electrode is a positive electrode capable of absorbing and desorbing lithium ions. The positive electrode preferably contains at least one positive electrode active material capable of absorbing and desorbing lithium ions.

[0108] 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.

[0109] 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. Aluminum foil is preferred as the positive electrode current collector. The material for the aluminum foil is not particularly limited, and examples include A1085 material, A3003 material, and the like.

[0110] The positive electrode mixture layer contains a positive electrode active material and a binder.

[0111] 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 ion secondary battery precursor.

[0112] 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 elements 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.

[0113] 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 O ２In 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 is 0.99 or more and 1.00 or less. Specific examples of NCM include LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ , LiNi ０．５ Co ０．３ Mn ０．２ O ２ , LiNi ０．５ Co ０．２ Mn ０．３ O ２ , LiNi ０．６ Co ０．２ Mn ０．２ O ２ , LiNi ０．８ Co ０．１ Mn ０．１ O ２ Examples include:

[0114] 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 O ２ ... 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. Specific examples of NCA include LiNi ０．８ Co ０．１５ Al ０．０５ O ２ Examples include:

[0115] When the positive electrode in the lithium ion secondary battery precursor 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.

[0116] 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 of the positive electrode active materials to each other 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.

[0117] The positive electrode mixture layer preferably contains a conductive additive. Known conductive additives can be used as the conductive additive. A conductive carbon material is preferred as the known conductive additive. Examples of conductive carbon materials include graphite, carbon black, conductive carbon fiber, and fullerene. These materials 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 conductive additive may be a commercially available product. Commercially available carbon black products include, for example, Toka Black #4300, #4400, #4500, #5500, etc. (furnace black, manufactured by Tokai Carbon Co., Ltd.), Printex L, etc. (furnace black, manufactured by Evonik Co., Ltd.), Raven 7000, 5750, 5250, 5000ULTRAIII, 5000ULTRA, etc., Conductex SC ULTRA, Conductex 975 ULTRA, etc., and PUER BLACK 100, 115, 205, etc. (Columbian Furnace Black), #2350, #2400B, #2600B, #30050B, #3030B, #3230B, #3350B, #3400B, #5400B, etc. (Mitsubishi Chemical Furnace Black), MONARCH 1400, 1300, 900, Vulcan XC-72R, BlackPearls 2000, Examples of such blacks include LITX-50 and LITX-200 (furnace blacks manufactured by Cabot Corporation), Ensaco 250G, Ensaco 260G, Ensaco 350G, and Super-P (manufactured by TIMCAL), Ketjen Black EC-300J and EC-600JD (manufactured by Akzo Chemicals), and Denka Black, Denka Black HS-100 and FX-35 (acetylene blacks manufactured by Denka Co., Ltd.).

[0118] The positive electrode mixture layer may contain other components such as a thickener, a surfactant, a dispersant, a wetting agent, and an antifoaming agent.

[0119] <Negative Electrode> The negative electrode is capable of absorbing and desorbing lithium ions. The negative electrode preferably contains at least one negative electrode active material capable of absorbing and desorbing lithium ions.

[0120] 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.

[0121] 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.

[0122] The negative electrode mixture layer contains a negative electrode active material and a binder.

[0123] 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 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").

[0124] 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. The form of the carbon material is not particularly limited, and examples include fibrous, spherical, potato-like, and flake-like shapes. 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 coating the graphite material include gold, platinum, silver, copper, and tin. The graphite material may be a mixture of amorphous carbon and graphite.

[0125] 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.

[0126] 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.

[0127] <Separator> An example of the separator is a porous resin flat plate. Examples of materials for the porous resin flat plate include resins and nonwoven fabrics containing such resins. Examples of resins include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, and polyamide. Among these, the separator is preferably a porous resin sheet having a single layer or multilayer structure. The material of the porous resin sheet is mainly composed of one or more polyolefin resins. The thickness of the separator is preferably 5 μm or more and 30 μm or less. The separator is preferably disposed between the positive electrode and the negative electrode.

