Nonaqueous electrolyte and energy device using the same

Abstract

To provide a non-aqueous electrolyte capable of realizing an energy device that has improved input / output characteristics, and further has good input / output maintenance rate, capacity maintenance rate, battery swelling, and metal elution during cycle operation and high-temperature storage.SOLUTION: A non-aqueous electrolyte includes one or more compounds selected from group (A) consisting of compounds represented by the following formula (1) of X-SO2-Y-SO2-Z(1). [In the formula (1), Y is an organic group containing either a nitrogen atom or a carbon atom; X and Z are independently a hydrocarbon group having 1 to 12 carbon atoms, which may contain a fluorine atom, or a fluorine atom. X and Z may bond to each other to form a ring structure; and n is an integer of 1 to 2.] and cyclic compounds having an SO3 structure, and a fluorosulfonate salt (B) represented by the following formula (2) of (FSO3)xM(2) [In the formula (2), M is a metal atom, and x is the valence of the metal atom M, an integer of 1 or greater].SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a non-aqueous electrolyte and an energy device using the same.

Background Art

[0002] In a wide range of applications such as in-vehicle power supplies for driving such as automobiles and stationary large-scale power supplies from so-called consumer power supplies such as mobile phones and notebook computers, energy devices using non-aqueous electrolytes such as non-aqueous electrolyte secondary batteries, electric double layer capacitors, and lithium ion capacitors have been put into practical use. However, in recent years, the demand for higher performance of energy devices has been increasing more and more. Particularly in non-aqueous electrolyte secondary batteries, it is required to achieve various characteristics such as battery characteristics, for example, input / output characteristics, durability such as cycle characteristics and storage characteristics, and safety at a high level. So far, as means for improving the capacity, battery swelling, positive electrode metal elution, and safety during endurance tests such as input / output characteristics, cycle characteristics, and storage characteristics of non-aqueous electrolyte secondary batteries, many technologies have been studied for various battery components including active materials of positive and negative electrodes and non-aqueous electrolytes.

[0003] For example, Patent Document 1 discloses a non-aqueous electrolyte battery excellent in output characteristics by containing an N(SO2F)2 anion and a fluorine-containing inorganic anion and setting the mixing ratio of the N(SO2F)2 anion in the total amount of anions in the non-aqueous electrolyte to 50 mol% or less.

[0004] Further, Patent Document 2 discloses a technique for providing a non-aqueous electrolyte battery in which low-temperature output characteristics, high-temperature cycle characteristics, output characteristics after high-temperature storage, capacity characteristics, and battery swelling are improved by using a non-aqueous organic solvent containing propylene carbonate and a non-aqueous electrolyte containing lithium bis(fluorosulfonyl)imide.

[0005] In addition, Patent Document 3 discloses a technique for providing an electrolyte for a lithium secondary battery that uses a non-aqueous electrolyte containing a cyclic sulfate ester and has less decomposition on the carbon negative electrode as the charge-discharge cycle progresses.

[0006] In addition, Patent Document 4 includes a lithium-nickel composite oxide having a layered structure as a positive electrode active material, and the electrolyte has a methylenedisulfone structure (R 1 -SO2-C(R 2 R 3 )2-SO2-R 4 ) compound, and discloses a technique for obtaining a lithium secondary battery having excellent characteristics such as energy density and electromotive force, and excellent cycle life and storage stability.

[0007] In addition, Patent Document 5 discloses a technique in which, by using a non-aqueous electrolyte containing an unsaturated sultone, the decomposition reaction of the solvent on the negative electrode is suppressed, and the capacity reduction of the battery during high-temperature storage, the generation of gas, and the deterioration of the load characteristics of the battery are suppressed.

[0008] In addition, Patent Document 6 discloses a non-aqueous electrolyte containing LiPF6 and a fluorosulfonate, and by setting the molar content of FSO3 to the molar content of PF6 to 0.001 to 1.2, the initial charge capacity, input / output characteristics, and impedance characteristics are improved, and not only the initial battery characteristics and durability but also high input / output characteristics and impedance characteristics are maintained even after durability. A technique for providing a non-aqueous electrolyte secondary battery is disclosed.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0010] As described above, in recent years, as the demand for higher performance of non-aqueous electrolyte secondary batteries has increased, further improvement in the performance of non-aqueous electrolyte secondary batteries is required, that is, improvement in capacity, battery swelling, positive electrode metal elution, and safety during endurance tests such as input / output characteristics, cycle characteristics, and storage characteristics. However, in non-aqueous electrolyte batteries using the compounds described in Patent Documents 1 to 6 and electrolytes using the same, it has been difficult to say that the above problems have been sufficiently improved.

[0011] The reason for this has not been fully elucidated at present, but it is presumed as follows. That is, in order to improve the charge transfer reaction rate of lithium ions, it is necessary to suppress side reactions such as solvent decomposition on the electrode surface and promote the permeation of lithium ions. However, with only the technologies described in Patent Documents 1 to 6, the balance between the two is insufficient, and as a result, both the input / output characteristics and durability have not been improved to the maximum extent. In particular, in recent batteries with a reduced amount of electrolyte injection aiming for higher energy density, side reactions are likely to occur if there are few additives that reduce the reactivity of the electrode surface, and the degradation of input / output characteristics becomes significant.

[0012] The present invention has been made in view of such background art, and its object is to provide a non-aqueous electrolyte excellent in input / output characteristics and durability. [Means for Solving the Problems]

[0013] As a result of intensive studies to solve the above problems, the present inventors have found that a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the same is added with one or more compounds selected from the group consisting of compounds represented by X-SO2-Y-SO2-Z and cyclic compounds having an SO3 structure, and a fluorosulfonate having a specific structure. When the content of the compound selected from the group consisting of the compound represented by X-SO2-Y-SO2-Z and the cyclic compound having an SO3 structure in the non-aqueous electrolyte is within a specific range and the mass ratio of the content of the specific fluorosulfonate to the content is 1 or less, the input / output characteristics can be significantly improved. Thus, the present invention has been completed.

[0014] More specifically, the present inventors focused on the film formation mechanism and elementary reaction rate on the surfaces of the positive and negative electrodes of a non-aqueous electrolyte secondary battery as an energy device in order to develop a novel non-aqueous electrolyte that significantly improves input / output characteristics and durability compared to the prior art, and conducted various studies on the action effects of various compounds and their combinations.

[0015] The electrode reaction rate related to the input / output characteristics of a non-aqueous electrolyte battery is determined by various factors such as the oxidation / reduction stability of the compound itself, the concentration and viscosity (diffusion coefficient) of the compound on the electrode surface, and the stability of the product after the reaction. The techniques described in Patent Documents 1 and 2 control the charge transfer reaction on the electrode surface by directly introducing (FSO2)2NLi into the electrolyte. The specific compounds described in Patent Documents 3 to 5 are not electrolyte salts, but are decomposed by electrochemical reduction or the like in the battery to form sulfonates. They generate sulfates and the like. These compounds have the effect of promoting the supply of lithium ions to the battery surface. However, from the perspective of, for example, the deactivation of reactive sites on the electrode surface, they are insufficient, and as a result, there is a drawback that the initial resistance and the resistance after durability tend to increase. The inventor has found that a specific fluorosulfonate having the property of increasing the lithium ion concentration on the surfaces of the positive and negative electrodes or deactivating the active sites on the surfaces of the positive and negative electrodes to efficiently protect the surfaces of the positive and negative electrodes, a compound represented by X-SO2-Y-SO2-Z and a cyclic compound having an SO3 structure, are introduced together, and by controlling the contents of both, the improvement effect of input / output characteristics and durability is maximized due to the balance between lithium ion supplyability and electrode reactivity, and the present invention has been completed.

[0016] That is, the present invention provides the following specific embodiments [1] to [9] and the like. [1] The following formula (1): X-SO2-Y-SO2-Z (1) [In formula (1), Y is an organic group containing either a nitrogen atom or a carbon atom. When it is a nitrogen atom, it is a lithium salt of an imide structure that becomes N-Li. When it is a carbon atom, it is an alkylene diester structure of -O-(CH2) n -O-. X and Z are a hydrocarbon group that may contain a fluorine atom having 1 to 12 carbon atoms or a fluorine atom. X and Z may be the same or different, and may be bonded to each other to form a ring structure. When forming a ring structure, either one of X or Z may be removed. n is an integer of 1 or more and 2 or less.] A non-aqueous electrolyte containing one or more compounds selected from the group (A) consisting of a compound represented by the formula and a cyclic compound having an SO3 structure, The following formula (2): (FSO3) x M (2) [In formula (2), M is a metal atom, and x is the valence of the metal atom M and is an integer of 1 or more] and a fluorosulfonate (B) represented by the formula, A non-aqueous electrolyte in which the ratio of the content mass of the fluorosulfonate (B) to the content mass of the compound belonging to the group (A) in the non-aqueous electrolyte is 1 or less, and the content of the compound belonging to the group (A) in the non-aqueous electrolyte is 0.01% by mass or more and 8% by mass or less. 〔2〕The non-aqueous electrolyte according to 〔1〕, wherein the content of the fluorosulfonate (B) in the non-aqueous electrolyte is 2% by mass or less. 〔3〕The non-aqueous electrolyte according to 〔1〕 or 〔2〕, wherein the fluorosulfonate (B) contains FSO3Li. 〔4〕The non-aqueous electrolyte according to any one of 〔1〕 to 〔3〕, wherein the compound represented by the formula (1) is (FSO2)2NLi, (CF3SO2)2NLi, or (C2F5SO2)2NLi. 〔5〕The non-aqueous electrolyte according to any one of 〔1〕 to 〔4〕, wherein the cyclic compound having the SO3 structure is 1,3-propanesultone, 1,3-propenesultone, or 1,2-ethylene sulfate. 〔6〕The non-aqueous electrolyte according to any one of 〔1〕 to 〔5〕, wherein the non-aqueous electrolyte contains LiPF6. 〔7〕An energy device comprising a plurality of electrodes capable of occluding and releasing metal ions and the non-aqueous electrolyte according to any one of 〔1〕 to 〔6〕. 〔8〕The energy device according to 〔7〕, wherein the plurality of electrodes capable of occluding and releasing metal ions are a positive electrode and a negative electrode, and the negative electrode contains a carbonaceous material or a material containing silicon. 〔9〕The energy device according to 〔7〕 or 〔8〕, wherein the plurality of electrodes capable of occluding and releasing metal ions are a positive electrode and a negative electrode, and the positive electrode contains a transition metal oxide.

Advantages of the Invention

[0017] According to the present invention, the initial input / output characteristics are significantly improved, and further during cycle operation and high-temperature storage It is possible to provide a non-aqueous electrolyte capable of realizing energy devices such as non-aqueous electrolyte secondary batteries with good input / output retention rate, capacity retention rate, battery swelling, and metal elution at that time. Further, according to a preferred embodiment of the present invention, it is possible to provide a non-aqueous electrolyte capable of realizing an energy device that is excellent not only in input / output characteristics but also in impedance characteristics, charge / discharge rate characteristics, etc., and further excellent in continuous charging characteristics, safety, etc. Further, it is possible to provide an energy device using this non-aqueous electrolyte.

Embodiment for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples (representative examples) of the embodiments of the present invention, and the present invention is not limited thereto. Further, the present invention can be arbitrarily modified and implemented without departing from the gist thereof.

[0019] <1. Compounds Essential for the Non-Aqueous Electrolyte of the Present Invention> The non-aqueous electrolyte of the present invention has the following formula (1): X-SO2-Y-SO2-Z (1) [In formula (1), Y is an organic group containing either a nitrogen atom or a carbon atom. In the case of a nitrogen atom, it is a lithium salt of an imide structure that becomes N-Li, and in the case of a carbon atom, it is an alkylene diester structure of -O-(CH2) n -O-. X and Z are hydrocarbon groups that may contain fluorine atoms having 1 to 12 carbon atoms or fluorine atoms. X and Z may be the same or different, and may also be bonded to each other to form a ring structure. When forming a ring structure, either X or Z may be removed. n is an integer of 1 or more and 2 or less.] contains at least one compound selected from the group (A) consisting of compounds represented by the following formula (2): (FSO3) x M (2) [In formula (2), M is a metal atom, and x is the valence of the metal atom M and is an integer of 1 or more] and contains a fluorosulfonate (B) represented by the following formula:

[0020] <A compound selected from the group (A) consisting of a compound represented by <1-1.X-SO2-Y-SO2-Z> and a cyclic compound having an SO3 structure> <A compound represented by <1-1-1.X-SO2-Y-SO2-Z>> In formula (1), Y is an organic group containing either a nitrogen atom or a carbon atom. When Y is a nitrogen atom, it is a lithium salt of an imide structure where N-Li. When Y is a carbon atom, it is an alkylene diester structure of -O-(CH2) n -O-. X and Z are a hydrocarbon group which may contain a fluorine atom having 1 to 12 carbon atoms or a fluorine atom. X and Z may be the same or different, and may also be bonded to each other to form a ring structure. When forming a ring structure, either one of X or Z may be removed. n is an integer of 1 or more and 2 or less.

[0021] When Y is a nitrogen atom, it is a lithium salt of an imide structure. It is preferable that X and Z are a hydrocarbon group containing a fluorine atom having 1 to 4 carbon atoms or a fluorine atom from the viewpoint of increasing the lithium ion concentration and improving the conductivity derived from lithium ions.

[0022] Preferred lithium salts of the imide structure include (FSO2)2NLi, (FSO2)(CF3SO2)NLi, (CF3SO2)2NLi, (C2F5SO2)2NLi, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, (CF3SO2)(C4F9SO2)NLi, and the like.

[0023] Among these, (FSO2)2NLi, (CF3SO2)2NLi, and (C2F5SO2)2NLi are more preferable from the viewpoint of not reducing the viscosity of the electrolytic solution, and (FSO2)2NLi is more preferable from the viewpoint of the effect of improving the input / output characteristics and durability.

[0024] When Y is a carbon atom, a compound having an alkylene diester structure is preferred from the viewpoint of not reducing the viscosity of the electrolytic solution, where X and Z are hydrocarbon groups having 1 to 6 carbon atoms.

