Nonaqueous electrolyte secondary battery

Abstract

To exhibit excellent battery characteristics even when the battery is stored for a long period of time in a high-temperature environment.SOLUTION: When an anode coating formed on the surface of an anode is subjected to narrow scan analysis by X-ray photoelectron spectroscopy (XPS) using sulfur as a measurement element, the resulting S2p orbital spectrum satisfies the following formula 1. [Formula 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)≥0.1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[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, and as a result, they 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 regarding various characteristics such as output characteristics, charge / discharge characteristics, and gas generation, but one very important evaluation item is, for example, the small decrease in output when stored for a long period of time in a high-temperature environment.

[0003] Patent Document 1 describes a battery that includes a nonaqueous electrolyte solution containing a specific additive containing sulfur atoms and oxygen atoms, and when a narrow spectrum of sulfur atoms is measured on the surface of the negative electrode by X-ray photoelectron spectroscopy and peak separation is performed for the S2p orbital, the area ratio of Peak 1 observed in the range of 168.4 eV to 171.1 eV to Peak 2 observed in the range of 166.3 eV to 169.0 eV is 10 to 150, and it is reported that an increase in battery resistance during storage is suppressed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-169802 Summary of the Invention [Problem to be solved by the invention]

[0005] However, non-aqueous electrolyte secondary batteries are required to achieve excellent battery characteristics, such as a capacity retention rate and suppressed increases in battery resistance, when stored for a long period of time in a high-temperature environment. Therefore, an object of one embodiment of the present disclosure is to provide a non-aqueous electrolyte secondary battery that exhibits excellent battery characteristics even when stored for a long period of time in a high-temperature environment. [Means for solving the problem]

[0006] Means for solving the above-mentioned problems include the following aspects. <1> A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, wherein a negative electrode coating formed on the surface of the negative electrode has an S2p orbital spectrum that satisfies the following formula 1 when narrow scan analysis is performed by X-ray photoelectron spectroscopy (XPS) using sulfur as the measurement element: [Equation 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)≧0.1 <2> When the positive electrode coating formed on the surface of the positive electrode is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using fluorine as the measurement element, the obtained F1s orbital spectrum has a region that satisfies the following formula 2: <1> The non-aqueous electrolyte secondary battery according to claim 1. [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)≦1.0 <3> When the negative electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 3: <1> or <2> The non-aqueous electrolyte secondary battery according to claim 1. [Equation 3]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1 <4> When the positive electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 4: <1> ~ <3> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1 <5> the nonaqueous electrolyte solution contains at least one compound selected from the group consisting of a sulfonyl compound represented by the following formula (I-1) and a decomposition product thereof, a sulfonyl compound represented by the following formula (I-2) and a decomposition product thereof, a sulfonyl compound represented by the following formula (I-3) and a decomposition product thereof, and a sulfonyl compound represented by the following formula (I-4) and a decomposition product thereof: <1> ~ <4> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [ka] (R in formula (I-1) 111 , R in formula (I-2) 121 , R in formula (I-3) 131 and R in formula (I-4) 141 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 in formula (I-1) 112 , R in formula (I-2) 122 and R in formula (I-2) 132each independently 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 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 (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-S03H), a cyano group (-CN), and an isocyanate group (-NCO) as a substituent, a fluorosulfonyl group (-SO2F), a sulfo group (-S03H), a cyano group (-CN), or an isocyanate group (-NCO). L in formula (I-1) 111 represents a linking group selected from the group consisting of formulas (L1) to (L4) or a single bond (-); L in formula (I-2) 121 represents a linking group selected from the group consisting of formulae (L1) to (L3) and (L5) or a single bond (-). [ka] In formula (I-1), formula (I-4), and formula (L3), (M 1 ) + 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. 112 and R in formula (L5) 122 respectively represent R in formula (I-1). 112 and R in formula (I-2) 122 is the same as However, in formula (I-1), there are two R 112 When two R 112 The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R 122 The hydrocarbon groups may be bonded to each other to form a cyclic structure. <6> The non-aqueous electrolyte solution contains at least one selected from the group consisting of a salt represented by the following formula (II) and a decomposition product thereof: <1> ~ <5> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [ka] (In formula (II), (M 2 ) + 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 2 each independently represents a single bond (-) or a divalent hydrocarbon group having 1 to 6 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), and an iodo group (-I) as a substituent; Q 2 each independently represents an oxa group (-O-) or a secondary amino group (-NH-), and X 2 each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), or an iodo group (-I); Z 2 represents a boron atom or a phosphorus atom, and h represents the Z 2 is a boron atom, 1 or 2, 2 represents an integer of 1 to 3 when is a phosphorus atom, and i is 2 is a boron atom, 0 or 2; 2 When is a phosphorus atom, it represents 0, 2, or 4.)

[0007] <7> A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, wherein a positive electrode coating formed on the surface of the positive electrode has an F1s orbital spectrum that satisfies the following formula 2 when subjected to narrow scan analysis by X-ray photoelectron spectroscopy using fluorine as the measurement element: [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)≦1.0 <8> When the negative electrode coating formed on the surface of the negative electrode is subjected to narrow scan analysis by X-ray photoelectron spectroscopy (XPS) using sulfur as the measurement element, the obtained S2p orbital spectrum has a region that satisfies the following formula 1: <7> The nonaqueous electrolyte secondary battery according to claim 1. [Equation 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)≧0.1 <9> When the negative electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 3: <7> or <8> The nonaqueous electrolyte secondary battery according to claim 1. [Equation 3]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1 <10> When the positive electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 4: <7> ~ <9> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1 <11> the nonaqueous electrolyte solution contains at least one compound selected from the group consisting of a sulfonyl compound represented by the following formula (I-1) and a decomposition product thereof, a sulfonyl compound represented by the following formula (I-2) and a decomposition product thereof, a sulfonyl compound represented by the following formula (I-3) and a decomposition product thereof, and a sulfonyl compound represented by the following formula (I-4) and a decomposition product thereof: <7> ~ <10> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [ka] (R in formula (I-1) 111 , R in formula (I-2) 121 , R in formula (I-3) 131 and R in formula (I-4) 141each 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 in formula (I-1) 112 , R in formula (I-2) 122 and R in formula (I-2) 132 each independently 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 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 (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-S03H), a cyano group (-CN), and an isocyanate group (-NCO) as a substituent, a fluorosulfonyl group (-SO2F), a sulfo group (-S03H), a cyano group (-CN), or an isocyanate group (-NCO). L in formula (I-1) 111 represents a linking group selected from the group consisting of formulas (L1) to (L4) or a single bond (-); L in formula (I-2) 121 represents a linking group selected from the group consisting of formulae (L1) to (L3) and (L5) or a single bond (-). [ka] In formula (I-1), formula (I-4), and formula (L3), (M 1 ) + 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. 112 and R in formula (L5) 122 respectively represent R in formula (I-1). 112 and R in formula (I-2)122 is the same as However, in formula (I-1), there are two R 112 When two R 112 The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R 122 The hydrocarbon groups may be bonded to each other to form a cyclic structure. <12> The non-aqueous electrolyte solution contains at least one selected from the group consisting of a salt represented by the following formula (II) and a decomposition product thereof: <7> ~ <11> 10. The non-aqueous electrolyte secondary battery according to claim 9, wherein the non-aqueous electrolyte secondary battery is a [ka] (In formula (II), (M 2 ) + 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 2 each independently represents a single bond (-) or a divalent hydrocarbon group having 1 to 6 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), and an iodo group (-I) as a substituent; Q 2 each independently represents an oxa group (-O-) or a secondary amino group (-NH-), and X 2 each independently represents a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), or an iodo group (-I); Z 2 represents a boron atom or a phosphorus atom, and h represents the Z 2 is a boron atom, 1 or 2, 2 represents an integer of 1 to 3 when is a phosphorus atom, and i is 2 is a boron atom, 0 or 2; 2 When is a phosphorus atom, it represents 0, 2, or 4.) [Effects of the Invention]

[0008] According to one aspect of the present disclosure, it is possible to provide a nonaqueous electrolyte secondary battery that can maintain excellent battery characteristics even when stored for a long period of time in a high-temperature environment. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a main portion of a nonaqueous electrolyte secondary battery according to the present disclosure. [Figure 2] 1 is a cross-sectional view showing a main part of a coin-type lithium ion secondary battery, which is an example of a nonaqueous electrolyte secondary battery according to the present disclosure. [Figure 3] FIG. 10 is a characteristic diagram showing the results of measuring the S2p orbital spectrum of the negative electrode coating. [Figure 4] FIG. 10 is a characteristic diagram showing the results of measuring the F1s orbital spectrum of the positive electrode coating. [Figure 5] FIG. 10 is a characteristic diagram showing the results of measuring the N1s orbital spectrum of the negative electrode coating. [Figure 6] FIG. 10 is a characteristic diagram showing the results of measuring the N1s orbital spectrum of the positive electrode coating. DETAILED DESCRIPTION OF THE INVENTION

[0010] In explaining the present disclosure, specific examples will be given, but the present disclosure is not limited to the following content and can be modified as appropriate without departing from the spirit of the present disclosure.

[0011] In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits. In the present disclosure, in the numerical ranges described in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with the value shown in the examples. In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified. In the present disclosure, combinations of preferred aspects are more preferred aspects. 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.

[0012] [Nonaqueous electrolyte secondary battery] A nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure (hereinafter simply referred to as "nonaqueous electrolyte secondary battery") is a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator, wherein a negative electrode coating formed on the surface of the negative electrode has a region in which the S2p orbital spectrum obtained by narrow scan analysis using X-ray photoelectron spectroscopy (XPS) with sulfur as the measurement element satisfies the following formula 1: [Equation 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)≧0.1

[0013] The nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics even when stored for a long period of time (e.g., 30 days) in a high-temperature (e.g., 60°C) environment. This is because the coating formed on the surface of the negative electrode (hereinafter referred to as the "negative electrode coating") has a region that satisfies the above-mentioned condition (i.e., the above [Formula 1]). In particular, the nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics, such as a high capacity retention rate and a suppressed resistance increase rate after high-temperature storage. Note that the "long-term storage (e.g., 30 days) in a high-temperature (e.g., 60°C) environment" is an example of the "long-term storage in a high-temperature environment" in the present disclosure, and is merely an example of the conditions for evaluating the capacity retention rate and the resistance increase rate. In other words, the nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics, such as a high capacity retention rate and a suppressed resistance increase rate, even under conditions different from the "long-term storage (e.g., 30 days) in a high-temperature (e.g., 60°C) environment."