[0128] <Specific Example of Lithium-Ion Secondary Battery Precursor> A specific example of a lithium-ion secondary battery precursor is a laminated battery precursor. As shown in FIG. 1 , the lithium-ion secondary battery precursor 1 is a laminated battery precursor. Specifically, in the lithium-ion secondary battery precursor 1, a battery element 10 is enclosed inside an exterior body 30. The exterior body 30 is formed of a laminate film. A positive electrode lead 21 and a negative electrode lead 22 are attached to the battery element 10. The positive electrode lead 21 and the negative electrode lead 22 are led out in opposite directions, from the inside to the outside of the exterior body 30.

[0129] 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 composite layer 11B on both main surfaces of a positive electrode current collector 11A. The negative electrode 12 is formed by forming a negative electrode composite layer 12B on both main surfaces of a negative electrode current collector 12A. The positive electrode composite layer 11B formed on one main surface of the positive electrode current collector 11A of the positive electrode 11 and the negative electrode composite layer 12B formed on one main surface of the negative electrode current collector 12A of the negative electrode 12 adjacent to the positive electrode 11 face each other with the separator 13 interposed therebetween.

[0130] The nonaqueous electrolyte solution of the present disclosure is injected into the interior of the exterior housing 30 of the lithium ion 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 ion secondary battery precursor 1, one single 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.

[0131] Although the lithium ion secondary battery precursor 1 is a laminated type lithium ion secondary battery precursor, the lithium ion secondary battery precursor is not limited to this and may be, for example, a wound type lithium ion secondary battery precursor. A wound type lithium ion secondary battery precursor is formed by stacking a positive electrode, a separator, a negative electrode, and a separator in this order and winding them into a layered configuration. Wound type lithium ion secondary battery precursors include cylindrical type lithium ion secondary battery precursors and prismatic type lithium ion secondary battery precursors.

[0132] 1 , in the lithium ion 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.

[0133] An example of the non-aqueous electrolyte secondary battery described below is a lithium ion secondary battery obtained by charging and discharging a lithium ion secondary battery precursor 1 shown in FIG.

[0134] A specific example of a lithium ion secondary battery precursor is a coin-type battery precursor. In the coin-type lithium ion secondary battery precursor 2 shown in FIG. 2 , a disc-shaped negative electrode 42, a separator 45 filled with a nonaqueous electrolyte solution, a disc-shaped positive electrode 41, and, if necessary, a spacer plate 47 made of stainless steel, aluminum, or the like are stacked in this order. A spacer plate 48 is provided on the disc-shaped negative electrode 42 side, and the precursor is housed between a positive electrode can 43 (hereinafter also referred to as a "battery can") and a sealing plate 44 (hereinafter also referred to as a "battery can lid"). The positive electrode can 43 and the sealing plate 44 are crimped and sealed via a gasket 46. In this example, the nonaqueous electrolyte solution of the present disclosure is used as the nonaqueous electrolyte solution filled in the separator 45.

[0135] An example of the nonaqueous electrolyte secondary battery of the present disclosure, which will be described later, is a lithium ion secondary battery obtained by charging and discharging the coin-type lithium ion secondary battery precursor shown in FIG. 2 .

[0136] [Lithium-ion secondary battery and manufacturing method thereof] A manufacturing method of a lithium-ion secondary battery according to the present disclosure includes the steps of: preparing the lithium-ion secondary battery precursor according to the present disclosure described above (hereinafter also referred to as the "preparation step"); and charging and discharging the lithium-ion secondary battery precursor. The lithium-ion secondary battery according to the present disclosure is a lithium-ion secondary battery obtained by charging and discharging the lithium-ion secondary battery precursor according to the present disclosure described above.

[0137] According to the lithium ion secondary battery and the method for manufacturing the same of the present disclosure, it is possible to reduce the room temperature resistance increase rate of the lithium ion secondary battery when stored at high temperatures.

[0138] The preparation step may be a step of simply preparing a previously manufactured lithium ion secondary battery precursor for a step of charging and discharging, or may be a step of manufacturing a lithium ion secondary battery precursor. The lithium ion secondary battery precursor is as described above.