[0025] Preferred compounds having an alkylene disulfonate structure include cyclic disulfonate compounds such as methylene methanedisulfonate, ethylene methanedisulfonate, methylene ethanedisulfonate, and ethylene ethanedisulfonate; chain disulfonate compounds such as methylene bis(methanesulfonate), methylene bis(ethanesulfonate), methylene bis(benzenesulfonate), ethylene bis(methanesulfonate), ethylene bis(ethanesulfonate), and ethylene bis(benzenesulfonate); and the like.

[0026] Among these, methylene methanedisulfonate, ethylene methanedisulfonate, and methylene bis(methanesulfonate) are preferred from the viewpoint of improving the input / output characteristics, and methylene methanedisulfonate is more preferred from the viewpoints of improving the input / output characteristics and the durability improvement effect.

[0027] The content of the compound represented by X-SO2-Y-SO2-Z in the non-aqueous electrolytic solution of the present invention is 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and 8% by mass or less, preferably 7% by mass or less, more preferably 6% by mass or less. Within the above range, it is preferable because not only the input / output characteristics but also the durability such as the cycle capacity and the storage capacity can be further improved, the battery swelling and the metal elution amount can be further reduced, and the safety can be improved.

[0028] <1-1-2.Cyclic compound having a SO3 group> In the non-aqueous electrolyte of the present invention, as the cyclic compound having a SO3 group that can be used, the type is not particularly limited as long as it is a cyclic compound having a SO3 group in the molecule, but a compound having a cyclic sulfonic acid ester or a cyclic sulfuric acid ester (hereinafter, may be abbreviated as a cyclic sulfonic acid ester compound or a cyclic sulfuric acid ester compound, respectively) is preferable, and a compound represented by the following general formula (3) is more preferable. The production method of the cyclic compound having a SO3 group is not particularly limited, and a known method can be arbitrarily selected for production.

[0029]

Chemical formula

[0030] In general formula (3), R 7 and R 8 each independently represent an organic group composed of atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a halogen atom, and R 7 and R 8 may contain an unsaturated bond together with -SO3-. Here, R 7 and R 8 are preferably organic groups composed of atoms selected from a carbon atom, a hydrogen atom, an oxygen atom, and a sulfur atom, and among them, a hydrocarbon group having 1 to 3 carbon atoms and an organic group having -SO3- are preferable.

[0031] The molecular weight of the cyclic compound having a SO3 group is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight of the cyclic compound having a SO3 group is usually 100 or more, preferably 110 or more, and is usually 250 or less, preferably 220 or less. Within this range, it is easy to ensure the solubility of the cyclic compound having a SO3 group in the non-aqueous electrolyte, and the effects of the present invention are likely to be exhibited.

[0032] Specific examples of the compound represented by general formula (3) include, for example, 1,3 - propane sultone, 1 - fluoro - 1,3 - propane sultone, 2 - fluoro - 1,3 - propane sultone, 3 - fluoro - 1,3 - propane sultone, 1 - methyl - 1,3 - propane sultone, 2 - methyl - 1,3 - propane sultone, 3 - methyl - 1,3 - propane sultone, 1 - propene - 1,3 - sultone, 2 - propene - 1,3 - sultone, 1 - fluoro - 1 - propene - 1,3 - sultone, 2 - fluoro - 1 - propene - 1,3 - sultone, 3 - fluoro - 1 - propene - 1,3 - sultone, 1 - fluoro - 2 - propene - 1,3 - sultone, 2 - fluoro - 2 - propene - 1,3 - sultone, 3 - fluoro - 2 - propene - 1,3 - sultone, 1 - methyl - 1 - propene - 1,3 - sultone, 2 - methyl - 1 - propene - 1,3 - sultone, 3 - methyl - 1 - propene - 1,3 - sultone, 1 - methyl - 2 - propene - 1,3 - sultone, 2 - methyl - 2 - propene - 1,3 - sultone, 3 - methyl - 2 - propene - 1,3 - sultone, 1,4 - butane sultone, 1 - fluoro - 1,4 - butane sultone, 2 - fluoro - 1,4 - butane sultone, 3 - fluoro - 1,4 - butane sultone, 4 - fluoro - 1,4 - butane sultone, 1 - methyl - 1,4 - butane sultone, 2 - methyl - 1,4 - butane sultone, 3 - methyl - 1,4 - butane sultone, 4 - methyl - 1,4 - butane sultone, 1 - butene - 1,4 - sultone, 2 - butene - 1,4 - sultone, 3 - butene - 1,4 - sultone, 1 - fluoro - 1 - butene - 1,4 - sultone, 2 - fluoro - 1 - butene - 1,4 - sultone, 3 - fluoro - 1 - butene - 1,4 - sultone, 4 - fluoro - 1 - butene - 1,4 - sultone, 1 - fluoro - 2 - butene - 1,4 - sultone, 2 - fluoro - 2 - butene - 1,4 - sultone, 3 - fluoro - 2 - butene - 1,4 - sultone, 4 - fluoro - 2 - butene - 1,4 - sultone, 1 - fluoro - 3 - butene - 1,4 - sultone, 2 - fluoro - 3 - butene - 1,4 - sultone, 3 - fluoro - 3 - butene - 1,4 - sultone, 4 - fluoro - 3 - butene - 1,4 - sultone, 1 - methyl - 1 - butene - 1,4 - sultone, 2 - methyl - 1 - butene - 1,4 - sultone, 3 - methyl - 1 - butene - 1,4 - sultone, 4 - methyl - 1 - butene - 1,4 - sultone, 1 - methyl - 2 - butene - 1,4-Sultone, 2-Methyl-2-butene-1,4-sultone, 3-Methyl-2-butene-1,4-sultone, 4-Methyl-2-butene-1,4-sultone, 1-Methyl-3-butene-1,4-sultone, 2-Methyl-3-butene-1,4-sultone, 3-Methyl-3-butene-1,4-sultone, 4-Methyl-3-butene-1,4-sultone, 1,5-Pentanesultone, 1-Fluoro-1,5-pentanesultone, 2-Fluoro-1,5-pentanesultone, 3-Fluoro-1,5-pentanesultone, 4-Fluoro-1,5-pentanesultone, 5-Fluoro-1,5-pentanesultone, 1-Methyl-1,5-pentanesultone, 2-Methyl-1,5-pentanesultone, 3-Methyl-1,5-pentanesultone, 4-Methyl-1,5-pentanesultone, 5-Methyl-1,5-pentanesultone, 1-Pentene-1,5-sultone, 2-Pentene-1,5-sultone, 3-Pentene-1,5-sultone, 4-Pentene-1,5-sultone, 1-Fluoro-1-pentene-1,5-sultone, 2-Fluoro-1-pentene-1,5-sultone, 3-Fluoro-1-pentene-1,5-sultone, 4-Fluoro-1-pentene-1,5-sultone, 5-Fluoro-1-pentene-1,5-sultone, 1-Fluoro-2-pentene-1,5-sultone, 2-Fluoro-2-pentene-1,5-sultone, 3-Fluoro-2-pentene-1,5-sultone, 4-Fluoro-2-pentene-1,5-sultone, 5-Fluoro-2-pentene-1,5-sultone, 1-Fluoro-3-pentene-1,5-sultone, 2-Fluoro-3-pentene-1,5-sultone, 3-Fluoro-3-pentene-1,5-sultone, 4-Fluoro-3-pentene-1,5-sultone, 5-Fluoro-3-pentene-1,5-sultone, 1-Fluoro-4-pentene-1,5-sultone, 2-Fluoro-4-pentene-1,5-sultone, 3-Fluoro-4-pentene-1,5-sultone, 4-Fluoro-4-pentene-1,5-sultone, 5-Fluoro-4-pentene-1,5-sultone, 1-Methyl-1-pentene-1,5-sultone, 2-Methyl-1-pentene-1,5-sultone, 3-Methyl-1-pentene-1,5-sultone, 4-Methyl-1-pentene-1,5-sultone, 5-Methyl-1-pentene-1,5-Sulton, 1-methyl-2-pentene-1,5-sulton, 2-methyl-2-pentene-1,5-sulton, 3-methyl-2-pentene-1,5-sulton, 4-methyl-2-pentene-1,5-sulton, 5-methyl-2-pentene-1,5-sulton, 1-methyl-3-pentene-1,5-sulton, 2-methyl-3-pentene-1,5-sulton, 3-methyl-3-pentene-1,5-sulton, 4-methyl-3-pentene-1,5-sulton, 5-methyl-3-pentene-1,5-sulton, 1-methyl-4-pentene-1,5-sulton, 2-methyl-4-pentene-1,5-sulton, 3-methyl-4-pentene-1,5-sulton, 4-methyl-4-pentene-1,5-sulton, 5-methyl-4-pentene-1,5-sulton, 1,2-oxathiolane-2,2-dioxide-4-yl-acetate, 1,2-oxathiolane-2,2-dioxide-4-yl-propionate, 5-methyl-1,2-oxathiolane-2,2-dioxide-4-one-2,2-dioxide, 5,5-dimethyl-1,2-oxathiolane-2,2-dioxide-4-one-2,2-dioxide and other sultone compounds;,

[0033] Nitrogen-containing compounds such as 1,2,3-oxathiazolidine-2,2-dioxide, 3-methyl-1,2,3-oxathiazolidine-2,2-dioxide, 3H-1,2,3-oxathiazole-2,2-dioxide, 5H-1,2,3-oxathiazole-2,2-dioxide, 1,2,4-oxathiazolidine-2,2-dioxide, 4-methyl-1,2,4-oxathiazolidine-2,2-dioxide, 3H-1,2,4-oxathiazole-2,2-dioxide, 5H-1,2,4-oxathiazole-2,2-dioxide, 1,2,5-oxathiazolidine-2,2-dioxide, 5-methyl-1,2,5-oxathiazolidine-2,2-dioxide, 3H-1,2,5-oxathiazole-2,2-dioxide, 5H-1,2,5-oxathiazole-2,2-dioxide, 1,2,3-oxathiadinane-2,2-dioxide, 3-methyl-1,2,3-oxathiadinane-2,2-dioxide, 5,6-dihydro-1,2,3-oxathiazine-2,2-dioxide, 1,2,4-oxathiadinane-2,2-dioxide, 4-methyl-1,2,4-oxathiadinane-2,2-dioxide, 5,6-dihydro-1,2,4-oxathiazine-2,2-dioxide, 3,6-dihydro-1,2,4-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,4-oxathiazine-2,2-dioxide, 1,2,5-oxathiadinane-2,2-dioxide, 5-methyl-1,2,5-oxathiadinane-2,2-dioxide, 5,6-dihydro-1,2,5-oxathiazine-2,2-dioxide, 3,6-dihydro-1,2,5-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,5-oxathiazine-2,2-dioxide, 1,2,6-oxathiadinane-2,2-dioxide, 6-methyl-1,2,6-oxathiadinane-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide, 3,4-dihydro-1,2,6-oxathiazine-2,2-dioxide, 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide; 1,2,3 - Oxathiazirane - 2,2 - dioxide, 3 - methyl - 1,2,3 - oxathiazirane - 2,2 - dioxide, 3 - methyl - 1,2,3 - oxathiazirane - 2,2,3 - trioxide, 3 - methoxy - 1,2,3 - oxathiazirane - 2,2,3 - trioxide, 1,2,4 - oxathiazirane - 2,2 - dioxide, 4 - methyl - 1,2,4 - oxathiazirane - 2,2 - dioxide, 4 - methyl - 1,2,4 - oxathiazirane - 2,2,4 - trioxide, 4 - methoxy - 1,2,4 - oxathiazirane - 2,2,4 - trioxide, 1,2,5 - oxathiazirane - 2,2 - dioxide, 5 - methyl - 1,2,5 - oxathiazirane - 2,2 - dioxide, 5 - methyl - 1,2,5 - oxathiazirane - 2,2,5 - trioxide, 5 - methoxy - 1,2,5 - oxathiazirane - 2,2,5 - trioxide, 1,2,3 - oxathiazinane - 2,2 - dioxide, 3 - methyl - 1,2,3 - oxathiazinane - 2,2 - dioxide, 3 - methyl - 1,2,3 - oxathiazinane - 2,2,3 - trioxide, 3 - methoxy - 1,2,3 - oxathiazinane - 2,2,3 - trioxide, 1,2,4 - oxathiazinane - 2,2 - dioxide, 4 - methyl - 1,2,4 - oxathiazinane - 2,2 - dioxide, 4 - methyl - 1,2,4 - oxathiazinane - 2,2,3 - trioxide, 4 - methyl - 1,5,2,4 - dioxathiazinane - 2,4 - dioxide, 4 - methoxy - 1,5,2,4 - dioxathiazinane - 2,4 - dioxide, 3 - methoxy - 1,2,4 - oxathiazinane - 2,2,3 - trioxide, 1,2,5 - oxathiazinane - 2,2 - dioxide, 5 - methyl - 1,2,5 - oxathiazinane - 2,2 - dioxide, 5 - methyl - 1,2,5 - oxathiazinane - 2,2,3 - trioxide, 5 - methoxy - 1,2,5 - oxathiazinane - 2,2,3 - trioxide, 1,2,6 - oxathiazinane - 2,2 - dioxide, 6 - methyl - 1,2,6 - oxathiazinane - 2,2 - dioxide, 6 - methyl - 1,2,6 - oxathiazinane - 2,2,3 - trioxide, 6 - methoxy - 1,2,6 - oxathiazinane - 2,2,Phosphorus-containing compounds such as trioxide; Alkylene sulfate compounds such as 1,2-ethylene sulfate, 1,2-propylene sulfate, 1,3-propylene sulfate, 1,2-butylene sulfate, 1,3-butylene sulfate, 1,4-butylene sulfate, 1,2-pentylene sulfate, 1,3-pentylene sulfate, 1,4-pentylene sulfate, 1,5-pentylene sulfate, and vinylene sulfate; And the like.

[0034] Among these, 1,3-propanesultone, 1-fluoro-1,3-propanesultone, 2-fluoro-1,3-propanesultone, 3-fluoro-1,3-propanesultone, 1-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1,4-butanesultone, methylene methanedisulfonate, ethylene methanedisulfonate, 1,2-ethylene sulfate, 1,2-propylene sulfate or 1,3-propylene sulfate are preferable from the viewpoint of improving the storage characteristics, and 1,3-propanesultone, 1-fluoro-1,3-propanesultone, 2-fluoro-1,3-propanesultone, 3-fluoro-1,3-propanesultone, 1-propene-1,3-sultone, methylene methanedisulfonate, ethylene methanedisulfonate, 1,2-ethylene sulfate or 1,3-propylene sulfate are more preferable.