[0014] [Negative electrode coating] The "negative electrode coating" and "X-ray photoelectron spectroscopy (XPS)" measurements according to the present disclosure will be described in detail below.

[0015] In the nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure, the term "negative electrode coating" refers to a solid electrolyte interphase (SEI), which is known to form at the electrode-electrolyte interface of nonaqueous electrolyte secondary batteries such as lithium ion secondary batteries, and particularly refers to a coating formed on the surface of the negative electrode. The negative electrode coating is believed to form primarily after charging or other procedures are performed on the nonaqueous electrolyte secondary battery. The nonaqueous electrolyte secondary battery of the present disclosure includes not only batteries on which a negative electrode coating is formed on the negative electrode surface, but also batteries on which a negative electrode coating has not yet been formed. The nonaqueous electrolyte secondary battery on which a negative electrode coating has not yet been formed is not particularly limited, and examples thereof include nonaqueous electrolyte secondary batteries immediately after assembly. In other words, even a nonaqueous electrolyte secondary battery on which a negative electrode coating has not yet been formed immediately after assembly is also included in the nonaqueous electrolyte secondary battery of the present disclosure, as long as the negative electrode coating is subsequently formed.

[0016] Furthermore, in the nonaqueous electrolyte secondary battery of the present disclosure, the negative electrode coating does not need to be formed on the entire surface of the negative electrode, but may be formed on a partial region of the surface of the negative electrode. Furthermore, the entire negative electrode coating may satisfy the above formula 1, but only a portion of the negative electrode coating may satisfy the above formula 1. In other words, in the nonaqueous electrolyte secondary battery of the present disclosure, it is sufficient that the negative electrode coating is formed on a portion of the surface of the negative electrode, and that the portion of the formed negative electrode coating satisfies the above formula 1.

[0017] Equation 1 above is a formula obtained by performing narrow scan analysis of the negative electrode surface on which a negative electrode coating is formed by X-ray photoelectron spectroscopy, using sulfur as the measurement element, and substituting the peak intensity of the maximum intensity peak in a predetermined range of the obtained S2p orbital spectrum. In narrow scan analysis by X-ray photoelectron spectroscopy, the analysis region is typically about 10 μm to 100 μm in diameter, which is a very narrow region compared to the surface area of the negative electrode or the negative electrode coating. Therefore, rather than performing the narrow scan analysis comprehensively on the negative electrode surface on which a negative electrode coating is formed, the narrow scan analysis may be performed partially on the negative electrode surface on which a negative electrode coating is formed.

[0018] The negative electrode coating of the nonaqueous electrolyte secondary battery of the present disclosure may have at least one region that satisfies the above formula 1 as a result of the narrow scan analysis. For example, the analysis region for the narrow scan analysis may be one or more regions, for example, two, three, or four regions, on the surface of the negative electrode. When the narrow scan analysis is performed on these one or more regions, it is sufficient that at least one analysis region satisfies the above formula 1. The analysis region for the narrow scan analysis is not particularly limited and may be near the center of the surface of the negative electrode, or may be multiple regions that are approximately evenly distributed.

[0019] Note that some X-ray photoelectron spectroscopy can perform not only analysis of the outermost surface but also analysis in the depth direction by using sputter etching. In the nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure, analysis in the depth direction is not necessary, and it is sufficient to analyze the outermost surface of the negative electrode coating by X-ray photoelectron spectroscopy to determine whether the above formula 1 is satisfied.

[0020] The value calculated by formula 1 "(peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)" is 0.1 or more, preferably 0.2 or more, preferably 0.3 or more, preferably 0.4 or more, preferably 0.5 or more, more preferably 0.7 or more, even more preferably 0.8 or more, particularly preferably 0.9 or more, and is usually 3.0 or less. When this value is within the above range, the capacity retention rate after high-temperature storage can be increased, and the rate of increase in resistance after high-temperature storage can be suppressed.

[0021] In the nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure, when narrow scan analysis is performed on the negative electrode coating by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the resulting N1s orbital spectrum preferably has a region that satisfies the following formula 3: [Equation 3]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1

[0022] The value calculated by formula 3, "(peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)", is usually 0.1 or more, preferably 0.2 or more, preferably 0.3 or more, preferably 0.4 or more, preferably 0.5 or more, more preferably 0.6 or more, even more preferably 0.7 or more, particularly preferably 0.75 or more, and is usually 5.0 or less. When this value is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0023] [Positive electrode coating] The nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure preferably has a positive electrode coating as defined below: That is, when narrow scan analysis is performed on the surface of the positive electrode on which the positive electrode coating is formed by X-ray photoelectron spectroscopy using fluorine as the measurement element, the obtained F1s orbital spectrum preferably has a region that satisfies the following formula 2: [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)≦1.0

[0024] Here, the positive electrode coating, like the negative electrode coating, refers to a coating formed on the surface of a positive electrode. Like the negative electrode coating, the positive electrode coating includes a solid electrolyte interphase (SEI), which is known to form at the electrode-electrolyte interface of nonaqueous electrolyte secondary batteries such as lithium ion secondary batteries, and particularly refers to a coating formed on the surface of a positive electrode. The positive electrode coating is believed to form mainly after charging or the like of a nonaqueous electrolyte secondary battery. The nonaqueous electrolyte secondary battery of the present disclosure includes not only a battery with a positive electrode coating formed on the positive electrode surface, but also a battery without a positive electrode coating yet formed. The nonaqueous electrolyte secondary battery without a positive electrode coating yet formed is not particularly limited, and examples thereof include a nonaqueous electrolyte secondary battery immediately after assembly. In other words, even a nonaqueous electrolyte secondary battery without a positive electrode coating immediately after assembly is also included in the nonaqueous electrolyte secondary battery of the present disclosure, as long as the positive electrode coating is later formed.

[0025] Furthermore, in the nonaqueous electrolyte secondary battery of the present disclosure, the positive electrode coating does not need to be formed on the entire surface of the positive electrode, but may be formed on a partial region of the surface of the positive electrode. Furthermore, the entire positive electrode coating may satisfy the above formula 2, but only a portion of the positive electrode coating may satisfy the above formula 2. In other words, in the nonaqueous electrolyte secondary battery of the present disclosure, it is sufficient that the positive electrode coating is formed on a portion of the surface of the positive electrode, and that the portion of the formed positive electrode coating satisfies the above formula 2.

[0026] As with the negative electrode coating, the positive electrode coating of the nonaqueous electrolyte secondary battery of the present disclosure may have at least one region that satisfies the above formula 2 as a result of the narrow scan analysis. For example, the analysis region for the narrow scan analysis may be one or more regions, for example, two, three, or four regions, on the surface of the positive electrode. When the narrow scan analysis is performed on these one or more regions, it is sufficient that at least one analysis region satisfies the above formula 2. The analysis region for the narrow scan analysis is not particularly limited and may be near the center of the surface of the positive electrode, or may be multiple regions that are approximately evenly distributed.

[0027] In the nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure, the surface of the positive electrode on which the positive electrode coating is formed may be analyzed by X-ray photoelectron spectroscopy to determine whether the above formula 2 is satisfied.

[0028] The value calculated by Equation 2, "(peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)", is usually 1.0 or less, preferably 0.95 or less, more preferably 0.90 or less, even more preferably 0.85 or less, and particularly preferably 0.70 or less, and is usually 0.1 or more. When this value is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0029] In the nonaqueous electrolyte secondary battery according to one embodiment of the present invention, when narrow scan analysis is performed on the positive electrode coating by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum preferably has a region that satisfies the following formula 4: [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1

[0030] The value calculated by Equation 4, "(peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)," is usually 0.1 or more, preferably 0.3 or more, more preferably 0.35 or more, even more preferably 0.4 or more, particularly preferably 0.45 or more, particularly preferably 0.50 or more, particularly preferably 0.55 or more, particularly preferably 0.60 or more, particularly preferably 0.65 or more, particularly preferably 0.70 or more, particularly preferably 0.75 or more, particularly preferably 0.80 or more, and is usually 5.0 or less. When this value is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0031] Other Embodiments A nonaqueous electrolyte secondary battery according to another embodiment of the present disclosure is a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator, wherein a positive electrode coating formed on the surface of the positive electrode has a region in the F1s orbital spectrum that satisfies the following formula 2 when narrow scan analysis is performed by X-ray photoelectron spectroscopy using fluorine as the measurement element: [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)≦1.0

[0032] The nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics even when stored for a long period of time (e.g., 30 days) in a high-temperature (e.g., 60°C) environment. This is because, as a result of X-ray photoelectron spectroscopy analysis of the surface of the positive electrode on which the positive electrode coating is formed, the positive electrode coating has a region that satisfies the above-mentioned condition (i.e., the above [Formula 2]). In particular, the nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics, such as a high capacity retention rate and a suppressed resistance increase rate after high-temperature storage. Note that the "long-term storage (e.g., 30 days) in a high-temperature (e.g., 60°C) environment" is an example of the "long-term storage in a high-temperature environment" in the present disclosure, and is merely an example of the conditions for evaluating the capacity retention rate and the resistance increase rate. In other words, the nonaqueous electrolyte secondary battery of the present disclosure exhibits excellent battery characteristics, such as a high capacity retention rate and a suppressed resistance increase rate, even under conditions different from the "long-term storage (e.g., 30 days) in a high-temperature (e.g., 60°C) environment."

[0033] In the nonaqueous electrolyte secondary battery of this embodiment, when narrow scan analysis is performed on the positive electrode coating by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum preferably has a region that satisfies the following formula 4: [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1

[0034] The value calculated by Equation 4, "(peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)," is usually 0.1 or more, preferably 0.3 or more, more preferably 0.35 or more, even more preferably 0.4 or more, particularly preferably 0.45 or more, particularly preferably 0.50 or more, particularly preferably 0.55 or more, particularly preferably 0.60 or more, particularly preferably 0.65 or more, particularly preferably 0.70 or more, particularly preferably 0.75 or more, particularly preferably 0.80 or more, and is usually 5.0 or less. When this value is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0035] Furthermore, the nonaqueous electrolyte secondary battery of this embodiment preferably has the negative electrode coating described in the nonaqueous electrolyte secondary battery of the above embodiment. That is, by having the negative electrode coating have a region that satisfies the above formula 1 and / or the above formula 3, the capacity retention rate after high-temperature storage can be further increased and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0036] The nonaqueous electrolyte secondary battery according to this embodiment includes not only those on which the positive electrode coating and / or the negative electrode coating are formed, but also those on which the positive electrode coating and / or the negative electrode coating are not yet formed. That is, for example, even a nonaqueous electrolyte secondary battery immediately after assembly on which the positive electrode coating and / or the negative electrode coating are not formed is included in the nonaqueous electrolyte secondary battery of this embodiment, as long as the positive electrode coating and / or the negative electrode coating are formed later.