[0139] In the step of charging and discharging, the charging and discharging of the lithium ion secondary battery precursor can be carried out according to a known method. In this step, the charging and discharging cycle may be repeated multiple times for the lithium ion secondary battery precursor. As described above, this charging and discharging preferably forms an SEI (Solid Electrolyte Interface) film on the surface of the positive electrode (particularly the positive electrode active material) and / or the negative electrode (particularly the negative electrode active material) in the lithium ion secondary battery precursor.

[0140] In the step of charging and discharging, the lithium ion 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.

[0141] Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples. Hereinafter, "%" means "% by mass" unless otherwise specified.

[0142] Example 1 Preparation of Non-Aqueous Electrolyte Solution Ethylene carbonate (hereinafter sometimes abbreviated as "EC"), dimethyl carbonate (hereinafter sometimes abbreviated as "DMC"), and ethyl methyl carbonate (hereinafter sometimes abbreviated as "EMC") were mixed in a volume ratio of EC:DMC:EMC = 30:35:35. This resulted in a mixed solvent as a non-aqueous solvent. LiPF as an electrolyte was added to the obtained mixed solvent. ６was dissolved in the non-aqueous electrolyte solution to a concentration of 1 mol / L to obtain an electrolyte solution (hereinafter, sometimes abbreviated as "basic electrolyte solution"). N,N'-di-i-propylcarbodiimide (one of the carbodiimide compounds represented by formula (I)) represented by the following formula (IA) and lithium fluorosulfonate (LiSO ) represented by the following formula (II-4A) were added to the obtained basic electrolyte solution. ３ F, one of the sulfonyl compounds represented by formula (II-4). ) was added so that the content relative to the total amount of the non-aqueous electrolyte solution finally obtained (a numerical value when the total amount of the non-aqueous electrolyte solution is 100% by mass) would be the content (mass%) shown in Table 1, and a non-aqueous electrolyte solution was obtained. In Table 1, the contents of the carbodiimide compound and the sulfonyl compound relative to the total amount of the non-aqueous electrolyte solution are each listed in the "Content of each additive in the non-aqueous electrolyte solution" column. Also, in Table 1, since the compound represented by formula (IA) is a carbodiimide compound represented by formula (I), the column above "(IA)" is labeled "carbodiimide compound represented by formula (I)". Similarly, the columns above "(II-1A)", "(II-1N)", "(II-1O)", "(II-3B)", "(II-3M)", "(II-4A)", and "(II-4B)" are labeled "sulfonyl compounds represented by formulas (II-1) to (II-4)".

[0143]

[0144] <Preparation of Positive Electrode> Li (Ni) was used as the positive electrode active material. ０．５ Co ０．２ Mn ０．３ O ２ A mixture was obtained by adding 94% by mass of cellulose acetate (C10) as a conductive additive, 3% by mass of carbon black as a conductive additive, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder. The resulting mixture was dispersed in an N-methylpyrrolidone solvent to obtain a positive electrode composite slurry. Aluminum foil with a thickness of 20 μm was prepared as a positive electrode current collector. The resulting positive electrode composite slurry was applied to aluminum foil, dried, and then rolled using a press to obtain a sheet-shaped positive electrode. The positive electrode consisted of a positive electrode current collector and a positive electrode active material layer.

[0145] <Negative Electrode Fabrication> Graphite (96% by mass) was used as the negative electrode active material, carbon black (1% by mass) as a conductive additive, 1% by mass of sodium carboxymethyl cellulose dispersed in pure water as a thickener (solid content), and 2% by mass of styrene-butadiene rubber (SBR) dispersed in pure water (solid content) as a binder were mixed to obtain a negative electrode composite slurry. A 10 μm-thick copper foil was prepared as the negative electrode current collector. The obtained negative electrode composite slurry was applied to copper foil, dried, and then rolled in a press to obtain a sheet-shaped negative electrode. The negative electrode consisted of a negative electrode current collector and a negative electrode active material layer.

[0146] <Preparation of Separator> A porous polyethylene film was prepared as a separator.