[0035] The cyclic compound having an SO3 group may be used alone or in combination of two or more in any combination and ratio. The content of the cyclic compound having an SO3 group with respect to the entire non-aqueous electrolyte of the present invention is 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, and 8% by mass or less, preferably 5% by mass or less, more preferably 4% by mass or less, still more preferably 3% by mass or less with respect to the non-aqueous electrolyte of the present invention. When the above range is satisfied, it is preferable from the viewpoints of improving cycle characteristics, high-temperature storage characteristics, etc. and reducing battery swelling.

[0036] The non-aqueous electrolyte of the present invention may contain a plurality of types of compounds belonging to group (A). In that case, with respect to the non-aqueous electrolyte of the present invention, the total content of the compounds belonging to group (A) is 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and is 8% by mass or less, preferably 7% by mass or less, more preferably 6% by mass or less. The method for producing a compound selected from the group consisting of a compound represented by X-SO2-Y-SO2-Z and a cyclic compound having an SO3 structure is not particularly limited, and can be produced by combining known methods.

[0037] <1-2.(FSO3) x M> The non-aqueous electrolyte of the present invention contains a fluorosulfonate (B) represented by the formula (2): (FSO3) x M. In the formula (2), M is a metal atom, and x is the valence of the metal atom M and is an integer of 1 or more. The above fluorosulfonate (B) may be used alone or in combination of two or more.

[0038] In the formula (2), x is the valence of the metal atom and is an integer of 1 or more, and specifically, 1, 2 or 3 can be mentioned. Examples of the metal atom include alkali metals such as lithium, sodium, potassium, and cesium, alkaline earth metals such as magnesium and calcium, transition metals such as iron and copper, etc., and lithium is particularly preferable.

[0039] Preferable fluorosulfonates (B) include FSO3Li, FSO3Na, FSO3K, FSO3Cs, (FSO3)2Mg, (FSO3)2Ca, (FSO3)2Fe, (FSO3)2Cu, (FSO3)3Al, etc. Among them, FSO3Li, FSO3Na, and FSO3K are particularly preferable, and FSO3Li is most preferable from the viewpoint of improving the lithium ion concentration in the battery. The method for synthesizing and obtaining the fluorosulfonate (B) is not particularly limited, and it can be used regardless of whether it is synthesized by any method or obtained. Examples of the method for synthesizing the metal salt (B) of fluorosulfonic acid include a method of reacting a metal fluoride or a metal fluorosilicate compound with SO3 to obtain a metal salt of fluorosulfonic acid, a method of reacting fluorosulfonic acid with a metal and obtaining a metal salt of fluorosulfonic acid by ion exchange, a method of reacting an ammonium salt of fluorosulfonic acid with a metal to obtain a metal salt of fluorosulfonic acid, a method of reacting fluorosulfonic acid with a metal salt of acetic acid and obtaining a metal salt of fluorosulfonic acid by ion exchange, a method of reacting fluorosulfonic acid with a metal halide to obtain a metal salt of fluorosulfonic acid, and the like.

[0040] In the non-aqueous electrolyte of the present invention, the fluorosulfonate (B) may be contained in one or more kinds, and it may be used alone or in combination of two or more kinds. When two or more kinds are used, it is preferable that one of them is FSO3Li. In particular, a combination of FSO3Li and one or more kinds selected from FSO3Na and FSO3K is preferable. Specifically, the combinations of FSO3Li and FSO3Na, and FSO3Li and FSO3K are preferable in terms of increasing the lithium concentration in the non-aqueous electrolyte.

[0041] The content of the fluorosulfonate (B) in the non-aqueous electrolyte of the present invention is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. Usually, it is 0.001% by mass or more, preferably 0.01% by mass, more preferably 0.1% by mass, and usually 2% by mass, preferably 1.7% by mass, more preferably 1.5% by mass. By setting this concentration, the amount of interaction on the surfaces of the positive and negative electrodes can be optimized, and the input / output characteristics can be maximized.

[0042] <1-3. Content of the above essential compounds in the non-aqueous electrolyte of the present invention> In the non-aqueous electrolyte of the present invention, the ratio of the content mass of the fluorosulfonate (B) to the content mass of the compound belonging to the group (A) [(content mass of fluorosulfonate (B)) / (content mass of the compound belonging to the group (A))] is 1 or less. Also, usually 0.00 is 05 or more, preferably 0.001 or more, more preferably 0.002 or more, and preferably 0.8 or less, more preferably 0.7 or less. By setting this ratio, the balance between the amount of interaction on the surfaces of the positive and negative electrodes and the amount of lithium ion supply can be optimized, and the input / output characteristics can be maximized. Note that the above ratio can be applied to non-aqueous electrolytes in any state, and can be a non-aqueous electrolyte before being introduced into the energy device or a non-aqueous electrolyte extracted from the energy device.

[0043] Here, the preparation of the non-aqueous electrolyte containing the compound belonging to the group (A) and the fluorosulfonate (B) may be carried out by known methods and is not particularly limited. For example, a method of individually adding the compound belonging to the group (A) and the fluorosulfonate (B) to the non-aqueous electrolyte, a method of adding the compound belonging to the group (A) and / or the fluorosulfonate (B) to a solvent and then mixing each component to form a non-aqueous electrolyte, a method of mixing the compound belonging to the group (A) and the fluorosulfonate (B) in battery components such as active materials and electrode plates described later to construct a battery element (battery cell), and dissolving the compound belonging to the group (A) and the fluorosulfonate (B) in the non-aqueous electrolyte when assembling an energy device such as a non-aqueous electrolyte secondary battery by injecting the non-aqueous electrolyte, a method of obtaining an electrolyte containing the compound belonging to the group (A) and the fluorosulfonate (B) by previously mixing a compound capable of generating the compound belonging to the group (A) and the fluorosulfonate (B) in the non-aqueous electrolyte or in the energy device, etc. can be mentioned.

[0044] <2. Non-aqueous electrolyte> <2-1. Other electrolyte salts> In addition to the compound belonging to group (A) and the fluorosulfonate (B), the non-aqueous electrolyte in the present invention may contain one or more other electrolyte salts. As the electrolyte salt, a lithium salt is preferable. There is no particular limitation as long as it is known to be used as an electrolyte salt, and any one can be used, and specific examples include the following.

[0045] For example, Inorganic lithium salts such as LiBF4, LiClO4, LiAlF4, LiPF6, LiSbF6, LiTaF6, LiWF7; Lithium fluorophosphate salts other than LiPF6 such as LiPO3F, LiPO2F2; Lithium tungstate salts such as LiWOF5; Lithium carboxylate salts such as HCO2Li, CH3CO2Li, CH2FCO2Li, CHF2CO2Li, CF3CO2Li, CF3CH2CO2Li, CF3CF2CO2Li, CF3CF2CF2CO2Li, CF3CF2CF2CF2CO2Li; Lithium sulfonate salts such as CH3SO3Li, CH2FSO3Li, CHF2SO3Li, CF3SO3Li, CF3CF2SO3Li, CF3CF2CF2SO3Li, CF3CF2CF2CF2SO3Li; Lithium methide salts such as (FSO2)3CLi, (CF3SO2)3CLi, (C2F5SO2)3CLi; Lithium oxalate salts such as lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate; In addition, fluorine-containing organic lithium salts such as LiPF4(CF3)2, LiPF4(C2F5)2, LiPF4(CF3SO2)2, LiPF4(C2F5SO2)2, LiBF3CF3, LiBF3C2F5, LiBF3C3F7, LiBF2(CF3)2, LiBF2(C2F5)2, LiBF2(CF3SO2)2, LiBF2(C2F5SO2)2; etc. are included. Among these, the initial input / output characteristics, and input / output characteristics after durability tests such as cycle tests and high-temperature storage tests From the viewpoint of further enhancing the effects of improving the output characteristics, charge / discharge rate characteristics, and impedance characteristics, it is preferable to use a material selected from inorganic lithium salts, lithium fluorophosphate salts, lithium sulfonate salts, and lithium oxalate salts. Among these, LiPF6, LiBF4, LiSbF6, LiTaF6, LiPO3F, LiPO2F2, CF3SO3Li, (FSO2)3CLi, (CF3SO2)3CLi, (C2F5SO2)CLi3, lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate and lithium tris(oxalato)phosphate are particularly preferred because they have the effect of improving input / output characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, cycle characteristics, etc.

[0046] The total concentration of the compound belonging to group (A), the fluorosulfonate (B) and other electrolyte salts in the non-aqueous electrolyte is not particularly limited, but is usually 8% by mass or more, preferably 8.5% by mass or more, more preferably 9% by mass or more. The upper limit is usually 18% by mass or less, preferably 17% by mass or less, more preferably 16% by mass or less. If the total concentration of the compound belonging to group (A), the fluorosulfonate (B) and other electrolyte salts in the non-aqueous electrolyte is within the above range, it is preferable because the electrical conductivity and viscosity are appropriate for battery operation.

[0047] In addition, other electrolyte salts may be used alone or in combination of two or more. A preferred example of using two or more in combination is the combination of LiPF6 and LiBF4, LiPF6 and LiPO2F2, LiPF6 and lithium bis(oxalato)borate, LiPF6 and lithium tetrafluorooxalatophosphate, LiPF6 and lithium difluorobis(oxalato)phosphate, LiPF6 and LiBF4 and LiPO2F2, LiPF6 and LiPO2F2 and lithium bis(oxalato)borate, or LiPF6 and LiPO2F2 and lithium difluorobis(oxalato)phosphate, which has the effect of improving input / output characteristics, high-temperature storage characteristics, and cycle characteristics. In this case, the content of LiPF6 in the non-aqueous electrolyte is preferably 4% by mass or more, more preferably 5% by mass or more, still more preferably 6% by mass or more, preferably 14% by mass or less, more preferably 13% by mass or less, and still more preferably 12% by mass or less. Also, the content of LiBF4, LiPO2F2, lithium bis(oxalato)borate, or lithium difluorobis(oxalato)phosphate in the non-aqueous electrolyte is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less. When the concentration of LiPF6 is within the above-preferred range, the total ion content and viscosity in the non-aqueous electrolyte are in an appropriate balance, so that the internal impedance of the energy device is lowered without excessively reducing the ionic conductivity, and the effects of improving the input / output characteristics, cycle characteristics, and storage characteristics due to the blending of LiPF6 are more likely to be manifested.

[0048] In addition, a particularly preferred combination as the electrolyte is the combination of LiPF6 and LiPO2F2, LiPF6 and lithium bis(oxalato)borate, or LiPF6 and LiPO2F2 and lithium bis(oxalato)borate. By combining these with the compound belonging to group (A) and the fluorosulfonate (B), the effects of the present invention, that is, the input / output characteristics, durability such as cycle capacity and storage capacity, reduction effects of battery swelling and metal elution amount, and improvement of safety can be maximally exerted.

[0049] These electrolyte materials can be manufactured by conventionally known methods. Here, the preparation of the non-aqueous electrolyte solution containing the above electrolyte materials may be carried out by known methods and is not particularly limited. For example, a method of adding the separately synthesized above electrolyte material to the non-aqueous electrolyte solution, or mixing the above electrolyte material in battery components such as the active material and the electrode plate described later to construct a battery element (battery cell), and dissolving the above electrolyte material in the non-aqueous electrolyte solution when injecting the non-aqueous electrolyte solution to assemble the battery, a method of allowing water to coexist in battery components such as the active material, the electrode plate, and the separator, and generating other electrolyte materials in the system when assembling a non-aqueous electrolyte secondary battery using the non-aqueous electrolyte solution containing the above electrolyte material, etc. may be mentioned. In the present invention, any method may be used. As a method for measuring the content of each electrolyte in the above non-aqueous electrolyte solution and the non-aqueous electrolyte secondary battery, there is no particular limitation, and any known method can be arbitrarily used. Specifically, ion chromatography, nuclear magnetic resonance spectroscopy (NMR), etc. may be mentioned.

[0050]

[0050]

[0051] <2-2. Non-aqueous solvent> The non-aqueous electrolyte solution according to an embodiment of the present invention, like a general non-aqueous electrolyte solution, usually contains, as its main component, a non-aqueous solvent that dissolves the above-described electrolyte. There is no particular limitation on the non-aqueous solvent used here, and known organic solvents can be used. Examples of the organic solvent include saturated cyclic carbonates, chain carbonates, chain carboxylic acid esters, cyclic carboxylic acid esters, ether compounds, sulfone compounds, etc., but are not particularly limited thereto. These can be used alone or in combination of two or more. Further, in one embodiment of the present invention, it is preferable that the non-aqueous electrolyte solution contains one or more selected from the group consisting of cyclic carbonates, chain carbonates, and chain esters.

[0052] <2-2-1. Saturated cyclic carbonate> Examples of the saturated cyclic carbonate include those having an alkylene group with 2 to 4 carbon atoms. Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, butylene carbonate, and the like. Among them, ethylene carbonate and propylene carbonate are preferable from the viewpoint of improving battery characteristics due to an improvement in lithium ion dissociation degree. The saturated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio.

[0053] The content of the saturated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. However, when using one kind alone, the lower limit of the content is usually 3% by volume or more, preferably 5% by volume or more in 100% by volume of the non-aqueous solvent. By setting it within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte can be avoided, and the high current discharge characteristics, stability against the negative electrode, and cycle characteristics of the non-aqueous electrolyte secondary battery can be easily made within a good range. The upper limit is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. By setting it within this range, the viscosity of the non-aqueous electrolyte can be set within an appropriate range, a decrease in ionic conductivity can be suppressed, and as a result, the input / output characteristics of the non-aqueous electrolyte secondary battery can be further improved, or the durability such as cycle characteristics and storage characteristics can be further improved, which is preferable.

[0054] In addition, the saturated cyclic carbonate can also be used in any combination of two or more kinds. One of the preferable combinations is a combination of ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably from 99:1 to 40:60, more preferably from 95:5 to 50:50. Furthermore, the lower limit of the amount of propylene carbonate in the whole non-aqueous solvent is usually 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more. The upper limit is usually 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less. Containing propylene carbonate within this range is preferable because the low temperature characteristics are further excellent.