[0037] Furthermore, in the nonaqueous electrolyte secondary battery of this embodiment, the positive electrode coating and / or the negative electrode coating do not need to be formed on the entire surface of the positive electrode and / or the negative electrode, but may be formed on a partial region of the surface of the positive electrode and / or the negative electrode. Furthermore, the positive electrode coating and / or the negative electrode coating may entirely satisfy the above-mentioned conditions, or only a portion of them may satisfy the above-mentioned conditions. In other words, in the nonaqueous electrolyte secondary battery of this embodiment, the positive electrode coating and / or the negative electrode coating are formed on a portion of the surface of the positive electrode and / or the negative electrode, and only a portion of the formed positive electrode coating and / or the negative electrode coating satisfies the above-mentioned conditions.

[0038] The nonaqueous electrolyte secondary battery of this embodiment may also have at least one region that satisfies the above conditions (Equations 1 to 4) as a result of narrow scan analysis. For example, the analysis region for the narrow scan analysis may be one or more regions, for example, two, three, or four regions, on the surface of the positive electrode and / or negative electrode. When the narrow scan analysis is performed on these one or more regions, it is sufficient that at least one analysis region satisfies the above conditions. The analysis region for the narrow scan analysis is not particularly limited, and may be near the center of the surface of the positive electrode and / or negative electrode, or may be multiple regions that are approximately evenly distributed.

[0039] In the nonaqueous electrolyte secondary battery of this embodiment, the outermost surfaces of the positive electrode and / or negative electrode may also be analyzed by X-ray photoelectron spectroscopy to determine whether the positive electrode coating and / or negative electrode coating satisfy the above conditions.

[0040] [Nonaqueous electrolyte] In the nonaqueous electrolyte secondary battery of the present disclosure, one or both of the negative electrode coating and the positive electrode coating have a region that satisfies the above-mentioned conditions. One method for forming such a region in the negative electrode coating and / or the positive electrode coating is to appropriately select an additive to be blended into the nonaqueous electrolyte. The additives that are preferably blended into the "nonaqueous electrolyte" are described in detail below.

[0041] The additive to be blended in the non-aqueous electrolyte preferably contains at least one selected from the group consisting of sulfonyl compounds represented by the following formula (I-1) and decomposition products thereof, sulfonyl compounds represented by the following formula (I-2) and decomposition products thereof, sulfonyl compounds represented by the following formula (I-3) and decomposition products thereof, and sulfonyl compounds represented by the following formula (I-4) and decomposition products thereof.

[0042] Here, the decomposition product includes compounds generated by decomposition of a sulfonyl compound represented by, for example, formula (I-1) when a nonaqueous electrolyte secondary battery containing a nonaqueous electrolyte blended with the sulfonyl compound is charged or otherwise processed. As described above, in a nonaqueous electrolyte secondary battery according to one embodiment of the present disclosure, the negative electrode coating and / or positive electrode coating formed after, for example, charging or otherwise process satisfies the above conditions. Therefore, the sulfonyl compound represented by formula (I-1) or the like may have already been decomposed by charging or otherwise process by the time the negative electrode coating and / or positive electrode coating satisfy the above conditions. Therefore, the additive contained in the nonaqueous electrolyte solution includes not only the sulfonyl compound represented by formula (I-1) or the like but also "its decomposition product."

[0043] [ka]

[0044] R in formula (I-1) 111 , R in formula (I-2) 121 , R in formula (I-3) 131 and R in formula (I-4) 141 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.

[0045] R in formula (I-1) 112 , R in formula (I-2) 122and R in formula (I-2) 132 each independently 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 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 (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-S03H), a cyano group (-CN), and an isocyanate group (-NCO) as a substituent, a fluorosulfonyl group (-SO2F), a sulfo group (-S03H), a cyano group (-CN), or an isocyanate group (-NCO).

[0046] L in formula (I-1) 111 represents a linking group selected from the group consisting of formulas (L1) to (L4) or a single bond (-); L in formula (I-2) 121 represents a linking group selected from the group consisting of formulae (L1) to (L3) and (L5) or a single bond (-).

[0047] [ka]

[0048] In formula (I-1), formula (I-4), and formula (L3), (M 1 ) + 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. 112 and R in formula (L5) 122 respectively represent R in formula (I-1). 112 and R in formula (I-2) 122 is the same as

[0049] However, in formula (I-1), there are two R 112 When two R 112 The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R122 The hydrocarbon groups may be bonded to each other to form a cyclic structure.

[0050] [Sulfonyl compound represented by formula (I-1)]

[0051] [ka]

[0052] In the above formula (I-1), (M 1 ) + represents "alkali metal ions," "alkaline earth metal ions," "ammonium ions," "imidazolium ions," "pyridinium ions," "pyrrolidinium ions," "piperidinium ions," and "phosphonium ions," but more specifically, it represents lithium ions (Li + ), sodium ions (Na + ), potassium ions (K + ), magnesium ions (Mg 2+ ), calcium ions (Ca 2+ ), ammonium ion (NH4 + ) are mentioned. Among them, (M 1 ) + is a lithium ion (Li + ) is particularly preferred.

[0053] In the above formula (I-1), L 111 represents "a linking group selected from the group consisting of formulae (L1) to (L4)" or "a single bond (-)".

[0054] [ka]

[0055] In the above formula (I-1), L 111 is a linking group represented by formula (L1), it means that the sulfonyl compound represented by formula (I-1) is a sulfonyl compound represented by the following formula (I-1-L1): 111is a linking group represented by formula (L2), it means that the sulfonyl compound represented by formula (I-1) is a sulfonyl compound represented by the following formula (I-1-L2): 111 is a linking group represented by formula (L3), it means that the sulfonyl compound represented by formula (I-1) is a sulfonyl compound represented by the following formula (I-1-L3): 111 is a linking group represented by formula (L4), it means that the sulfonyl compound represented by formula (I-1) is a sulfonyl compound represented by the following formula (I-1-L4): 111 is a single bond (-), it means that the sulfonyl compound represented by formula (I-1) is a sulfonyl compound represented by the following formula (I-1-L6). That is, the tip of the wavy line on the left side of formulas (L1) to (L4) is the -N in formula (I-1). - (M 1 ) + The end of the wavy line on the right side of formula (L1) to formula (L4) indicates that the group is bonded to the R 112 It means that it is bonded to the group.

[0056] [ka]

[0057] In the above formula (I-1), R 111represents 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, as a substituent, 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-)." Here, the "fluorocarbon group" refers to a group in which all hydrogen atoms of a hydrocarbon group have been substituted with fluorine atoms, and is not limited to a fluorocarbon group having a linear structure, but may also be a fluorocarbon 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). Furthermore, the "hydrocarbon group" is not limited to an aliphatic hydrocarbon group having a straight-chain structure, but 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). Furthermore, since the number of these structures is not limited, (acyclic) aliphatic hydrocarbon groups, monocyclic aliphatic hydrocarbon groups, polycyclic aliphatic hydrocarbon groups, monocyclic aromatic hydrocarbon groups, and polycyclic aromatic hydrocarbon groups 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, 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), 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), or an iodo group (-I), and a carbon atom of the hydrocarbon group may be substituted with an oxa group (-O-).

[0058] R 111 When R is a fluorocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. 111When is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less.

[0059] R 111 Examples include fluoro group (-F), trifluoromethyl group (-CF3), pentafluoroethyl group (-C2F5), n-heptafluoropropyl group (-C3F7), methyl group (-CH3), ethyl group (-CH2CH3), vinyl group (-CH=CH2), n-propyl group (-CH2CH2CH3), i-propyl group (-CH(CH3)2), n-butyl group (-CH2CH2CH2CH3), s-butyl group (-CH2CH(CH3)2), t-butyl group (-C(CH3)2), hexyl group (-CH2CH2CH2CH2CH2CH2CH3), cyclohexyl group (-CH6H 11 ), phenyl group (-C6H5), benzyl group (-CH2C6H5), trifluoromethoxymethyl group (-CH2OCF3), etc. 111 Particularly preferred are a fluoro group (-F), a trifluoromethyl group (-CF3), a pentafluoroethyl group (-C2F5), and an n-heptafluoropropyl group (-C3F7).

[0060] R 112 (two R 112 (each of which is independent when including a substituent) 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 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 (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-S03H), a cyano group (-CN), and an isocyanate group (-NCO) as a substituent," "a fluorosulfonyl group (-SO2F)," "a sulfo group (-S03H)," "a cyano group (-CN)," or "an isocyanate group (-NCO)." Here, "hydrocarbon group" refers to the R 111is the same as the case of (1), and is not limited to an aliphatic hydrocarbon group having a straight chain structure, but 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). Furthermore, the phrase "may contain, as a substituent, at least one functional group selected from the group consisting of 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 (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-S03H), a cyano group (-CN), and an isocyanate group (-NCO)" refers to the hydrogen atom of the hydrocarbon group. This means that atoms may be substituted with a fluoro group (-F), a chloro group (-Cl), a bromo group (-Br), a carboxyl group (-COOH), a fluorosulfonyl group (-SO2F), a fluorosulfoxyl group (-OSO2F), a sulfo group (-SO3H), a cyano group (-CN), an isocyanate group (-NCO), etc., and that carbon atoms of the hydrocarbon group may be substituted with an oxa group (-O-), a carbonyl group (>C=O), or a sulfonyl group (>S(=O)2). Furthermore, since the number of substituents (functional groups) within the hydrocarbon group is not limited, an oxa group (-O-) and a carbonyl group (>C=O) may be adjacent within the hydrocarbon group to form an oxycarbonyl group (-OC(=O)-), etc. The sulfonyl compound represented by formula (I-1-L4) has two R groups in the molecule. 112 It forms a structure including:

[0061] In addition, "two R in formula (I-1) 112 When two R 112 The hydrocarbon groups may be bonded to each other to form a ring structure" refers to two R 112This means that the hydrocarbon groups bond to each other to form a cyclic structure, resulting in a structure like the compound of the following formula. 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. Furthermore, since the carboxyl group (-COOH) and the sulfo group (-SOH) are acidic functional groups, their hydrogen ions may undergo ion exchange with alkali metal ions, alkaline earth metal ions, ammonium ions, etc. to form salts.

[0062] [ka]

[0063] R 112 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.