[0147] <Preparation of Lithium-Ion Secondary Battery Precursor> The negative electrode, positive electrode, and separator were each punched into a disk shape with a diameter of 14 mm, 13 mm, and 17 mm, respectively. This resulted in a coin-shaped negative electrode, coin-shaped positive electrode, and coin-shaped separator. The resulting coin-shaped negative electrode, coin-shaped separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (size: 2032). Next, 20 μL of nonaqueous electrolyte was poured into the battery can, immersing the separator, positive electrode, and negative electrode in the nonaqueous electrolyte. Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery can lid was crimped via a polypropylene gasket to seal the battery. This resulted in a coin-shaped lithium-ion secondary battery precursor (i.e., a lithium-ion secondary battery before charging and discharging) having the configuration shown in FIG. 2 . The lithium-ion secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.

[0148] <Fabrication of Lithium-Ion Secondary Battery> The lithium-ion 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-ion secondary battery.

[0149] <Evaluation of Initial Low-Temperature Resistance Value> A lithium-ion secondary battery was charged at 3.7 V and then cooled to −10°C in a thermostatic chamber. The DC resistance [Ω] was measured as the initial low-temperature resistance value (−10°C) based on the amount of 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 the current values ​​(i.e., current values ​​corresponding to discharge rates of 0.1 C to 0.6 C). Note that “CC10s discharge” here refers to discharging at a constant current for 10 seconds. The initial low-temperature resistance value (−10°C) of Comparative Example 1, which will be described later, was also measured using the same procedure. The initial low-temperature resistance value (−10°C) of Example 1 was calculated relative to the initial low-temperature resistance value (−10°C) of Comparative Example 1, which was set to 100, and this value was used as the “initial low-temperature resistance value (relative value).” The obtained "initial low-temperature resistance value (relative value)" (unit: "%)" is shown in Table 1.

[0150] <Evaluation of Low-Temperature Resistance Value After High-Temperature Storage> Next, the lithium-ion secondary battery after measuring the initial low-temperature resistance value was charged to 4.2 V, and the charged lithium-ion secondary battery was stored in a thermostatic chamber at 60°C for 14 days (hereinafter, sometimes abbreviated as "high-temperature storage"). Next, the low-temperature resistance value (-10°C) of the lithium-ion secondary battery after high-temperature storage was measured in the same manner as for the initial low-temperature resistance value (-10°C). For Comparative Example 1 described below, the low-temperature resistance value (-10°C) of the lithium-ion secondary battery after high-temperature storage was also measured in the same manner. From the above results, when the low-temperature resistance value (-10°C) of the lithium-ion secondary battery after high-temperature storage of Comparative Example 1 was set to 100, the relative value of the low-temperature resistance value (-10°C) of the lithium-ion secondary battery after high-temperature storage of Example 1 was calculated and defined as the "low-temperature resistance value (relative value) after high-temperature storage." The obtained "low-temperature resistance value (relative value) after high-temperature storage" (unit: "%") is shown in Table 1.

[0151] Example 2: Lithium fluorosulfonate (LiSO ３A nonaqueous electrolyte solution was prepared by the same procedures as described in Example 1, except that cation exchanger F) was changed to a sulfonyl compound represented by the following formula (II-1A) (one type of sulfonyl compound represented by formula (II-1)), and a lithium ion secondary battery was fabricated. Furthermore, by the same procedures as described in Example 1, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were each set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0152]

[0153] Example 3: Lithium fluorosulfonate (LiSO ３ A nonaqueous electrolyte solution was prepared by the same procedure as described in Example 1, except that Fluorine-containing compound (F) was changed to lithium bis(fluorosulfonyl)imide represented by the following formula (II-1N) (one of the sulfonyl compounds represented by formula (II-1)). A lithium ion secondary battery was then prepared. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured by the same procedure as described in Example 1, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were set to 100, were calculated and used as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0154]

[0155] Example 4: Lithium fluorosulfonate (LiSO ３A nonaqueous electrolyte solution was prepared by the same procedures as described in Example 1, except that HCl (II-3M) was changed to a sulfonyl compound represented by the following formula (II-3M) (one type of sulfonyl compound represented by formula (II-3)), and a lithium ion secondary battery was fabricated. Furthermore, by the same procedures as described in Example 1, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were each set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0156]