[0055] <2-2-2. Chain carbonate> As the chain carbonate, those having 3 to 7 carbon atoms are preferred. Specifically, examples of the chain carbonate having 3 to 7 carbon atoms include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n- propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate and the like. Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate or methyl-n-propyl carbonate are preferred, and dimethyl carbonate, diethyl carbonate or ethyl methyl carbonate are particularly preferred.

[0056] In addition, chain carbonates having a fluorine atom (hereinafter may be abbreviated as "fluorinated chain carbonate") can also be preferably used. The number of fluorine atoms in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or different carbons. Examples of the fluorinated chain carbonate include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, fluorinated diethyl carbonate derivatives and the like.

[0057] Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis(fluoromethyl) carbonate, bis(difluoro)methyl carbonate, bis(trifluoromethyl) carbonate and the like. Examples of fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trifluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, ethyl trifluoromethyl carbonate, and the like. Examples of fluorinated diethyl carbonate derivatives include ethyl-(2-fluoroethyl) carbonate, ethyl-(2,2-difluoroethyl) carbonate, bis(2-fluoroethyl) carbonate, ethyl-(2,2,2-trifluoroethyl) carbonate, 2,2-difluoroethyl-2'-fluoroethyl carbonate, bis(2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2'-fluoroethyl carbonate, 2,2,2-trifluoroethyl-2',2'-difluoroethyl carbonate, bis(2,2,2-trifluoroethyl) carbonate, and the like.

[0058] The chain carbonate may be used alone or in combination of two or more in any combination and ratio. The content of the chain carbonate is not particularly limited, but it is usually 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more in 100% by volume of the non-aqueous solvent. Also, it is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. By setting the content of the chain carbonate within the above range, the viscosity of the non-aqueous electrolyte can be set within an appropriate range, the decrease in ionic conductivity can be suppressed, and thus the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery can be easily set within a good range. Also, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte can be avoided, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery can be easily set within a good range.

[0059] Furthermore, by combining ethylene carbonate with a specific content for a specific chain carbonate, the battery performance can be significantly improved. For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonates, the content of ethylene carbonate is not particularly limited and can be arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 15% by volume or more, preferably 20% by volume, and usually 45% by volume or less, preferably 40% by volume or less. The content of dimethyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less. The content of ethyl methyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less. By setting the content within the above range, while reducing the low-temperature precipitation temperature of the electrolyte, the viscosity of the non-aqueous electrolyte can also be reduced to improve the ionic conductivity, and high input / output can be obtained even at low temperatures.

[0060] <2-2-3. Chain carboxylic acid ester> Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in total in its structural formula. Specifically, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, isopropyl isobutyrate, etc. can be mentioned. Among them, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, methyl butyrate or ethyl butyrate are preferable from the viewpoints of improving the ionic conductivity due to viscosity reduction and suppressing battery swelling during durability such as cycles and storage.

[0061] ​ The content of the chain carboxylic acid ester is not particularly limited and can be arbitrary as long as the effects of the present invention are not significantly impaired. However, in 100% by volume of the non-aqueous solvent, it is usually 5% by volume or more, preferably 8% by volume or more, and usually 80% by volume or less, preferably 70% by volume or less. When the content of the chain carboxylic acid ester is within the above range, the electrical conductivity of the non-aqueous electrolyte can be improved, and it is easier to improve the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery. In addition, an increase in the negative electrode resistance can be suppressed, and it is easier to keep the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery within a good range.

[0062] In addition, when using a chain carboxylic acid ester, it is preferably used in combination with a cyclic carbonate, and more preferably used in combination with a cyclic carbonate and a chain carbonate. For example, when using a cyclic carbonate and a chain carboxylic acid ester in combination, the content of the cyclic carbonate is not particularly limited and can be arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 15% by volume or more, preferably 20% by volume, and usually 45% by volume or less, preferably 40% by volume or less. The content of the chain carboxylic acid ester is usually 20% by volume or more, preferably 30% by volume or more, and usually 55% by volume or less, preferably 50% by volume or less. Also, when using a cyclic carbonate, a chain carbonate, and a chain carboxylic acid ester in combination, the content of the cyclic carbonate is not particularly limited and can be arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 15% by volume or more, preferably 20% by volume, and usually 45% by volume or less, preferably 40% by volume or less. The content of the chain carbonate is usually 25% by volume or more, preferably 30% by volume or more, and usually 84% by volume or less, preferably 80% by volume or less. By setting the content within the above range, while reducing the low-temperature precipitation temperature of the electrolyte, the viscosity of the non-aqueous electrolyte can also be reduced to improve the ionic conductivity, and higher input / output can be obtained even at low temperatures. Also, from the perspective of further reducing battery swelling, it is preferable.

[0063] <2-2-4. Cyclic Carboxylic Acid Ester> Examples of the cyclic carboxylic acid ester include those having 3 to 12 carbon atoms in total in its structural formula. It can be ridiculed. Specifically, gamma-butyrolactone, gamma-valerolactone, gamma-caprolactone, epsilon-caprolactone, etc. can be mentioned. Among them, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics due to the improvement of lithium ion dissociation degree.

[0064] The content of the cyclic carboxylic acid ester is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. However, in 100% by volume of the non-aqueous solvent, it is usually 3% by volume or more, preferably 5% by volume or more, and usually 60% by volume or less, preferably 50% by volume or less. When the content of the cyclic carboxylic acid ester is within the above range, the electrical conductivity of the non-aqueous electrolyte can be improved, and it becomes easier to improve the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery. In addition, the viscosity of the non-aqueous electrolyte is set within an appropriate range, the decrease in electrical conductivity is avoided, the increase in negative electrode resistance is suppressed, and it becomes easier to set the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery within a good range.

[0065] <2-2-5. Ether-based compound> As the ether-based compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms are preferable. Examples of chain ethers having 3 to 10 carbon atoms include diethyl ether, di(2-fluoroethyl) ether, di(2,2-difluoroethyl) ether, di(2,2,2-trifluoroethyl) ether, ethyl(2-fluoroethyl) ether, ethyl(2,2,2-trifluoroethyl) ether, ethyl(1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl)(2,2,2-trifluoroethyl) ether, (2-fluoroethyl)(1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl)(1,1,2,2-tetrafluoroethyl) ether, ethyl-n-propyl ether, ethyl(3-fluoro-n-propyl) ether, ethyl(3,3,3-trifluoro-n-propyl) ether, ethyl(2,2,3,3-tetrafluoro-n-propyl) ether, ethyl(2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl)(3-fluoro-n-propyl) ether, (2-fluoroethyl)(3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl-n-propyl ether, (2,2,2-trifluoroethyl)(3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl)(3,3,3-trifluoro-n-propyl) ether, (2,2,2-trifluoroethyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl)(3-fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl)(3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl)(2,2,3,3,3-Pentafluoro-n-propyl) ether, di-n-propyl ether, (n-propyl)(3-fluoro-n-propyl) ether, (n-propyl)(3,3,3-trifluoro-n-propyl) ether, (n-propyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (n-propyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, di(3-fluoro-n-propyl) ether, (3-fluoro-n-propyl)(3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (3-fluoro-n-propyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, di(3,3,3-trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl)(2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, di(2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl)(2,2,3,3,3-pentafluoro-n-propyl) ether, di(2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy(2-fluoroethoxy)methane, methoxy(2,2,2-trifluoroethoxy)methane methoxy(1,1,2,2-tetrafluoroethoxy)methane, diethoxymethane, ethoxy(2-fluoroethoxy)methane, ethoxy(2,2,2-trifluoroethoxy)methane, ethoxy(1,1,2,2-tetrafluoroethoxy)methane, di(2-fluoroethoxy)methane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)methane, (2-fluoroethoxy)(1,1,2,2-tetrafluoroethoxy)methane di(2,2,2-trifluoroethoxy)methane, (2,2,2-trifluoroethoxy)(1,1,2,2-tetrafluoroethoxy)methane, di(1,1,2,2-tetrafluoroethoxy)methane, dimethoxyethane, methoxyethoxyethane, methoxy(2-fluoroethoxy)ethane, methoxy(2,2,2-trifluoroethoxy)ethane, methoxy(1,1,2,2-tetrafluoroethoxy)ethane, diethoxyethane, ethoxy(2-fluoroethoxy)ethane, ethoxy(2,2,2-trifluoroethoxy)ethane, ethoxy(1,1,2,2-tetrafluoroethoxy)ethane, di(2-fluoroethoxy)ethane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)ethane, (2-fluoroethoxy)(1,1,2,2-tetrafluoroethoxy)ethane, di(2,2,2-trifluoroethoxy)ethane, (2,2,2-trifluoroethoxy)(1,1,2,2-tetrafluoroethoxy)ethane, di(1,1,2,2-tetrafluoroethoxy)ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. can be mentioned.,

[0066] Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane, etc., and fluorinated compounds thereof. Among these, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether or diethylene glycol dimethyl ether are preferable in terms of having a high solvating ability to lithium ions and improving ion dissociation. Particularly preferable are dimethoxymethane, diethoxymethane or ethoxymethoxymethane because of their low viscosity and high ion conductivity.

[0067] The content of the ether-based compound is not particularly limited and may be any content as long as it does not significantly impair the effects of the present invention, but is usually 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less, in 100% by volume of the non-aqueous solvent. If the content of the ether-based compound is within the above-mentioned preferred range, it is easy to ensure the effect of improving the lithium ion dissociation degree of the chain ether and improving the ion conductivity due to the viscosity reduction. In addition, when the negative electrode active material is a carbonaceous material, the phenomenon in which the chain ether is co-inserted with the lithium ion can be suppressed, so that the input / output characteristics and the charge / discharge rate characteristics can be set to appropriate ranges.

[0068] <2-2-6. Sulfone compounds> The sulfone-based compound is preferably a cyclic sulfone having 3 to 6 carbon atoms, or a chain sulfone having 2 to 6 carbon atoms. The number of sulfonyl groups in one molecule is preferably 1 or 2. Cyclic sulfones include monosulfone compounds such as trimethylene sulfones and tetramethylsulfones. and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferred, and tetramethylene sulfones (sulfolanes) are particularly preferred.

[0069] The sulfolane is preferably sulfolane and / or a sulfolane derivative (hereinafter, sulfolane may be abbreviated as "sulfolane") The sulfolane derivative is preferably one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group. Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methylsulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoromethylsulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3-(trifluoromethyl)sulfolane, 3-fluoro-3-(trifluoromethyl)sulfolane, 4-fluoro-3-(trifluoromethyl)sulfolane, 5-fluoro-3-(trifluoromethyl)sulfolane, etc. are preferable in terms of high ionic conductivity and high input / output.

[0070] Examples of the chain sulfone include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n-butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, perfluoroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di(trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone, trifluoromethyl-n-propyl sulfone, fluoromethyl isopropyl sulfone, difluoromethyl isopropyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl-n-propyl sulfone, trifluoroethyl isopropyl sulfone, pentafluoroethyl-n-propyl sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone, pentafluoroethyl-n-butyl sulfone, pentafluoroethyl-t-butyl sulfone, and the like.

[0071] Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone, trifluoromethyl-n-butyl sulfone or trifluoromethyl-t-butyl sulfone are preferable in terms of high ionic conductivity and high input / output.

[0072] The content of the sulfone compound is not particularly limited and can be arbitrary as long as the effects of the present invention are not significantly impaired. However, in 100% by volume of the non-aqueous solvent, it is usually 0.3% by volume or more, preferably 0.5% by volume or more, more preferably 1% by volume or more, and usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less. When the content of the sulfone compound is within the above range, the effect of improving the durability such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set within an appropriate range, avoiding a decrease in electrical conductivity, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery can be set within an appropriate range.

[0073] <2-3. Auxiliary agent> The non-aqueous electrolyte of the present invention may further contain various auxiliary agents described in detail below.

[0074] <2-3-1. Carbonate having at least one of a carbon-carbon unsaturated bond and a fluorine atom> The non-aqueous electrolyte according to an embodiment of the present invention may further contain at least one of a carbonate having a carbon-carbon unsaturated bond and a carbonate having a fluorine atom. Examples of the carbonate having a carbon-carbon unsaturated bond preferably include a cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter, may be abbreviated as "unsaturated cyclic carbonate"), and examples of the carbonate having a fluorine atom preferably include a cyclic carbonate having a fluorine atom.

[0075] The cyclic carbonate having a carbon-carbon unsaturated bond is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon unsaturated bond, and any carbonate having a carbon-carbon unsaturated bond can be used. In addition, a cyclic carbonate having a substituent having an aromatic ring is also included in the cyclic carbonate having a carbon-carbon unsaturated bond. The method for producing the unsaturated cyclic carbonate is not particularly limited, and a known method can be arbitrarily selected for production. Examples of the unsaturated cyclic carbonate include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, phenyl carbonates, vinyl carbonates, allyl carbonates, and the like.

[0076] Examples of the vinylene carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, allyl vinylene carbonate, and the like. Specific examples of the ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, phenyl ethylene carbonate, 4,5-diphenyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, and the like. Among them, vinylene carbonates and ethylene carbonates substituted with substituents having an aromatic ring or a carbon-carbon unsaturated bond are preferable, and in particular, vinylene carbonate, 4,5-diphenylvinylene carbonate, 4,5-dimethylvinylene carbonate, vinyl ethylene carbonate or ethynyl ethylene carbonate are more preferably used because they form a stable interfacial protective film.

[0077] The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight of the unsaturated cyclic carbonate is usually 50 or more, preferably 80 or more, and usually 250 or less, preferably 150 or less. Within this range, it is easy to ensure the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolyte, and the effects of the present invention are likely to be fully exhibited. The unsaturated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio. Also, the content of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the unsaturated cyclic carbonate is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, in 100% by mass of the non-aqueous electrolyte, and is usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less. Within the above range, the non-aqueous electrolyte secondary battery is likely to exhibit sufficient high-temperature storage characteristics and an effect of improving cycle characteristics.