[0064] R 112 Examples include fluorosulfonyl group (-SO2F), sulfo group (-SO3H), cyano group (-CN), isocyanate group (-NCO), methyl group (-CH3), ethyl group (-CH2CH3), vinyl group (-CH=CH2), n-propyl group (-CH2CH2CH3), i-propyl group (-CH(CH3)2), n-butyl group (-CH2CH2CH2CH3), s-butyl group (-CH2CH(CH3)2), t-butyl group (-C(CH3)2), cyclohexyl group (-CH6H 11 ), phenyl group (-CH), 1-(ethoxycarbonyl)ethyl group (-CH(COOCHCH)CH), 1-sulfomethyl group (-CHSOH(Li)), 2-sulfoethyl group (-CHCHSOH(Li)), 3-sulfo-n-propyl group (-CHCHCHSOH(Li)), etc.

[0065] Examples of the sulfonyl compound represented by formula (I-1) include sulfonyl compounds represented by the following formulas.

[0066] [ka]

[0067] The non-aqueous electrolyte may contain two or more types of sulfonyl compounds represented by formula (I-1).

[0068] [Sulfonyl compound represented by formula (I-2)]

[0069] [ka]

[0070] In the above formula (I-2), L 121 represents "a linking group selected from the group consisting of formulae (L1) to (L3) and formula (L5)" or "a single bond (-)".

[0071] [ka]

[0072] In the above formula (I-2), L 121 is a linking group represented by formula (L1), it means that the sulfonyl compound represented by formula (I-2) is a sulfonyl compound represented by the following formula (I-2-L1): 121 is a linking group represented by formula (L2), it means that the sulfonyl compound represented by formula (I-2) is a sulfonyl compound represented by the following formula (I-2-L2): 121 is a linking group represented by formula (L3), it means that the sulfonyl compound represented by formula (I-2) is a sulfonyl compound represented by the following formula (I-2-L3): 121 is a linking group represented by formula (L5), it means that the sulfonyl compound represented by formula (I-2) is a sulfonyl compound represented by the following formula (I-2-L5): 121is a single bond (-), it means that the sulfonyl compound represented by formula (I-2) is a sulfonyl compound represented by the following formula (I-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 122 The end of the wavy line on the right side of formula (L1) to formula (L3) and formula (L5) indicates that the group is bonded to the R 122 It means that it is bonded to the group.

[0073] [ka]

[0074] In the above formula (I-2), R 121 represents R in the above formula (I-1). 111 In addition, in the above formula (I-2), R 122 represents R in the above formula (I-1). 112 and "two R in formula (I-2)" 122 When two R 122 The hydrocarbon groups may be bonded to each other to form a ring structure" refers to two R 122 forms a cyclic structure to form a compound of the following formula:

[0075] [ka]

[0076] Examples of the sulfonyl compound represented by formula (I-2) include sulfonyl compounds represented by the following formula:

[0077] [ka]

[0078] The non-aqueous electrolyte may contain two or more sulfonyl compounds represented by formula (I-2).

[0079] [Sulfonyl compound represented by formula (I-3)]

[0080] [ka]

[0081] In the above formula (I-3), R 131 represents R in the above formula (I-1). 111 In addition, in the above formula (I-3), R 132 represents R in the above formula (I-1). 112 It is synonymous with R. 131 When R is a fluorocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. 131 When is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less.

[0082] R 131 Examples include fluoro group (-F), trifluoromethyl group (-CF3), pentafluoroethyl group (-C2F5), n-heptafluoropropyl group (-C3F7), methyl group (-CH3), ethyl group (-CH2CH3), vinyl group (-CH=CH2), n-propyl group (-CH2CH2CH3), i-propyl group (-CH(CH3)2), n-butyl group (-CH2CH2CH2CH3), s-butyl group (-CH2CH(CH3)2), t-butyl group (-C(CH3)2), hexyl group (-CH2CH2CH2CH2CH2CH2CH3), cyclohexyl group (-CH6H 11 ), a phenyl group (-C6H5), a benzyl group (-CH2C6H5), a trifluoromethoxymethyl group (-CH2OCF3), etc. 131 Particularly preferred are a fluoro group (-F), a trifluoromethyl group (-CF3), a pentafluoroethyl group (-C2F5), and an n-heptafluoropropyl group (-C3F7).

[0083] R 132When 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.

[0084] R 132 Examples include methyl group (-CH3), ethyl group (-CH2CH3), vinyl group (-CH=CH2), n-propyl group (-CH2CH2CH3), 3-fluorosulfoxyl-n-propyl group (-CH2CH2CH2OSO2F), i-propyl group (-CH(CH3)2), n-butyl group (-CH2CH2CH2CH3), 4-fluorosulfoxyl-n-butyl group (-CH2CH2CH2CH2OSO2F), s-butyl group (-CH2CH(CH3)2), t-butyl group (-C(CH3)2), cyclohexyl group (-CH 11 ), a phenyl group (—C6H5), a 4-fluorosulfoxylphenyl group (—C6H4OSO2F), a 3,5-bis(fluorosulfoxyl)phenyl group (—C6H4(OSO2F)2), and the like.

[0085] Examples of the sulfonyl compound represented by formula (I-3) include sulfonyl compounds represented by the following formulas:

[0086] [ka]

[0087] The non-aqueous electrolyte may contain two or more types of sulfonyl compounds represented by formula (I-3).

[0088] [Fluorosulfonyl compound represented by formula (I-4)] [ka]

[0089] In the above formula (I-4), (M 1 ) +represents "alkali metal ions," "alkaline earth metal ions," "ammonium ions," "imidazolium ions," "pyridinium ions," "pyrrolidinium ions," "piperidinium ions," and "phosphonium ions," but more specifically, it represents lithium ions (Li + ), sodium ions (Na + ), potassium ions (K + ), magnesium ions (Mg 2+ ), calcium ions (Ca 2+ ), ammonium ion (NH4 + ) are mentioned. Among them, (M 1 ) + As for the lithium ion (Li + ) is particularly preferred.

[0090] In the above formula (I-4), R 141 represents R in the above formula (I-1). 111 It is synonymous with R. 141 When R is a fluorocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less. 141 When is a hydrocarbon group, the number of carbon atoms is preferably 10 or less, more preferably 8 or less, even more preferably 6 or less, and particularly preferably 4 or less.

[0091] R 141 Examples include fluoro group (-F), trifluoromethyl group (-CF3), pentafluoroethyl group (-C2F5), n-heptafluoropropyl group (-C3F7), methyl group (-CH3), ethyl group (-CH2CH3), vinyl group (-CH=CH2), n-propyl group (-CH2CH2CH3), i-propyl group (-CH(CH3)2), n-butyl group (-CH2CH2CH2CH3), s-butyl group (-CH2CH(CH3)2), t-butyl group (-C(CH3)2), hexyl group (-CH2CH2CH2CH2CH2CH2CH3), cyclohexyl group (-CH6H 11), a phenyl group (-C6H5), a benzyl group (-CH2C6H5), a trifluoromethoxymethyl group (-CH2OCF3), etc. 141 Particularly preferred are a fluoro group (-F), a trifluoromethyl group (-CF3), a pentafluoroethyl group (-C2F5), and an n-heptafluoropropyl group (-C3F7).

[0092] Examples of the sulfonyl compound represented by formula (I-4) include lithium fluorosulfonate represented by the following formula (I-4-1) and lithium trifluoromethanesulfonate represented by the following formula (I-4-2).

[0093] [ka]

[0094] The non-aqueous electrolyte may contain two or more types of sulfonyl compounds represented by formula (I-4).

[0095] [Additive content] The total content of the additives contained in the non-aqueous electrolyte is not particularly limited and can typically be 0.01% to 5.0% by mass relative to the total amount of the non-aqueous electrolyte (when the total amount of the non-aqueous electrolyte is taken as 100% by mass). In particular, the lower limit of the total content is 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. The upper limit of the total content is 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. When the total content of the additives is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the rate of increase in resistance after high-temperature storage can be further suppressed.

[0096] [Salt represented by formula (II)] The additive to be added to the non-aqueous electrolyte is not limited to the sulfonyl compound or its decomposition product, but may be at least one selected from the group consisting of a salt represented by the following formula (II) and its decomposition product. Here, as in the case of the sulfonyl compound, the decomposition product includes a compound generated by decomposition of the salt when a non-aqueous electrolyte secondary battery containing the non-aqueous electrolyte is charged or otherwise processed. As described above, in a non-aqueous electrolyte secondary battery according to one embodiment of the present disclosure, the negative electrode coating and / or positive electrode coating formed after, for example, charging or otherwise processes satisfy the above-mentioned conditions. Therefore, the salt represented by formula (II) may have already been decomposed by charging or otherwise processes when the negative electrode coating and / or positive electrode coating satisfy the above-mentioned conditions. Therefore, the additive to be added to the non-aqueous electrolyte includes not only the salt represented by formula (II) or the like, but also its decomposition product.

[0097] [ka]

[0098] In formula (II), (M 2 ) + represents "alkali metal ions," "alkaline earth metal ions," "ammonium ions," "imidazolium ions," "pyridinium ions," "pyrrolidinium ions," "piperidinium ions," and "phosphonium ions," but more specifically, it represents lithium ions (Li + ), sodium ions (Na + ), potassium ions (K + ), magnesium ions (Mg 2+ ), calcium ions (Ca 2+ ), ammonium ion (NH4 + ) are mentioned. Among them, (M 2 ) + is a lithium ion (Li + ) is particularly preferred.

[0099] In formula (II), R 2each independently represents a single bond (-) or a divalent hydrocarbon group having 1 to 6 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), and an iodo group (-I) as a substituent. 2 is a "single bond (-)" when R 2 means that two adjacent carbonyl groups (>C=O) are directly bonded to each other. Furthermore, a "divalent hydrocarbon group" refers to a hydrocarbon group having two bonding positions, and is not limited to an aliphatic hydrocarbon group having a straight-chain structure, but may also be a 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), or may also be an aromatic hydrocarbon group. In other words, alkylene groups, alkenylene groups, alkynylene groups, arylene groups, etc. are all included in the "divalent hydrocarbon group."

[0100] R 2 When is a hydrocarbon group, the number of carbon atoms is preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less.

[0101] R 2 Examples of R include a single bond (-), a methylene group (-CH2-), an ethylene group (-CH2CH2-), and an n-propylene group (-CH2CH2CH2-). 2 is particularly preferably a single bond (-) or a methylene group (-CH2-).

[0102] Q 2 each independently represents an "oxa group (-O-)" or a "secondary amino group (-NH-)", and two Q 2 is an "oxa group (-O-)" and R 2 is a single bond (-), the oxalate ion (C2O4 2- ) is a multidentate ligand, forming an oxalato complex. 2 As the group, an oxa group (—O—) is particularly preferred.