[0157] Comparative Example 1 N,N'-di-i-propylcarbodiimide represented by the above formula (IA) and lithium fluorosulfonate (LiSO 4) represented by the above formula (II-4A) ３ A nonaqueous electrolyte solution was prepared by the same procedure as described in Example 1, except that no additive (F) was added, and a lithium ion secondary battery was fabricated. Furthermore, by the same procedure as described in Example 1, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured, and these were used as reference values ​​for the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage" of Example 1, etc. The results are shown in Table 1.

[0158] Comparative Example 2 A nonaqueous electrolyte solution was prepared in the same manner as in Example 1, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0159] Comparative Example 3 A nonaqueous electrolyte solution was prepared in the same manner as in Example 2, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0160] Comparative Example 4 A nonaqueous electrolyte solution was prepared in the same manner as in Example 3, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0161] Comparative Example 5 A nonaqueous electrolyte solution was prepared in the same manner as in Example 4, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0162] Example 5: Lithium fluorosulfonate (LiSO３ A nonaqueous electrolyte solution was prepared by the same procedures as described in Example 1, except that the compound represented by formula (II-4B) was replaced with a sulfonyl compound represented by formula (II-4) (one of the sulfonyl compounds represented by formula (II-4)). A lithium ion secondary battery was fabricated by the same procedures as described in Example 1. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured by the same procedures as described in Example 1, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0163]

[0164] Example 6: Lithium fluorosulfonate (LiSO ３ A nonaqueous electrolyte solution was prepared in the same manner as in Example 1, except that the compound represented by formula (II-1F) was changed to a sulfonyl compound represented by the following formula (II-1O) (one type of sulfonyl compound represented by formula (II-1)), and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0165]

[0166] Example 7: Lithium fluorosulfonate (LiSO ３A nonaqueous electrolyte solution was prepared by the same procedures as described in Example 1, except that the compound represented by formula (II-3B) was changed to a sulfonyl compound represented by formula (II-3B) below (one type of sulfonyl compound represented by formula (II-3)). A lithium ion secondary battery was then prepared. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured by the same procedures as described in Example 1, and the relative values, where the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were set to 100, were calculated and used as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0167]

[0168] Comparative Example 6 A nonaqueous electrolyte solution was prepared in the same manner as in Example 5, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0169] Comparative Example 7 A nonaqueous electrolyte solution was prepared in the same manner as in Example 6, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0170] Comparative Example 8 A nonaqueous electrolyte solution was prepared in the same manner as in Example 7, except that the N,N'-di-i-propylcarbodiimide represented by formula (IA) was not added, and a lithium ion secondary battery was fabricated. Furthermore, the initial low-temperature resistance value (-10°C) and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage were measured in the same manner as in Example 1, and the relative values, with the initial low-temperature resistance value (-10°C) of the lithium ion secondary battery of Comparative Example 1 and the low-temperature resistance value (-10°C) of the lithium ion secondary battery after high-temperature storage, respectively, set to 100, were calculated and defined as the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage." The results are shown in Table 1.

[0171]

[0172] In Table 1, "-" means that the corresponding additive is not contained. In addition, in Table 1, "(IA)", "(II-1A)", "(II-1N)", "(II-1O)", "(II-3B)", "(II-3M)", "(II-4A)", and "(II-4B)" respectively represent sulfonyl compounds represented by the following formulas.