[0078] The cyclic carbonate having a fluorine atom (hereinafter, may be abbreviated as "fluorinated cyclic carbonate") is not particularly limited as long as it is a cyclic carbonate having a fluorine atom. Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group with 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivatives include fluorides of ethylene carbonate or ethylene carbonate substituted with an alkyl group (e.g., an alkyl group having 1 to 4 carbon atoms), and among them, those having 1 to 8 fluorine atoms are preferred.

[0079] Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methyl ethylene carbonate, 4,5-difluoro-4-methyl ethylene carbonate, 4-fluoro-5-methyl ethylene carbonate, 4,4-difluoro-5-methyl ethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate, 4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethyl ethylene carbonate, 4,5-difluoro-4,5-dimethyl ethylene carbonate, 4,4-difluoro-5,5-dimethyl ethylene carbonate, etc. can be mentioned. Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethyl ethylene carbonate is more preferable in that it imparts high ionic conductivity and preferably forms an interfacial protective film.

[0080] The fluorinated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio. The content of the fluorinated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. However, in 100% by mass of the non-aqueous electrolyte, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 8% by mass or less, preferably 6% by mass or less, more preferably 5% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit sufficient cycle characteristics and high-temperature storage characteristics. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit sufficient cycle characteristics and high-temperature storage characteristics.

[0081] In addition, the fluorinated cyclic carbonate may be used as an auxiliary agent for the non-aqueous electrolyte or as a non-aqueous solvent. When used as a non-aqueous solvent, the content of the fluorinated cyclic carbonate in 100% by mass of the non-aqueous electrolyte is usually 8% by mass or more, preferably 10% by mass or more and more preferably 12% by mass or more, and usually 85% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient effect of improving cycle characteristics and is likely to avoid a decrease in the discharge capacity retention rate.

[0082] In the non-aqueous electrolyte according to one embodiment of the present invention, it is preferable that the carbonate having at least one of the carbon-carbon unsaturated bond and the fluorine atom is at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, ethynyl ethylene carbonate, and fluoroethylene carbonate.

[0083] <2-3-2. Fluorinated Unsaturated Cyclic Carbonate> As the fluorinated cyclic carbonate, a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter, may be abbreviated as "fluorinated unsaturated cyclic carbonate") can be used. The fluorinated unsaturated cyclic carbonate is not particularly limited. Among them, those having one or two fluorine atoms are preferable. The production method of the fluorinated unsaturated cyclic carbonate is not particularly limited, and a known method can be arbitrarily selected for production. Examples of the fluorinated unsaturated cyclic carbonate include vinylene carbonate derivatives, ethylene carbonate derivatives substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, and the like.

[0084] Examples of the vinylene carbonate derivative include 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-phenylvinylene carbonate, 4,5-difluoroethylene carbonate, and the like. Examples of the ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond include 4-fluoro-4-vinyl ethylene carbonate, 4-fluoro-5-vinyl ethylene carbonate, 4,4-difluoro-4-vinyl ethylene carbonate, 4,5-difluoro-4-vinyl ethylene carbonate, 4-fluoro-4,5-divinyl ethylene carbonate, 4,5-difluoro-4,5-divinyl ethylene carbonate, 4-fluoro-4-phenyl ethylene carbonate, 4-fluoro-5-phenyl ethylene carbonate, 4,4-difluoro-5-phenyl ethylene carbonate, 4,5-difluoro-4-phenyl ethylene carbonate, and the like.

[0085] The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight of the fluorinated unsaturated cyclic carbonate is usually 50 or more, preferably 80 or more, and usually 250 or less, preferably 150 or less. Within this range, it is easy to ensure the solubility of the fluorinated cyclic carbonate in the non-aqueous electrolyte, and the effects of the present invention are likely to be exhibited.

[0086] The fluorinated unsaturated cyclic carbonate may be used alone or in combination of two or more thereof in any combination and ratio. Further, the blending amount of the fluorinated unsaturated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. The content of the fluorinated unsaturated cyclic carbonate is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more in 100% by mass of the non-aqueous electrolyte, and is usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient effect of improving cycle characteristics.

[0087] <2-3-3. Compound having a cyano group> In the non-aqueous electrolyte of the present invention, the compound having a cyano group that can be used is not particularly limited as long as it is a compound having a cyano group in the molecule, but the compound represented by the following general formula (4) is more preferable. The method for producing the compound having a cyano group is not particularly limited, and a known method can be arbitrarily selected for production.

Chemical formula

[0088] In the general formula (4), T represents an organic group composed of atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, and a halogen atom, and U is a V-valent organic group having 1 to 10 carbon atoms which may have a substituent. V is an integer of 1 or more, and when V is 2 or more, T may be the same or different from each other. The molecular weight of the compound having a cyano group is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight of the compound having a cyano group is usually 40 or more, preferably 45 or more, more preferably 50 or more, and is usually 200 or less, preferably 180 or less, more preferably 170 or less. Within this range, it is easy to ensure the solubility of the compound having a cyano group in the non-aqueous electrolyte, and the effects of the present invention are likely to be exhibited.

[0089] Specific examples of the compound represented by the general formula (4) include, for example, acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenedinitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3,3'-oxydipropionitrile, 3,3'-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile and other compounds having one cyano group; malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelaonitrile, sebaconitrile, undecanedinitrile, dodecanedinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylsuccinonitrile, 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, trimethylsuccinonitrile, tetramethylsuccinonitrile, 3,3'-(ethylenedioxy)dipropionitrile, 3,3'-(ethylenedithio)dipropionitrile and other compounds having two cyano groups; 1,2,3-tris(2-cyanoethoxy)propane, tris(2-cyanoethyl)amine and other compounds having three cyano groups; Cyano compounds such as methyl cyanate, ethyl cyanate, propyl cyanate, butyl cyanate, pentyl cyanate, hexyl cyanate, heptyl cyanate; Sulfur-containing compounds such as methyl thiocyanate, ethyl thiocyanate, propyl thiocyanate, butyl thiocyanate, pentyl thiocyanate, hexyl thiocyanate, heptyl thiocyanate, methanesulfonyl cyanide, ethanesulfonyl cyanide, propanesulfonyl cyanide, butanesulfonyl cyanide, pentanesulfonyl cyanide, hexanesulfonyl cyanide, heptanesulfonyl cyanide, methyl sulfurothiocyanate, ethyl sulfurothiocyanate, propyl sulfurothiocyanate, butyl sulfurothiocyanate, pentyl sulfurothiocyanate, hexyl sulfurothiocyanate, heptyl sulfurothiocyanate, etc.; ; Phosphorus-containing compounds such as cyanodimethylphosphine, cyanodimethylphosphine oxide, methyl cyanomethylphosphonate, methyl cyanomethylphosphite, cyanide dimethylphosphonate, cyanide dimethylphosphite, cyanodimethylphosphonate, cyanodimethylphosphite, cyanomethylphosphonate dimethyl, cyanomethylphosphite dimethyl, cyanodimethylphosphate, cyanodimethylphosphite; etc. can be mentioned.

[0090] Among these, acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelaonitrile, sebaconitrile, undecanedinitrile or dodecanedinitrile are preferable from the viewpoint of improving the preservation characteristics, and malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelaonitrile, sebaconitrile, undecanedinitrile, or dodecanedinitrile having two cyano groups are more preferable.

[0091] The compound having a cyano group may be used alone or in combination of two or more in any combination and ratio. There is no limitation on the content of the compound having a cyano group in the non-aqueous electrolyte of the present invention, and it is arbitrary as long as the effects of the present invention are not significantly impaired. However, for the non-aqueous electrolyte of the present invention, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. When the above range is satisfied, the effects such as input-output characteristics, charge-discharge rate characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

[0092] <2-3-4. Isocyanate compound> In the non-aqueous electrolyte of the present invention, the compound having an isocyanate group that can be used (hereinafter, may be abbreviated as "isocyanate compound") is not particularly limited as long as it is a compound having an isocyanate group in the molecule. As the isocyanate compound, a diisocyanate compound having two isocyanate groups in the molecule is preferable.

[0093] <2-3-4-1. Diisocyanate compound> In the non-aqueous electrolyte of the present invention, the diisocyanate compound that can be used is preferably a compound having a nitrogen atom only in the isocyanate group in the molecule and represented by the following general formula (5).

Chemical formula

[0094] In the above general formula (5), X may contain a cyclic structure and is an organic group having 1 to 15 carbon atoms. The number of carbon atoms of X is usually 2 or more, preferably 3 or more, more preferably 4 or more, and usually 14 or less, preferably 12 or less, more preferably 10 or less, still more preferably 8 or less. In the above general formula (5), X is particularly preferably an organic group having 4 to 15 carbon atoms having one or more cycloalkylene groups or aromatic hydrocarbon groups having 4 to 6 carbon atoms. At this time, the hydrogen atoms on the cycloalkylene group may be substituted with a methyl group or an ethyl group. Since the diisocyanate compound having the above cyclic structure is a bulky molecule, side reactions on the positive electrode are less likely to occur, and as a result, the cycle characteristics and high-temperature storage characteristics are improved. Here, the bonding site of the group bonded to the cycloalkylene group or aromatic hydrocarbon group is not particularly limited and may be any of the meta-position, para-position, and ortho-position, but the meta-position or para-position is preferable because the inter-film crosslinking distance is appropriate, which is advantageous for lithium ion conductivity and easily reduces the resistance. Further, the cycloalkylene group being a cyclopentylene group or a cyclohexylene group is preferable from the viewpoint that the diisocyanate compound itself is less likely to cause side reactions, and the cyclohexylene group is more preferable because the resistance is easily reduced due to the influence of molecular mobility. Further, it is preferable to have an alkylene group having 1 to 3 carbon atoms between the cycloalkylene group or aromatic hydrocarbon group and the isocyanate group. By having an alkylene group, it becomes sterically bulky, so side reactions on the positive electrode are less likely to occur. Furthermore, if the alkylene group has 1 to 3 carbon atoms, the proportion of the isocyanate group in the total molecular weight does not change significantly, so the effects of the present invention are more likely to be significantly manifested.

[0095] The molecular weight of the diisocyanate compound represented by the above general formula (5) is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is usually 80 or more, preferably 115 or more, more preferably 170 or more, and usually 300 or less, preferably 230 or less. Within this range, it is easy to ensure the solubility of the diisocyanate compound in the non-aqueous electrolyte, and the effects of the present invention are likely to be manifested.

[0096] Specific examples of the diisocyanate compound include, for example, Cycloalkane ring-containing diisocyanates such as 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, dicyclohexylmethane-3,3′-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate; Aromatic ring-containing diisocyanates such as 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene-2,3-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,5-diisocyanate, tolylene-2,6-diisocyanate, tolylene-3,4-diisocyanate, tolylene-3,5-diisocyanate, 1,2-bis(isocyanatomethyl)benzene, 1,3-bis(isocyanatomethyl)benzene, 1,4-bis(isocyanatomethyl)benzene, 2,4-diisocyanatobiphenyl, 2,6-diisocyanatobiphenyl, 2,2′-diisocyanatobiphenyl, 3,3′-diisocyanatobiphenyl, 4,4′-diisocyanato-2-methylbiphenyl, 4,4′-diisocyanato-3-methylbiphenyl, 4,4′-diisocyanato-3,3′-dimethylbiphenyl, 4,4′-diisocyanatodiphenylmethane, 4,4′-diisocyanato-2-methyldiphenylmethane, 4,4′-diisocyanato-3-methyldiphenylmethane, 4,4′-diisocyanato-3,3′-dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 1,8-diisocyanatonaphthalene, 2,3-diisocyanatonaphthalene, 1,5-bis(isocyanatomethyl)naphthalene, 1,8-bis(isocyanatomethyl)naphthalene, 2,3-bis(isocyanatomethyl)naphthalene; etc. can be mentioned.

[0097] Among these, 1,2 - diisocyanatocyclopentane, 1,3 - diisocyanatocyclopentane, 1,2 - diisocyanatocyclohexane, 1,3 - diisocyanatocyclohexane, 1,4 - diisocyanatocyclohexane, 1,2 - bis(isocyanatomethyl )cyclohexane, 1,3 - bis(isocyanatomethyl)cyclohexane, 1,4 - bis(isocyanatomethyl)cyclohexane, 1,2 - phenylenediisocyanate, 1,3 - phenylenediisocyanate, 1,4 - phenylenediisocyanate, 1,2 - bis(isocyanatomethyl)benzene, 1,3 - bis(isocyanatomethyl)benzene, 1,4 - bis(isocyanatomethyl)benzene, 2,4 - diisocyanatobiphenyl or 2,6 - diisocyanatobiphenyl are preferred because a denser composite film is formed on the negative electrode, and as a result, the battery durability is improved. Among these, 1,3 - bis(isocyanatomethyl)cyclohexane, 1,4 - bis(isocyanatomethyl)cyclohexane, 1,3 - phenylenediisocyanate, 1,4 - phenylenediisocyanate, 1,2 - bis(isocyanatomethyl)benzene, 1,3 - bis(isocyanatomethyl)benzene or 1,4 - bis(isocyanatomethyl)benzene are more preferred because a film advantageous for lithium ion conductivity is formed on the negative electrode due to the symmetry of their molecules, and as a result, the battery characteristics are further improved. In addition, the above - mentioned diisocyanate compound may be used alone or in combination of two or more in any combination and ratio.

[0098] In the non - aqueous electrolyte of the present invention, the content of the diisocyanate compound that can be used is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. However, with respect to the non - aqueous electrolyte of the present invention, it is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, and usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less. When the content is within the above range, the durability such as cycle and storage can be improved, and the effects of the present invention can be fully exerted. The method for producing the diisocyanate compound is not particularly limited, and a known method can be arbitrarily selected for production. Alternatively, a commercially available product may be used.

[0099] <2-3-4-2. Isocyanate Compounds Other than Diisocyanate Compounds> The non-aqueous electrolyte of the present invention may contain an isocyanate compound other than the diisocyanate compound. Hereinafter, isocyanate compounds other than the diisocyanate compound that can be used in the non-aqueous electrolyte of the present invention will be described with specific examples. Specific examples of the isocyanate compound include, for example, Hydrocarbon-based monoisocyanate compounds such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, t-butyl isocyanate, pentyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, and fluorophenyl isocyanate; Monoisocyanate compounds having a carbon-carbon unsaturated bond such as vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, and propynyl isocyanate; Isocyanate compounds such as (ortho-, meta-, para-) toluenesulfonyl isocyanate, benzenesulfonyl isocyanate, fluorosulfonyl isocyanate, phenoxysulfonyl isocyanate, pentafluorophenoxysulfonyl isocyanate, and methoxysulfonyl isocyanate; and the like.