[0103] X 2 Each of the groups independently represents a "fluoro group (-F)", a "chloro group (-Cl)", a "bromo group (-Br)", or an "iodine group (-I)". 2 is particularly preferably a fluoro group (—F).

[0104] Z 2 represents a "boron atom" or a "phosphorus atom." 2 A boron atom is particularly preferred.

[0105] h is Z 2 is a boron atom, 1 or 2, 2 represents an integer of 1 to 3 when is a phosphorus atom, and i is 2 is a boron atom, 0 or 2; 2 When the atom is phosphorus, it represents 0, 2, or 4, but when the atom is Z 2 It is particularly preferred that when is a boron atom, h is 2 and i is 0.

[0106] Examples of the salt represented by formula (II) include lithium bis(oxalato)borate (LiBOB) represented by the following formula (II-1-1), lithium difluorooxalatoborate (LiDFOB) represented by the following formula (II-1-2), lithium difluorobis(oxalato)phosphate (LiDFBOP) represented by the following formula (II-2-1), and lithium tetrafluorooxalatophosphate (LiTFOP) represented by the following formula (II-2-2).

[0107] [ka]

[0108] The non-aqueous electrolyte may contain two or more types of salts represented by formula (II).

[0109] The total content of the salt represented by formula (II) or its decomposition products contained in the non-aqueous electrolyte is not particularly limited and can usually be 0.01% to 5.0% by mass relative to the total amount of the non-aqueous electrolyte (when the total amount of the non-aqueous electrolyte is taken as 100% by mass). In particular, the lower limit of the total content is 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. The upper limit of the total content is 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. When the total content of the salt represented by formula (II) or its decomposition products is within the above range, the capacity retention rate after high-temperature storage can be further increased, and the resistance increase rate after high-temperature storage can be further suppressed.

[0110] [Non-aqueous solvent] In the nonaqueous electrolyte secondary battery of the present disclosure, the nonaqueous electrolyte contains a nonaqueous solvent. Various known nonaqueous solvents can be appropriately selected as the nonaqueous solvent. The nonaqueous solvent may be one type or two or more types.

[0111] Examples of non-aqueous solvents include cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, fluorine-containing chain carbonates, aliphatic carboxylic acid esters, fluorine-containing aliphatic carboxylic acid esters, γ-lactones, fluorine-containing γ-lactones, cyclic ethers, fluorine-containing cyclic ethers, chain ethers, fluorine-containing chain ethers, nitriles, amides, lactams, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, and dimethyl sulfoxide phosphate.

[0112] Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).

[0113] An example of the fluorine-containing cyclic carbonates is fluoroethylene carbonate (FEC).

[0114] Examples of chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), and dipropyl carbonate (DPC).

[0115] 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.

[0116] Examples of γ-lactones include γ-butyrolactone and γ-valerolactone.

[0117] Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, and 1,4-dioxane.

[0118] Examples of chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, 1,2-dimethoxyethane, and 1,2-dibutoxyethane.

[0119] Examples of nitriles include acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, and 3-methoxypropionitrile.

[0120] An example of the amides is N,N-dimethylformamide.

[0121] Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, and N,N'-dimethylimidazolidinone.

[0122] 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.

[0123] 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 to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass, based on the total amount of the non-aqueous solvent.

[0124] The non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates and chain carbonates.

[0125] In this case, the total proportion of the cyclic carbonates and chain carbonates in the non-aqueous solvent is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass, relative to the total amount of the non-aqueous solvent.

[0126] The upper limit of the content of the nonaqueous solvent is preferably 99 mass %, more preferably 97 mass %, and even more preferably 90 mass %, based on the total amount of the nonaqueous electrolyte. The lower limit of the content of the nonaqueous solvent is preferably 60 mass % or more, and even more preferably 70 mass % or more, based on the total amount of the nonaqueous electrolyte.

[0127] 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.

[0128] [Electrolyte] In the nonaqueous electrolyte secondary battery of the present disclosure, the nonaqueous electrolyte contains an electrolyte, which 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.

[0129] Examples of the fluorine-containing lithium salt include inorganic acid anion salts and organic acid anion salts.

[0130] Examples of inorganic acid anion salts include lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), and lithium hexafluorotantalate (LiTaF6).

[0131] Examples of organic acid anion salts include lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (Li(CF3SO2)2N), and lithium bis(pentafluoroethanesulfonyl)imide (Li(C2F5SO2)2N). Of these, lithium hexafluorophosphate (LiPF6) is more preferred as the fluorine-containing lithium salt.

[0132] Examples of fluorine-free lithium salts include lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), and lithium decachlorodecaborate (Li2B 10 Cl 10 ) are mentioned.

[0133] When the electrolyte contains a fluorine-containing lithium salt, the content of the fluorine-containing lithium salt is preferably 50% by mass to 100% by mass or less, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass or less, based on the total amount of the electrolyte.

[0134] When the fluorine-containing lithium salt contains lithium hexafluorophosphate (LiPF6), the content of lithium hexafluorophosphate (LiPF6) is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass, relative to the total amount of the electrolyte.

[0135] 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 to 3 mol / L, and more preferably 0.5 mol / L to 2 mol / L.

[0136] When the non-aqueous electrolyte contains lithium hexafluorophosphate (LiPF6), the concentration of lithium hexafluorophosphate (LiPF6) in the non-aqueous electrolyte is preferably 0.1 mol / L to 3 mol / L, and more preferably 0.5 mol / L to 2 mol / L.

[0137] [case] The shape of the case is not particularly limited and may be appropriately selected depending on the application of the lithium secondary battery precursor of the present disclosure, etc. Examples of the case include a case including a laminate film and a case consisting of a battery can and a battery can lid.

[0138] [Positive electrode] In the nonaqueous electrolyte secondary battery of the present disclosure, the positive electrode is a positive electrode capable of absorbing and desorbing lithium ions, and preferably contains at least one positive electrode active material capable of absorbing and desorbing lithium ions.

[0139] 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. In the nonaqueous electrolyte secondary battery of the present disclosure, the above-described positive electrode coating is formed on the surface of the positive electrode mixture layer.

[0140] Examples of the material for the positive electrode current collector include metals and alloys. Specific examples of the material for the positive electrode current collector include aluminum, nickel, stainless steel (SUS), and copper. Among these, aluminum is preferred as the material for the positive electrode current collector 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 thereof include A1085 and A3003.

[0141] The positive electrode mixture layer contains a positive electrode active material and a binder. The positive electrode active material is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions, and can be adjusted appropriately. Examples of the positive electrode active material 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 similar 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.

[0142] The positive electrode active material preferably contains a lithium-containing composite oxide (hereinafter, sometimes referred to as "NCM") represented by the following formula (P1): The lithium-containing composite oxide (P1) has the advantages of high energy density per unit volume and excellent thermal stability. LiNi a Co b Mn c O2… Formula (P1) In formula (P1), a, b, and c each independently represent a number greater than 0 and less than 1, and the sum of a, b, and c is 0.99 to 1.00. A specific example of NCM is LiNi 0.33 Co 0.33 Mn 0.33 O2, LiNi 0.5 Co 0.3 Mn 0.2 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1Mn 0.1 Examples include O2.

[0143] The positive electrode active material may contain a lithium-containing composite oxide (hereinafter, sometimes referred to as "NCA") represented by the following formula (P2). Li t Ni 1-x-y Co x Al y O2… Formula (P2) In formula (P2), t is 0.95 to 1.15, x is 0 to 0.3, y is 0.1 to 0.2, and the sum of x and y is less than 0.5. A specific example of NCA is LiNi 0.8 Co 0.15 Al 0.05 Examples include O2.

[0144] When the positive electrode includes a positive electrode current collector and a positive electrode mixture layer containing a positive electrode active material and a binder, the content of the positive electrode active material in the positive electrode mixture layer is preferably 10% by mass to 99.9% by mass, more preferably 30% by mass to 99.9% by mass, even more preferably 50% by mass to 99% by mass, and particularly preferably 70% by mass to 99% by mass, relative to the total amount of the positive electrode mixture layer.

[0145] 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.

[0146] Among these, fluororesins are preferred as binders 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.

[0147] The content of the binder in the positive electrode mixture layer is preferably 0.1% by mass to 4% by mass relative to 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) and battery performance. When the binder content is 0.1% by mass or more, the adhesion of the positive electrode mixture layer to the positive electrode current collector and the binding strength between the positive electrode active materials are further improved. When the binder content is 4% by mass or less, the amount of positive electrode active material in the positive electrode mixture layer can be increased, thereby further improving the discharge capacity.

[0148] 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.

[0149] The conductive additive may be a commercially available product. Examples of commercially available carbon black include Toka Black #4300, #4400, #4500, and #5500 (furnace black manufactured by Tokai Carbon Co., Ltd.), Printex L (furnace black manufactured by Orion Engineered Carbons Co., Ltd.), Raven 7000, 5750, 5250, 5000ULTRA III, and 5000ULTRA, Conductex SC ULTRA, Conductex 975ULTRA, and PUER BLACK100, 115, 205 (Columbian Furnace Black), #2350, #2400B, #2600B, #30050B, #3030B, #3230B, #3350B, #3400B, #5400B (Mitsubishi Chemical Furnace Black), MONARCH1400, 1300, 900, VulcanXC-72R, BlackPearls2000, Examples of suitable black blacks include LITX-50, LITX-200 (manufactured by Cabot Corporation, furnace black), Ensaco250G, Ensaco260G, Ensaco350G, and Super-P (manufactured by TIMCAL), Ketjenblack EC-300J and EC-600JD (manufactured by Akzo Chemicals), and Denkablack, Denkablack HS-100 and FX-35 (manufactured by Denka Corporation, acetylene black).

[0150] The positive electrode mixture layer may contain other components, such as a thickener, a surfactant, a dispersant, a wetting agent, and an antifoaming agent.

[0151] [Negative electrode] In the nonaqueous electrolyte secondary battery of the present disclosure, the negative electrode is capable of absorbing and desorbing lithium ions, and preferably contains at least one negative electrode active material capable of absorbing and desorbing lithium ions.

[0152] 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. In the nonaqueous electrolyte secondary battery according to the present disclosure, the negative electrode coating described above is formed on the surface of the negative electrode mixture layer.

[0153] 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.Specific examples of the material of the negative electrode current collector include aluminum, nickel, stainless steel (SUS), nickel-plated steel, and copper.Of these, copper is preferred as the material of the negative electrode current collector from the viewpoint of processability.Copper foil is preferred as the negative electrode current collector.