[0173]

[0174] From the results in Table 1, it is clear that the lithium ion secondary batteries of Examples 1 to 7, which used non-aqueous electrolyte solutions containing a carbodiimide compound represented by formula (I) and a sulfonyl compound represented by formulas (II-1) to (II-4), had suppressed low-temperature resistance values ​​after high-temperature storage compared to the lithium ion secondary batteries of Comparative Examples 1 to 8, which used non-aqueous electrolyte solutions not containing a carbodiimide compound represented by formula (I) and a sulfonyl compound represented by formulas (II-1) to (II-4). Therefore, it was demonstrated that the non-aqueous electrolyte solution or non-aqueous electrolyte secondary battery according to one embodiment of the present disclosure is a non-aqueous electrolyte solution and non-aqueous electrolyte secondary battery that can suppress an increase in resistance after high-temperature storage. Furthermore, from the results in Table 1, the lithium ion secondary batteries of Examples 1 to 7 had a sum of the "initial low-temperature resistance value (relative value)" and the "low-temperature resistance value (relative value) after high-temperature storage" of 195 or less. Therefore, it has been demonstrated that the nonaqueous electrolyte solution or nonaqueous electrolyte secondary battery according to an embodiment of the present disclosure not only suppresses an increase in resistance after high-temperature storage but also has excellent initial low-temperature resistance, and is an overall excellent nonaqueous electrolyte solution and nonaqueous electrolyte secondary battery having both of these features.

[0175] The disclosure of Japanese Patent Application No. 2023-213343, filed on December 18, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A non-aqueous electrolyte solution comprising a carbodiimide compound represented by the following formula (I) and a sulfonyl compound represented by the following formula (II-1), (II-2), (II-3), or (II-4). [In formula (I), R １１ each independently represents a hydrocarbon group having 1 to 12 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms. [In formulas (II-1) to (II-4), (L3), (L4), and (L5), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; L ２１ represents a linking group represented by any one of formulas (L1) to (L4) or a single bond (-); L ２２ represents a linking group represented by any one of formulas (L1) to (L3) and (L5) or a single bond (-); L ２３ represents an oxa group (-O-) or a single bond (-), R ２１１ , R ２２１ , R ２３１ , and R ２４１ each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ , R ２２２ , and R ２３２ each independently represents a substituent such as a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an oxa group (-O-), a carbonyl group (>C=O), a carboxyl group (-COOH), or a sulfonyl group (>S(=O) ２ ), a fluorosulfonyl group (-SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (-CN) and an isocyanate group (-NCO); a fluorosulfonyl group (-SO ２ F), trifluoromethylsulfonyl group (-SO ２ CF ３ ), sulfo group (-SO ３ In the formula (II-1), two R ２１２ If two R ２１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R ２２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

2. The non-aqueous electrolyte according to claim 1, wherein the content of the carbodiimide compound is 0.001% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte.

3. The non-aqueous electrolyte according to claim 1, wherein the content of the sulfonyl compound is 0.01% by mass to 5.0% by mass based on the total amount of the non-aqueous electrolyte.

4. The nonaqueous electrolyte solution according to claim 1, wherein the sulfonyl compound includes at least one selected from the group consisting of sulfonyl compounds represented by the following formula (II-1-L1) and sulfonyl compounds represented by the following formula (II-4A): [In formula (II-1-L1), M ＋ represents an alkali metal ion, an alkaline earth metal ion, an ammonium ion, an imidazolium ion, a pyridinium ion, a pyrrolidinium ion, a piperidinium ion, or a phosphonium ion; R ２１１ represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), a fluorocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), an iodo group (-I), and an oxa group (-O-) as a substituent; R ２１２ The substituents are fluoro (-F), chloro (-Cl), bromo (-Br), oxa (-O-), carbonyl (>C=O), carboxyl (-COOH), and sulfonyl (>S(=O) ２ ), a fluorosulfonyl group (-SO ２ F), fluorosulfoxyl group (-OSO ２ F), sulfo group (-SO ３ a hydrocarbon group having 1 to 20 carbon atoms which may contain at least one functional group selected from the group consisting of a cyano group (-CN) and an isocyanate group (-NCO); a fluorosulfonyl group (-SO ２ F), trifluoromethylsulfonyl group (-SO ２ CF ３ ), sulfo group (-SO ３ represents a cyano group (--H), a cyano group (--CN), or an isocyanate group (--NCO).

5. A nonaqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a nonaqueous electrolyte solution, and a separator, wherein the nonaqueous electrolyte solution is the nonaqueous electrolyte solution according to any one of claims 1 to 4.

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