[0100] The isocyanate compounds described above may be used alone or in combination of two or more in any combination and ratio. There is no limitation on the compounding amount of the isocyanate compound with respect to the entire non-aqueous electrolyte of the present invention, and it is arbitrary as long as the effects of the present invention are not significantly impaired. The compounding amount is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1% by mass or less, most preferably or 0.5% by mass or less with respect to the non-aqueous electrolyte of the present invention. When the content is within the above range, the durability such as cycle and storage can be improved, and the effects of the present invention can be fully exhibited. In addition, the production method of the isocyanate compound is not particularly limited, and it is possible to arbitrarily select a known method for production. Also, commercially available products may be used.

[0101] <2-3-5. Carboxylic Anhydride> In the non-aqueous electrolyte of the present invention, as the carboxylic anhydride that can be used, a compound represented by the following general formula (6) is preferable. The production method of the carboxylic anhydride is not particularly limited, and it is possible to arbitrarily select a known method for production. [Chemical Formula]

[0102] In general formula (6), R 9 and R 10 each independently represent a hydrocarbon group having 1 or more and 15 or less carbon atoms, which may have a substituent. R 9 and R 10 may be bonded to each other to form a cyclic structure. R 9 and R 10is not particularly limited as long as it is a monovalent hydrocarbon group. For example, it may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated hydrocarbon group or may contain an unsaturated bond (carbon-carbon double bond or carbon-carbon triple bond). Further, the aliphatic hydrocarbon group may be linear or cyclic, and in the case of a linear structure, it may be straight-chain or branched-chain. Furthermore, it may be a combination of a linear and a cyclic structure. Note that R 9 and R 10 may be the same as or different from each other.

[0103] Also, when R 9 and R 10 are bonded to each other to form a cyclic structure, the hydrocarbon group formed by the bonding of R 9 and R 10 is divalent. The type of the divalent hydrocarbon group is not particularly limited. That is, it may be an aliphatic group, an aromatic group, or a combination of an aliphatic group and an aromatic group. In the case of an aliphatic group, it may be a saturated group or an unsaturated group. Further, it may be a linear group or a cyclic group, and in the case of a linear group, it may be a straight-chain group or a branched-chain group. Furthermore, it may be a combination of a linear group and a cyclic group. Also, when the hydrocarbon groups of R 9 and R 10 have substituents, the type of the substituents is not particularly limited as long as it does not conflict with the gist of the present invention. Examples include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, preferably a fluorine atom. Or, as substituents other than halogen atoms, substituents having functional groups such as ester group, cyano group, carbonyl group, and ether group may be mentioned, preferably a cyano group and a carbonyl group. The hydrocarbon groups of R 9 and R 10 may have only one of these substituents or may have two or more of them. When having two or more substituents, these substituents may be the same as or different from each other.

[0104] R 9 and R10 Each hydrocarbon group usually has 1 or more carbon atoms, and usually 15 or less, preferably 12 or less, more preferably 10 or less, and even more preferably 9 or less carbon atoms. R 9 and R 10 When R 9 and R 10 are bonded to each other to form a divalent hydrocarbon group, the divalent hydrocarbon group usually has 1 or more carbon atoms, and usually 15 or less, preferably 13 or less, more preferably 10 or less, and even more preferably 8 or less carbon atoms. Incidentally, when the hydrocarbon groups of R 9 and R 10 have substituents containing carbon atoms, the total number of carbon atoms of R including the substituents preferably satisfies the above range.

[0105] Next, specific examples of the carboxylic acid anhydride represented by the above general formula (6) (hereinafter, may be abbreviated as "acid anhydride") will be described. In the following examples, "analog" refers to an acid anhydride obtained by replacing a part of the structure of the exemplified acid anhydride with another structure within a range not contrary to the gist of the present invention. For example, dimers, trimers, and tetramers composed of a plurality of acid anhydrides, or those having structural isomers such as branched chains with the same number of carbon atoms in the substituents, and those having different bonding sites of the substituents to the acid anhydride can be mentioned.

[0106] First, specific examples of acid anhydrides in which R 9 and R 10 are the same are given below. R 9 and R 10Specific examples of the acid anhydride in which R is a chain alkyl group include acetic anhydride, propionic anhydride, butanoic anhydride, 2-methylpropionic anhydride, 2,2-dimethylpropionic anhydride, 2-methylbutanoic anhydride, 3-methylbutanoic anhydride, 2,2-dimethylbutanoic anhydride, 2,3-dimethylbutanoic anhydride, 3,3-dimethylbutanoic anhydride, 2,2,3-trimethylbutanoic anhydride, 2,3,3-trimethylbutanoic anhydride, 2,2,3,3-tetramethylbutanoic anhydride, 2-ethylbutanoic anhydride, and the like, and analogs thereof. R 9 and R 10 Specific examples of the acid anhydride in which R is a cyclic alkyl group include cyclopropanecarboxylic anhydride, cyclopentanecarboxylic anhydride, cyclohexanecarboxylic anhydride, and the like, and analogs thereof.

[0107] R 9 and R 10 Specific examples of the acid anhydride in which R is an alkenyl group include acrylic anhydride, 2-methylacrylic anhydride, 3-methylacrylic anhydride, 2,3-dimethylacrylic anhydride, 3,3-dimethylacrylic anhydride, 2,3,3-trimethylacrylic anhydride, 2-phenylacrylic anhydride, 3-phenylacrylic anhydride, 2,3-diphenylacrylic anhydride, 3,3-diphenylacrylic anhydride, 3-butenoic anhydride, 2-methyl-3-butenoic anhydride, 2,2-dimethyl-3-butenoic anhydride, 3-methyl-3-butenoic anhydride, 2-methyl-3-methyl-3-butenoic anhydride, 2,2-dimethyl-3-methyl-3-butenoic anhydride, 3-pentenoic anhydride, 4-pentenoic anhydride, 2-cyclopentene-1-carboxylic anhydride, 3-cyclopentene-1-carboxylic anhydride, 4-cyclopentene-1-carboxylic anhydride, and the like, and analogs thereof. R 9 and R 10 Specific examples of the acid anhydride in which R is an alkynyl group include propiolic anhydride, 3-phenylpropiolic anhydride, 2-butynoic anhydride, 2-pentynoic anhydride, 3-butynoic anhydride, 3-pentynoic anhydride, 4-pentynoic anhydride, and the like, and analogs thereof. R 9 and R 10 Specific examples of the acid anhydride in which R and R are aryl groups include benzoic anhydride, 4-methylbenzoic anhydride, 4-ethylbenzoic anhydride, 4-tert-butylbenzoic anhydride, 2-methylbenzoic anhydride, 2,4,6-trimethylbenzoic anhydride, 1-naphthalenecarboxylic anhydride, 2-naphthalenecarboxylic anhydride, etc., and their analogs and the like.

[0108] Also, R 9 and R 10 Examples of the acid anhydride in which R and R are halogen atom-substituted groups are mainly examples of the acid anhydride substituted with a fluorine atom, which are listed below. Acid anhydrides obtained by substituting some or all of these fluorine atoms with chlorine atoms, bromine atoms, or iodine atoms are also included in the exemplified compounds. R 9 and R 10 Examples of the acid anhydride in which R and R are chain alkyl groups substituted with halogen atoms include fluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, 2-fluoropropionic anhydride, 2,2-difluoropropionic anhydride, 2,3-difluoropropionic anhydride, 2,2,3-trifluoropropionic anhydride, 2,3,3-trifluoropropionic anhydride, 2,2,3,3-tetrapropionic anhydride, 2,3,3, 3-tetrapropionic anhydride, 3-fluoropropionic anhydride, 3,3-difluoropropionic anhydride, 3,3,3-trifluoropropionic anhydride, perfluoropropionic anhydride, etc., and their analogs and the like. R 9 and R 10 Examples of the acid anhydride in which R and R are cyclic alkyl groups substituted with halogen atoms include 2-fluorocyclopentanecarboxylic anhydride, 3-fluorocyclopentanecarboxylic anhydride, 4-fluorocyclopentanecarboxylic anhydride, etc., and their analogs and the like. R 9 and R 10Examples of acid anhydrides in which the alkenyl group is substituted with a halogen atom include 2-fluoroacrylic anhydride, 3-fluoroacrylic anhydride, 2,3-difluoroacrylic anhydride, 3,3-difluoroacrylic anhydride, 2,3,3-trifluoroacrylic anhydride, 2-(trifluoromethyl)acrylic anhydride, 3-(trifluoromethyl)acrylic anhydride, 2,3-bis(trifluoromethyl)acrylic anhydride, 2,3,3-tris(trifluoromethyl)acrylic anhydride, 2-(4-fluorophenyl)acrylic anhydride, 3-(4-fluorophenyl)acrylic anhydride, 2,3-bis(4-fluorophenyl)acrylic anhydride, 3,3-bis(4-fluorophenyl)acrylic anhydride, 2-fluoro-3-butenoic anhydride, 2,2-difluoro-3-butenoic anhydride, 3-fluoro-2-butenoic anhydride, 4-fluoro-3-butenoic anhydride, 3,4-difluoro-3-butenoic anhydride, 3,3,4-trifluoro-3-butenoic anhydride, and the like, and their analogs.

[0109] R 9 and R 10 Examples of acid anhydrides in which the alkynyl group is substituted with a halogen atom include 3-fluoro-2-propynoic anhydride, 3-(4-fluorophenyl)-2-propynoic anhydride, 3-(2,3,4,5,6-pentafluorophenyl)-2-propynoic anhydride, 4-fluoro-2-butynoic anhydride, 4,4-difluoro-2-butynoic anhydride, 4,4,4-trifluoro-2-butynoic anhydride, and the like, and their analogs. R 9 and R 10 Examples of acid anhydrides in which the aryl group is substituted with a halogen atom include 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, 4-(trifluoromethyl)benzoic anhydride, and the like, and their analogs. R 9 and R 10Examples of acid anhydrides having substituents with functional groups such as esters, nitriles, ketones, and ethers include methoxyformic anhydride, ethoxyformic anhydride, methyl oxalic anhydride, ethyl oxalic anhydride, 2-cyanoacetic anhydride, 2-oxopropionic anhydride, 3-oxobutyric anhydride, 4-acetylbenzoic anhydride, methoxyacetic anhydride, 4-methoxybenzoic anhydride, and the like, and their analogs.

[0110] Subsequently, R 9 and R 10 Specific examples of acid anhydrides in which are different from each other are given below. R 9 and R 10 As, all combinations of the examples listed above and their analogs can be considered, but representative examples are given below. Examples of combinations of linear alkyl groups include propionic acetic anhydride, butyric acetic anhydride, propionic butyric anhydride, 2-methylpropionic acetic anhydride, and the like. Examples of combinations of a linear alkyl group and a cyclic alkyl group include cyclopentanecarboxylic acetic anhydride, cyclohexanecarboxylic acetic anhydride, cyclopentanecarboxylic propionic anhydride, and the like. Examples of combinations of a linear alkyl group and an alkenyl group include acrylic acetic anhydride, 3-methylacrylic acetic anhydride, 3-butenoic acetic anhydride, propionic acrylic anhydride, and the like. Examples of combinations of a linear alkyl group and an alkynyl group include propiolic acetic anhydride, 2-butynoic acetic anhydride, 3-butynoic acetic anhydride, 3-phenylpropiolic acetic anhydride, propiolic propionic anhydride, and the like. Examples of combinations of a linear alkyl group and an aryl group include benzoic acetic anhydride, 4-methylbenzoic acetic anhydride, 1-naphthalenecarboxylic acetic anhydride, propionic benzoic anhydride, and the like. Examples of combinations of a hydrocarbon group having a chain alkyl group and a functional group include fluoroacetic anhydride, trifluoroacetic anhydride, 4-fluorobenzoic anhydride, fluoroacetic propionic anhydride, alkyl oxalic anhydride, 2-cyanoacetic anhydride, 2-oxopropionic anhydride, methoxyacetic anhydride, methoxyacetic propionic anhydride, and the like.

[0111] Examples of combinations of cyclic alkyl groups include cyclopentanoic cyclohexanoic anhydride, and the like. Examples of combinations of a cyclic alkyl group and an alkenyl group include cyclopentanoic acrylic anhydride, 3-methylcyclopentanoic acrylic anhydride, 3-butenoic cyclopentanoic anhydride, cyclohexanoic acrylic anhydride, and the like. Examples of combinations of a cyclic alkyl group and an alkynyl group include cyclopentanoic propiolic anhydride, 2-butynoic cyclopentanoic anhydride, cyclohexanoic propiolic anhydride, and the like. Examples of combinations of a cyclic alkyl group and an aryl group include cyclopentanoic benzoic anhydride, 4-methylcyclopentanoic benzoic anhydride, cyclohexanoic benzoic anhydride, and the like. Examples of combinations of a cyclic alkyl group and a hydrocarbon group having a functional group include cyclopentanoic fluoroacetic anhydride, cyclopentanoic trifluoroacetic anhydride, cyclopentanoic 2-cyanoacetic anhydride, cyclopentanoic methoxyacetic anhydride, cyclohexanoic fluoroacetic anhydride, and the like.

[0112] Examples of combinations of alkenyl groups include acrylic 2-methylacrylic anhydride, acrylic 3-methylacrylic anhydride, acrylic 3-butenoic anhydride, 2-methylacrylic 3-methylacrylic anhydride, and the like. Examples of combinations of an alkenyl group and an alkynyl group include acrylic propiolic anhydride, acrylic 2-butynoic anhydride, 2-methylacrylic propiolic anhydride, and the like. Examples of the combination of an alkenyl group and an aryl group include acrylic benzoic anhydride, 4-methylacrylic benzoic anhydride, 2-methylacrylic benzoic anhydride, and the like. Examples of the combination of an alkenyl group and a hydrocarbon group having a functional group include acrylic fluoroacetic anhydride, acrylic trifluoroacetic anhydride, acrylic 2-cyanoacetic anhydride, acrylic methoxyacetic anhydride, 2-methylacrylic fluoroacetic anhydride, and the like.