[0154] The negative electrode mixture layer includes a negative electrode active material and a binder. The negative electrode active material is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions. The negative electrode active material is preferably at least one material selected from the group consisting of metallic lithium, lithium-containing alloys, metals or alloys capable of alloying with lithium, oxides capable of doping and dedoping lithium ions, transition metal nitrides capable of doping and dedoping lithium ions, and carbon materials capable of doping and dedoping lithium ions. Among these, the negative electrode active material is preferably a carbon material capable of doping and dedoping lithium ions (hereinafter simply referred to as "carbon material").

[0155] Examples of carbon materials include carbon black, activated carbon, graphite materials, and amorphous carbon materials. These carbon materials may be used alone or in combination of two or more. The form of the carbon material is not particularly limited, and examples include fibrous, spherical, potato-like, and flake-like forms. The particle size of the carbon material is not particularly limited, and is preferably 5 μm to 50 μm, and more preferably 20 μm to 30 μm.

[0156] Examples of amorphous carbon materials include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500° C. or less, and mesophase pitch carbon fiber (MCF).

[0157] Examples of graphite materials include natural graphite and artificial graphite. Examples of artificial graphite include graphitized MCMB and graphitized MCF. The graphite material may contain boron. The graphite material may be coated with a metal or amorphous carbon. Examples of metal materials that coat the graphite material include gold, platinum, silver, copper, and tin. The graphite material may be a mixture of amorphous carbon and graphite.

[0158] 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.

[0159] 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.

[0160] [Separator] In the nonaqueous electrolyte secondary battery of the present disclosure, the separator may be, for example, a porous resin flat plate. Examples of materials for the porous resin flat plate include resin and nonwoven fabric containing resin. Examples of resins include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, and polyamide.

[0161] In particular, the separator is preferably a porous resin sheet having a single layer or a multilayer structure. The material of the porous resin sheet is mainly made of one or more polyolefin resins. The thickness of the separator is preferably 5 μm to 30 μm. The separator is preferably disposed between the positive electrode and the negative electrode.

[0162] [Specific examples of non-aqueous electrolyte secondary batteries] As an embodiment of the nonaqueous electrolyte secondary battery of the present disclosure, a lithium secondary battery is exemplified. FIG. 1 is a schematic cross-sectional view showing a stacked lithium secondary battery, which is an example of the lithium secondary battery of this embodiment. In the following description, a lithium secondary battery before charging will be referred to as a "lithium secondary battery precursor," and a charged lithium secondary battery precursor will be referred to as a lithium secondary battery. The nonaqueous electrolyte secondary battery of the present disclosure includes both these lithium secondary battery precursors and lithium secondary batteries.

[0163] As shown in Fig. 1, the lithium ion secondary battery precursor 1 is a laminated type 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.

[0164] As shown in FIG. 1 , battery element 10 is formed by laminating positive electrode 11, separator 13, and negative electrode 12. Positive electrode 11 has positive electrode composite layer 11B formed on both main surfaces of positive electrode current collector 11A. Negative electrode 12 has negative electrode composite layer 12B formed on both main surfaces of negative electrode current collector 12A. Positive electrode composite layer 11B formed on one main surface of positive electrode current collector 11A of positive electrode 11 and negative electrode composite layer 12B formed on one main surface of negative electrode current collector 12A of negative electrode 12 adjacent to positive electrode 11 face each other with separator 13 interposed therebetween.

[0165] The nonaqueous electrolyte solution of the present disclosure is poured 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 unit cell layer 14 is formed by the adjacent positive electrode composite layer 11B, the separator 13, and the negative electrode composite layer 12B. Note that the positive electrode and the negative electrode may each have an active material layer formed on one side of the respective current collectors.

[0166] Although the lithium ion secondary battery precursor 1 is a stacked-type lithium ion secondary battery precursor, the lithium ion secondary battery precursor according to the present disclosure is not limited to this and may be, for example, a wound-type lithium ion secondary battery precursor. In a wound-type lithium ion secondary battery precursor, a positive electrode, a separator, a negative electrode, and a separator are stacked in this order to form a layer, which is then wound to form a battery element. Wound-type lithium ion secondary battery precursors include cylindrical lithium ion secondary battery precursors and prismatic lithium ion secondary battery precursors.

[0167] 1 , in the lithium-ion secondary battery precursor 1, the directions in which the positive electrode lead 21 and the negative electrode lead 22 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 21 and the negative electrode lead 22 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.

[0168] The negative electrode coating and / or positive electrode coating described above is formed by charging the lithium ion secondary battery precursor 1 of the present disclosure configured as described above. The negative electrode coating is formed at the interface between negative electrode mixture layer 12B and separator 13. The positive electrode coating is formed at the interface between positive electrode mixture layer 11B and separator 13.

[0169] FIG. 2 is a schematic cross-sectional view showing a coin-type lithium ion secondary battery precursor, which is another example of the lithium ion secondary battery precursor of the present disclosure.

[0170] The coin-shaped lithium ion secondary battery precursor shown in FIG. 2 includes a disc-shaped positive electrode 41, a disc-shaped negative electrode 42, and a separator 45 filled with a nonaqueous electrolyte, disposed between the disc-shaped positive electrode 41 and the disc-shaped negative electrode 42. The lithium ion secondary battery precursor may include spacer plates 47 and 48 made of stainless steel, aluminum, or the like, disposed to sandwich a laminate including the disc-shaped positive electrode 41, the disc-shaped negative electrode 42, and the separator 45. In the lithium secondary battery precursor, a laminate including the spacer plate 47, the disc-shaped positive electrode 41, the separator 45, the disc-shaped negative electrode 42, and the spacer plate 48 stacked in this order 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 together via a gasket 46 to seal the interior. In this example, the nonaqueous electrolyte of the present disclosure is used as the nonaqueous electrolyte injected into separator 45 .

[0171] The coin-shaped lithium ion secondary battery precursor configured as above is also charged, whereby the above-mentioned negative electrode coating and / or positive electrode coating are formed. The negative electrode coating is formed at the interface between the disc-shaped negative electrode 42 and the separator 45. The positive electrode coating is formed at the interface between the disc-shaped positive electrode 41 and the separator 45.

[0172] [Method for manufacturing non-aqueous electrolyte secondary battery] To manufacture the nonaqueous electrolyte secondary battery of the present disclosure, a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator is assembled, and then charged and discharged. For example, the method for manufacturing the lithium secondary battery shown in Fig. 1 or 2 includes a step of preparing the lithium secondary battery precursor (hereinafter also referred to as the "preparation step") and a step of charging and discharging the lithium secondary battery precursor.

[0173] As described above, by charging and discharging the lithium secondary battery precursor, a lithium ion secondary battery having an anode coating and / or a cathode coating that satisfy the above-mentioned conditions can be manufactured. That is, the above method can manufacture a lithium ion secondary battery that has a high capacity retention rate after high-temperature storage and a suppressed rate of increase in resistance.

[0174] The preparation step may be a step of simply preparing a pre-assembled lithium secondary battery precursor for a step of charging and discharging, or may include a step of assembling a lithium secondary battery precursor.

[0175] In the step of charging and discharging, the charging and discharging of the lithium secondary battery precursor can be performed according to a known method. In this step, the charging and discharging cycle of the lithium secondary battery precursor may be repeated multiple times.

[0176] In the step of charging and discharging, the lithium secondary battery precursor is preferably subjected to a combination of charging and discharging at least once in an environment of 25°C to 70°C. [Example]

[0177] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples. Hereinafter, "%" means "% by mass" unless otherwise specified.

[0178] Example 1 <Preparation of non-aqueous electrolyte> Ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (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. LiPF6 was dissolved as an electrolyte in the resulting mixed solvent so that the concentration in the final non-aqueous electrolyte solution was 1 mol / L, to obtain an electrolyte solution. Hereinafter, the resulting electrolyte solution will be referred to as the "base electrolyte solution." As an additive, a sulfonyl compound represented by the following formula (I-1-1) was added to the base electrolyte solution so that the content relative to the total amount of the finally obtained non-aqueous electrolyte solution would be the content (mass%) shown in Table 1. In this way, a non-aqueous electrolyte solution was obtained.

[0179] [ka]

[0180] <Preparation of positive electrode> Li(Ni) as the positive electrode active material 0.8 Co 0.1 Mn 0.1 A mixture was obtained by adding 98% by mass of ZnO (O2), 1% by mass of carbon black as a conductive additive, and 1% by mass of polyvinylidene fluoride (PVDF) as a binder. The resulting mixture was dispersed in N-methylpyrrolidone solvent to obtain a slurry for the positive electrode composite. Aluminum foil with a thickness of 20 μm was prepared as a positive electrode current collector. The obtained slurry for the positive electrode composite was applied to the aluminum foil, dried, and then rolled with a press to obtain a sheet-shaped positive electrode base plate. This positive electrode base plate included a region where a positive electrode active material layer (hereinafter referred to as the "positive electrode composite layer") was formed and a region where the positive electrode composite layer was not formed (hereinafter referred to as the "uncoated area for tab adhesion").

[0181] The resulting positive electrode blank was slit to obtain a positive electrode. The positive electrode had a positive electrode composite layer and an uncoated portion for tab bonding. The positive electrode composite layer had a width of 29 mm and a length of 40 mm. The uncoated portion for tab bonding had a width of 5 mm and a length of 11 mm.

[0182] <Preparation of negative electrode> A negative electrode composite slurry was prepared by mixing graphite (98% by mass) as the negative electrode active material, 1% by mass of carboxymethylcellulose sodium dispersed in pure water as a thickener (solid content), and 1% by mass of styrene-butadiene rubber (SBR) dispersed in pure water as a binder (solid content). A 16 μm-thick copper foil was prepared as the negative electrode current collector. The obtained negative electrode composite slurry was applied to the copper foil (negative electrode current collector), dried, and then rolled with a press to obtain a negative electrode blank. This negative electrode blank included a region where a negative electrode active material composite layer (hereinafter referred to as the "negative electrode composite layer") was formed and a region where the negative electrode composite layer was not formed (hereinafter referred to as the "uncoated portion for tab bonding"). The uncoated portion for tab bonding was an uncoated portion that served as a margin.

[0183] The resulting negative electrode blank was slit to obtain a negative electrode. The negative electrode had a negative electrode composite layer and an uncoated portion for tab bonding. The negative electrode composite layer had a width of 30 mm and a length of 41 mm. The uncoated portion for tab bonding had a width of 5 mm and a length of 11 mm.

[0184] <Preparing the separator> A porous polyethylene film was prepared as a separator.

[0185] <Preparation of lithium-ion secondary battery precursor> In this example, a laminate-type lithium ion secondary battery precursor was fabricated as follows using the nonaqueous electrolyte, positive electrode, negative electrode, and separator prepared as described above.

[0186] That is, first, a positive electrode, a negative electrode, and a separator were stacked with the coated surface of the negative electrode in contact with the separator and the coated surface of the positive electrode in contact with the separator to obtain a laminate. Next, an aluminum positive electrode tab (positive electrode lead) was bonded to the uncoated tab-bonding portion of the positive electrode of the obtained laminate using an ultrasonic bonding machine. A nickel negative electrode tab (negative electrode lead) was bonded to the uncoated tab-bonding portion of the negative electrode of the obtained laminate using an ultrasonic bonding machine. The laminate with the bonded positive electrode tab and negative electrode tab was sandwiched between a pair of laminate films (cases) in which both sides of the aluminum were coated with a resin layer, and then three sides were heat-sealed to obtain a laminate (assembly). At this time, the positive electrode tab and negative electrode tab were allowed to protrude from one of the three sealed sides of the laminate that was adjacent to the unsealed opening.

[0187] Next, the nonaqueous electrolyte solution obtained above was poured into the opening of the laminate body, and the opening of the laminate body was sealed, thereby obtaining a laminate-type lithium ion secondary battery precursor.

[0188] <Evaluation test> The obtained lithium ion secondary battery precursor was subjected to the aging treatment described below to obtain a first battery. The obtained first battery was subjected to the initial charge / discharge treatment described below to obtain a second battery. The obtained second battery was subjected to the treatment described below for DC resistance evaluation to obtain a third battery. The obtained third battery was subjected to the high-temperature storage treatment described below to obtain a fourth battery. The obtained fourth battery was subjected to the later charge / discharge treatment described below to obtain a fifth battery. The resulting first to fifth batteries were used to measure the capacity retention rate, resistance after high-temperature storage, and resistance increase rate by the following measurement methods. Table 1 shows the measurement results.

[0189] <Aging treatment> First, the lithium ion secondary battery precursor was charged at a temperature range of 25°C to 70°C with a cut-off voltage range of 1.5V to 3.5V, and then rested for 5 to 50 hours. Next, the battery precursor was charged at a temperature range of 25°C to 70°C with a cut-off voltage range of 3.5V to 4.2V, and held for 5 to 50 hours. Next, the battery precursor was charged to 4.2V at a temperature range of 25°C to 70°C, and then discharged to 2.5V. A first battery was obtained through this aging treatment.

[0190] <Initial charge / discharge process> First, the first battery was stored in a 25°C environment for 12 hours. Next, the first battery was charged at a constant current and constant voltage (0.2C-CCCV) at a charge rate of 0.2C to 4.2V (SOC (State of Charge) 100%), then rested for 30 minutes, and then discharged at a constant current (0.2C-CC) at a discharge rate of 0.2C to 2.5V. This cycle was repeated three times to stabilize the battery. Subsequently, the first battery was charged at a constant current and constant voltage (0.5C-CCCV) at a charge rate of 0.2C to 4.2V, then rested for 30 minutes, then discharged at a constant current (1C-CC) at a discharge rate of 1C to 2.5V, and then discharged at a constant current (1 / 3C-CC) at a discharge rate of 1 / 3C to 2.5V. The sum of the constant current discharges (1C-CC) and (1 / 3C-CC) at this time was taken as the discharge capacity of the second battery. This initial charge / discharge process yielded a second battery.

[0191] <Processing for DC resistance evaluation> The DC resistance evaluation process was carried out in a temperature environment of 25°C. First, the second battery was CC discharged at a discharge rate of 0.2C to 2.5V, and then CCCV charged at a charge rate of 0.2C to 3.7V. Note that "CCCV charging" refers to constant current constant voltage (CCCV) charging.

[0192] The second battery was then subjected to CC10s discharge at a discharge rate of 0.2C and CC10s charging at a charge rate of 0.2C. "CC10s discharge" means discharging at a constant current for 10 seconds. "CC10s charging" means charging at a constant current for 10 seconds.

[0193] Next, the second battery was subjected to CC10s discharge at a discharge rate of 0.5C and CC25s charge at a charge rate of 0.2C. Next, the second battery was subjected to CC10s discharge at a discharge rate of 1C and CC50s charge at a charge rate of 0.2C. Next, the second battery was subjected to CC10s discharge at a discharge rate of 2C and CC100s charge at a charge rate of 0.2C. A third battery was obtained through this DC resistance evaluation process.

[0194] <High-temperature preservation treatment> First, the third battery was charged at a constant current of 25° C. at a charge rate of 0.2 C up to 4.2 V. Then, the charged battery was left standing in an atmosphere at 60° C. for 30 days. This high-temperature storage treatment gave a fourth battery.

[0195] <Late-stage charge / discharge treatment> First, the fourth battery was cooled in a 25°C environment. It was then discharged at a constant current (1C-CC) at a discharge rate of 1C to 2.5V, and then discharged at a constant current (1 / 3C-CC) at a discharge rate of 1 / 3C to 2.5V (first discharge). It was then charged at a constant current (0.2C-CCCV) at a charge rate of 0.2C to 4.2V (first charge). Next, the fourth battery was discharged at a constant current (1C-CC) at a discharge rate of 1C to 2.5V, and then discharged at a constant current (1 / 3C-CC) at a discharge rate of 1 / 3C to 2.5V (second discharge). The sum of the constant current discharges (1C-CC) and (1 / 3C-CC) was taken as the discharge capacity of the fifth battery. This later charge-discharge treatment yielded the fifth battery.

[0196] <Method for measuring capacity retention> As shown in the following formula (X1), the discharge capacity of the fifth battery relative to the discharge capacity of the second battery was calculated as the capacity retention rate [%]. Then, as shown in the following formula (X2), the relative value of the capacity retention rate [%] in this example relative to the capacity retention rate [%] in Comparative Example 1 described later was defined as the "capacity retention rate [relative value]." Capacity retention rate [%] = (discharge capacity of the fifth battery [mAh / g] / discharge capacity of the second battery [mAh / g]) x 100...(X1) Capacity retention rate [relative value] = (Capacity retention rate [%] determined in X1 / Capacity retention rate [%] determined in X1 for Comparative Example 1) × 100 (X2)

[0197] <Method for measuring resistance after high temperature storage> As shown in the following formula (X3), the relative value of the direct current internal resistance (DCIR) of the fifth battery in this example to the direct current internal resistance (DCIR) of the fifth battery in Comparative Example 1 described later was defined as the "resistance after high-temperature storage [%]." Resistance after high-temperature storage [%] = (DC resistance [Ω] of the fifth battery / DC resistance [Ω] of the fifth battery of Comparative Example 1) × 100 (X3) The DC resistance was measured by the following method. The fifth battery was subjected to the same DC resistance evaluation process as described above. In a temperature environment of 25°C or -10°C, the voltage drop (= voltage before the start of discharge - voltage 10 seconds after the start of discharge) and each current value (i.e., each current value corresponding to a discharge rate of 0.2C to 1C) due to "CC10s discharge" were measured to determine the DC resistance (Ω) of the fifth battery.

[0198] <Method for measuring resistance increase rate> As shown in the following formula (X4), the relative value of the resistance increase rate in this example to the resistance increase rate in Comparative Example 1, which will be described later, was taken as "resistance increase rate [%]." Resistance increase rate [%] = (resistance increase rate / resistance increase rate of Comparative Example 1) × 100 ... (X4) The resistance increase rate is obtained by dividing the DC resistance (Ω) of the fourth battery by the DC resistance (Ω) of the second battery. The DC resistance (Ω) of the fourth battery and the DC resistance (Ω) of the second battery are the same as the measurement method of the DC resistance (Ω) of the fifth battery in the measurement method of the resistance after high-temperature storage described above. The relative value of the DC resistance of the fifth battery after the high-temperature storage test corresponds to the increase rate (%) of the DC resistance due to high-temperature storage (hereinafter, also simply referred to as "resistance increase rate"). Here, when there is neither an increase nor a decrease, the increase rate is set to 100%, when it increases, it is shown as a value exceeding 100%, and when it decreases, it is shown as a value less than 100%.

[0199] <Spectrum measurement by XPS> First, the fifth battery was discharged at a discharge rate of 1C to 2.5V under constant current discharge (1C-CC). Next, the discharged battery was disassembled in a glove box, and the taken-out positive and negative electrodes were washed with a cleaning solution (diethyl carbonate) in a dry environment and dried. The dried positive and negative electrodes were used as samples and transferred to an XPS apparatus using a transfer vessel. After installing the samples in the apparatus, wide-area photoelectron spectra were measured for the positive electrode surface and the negative electrode surface, respectively, and the presence of each element was confirmed. Then, narrow scan analysis of each element was performed to estimate the chemical bonding state from the binding energy position. As the XPS apparatus, Quantera of ULVAC-PHI was used. The excitation X-ray during measurement was a monochromatic Al Kα ray (1486.7 eV), and the X-ray diameter was 100 μm. In terms of peak intensity, the background was calculated using the linear method, and the peak intensity of the maximum intensity peak above the background and within the specified range was adopted.

[0200] Specifically, for the negative electrode surface, the maximum intensity peaks in the range of 168 eV to 171 eV and the maximum intensity peaks in the range of 162 eV to 165 eV were measured as the S2p orbital spectrum. Furthermore, for the negative electrode surface, the maximum intensity peaks in the range of 398 eV to 493 eV and the maximum intensity peaks in the range of 283 eV to 286 eV were measured as the N1s orbital spectrum. Note that, since sulfur atoms that are not originally present on the negative electrode surface were observed by the narrow scan analysis described above, it is clear that a coating film has formed on the negative electrode surface. For the positive electrode surface, the maximum intensity peak in the range of 684 eV to 686 eV and the maximum intensity peak in the range of 686 eV to 688 eV were measured as the F1s orbital spectrum. For the positive electrode surface, the maximum intensity peak in the range of 398 eV to 493 eV and the maximum intensity peak in the range of 283 eV to 286 eV were measured as the N1s orbital spectrum. As with the negative electrode, the narrow scan analysis described above clearly shows that a coating is formed on the positive electrode surface.

[0201] Then, the following [Equation 1] and [Equation 3] were calculated based on the peak intensity of the maximum intensity peak measured on the negative electrode surface, and the following [Equation 2] and [Equation 4] were calculated based on the peak intensity of the maximum intensity peak measured on the positive electrode surface. [Equation 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV) [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV) [Equation 3]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV) [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)

[0202] The results are shown in Table 1. In Table 1, the values calculated using [Formula 1] and [Formula 3] are shown in the columns "S2p peak intensity ratio" and "N1s peak intensity ratio" of the "Negative electrode surface XPS spectrum," respectively. In Table 1, the values calculated using [Formula 2] and [Formula 4] are shown in the columns "F1s peak intensity ratio" and "N1s peak intensity ratio" of the "Positive electrode surface XPS spectrum," respectively.