[0113] Examples of the combination of alkynyl groups include propiolic 2-butynoic anhydride, propiolic 3-butynoic anhydride, 2-butynoic 3-butynoic anhydride, and the like. Examples of the combination of an alkynyl group and an aryl group include benzoic propiolic anhydride, 4-methylbenzoic propiolic anhydride, benzoic 2-butynoic anhydride, and the like. Examples of the combination of an alkynyl group and a hydrocarbon group having a functional group include propiolic fluoroacetic anhydride, propiolic trifluoroacetic anhydride, propiolic 2-cyanoacetic anhydride, propiolic methoxyacetic anhydride, 2-butynoic fluoroacetic anhydride, and the like.

[0114] Examples of the combination of aryl groups include benzoic 4-methylbenzoic anhydride, benzoic 1-naphthalenecarboxylic anhydride, 4-methylbenzoic 1-naphthalenecarboxylic anhydride, and the like. Examples of the combination of an aryl group and a hydrocarbon group having a functional group include benzoic fluoroacetic anhydride, benzoic trifluoroacetic anhydride, benzoic 2-cyanoacetic anhydride, benzoic methoxyacetic anhydride, 4-methylbenzoic fluoroacetic anhydride, and the like.

[0115] Examples of the combination of hydrocarbon groups having functional groups include fluoroacetic trifluoroacetic anhydride, fluoroacetic 2-cyanoacetic anhydride, fluoroacetic methoxyacetic anhydride, trifluoroacetic 2-cyanoacetic anhydride, and the like. Among the acid anhydrides forming the above chain structure, preferably, acetic anhydride, propionic anhydride, 2-methylpropionic anhydride, cyclopentanecarboxylic anhydride, cyclohexanecarboxylic anhydride, etc., acrylic anhydride, 2-methylacrylic anhydride, 3-methylacrylic anhydride, 2,3-dimethylacrylic anhydride, 3,3-dimethylacrylic anhydride, 3-butenoic anhydride, 2-methyl-3-butenoic anhydride, propiolic anhydride, 2-butynoic anhydride, benzoic anhydride, 2-methylbenzoic anhydride, 4-methylbenzoic anhydride, 4-tert-butylbenzoic anhydride, trifluoroacetic anhydride, 3,3,3-trifluoropropionic anhydride, 2-(trifluoromethyl)acrylic anhydride, 2-(4-fluorophenyl)acrylic anhydride, 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, methoxyformic anhydride, ethoxyformic anhydride, and more preferably, acrylic anhydride, 2-methylacrylic anhydride, 3-methylacrylic anhydride, benzoic anhydride, 2-methylbenzoic anhydride, 4-methylbenzoic anhydride, 4-tert-butylbenzoic anhydride, 4-fluorobenzoic anhydride, 2,3,4,5,6-pentafluorobenzoic anhydride, methoxyformic anhydride, ethoxyformic anhydride. These compounds are preferable from the viewpoint that they can appropriately form a bond with lithium oxalate salt to form a film with excellent durability, and can particularly improve the charge-discharge rate characteristics, input-output characteristics, and impedance characteristics after the durability test.

[0116] Subsequently, specific examples of the acid anhydride in which R 9 and R 10 are bonded to each other to form a cyclic structure are given below. First, R 9 and R 10Specific examples of the acid anhydride in which R and R are bonded to each other to form a 5-membered ring structure include succinic anhydride, 4-methylsuccinic anhydride, 4,4-dimethylsuccinic anhydride, 4,5-dimethylsuccinic anhydride, 4,4,5-trimethylsuccinic anhydride, 4,4,5,5-tetramethylsuccinic anhydride, 4-vinylsuccinic anhydride, 4,5-divinylsuccinic anhydride, 4-phenylsuccinic anhydride, 4,5-diphenylsuccinic anhydride, 4,4-diphenylsuccinic anhydride, citraconic anhydride, maleic anhydride, 4-methylmaleic anhydride, 4,5-dimethylmaleic anhydride, 4-phenylmaleic anhydride, 4,5-diphenylmaleic anhydride, itaconic anhydride, 5-methylitaconic anhydride, 5,5-dimethylitaconic anhydride, phthalic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, and the like, and their analogs. R 9 and R 10 Specific examples of the acid anhydride in which R and R are bonded to each other to form a 6-membered ring structure include cyclohexane-1,2-dicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, glutaric anhydride, and the like, and their analogs. R 9 and R 10 Specific examples of the acid anhydride in which R and R are bonded to each other to form other cyclic structures include 5-norbornene-2,3-dicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, diglycolic anhydride, and the like, and their analogs. R 9 and R 10 Specific examples of the acid anhydride in which R and R are bonded to each other to form a cyclic structure and are substituted with a halogen atom include 4-fluorosuccinic anhydride, 4,4-difluorosuccinic anhydride, 4,5-difluorosuccinic anhydride, 4,4,5-trifluorosuccinic anhydride, 4,4,5,5-tetrafluorosuccinic anhydride, 4-fluoromaleic anhydride, 4,5-difluoromaleic anhydride, 5-fluoroitaconic anhydride, 5,5-difluoroitaconic anhydride, and the like, and their analogs. anhydride, 4,4,5,5-tetrafluorosuccinic anhydride, 4-fluoromaleic anhydride, 4,5-difluoromaleic anhydride, 5-fluoroitaconic anhydride, 5,5-difluoroitaconic anhydride, and the like, and their analogs.

[0117] The above R 9 and R 10 Among the acid anhydrides in which are combined, preferably, succinic anhydride, 4-methylsuccinic anhydride, 4-vinylsuccinic anhydride, 4-phenylsuccinic anhydride, citraconic anhydride, maleic anhydride, 4-methylmaleic anhydride, 4-phenylmaleic anhydride, itaconic anhydride, 5-methylitaconic anhydride, glutaric anhydride, phthalic anhydride, cyclohexane-1,2-dicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, 4-fluorosuccinic anhydride, 4-fluoromaleic anhydride, 5-fluoroitaconic anhydride, and more preferably, succinic anhydride, 4-methylsuccinic anhydride, 4-vinylsuccinic anhydride, citraconic anhydride, cyclohexane-1,2-dicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, 4-fluorosuccinic anhydride. These compounds are preferred because they can appropriately form a bond with lithium oxalate salt to form a film with excellent durability, and in particular, the capacity retention rate after the durability test is improved.

[0118] Note that there is no limitation on the molecular weight of the carboxylic anhydride, and it is arbitrary as long as the effects of the present invention are not significantly impaired. Usually, it is 90 or more, preferably 95 or more. On the other hand, it is usually 300 or less, preferably 200 or less. When the molecular weight of the carboxylic anhydride is within the above range, an increase in the viscosity of the electrolytic solution can be suppressed, and the film density can be optimized, so that the durability can be appropriately improved. In addition, there is no particular limitation on the production method of the carboxylic anhydride, and it is possible to arbitrarily select a known method for production. The carboxylic anhydride described above may be contained alone as any one kind in the non-aqueous electrolytic solution of the present invention, or two or more kinds may be jointly possessed in any combination and ratio. Moreover, there is no particular limitation on the content of the carboxylic anhydride in the non-aqueous electrolyte of the present invention, and it is arbitrary as long as the effects of the present invention are not significantly impaired. However, with respect to the non-aqueous electrolyte of the present invention, it is usually contained at a concentration of 0.01% by mass or more, preferably 0.1% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less. When the content of the carboxylic anhydride is within the above range, the effect of improving the cycle characteristics is likely to be exhibited, and the reactivity is suitable, so the battery characteristics are likely to be improved.

[0119] <2-3-6. Overcharge Preventive Agent> In the non-aqueous electrolyte of the present invention, an overcharge preventive agent can be used in order to effectively suppress the rupture and ignition of the battery when the non-aqueous electrolyte secondary battery is in a state such as overcharge. Examples of overcharge prevention agents include aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindane; partially fluorinated compounds of the above aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; fluorine-containing anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole; aromatic acetates such as 3-propylphenyl acetate, 2-ethylphenyl acetate, benzylphenyl acetate, methylphenyl acetate, benzyl acetate, phenethylphenyl acetate; and aromatic carbonates such as diphenyl carbonate and methylphenyl carbonate. Among them, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindane, 3-propylphenyl acetate, 2-ethylphenyl acetate, benzylphenyl acetate, methylphenyl acetate, benzyl acetate, phenethylphenyl acetate, diphenyl carbonate, and methylphenyl carbonate are preferred. These may be used alone or in combination of two or more. When using two or more in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, and at least one selected from oxygen-free aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran are preferably used in combination from the viewpoint of the balance between overcharge prevention characteristics and high-temperature storage characteristics. The content of the overcharge inhibitor is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired. The content of the overcharge inhibitor is usually 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and usually 5% by mass or less, preferably 4.8% by mass or less, more preferably 4.5% by mass or less in 100% by mass of the non-aqueous electrolyte. Within this range, the effects of the overcharge inhibitor are easily fully exhibited, and the characteristics of the battery such as high-temperature storage characteristics are improved.

[0120] <2-3-7. Other Auxiliaries> Known other auxiliaries can be used in the non-aqueous electrolyte of the present invention. Examples of other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; triple bond-containing compounds such as methyl-2-propynyl oxalate, ethyl-2-propynyl oxalate, bis(2-propynyl) oxalate, 2-propynyl acetate, 2-propynyl formate, 2-propynyl methacrylate, di(2-propynyl) glutarate, methyl-2-propynyl carbonate, ethyl-2-propynyl carbonate, bis(2-propynyl) carbonate, 2-butyne-1,4-diyl-dimethanesulfonate, 2-butyne-1,4-diyl-diethanesulfonate, 2-butyne-1,4-diyl-diformate, 2-butyne-1,4-diyl-diacetate, 2-butyne-1,4-diyl-dipropionate, 4-hexadiyne-1,6-diyl-dimethanesulfonate, 2-propynyl-methanesulfonate, 1-methyl-2-propynyl-methanesulfonate, 1,1-dimethyl-2-propynyl-methanesulfonate, 2-propynyl-ethanesulfonate, 2-propynyl-vinylsulfonate, 2-propynyl-2-(diethoxyphosphoryl) acetate, 1-methyl-2-propynyl-2-(diethoxyphosphoryl) acetate, 1,1-dimethyl-2-propynyl-2-(diethoxyphosphoryl) acetate; Spiro compounds such as 2,4,8,10-tetraoxaspiro[5.5]undecane and 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]undecane; Sulfur-containing compounds such as ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, diphenyl sulfone, N,N-dimethylmethanesulfonamide, N,N-diethylmethanesulfonamide, trimethylsilyl methyl sulfate, trimethylsilyl ethyl sulfate, and 2-propynyl-trimethylsilyl sulfate; Isocyanate compounds such as 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2-(2-isocyanatoethoxy)ethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, and 2-(2-isocyanatoethoxy)ethyl crotonate; Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone, and N-methylsuccinimide; Hydrocarbon compounds such as heptane, octane, nonane, decane, and cycloheptane; Fluorine-containing aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene, benzotrifluoride, pentafluorophenyl methanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate, pentafluorophenyl trifluoroacetate, and methyl pentafluorophenyl carbonate; Silane compounds such as tris(trimethylsilyl) borate, tris(trimethoxysilyl) borate, tris(trimethylsilyl) phosphate, tris(trimethoxysilyl) phosphate, dimethoxyaluminoxytriethoxysilane, diethoxyaluminoxytriethoxysilane, dipropoxyaluminoxytriethoxysilane, dibutoxyaluminoxytriethoxysilane, dibutoxyaluminoxytriethoxysilane, titanium tetrakis(trimethylsiloxide), and titanium tetrakis(triethylsiloxide); and the like; Ester compounds such as 2-propynyl 2-(methanesulfonyloxy)propionate, 2-methyl 2-(methanesulfonyloxy)propionate, 2-ethyl 2-(methanesulfonyloxy)propionate, 2-propynyl methanesulfonyloxyacetate, 2-methyl methanesulfonyloxyacetate, 2-ethyl methanesulfonyloxyacetate; Lithium salts such as lithium ethylmethyloxycarbonylphosphonate, lithium ethylethyloxycarbonylphosphonate, lithium ethyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1-methyl-2-propynyloxycarbonylphosphonate, lithium ethyl-1,1-dimethyl-2-propynyloxycarbonylphosphonate; etc. These may be used alone or in combination of two or more. By adding these auxiliaries, the capacity retention characteristics and cycle characteristics after high-temperature storage can be improved. The content of other auxiliaries is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of other auxiliaries is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more in 100% by mass of the non-aqueous electrolyte, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. Within this range, the effects of other auxiliaries are easily fully manifested, and the characteristics of the battery such as high-load discharge characteristics are improved.

[0121] The non-aqueous electrolyte described above also includes those present inside energy devices such as non-aqueous electrolyte secondary batteries according to an embodiment of the present invention. Specifically, components of the non-aqueous electrolyte such as lithium salts, solvents, and auxiliary agents are separately synthesized, and the non-aqueous electrolyte is prepared from substantially isolated ones, and injected into a battery separately assembled by the method described below. This includes cases where it is the non-aqueous electrolyte inside the non-aqueous electrolyte secondary battery obtained, cases where the components of the non-aqueous electrolyte of the present invention are individually placed inside the battery and mixed inside the non-aqueous electrolyte secondary battery to obtain the same composition as the non-aqueous electrolyte of the present invention, and further cases where the compounds constituting the non-aqueous electrolyte of the present invention are generated inside the non-aqueous electrolyte secondary battery to obtain the same composition as the non-aqueous electrolyte of the present invention.