[0203] Comparative Example 1 A non-aqueous electrolyte solution was prepared in the same manner as in Example 1, except that the sulfonyl compound represented by formula (I-1-1) was not added to the non-aqueous electrolyte solution, and a lithium ion secondary battery was fabricated. Furthermore, the capacity retention rate, resistance after high-temperature storage, and resistance increase rate were measured in the same manner as in Example 1, and the results were used as the reference values (100) for the capacity retention rate, resistance after high-temperature storage, and resistance increase rate. Furthermore, in the same manner as in Example 1, XPS spectrum measurement was performed, and [Equation 1] to [Equation 4] were calculated.

[0204] [Reference example] A non-aqueous electrolyte solution was prepared in the same manner as in Example 1, except that lithium bis(oxalato)borate (LiBOB) represented by the following formula (II-1-1) was added in a content of 0.5 mass% relative to the total mass of the non-aqueous electrolyte solution, instead of the sulfonyl compound represented by formula (I-1-1). A lithium ion secondary battery was then fabricated using this solution. Furthermore, the capacity retention rate, resistance after high-temperature storage, and resistance increase rate were measured in the same manner as in Example 1, and relative values were calculated using the capacity retention rate, resistance after high-temperature storage, and resistance increase rate of Comparative Example 1 as reference values. Furthermore, spectrum measurement was performed by XPS in the same manner as in Example 1, and [Equation 1] to [Equation 4] were calculated. These results are shown in Table 1.

[0205] [ka]

[0206] Example 2 A non-aqueous electrolyte solution was prepared in the same manner as in Example 1, except that in addition to the sulfonyl compound represented by formula (I-1-1), lithium bis(oxalato)borate (LiBOB) represented by formula (II-1-1) was added so that the content relative to the total mass of the non-aqueous electrolyte was 0.5 mass %, and a lithium ion secondary battery was fabricated. Furthermore, the capacity retention rate, resistance after high-temperature storage, and resistance increase rate were measured in the same manner as in Example 1, and relative values were calculated using the capacity retention rate, resistance after high-temperature storage, and resistance increase rate of Comparative Example 1 as reference values. Furthermore, spectrum measurement was performed by XPS in the same manner as in Example 1, and [Equation 1] to [Equation 4] were calculated. These results are shown in Table 1.

[0207] Example 3 In addition to the sulfonyl compound represented by formula (I-1-1), lithium bis(oxalato)borate (LiBOB) represented by the above formula (II-1-1) was added so that its content relative to the total mass of the nonaqueous electrolyte was 0.3 mass%. Furthermore, lithium bis(oxalato)borate (LiBOB) represented by the following formula (II-1-2) was added so that its content relative to the total mass of the nonaqueous electrolyte was 0.2 mass%. A nonaqueous electrolyte was prepared in the same manner as in Example 1, and a lithium ion secondary battery was fabricated. Furthermore, the capacity retention rate, resistance after high-temperature storage, and resistance increase rate were measured in the same manner as in Example 1, and relative values were calculated using the capacity retention rate, resistance after high-temperature storage, and resistance increase rate of Comparative Example 1 as reference values. Furthermore, spectrum measurement was performed by XPS in the same manner as in Example 1, and [Equation 1] to [Equation 4] were calculated. These results are shown in Table 1.

[0208] [ka]

[0209] 〔result〕 For Examples 1 to 3, Comparative Example 1, and Reference Example, the S2p orbital spectrum of the negative electrode surface was measured for peaks in the range of 168 eV to 171 eV and peaks in the range of 162 eV to 165 eV, and the results are shown in Figure 3. Furthermore, for Examples 1 to 3, Comparative Example 1, and Reference Example, the F1s orbital spectrum of the positive electrode surface was measured for peaks in the range of 684 eV to 686 eV and peaks in the range of 686 eV to 688 eV, and the results are shown in Figure 4. Furthermore, for Examples 1 to 3, Comparative Example 1, and Reference Example, the N1s orbital spectrum of the negative electrode surface was measured for peaks in the range of 398 eV to 493 eV and peaks in the range of 283 eV to 286 eV, and the results are shown in Figure 5. Furthermore, for Examples 1 to 3, Comparative Example 1, and Reference Example, the N1s orbital spectrum of the positive electrode surface was measured for peaks in the range of 398 eV to 493 eV and peaks in the range of 283 eV to 286 eV, and the results are shown in Figure 6.

[0210] Table 1 is shown below. [Table 1]

[0211] In Table 1, "no peak" in the "S2p peak intensity ratio" column indicates that neither a "peak in the range of 168 eV to 171 eV" nor a "peak in the range of 162 eV to 165 eV" was observed. In Table 1, "0" in the "N1s peak intensity ratio" column indicates that a "peak in the range of 283 eV to 286 eV" was observed, but no "peak in the range of 398 eV to 493 eV" was observed.

[0212] As shown in Table 1, in Examples 1 to 3 and Reference Example, in which the S2p peak intensity ratio on the negative electrode surface was 0.1 or more or the F1s peak intensity ratio on the positive electrode surface was 1.0 or less, it was confirmed that the capacity retention rate after high-temperature storage was high and the increase in battery resistance was suppressed. On the other hand, in Comparative Example 1, no S2p peak was observed on the negative electrode surface and the F1s peak intensity ratio on the positive electrode surface exceeded 1.0, so the capacity retention rate after high-temperature storage was low and the increase in battery resistance tended to be large.

[0213] Furthermore, it was confirmed that in Examples 1 to 3, in which the N1s peak intensity ratio of the positive electrode surface and / or the negative electrode surface was 0.1 or more, the capacity retention rate after high-temperature storage was even higher and the increase in battery resistance could be further suppressed compared to Comparative Example 1 and the Reference Example.

[0214] As described above, this example confirmed that, unlike the battery performance in which the resistance value itself is low, it is possible to achieve extremely important battery performance that avoids the inconvenience of an increase in resistance value due to deterioration during storage, etc. [Explanation of symbols]

[0215] 1...Lithium ion secondary battery precursor 1, 10...Battery element, 11...Positive electrode, 12...Negative electrode, 13...Separator, 14...Single cell layer, 21...Positive electrode lead, 22...Negative electrode lead, 30...Exterior body, 41...Disk-shaped positive electrode, 42...Disk-shaped negative electrode, 43...Positive electrode can, 44...Sealing plate, 45...Separator, 46...Gasket, 47...Spacer plate, 48...Spacer plate

Claims

1. A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator, a negative electrode coating formed on the surface of the negative electrode, wherein when narrow scan analysis is performed by X-ray photoelectron spectroscopy (XPS) using sulfur as the measurement element, the S2p orbital spectrum obtained has a region that satisfies the following formula 1: [Equation 1]: (peak intensity of the maximum intensity peak observed in the range of 168 eV to 171 eV) / (peak intensity of the maximum intensity peak observed in the range of 162 eV to 165 eV)≧0.1

2. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein, when a narrow scan analysis of the positive electrode coating formed on the surface of the positive electrode is performed by X-ray photoelectron spectroscopy using fluorine as the measurement element, the obtained F1s orbital spectrum has a region that satisfies the following formula 2: [Equation 2]: (peak intensity of the maximum intensity peak observed in the range of 684 eV to 686 eV) / (peak intensity of the maximum intensity peak observed in the range of 686 eV to 688 eV)≦1.0

3. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein, when the negative electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 3: [Equation 3]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1

4. 3. The nonaqueous electrolyte secondary battery according to claim 2, wherein, when the positive electrode coating is subjected to narrow scan analysis by X-ray photoelectron spectroscopy using nitrogen as the measurement element, the obtained N1s orbital spectrum has a region that satisfies the following formula 4: [Equation 4]: (peak intensity of the maximum intensity peak observed in the range of 398 eV to 493 eV) / (peak intensity of the maximum intensity peak observed in the range of 283 eV to 286 eV)≧0.1

5. The nonaqueous electrolyte secondary battery according to claim 1, wherein the nonaqueous electrolyte solution contains at least one selected from the group consisting of sulfonyl compounds represented by the following formula (I-1) and decomposition products thereof, sulfonyl compounds represented by the following formula (I-2) and decomposition products thereof, sulfonyl compounds represented by the following formula (I-3) and decomposition products thereof, and sulfonyl compounds represented by the following formula (I-4) and decomposition products thereof. 【Chemical 1】 (R in formula (I-1) １１１ , R in formula (I-2) １２１ , R in formula (I-3) １３１ and R in formula (I-4) １４１ 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 in formula (I-1) １１２ , R in formula (I-2) １２２ and R in formula (I-3) １３２ 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), sulfo group (-SO ３ represents a hydroxyl group (-H), a cyano group (-CN), or an isocyanate group (-NCO). L in formula (I-1) １１１ represents a linking group selected from the group consisting of formulae (L1) to (L4) or a single bond (-); L in formula (I-2) １２１ represents a linking group selected from the group consisting of formulae (L1) to (L3) and (L5) or a single bond (-). 【Chemistry 2】 In formula (I-1), formula (I-4), and formula (L3), (M １ ) ＋ 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. １１２ and R in formula (L5) １２２ respectively represent R in formula (I-1). １１２ and R in formula (I-2) １２２ is the same as: However, in formula (I-1), two R １１２ When two R １１２ The hydrocarbon groups may be bonded to each other to form a cyclic structure, and two or more R １２２ The hydrocarbon groups may be bonded to each other to form a cyclic structure.

6. 2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the nonaqueous electrolyte contains at least one selected from the group consisting of salts represented by the following formula (II) and decomposition products thereof: 【Chemistry 3】 (In formula (II), (M ２ ) ＋ 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 ２ each independently represents a single bond (-) or a divalent hydrocarbon group having 1 to 6 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), and an iodo group (-I) as a substituent; Q ２ each independently represents an oxa group (—O—) or a secondary amino group (—NH—), and X ２ each independently represents a fluoro group (—F), a chloro group (—Cl), a bromo group (—Br), or an iodo group (—I); Z ２ represents a boron atom or a phosphorus atom, and h represents the Z ２ is a boron atom, 1 or 2; ２ represents an integer of 1 to 3 when is a phosphorus atom, and i is the same as Z ２ is a boron atom, 0 or 2; ２ represents 0, 2, or 4 when is a phosphorus atom.)

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