[0122] <2-4. Manufacturing method of non-aqueous electrolyte> The non-aqueous electrolyte of the present invention can be prepared by dissolving an electrolyte, a compound belonging to group (A) having a predetermined content ratio, and fluorosulfonate (B) in the aforementioned non-aqueous solvent, and, if necessary, the aforementioned "auxiliary agent" and the like. When preparing the non-aqueous electrolyte, each raw material of the non-aqueous electrolyte, that is, an electrolyte such as a lithium salt, a compound belonging to group (A), fluorosulfonate (B), a non-aqueous solvent, an auxiliary agent, etc. It is preferably dehydrated in advance. As for the degree of dehydration, it is usually desirable to dehydrate until it becomes 50 ppm or less, preferably 30 ppm or less. By removing the moisture in the non-aqueous electrolyte, electrolysis of water, reaction between water and lithium metal, hydrolysis of lithium salts, etc. are less likely to occur. There is no particular limitation on the means of dehydration. For example, when the object to be dehydrated is a liquid such as a non-aqueous solvent, a desiccant such as molecular sieve may be used. When the object to be dehydrated is a solid such as an electrolyte, it may be dried by heating at a temperature below the temperature at which decomposition occurs.

[0123] <3. Energy devices using non-aqueous electrolyte> The energy device using the non-aqueous electrolyte of the present invention includes a plurality of electrodes capable of occluding or releasing metal ions and the non-aqueous electrolyte of the present invention described above. Specific examples of the type of energy device include primary batteries, secondary batteries, and metal ion capacitors such as lithium ion capacitors. Among them, a primary battery or a secondary battery is preferable, and a secondary battery is particularly preferable. Note that the non-aqueous electrolyte used in these energy devices is preferably a so-called gel electrolyte that is pseudo-solidified with a polymer, a filler, or the like. Hereinafter, the energy device will be described.

[0124] <3-1. Non-aqueous electrolyte secondary battery> <3-1-1. Battery configuration> The non-aqueous electrolyte secondary battery according to an embodiment of the present invention (hereinafter, also referred to as the non-aqueous secondary battery of the present invention) is the same as a conventionally known non-aqueous electrolyte secondary battery in terms of the configuration other than the non-aqueous electrolyte. Usually, a positive electrode and a negative electrode are laminated via a porous membrane (separator) impregnated with the non-aqueous electrolyte of the present invention, and they are housed in a case (outer package). Therefore, the shape of the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and it may be any of a cylindrical shape, a rectangular shape, a laminate shape, a coin shape, a large size, etc.

[0125] <3-1-2. Non-aqueous electrolyte> As the non-aqueous electrolyte, the non-aqueous electrolyte of the present invention described above is used. Note that within a range not departing from the gist of the present invention, it is also possible to mix and use other non-aqueous electrolytes with the non-aqueous electrolyte of the present invention.

[0126] <3-1-3. Negative electrode> The negative electrode active material used for the negative electrode is not particularly limited as long as it can electrochemically occlude and release metal ions. Specific examples thereof include carbonaceous materials, metal compound-based materials, lithium-containing metal composite oxide materials, and the like. These may be used alone or in any combination of two or more. Among these, carbonaceous materials and metal compound-based materials are preferred. Among the metal compound-based materials, materials containing silicon are preferred. Therefore, as the negative electrode active material, carbonaceous materials and materials containing silicon are particularly preferred.

[0127] <3-1-3-1. Carbonaceous materials> The carbonaceous materials used as the negative electrode active material are not particularly limited, but those selected from the following (a) to (e) are preferred because they provide a secondary battery with a good balance between the initial irreversible capacity and the charge-discharge characteristics at a high current density. (a) Natural graphite (b) Carbonaceous materials obtained by heat-treating artificial carbonaceous substances and artificial graphite-like substances at least once in the range of 400°C to 3200°C (c) Carbonaceous materials in which the negative electrode active material layer is composed of at least two types of carbonaceous materials having different crystallinities and / or has an interface where the carbonaceous materials of different crystallinities are in contact with each other (d) The negative electrode active material layer is composed of at least two types of carbonaceous materials having different orientations and / or has an interface where the carbonaceous materials of different orientations are in contact with each other. (a) to (e) The carbonaceous materials may be used alone or in combination of two or more in any combination and ratio. Specific examples of the artificial carbonaceous substances or artificial graphite-like substances in the above (b) include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, and those obtained by oxidizing these pitches; needle coke, pitch coke, and carbon materials partially graphitized therefrom; pyrolyzates of organic substances such as furnace black, acetylene black, and pitch-based carbon fibers; carbonizable organic substances and their carbides; and solutions of carbonizable organic substances dissolved in low-molecular organic solvents such as benzene, toluene, xylene, quinoline, and n-hexane. In addition, all of the carbonaceous materials in the above (a) to (e) are conventionally known, and their manufacturing methods are well known to those skilled in the art, and these commercial products can also be purchased.

[0128] <3-1-3-2. Metal compound-based materials> As the metal compound-based material used as the negative electrode active material, as long as it can occlude and release lithium, it is not particularly limited, and a simple metal or alloy that forms an alloy with lithium, or a compound such as their oxide, carbide, nitride, silicide, sulfide, phosphide, etc. can be used. Examples of such metal compounds include compounds containing metals such as Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn, Sr, Zn, etc. Among them, it is preferably a simple metal or alloy that forms an alloy with lithium, more preferably a material containing a metal or semi-metal element in Group 13 or 14 of the periodic table (that is, excluding carbon. Also, hereinafter, metals and semi-metals are collectively referred to as "metals"). Even more preferably, it is a simple metal of silicon (Si), tin (Sn), or lead (Pb) (hereinafter, these three elements may be referred to as "SSP metal elements") or an alloy containing these atoms, or a compound of these metals (SSP metal elements). Particularly preferred is a compound containing silicon. These may be used alone, or two or more of them may be used in combination in any combination and ratio.

[0129] <3-1-3-3. Lithium-containing metal composite oxide material> As the lithium-containing metal composite oxide material used as the negative electrode active material, as long as it can occlude and release lithium, it is not particularly limited, but a lithium-containing composite metal oxide material containing titanium is preferred, and a composite oxide of lithium and titanium (hereinafter, may be abbreviated as "lithium titanium composite oxide") is particularly preferred. That is, when a lithium titanium composite oxide having a spinel structure is contained in the negative electrode active material for a lithium ion non-aqueous electrolyte secondary battery and used, the output resistance of the secondary battery is greatly reduced, so it is particularly preferred. Also preferred are those in which lithium or titanium of the lithium titanium composite oxide is substituted with at least one element selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. Preferred lithium titanium composite oxides as the negative electrode active material include lithium titanium composite oxides represented by the following general formula (7). Li x Ti y M z O4(7) (In general formula (7), M represents at least one element selected from the group consisting of Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. Also, in general formula (7), it is preferable that 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, and 0 ≦ z ≦ 1.6 because the structure is stable during the doping and undoping of lithium ions.)

[0130] <3-1-3-4. Configuration, Physical Properties, and Preparation Method of Negative Electrode> For the negative electrode containing the above active material, polarization method, and current collector, known technical configurations can be adopted, but it is desirable to simultaneously satisfy any one or more of the following (i) to (vi). It is desirable to satisfy simultaneously.

[0131] (i) Fabrication of Negative Electrode For the production of the negative electrode, any known method can be used as long as it does not significantly limit the effects of the present invention. For example, a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. are added to the negative electrode active material to form a slurry-like negative electrode forming material, which is applied to a current collector, dried, and then pressed to form a negative electrode active material layer.

[0132] (ii) Current Collector As the current collector for holding the negative electrode active material, known ones can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel, but copper is particularly preferable in terms of ease of processing and cost. In addition, when the current collector is made of a metal material, examples of the shape of the current collector include a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, expanded metal, punched metal, and foamed metal. Among these, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil obtained by a rolling method and an electrolytic copper foil obtained by an electrolysis method are even more preferable.

[0133] (iii) Ratio of the thickness of the current collector to the negative electrode active material layer The ratio of the thickness of the current collector to the negative electrode active material layer is not particularly limited, but the value of “(thickness of the negative electrode active material layer on one side immediately before the non-aqueous electrolyte injection step) / (thickness of the current collector)” is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, and also preferably 0.1 or more, more preferably 0.4 or more, and particularly preferably 1 or more. When the ratio of the thickness of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat during high current density charge and discharge of the secondary battery. On the other hand, when it is below the above range, the volume ratio of the current collector to the negative electrode active material increases, and the capacity of the secondary battery may decrease.

[0134] (iv) Electrode density The electrode structure when the negative electrode active material is polarized is not particularly limited, and the density of the negative electrode active material present on the current collector is 1 g·cm -3 or more, preferably 1.2 g·cm -3 or more, more preferably 1.3 g·cm -3 or more, even more preferably, and also preferably 4 g·cm -3 or less, preferably 3 g·cm -3 or less, more preferably 2.5 g·cm -3 or less, even more preferably 1.7 g·cm -3 or less, particularly preferably. When the density of the negative electrode active material present on the current collector is within the above range, the negative electrode active material particles are less likely to be destroyed, it is easy to prevent an increase in the initial irreversible capacity of the secondary battery and deterioration of the high current density charge and discharge characteristics due to a decrease in the permeability of the non-aqueous electrolyte near the current collector / negative electrode active material interface. Furthermore, the conductivity between the negative electrode active materials can be ensured, the battery resistance does not increase, and the capacity per unit volume can be achieved.

[0135] (v) Binder, solvent, etc. The slurry for forming the negative electrode active material layer is usually prepared by adding a mixture of a binder (adhesive), a thickener, etc. in a solvent to the negative electrode active material. The binder for binding the negative electrode active material is not particularly limited as long as it is a material stable to the non-aqueous electrolyte and the solvent used during electrode manufacturing. Specific examples thereof include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, and nitrocellulose; Rubbery polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), and ethylene-propylene rubber; Styrene-butadiene-styrene block copolymer or its hydrogenated product; EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-styrene copolymer, Thermoplastic elastomer-like polymers such as styrene-isoprene-styrene block copolymer or its hydrogenated product; Syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, soft resin-like polymers such as propylene-α-olefin copolymer; Fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene-ethylene copolymer; Polymer compositions having ionic conductivity of alkali metal ions (especially lithium ions) etc. These may be used alone or in any combination and ratio of two or more. The solvent for forming the slurry is not particularly limited in type as long as it can dissolve or disperse the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Either an aqueous solvent or an organic solvent may be used. Examples of the aqueous solvent include water, alcohol, etc., and examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N,N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphoramide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. Particularly when using an aqueous solvent, it is preferable to contain a dispersant, etc. together with a thickener and form a slurry using a latex such as SBR. These solvents may be used alone, or two or more kinds may be used in combination at any combination and ratio.

[0136] The ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 0.6 part by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less, and particularly preferably 8 parts by mass or less. When the ratio of the binder to the negative electrode active material is within the above range, the ratio of the binder that does not contribute to the battery capacity does not increase, so it is difficult to cause a decrease in the battery capacity. Furthermore, it is difficult to cause a decrease in the strength of the negative electrode. Particularly, when the slurry, which is a negative electrode forming material, contains a rubber-like polymer typified by SBR as a main component, the ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 0.6 part by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 2 parts by mass or less. Also, when the slurry contains a fluorine-based polymer typified by polyvinylidene fluoride as a main component, the ratio of the binder to 100 parts by mass of the negative electrode active material is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 8 parts by mass or less.

[0137] The thickener is usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specifically, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof can be mentioned. These may be used alone or in combination of two or more in any combination and ratio. When using a thickener, the ratio of the thickener to 100 parts by mass of the negative electrode active material is usually 0.1 part by mass or more, preferably 0.5 part by mass or more, and more preferably 0.6 part by mass or more. Also, the ratio is usually 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 2 parts by mass or less. When the ratio of the thickener to the negative electrode active material is within the above range, the coatability of the slurry becomes good. Furthermore, the ratio of the negative electrode active material in the negative electrode active material layer also becomes appropriate, and problems such as a decrease in battery capacity and an increase in resistance between the negative electrode active materials are less likely to occur.

[0138] (vi) The area of the negative electrode plate The area of the negative electrode plate is not particularly limited, but it is preferably designed to be slightly larger than the opposing positive electrode plate so that the positive electrode plate does not protrude outside the negative electrode plate. Also, from the viewpoint of suppressing the cycle life when the charge and discharge of the secondary battery are repeated and deterioration due to high-temperature storage, it is preferable to make the area as close as possible to that of the positive electrode, because it increases the proportion of the electrode that works more uniformly and effectively, improving the characteristics. In particular, when the secondary battery is used at a high current, the design of the area of this negative electrode plate is important.

[0139] <3-1-4. Positive electrode> The positive electrode used in the non-aqueous electrolyte secondary battery of the present invention will be described below. <3-1-4-1. Positive electrode active material> The positive electrode active material used in the positive electrode will be described below.

[0140] (1) Composition The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release metal ions. For example, those that can electrochemically occlude and release lithium ions are preferred, and substances containing lithium and at least one transition metal are preferred. Specific examples include lithium transition metal composite oxides, lithium-containing transition metal phosphate compounds, lithium-containing transition metal silicate compounds, and lithium-containing transition metal borate compounds. As the transition metal of the lithium transition metal composite oxide, V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferred. Specific examples of the composite oxide include lithium-cobalt composite oxides such as LiCoO2, lithium-nickel composite oxides such as LiNiO2, lithium-manganese composite oxides such as LiMnO2, LiMn2O4, and Li2MnO4, and those in which part of the transition metal atoms that are the main components of these lithium transition metal composite oxides are substituted with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W. Specific examples of the substituted ones include, for example, LiNi 0.5 Mn 0.5 O2, LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.33 Co 0.33 Mn 0.33 O2, LiMn2O4, LiMn 1.8 Al 0.2 O4, Li 1.1 Mn 1.9 Al 0.1 O4, LiMn 1.5 Ni 0.5 O4, etc. Among them, composite oxides containing lithium, nickel, and cobalt are more preferred. This is because composite oxides containing cobalt and nickel can increase the capacity when used at the same potential.

[0141] On the other hand, cobalt is a metal with a small resource amount and high cost. In large batteries that require high capacity such as automotive applications, the amount of active material used increases. Therefore, from the perspective of cost, it is also desirable to use manganese as the main component as a cheaper transition metal. That is, lithium nickel cobalt manganese composite oxide is more preferable. Among them, from the perspective of highly satisfying the balance between cost and capacity, lithium nickel cobalt manganese composite oxide with a reduced amount of cobalt used and an increased amount of nickel used is particularly preferable. For example, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, etc. can be cited as particularly preferable specific examples. Also, considering the stability as a compound and the procurement cost due to ease of manufacture, lithium manganese composite oxide having a spinel-type structure is also preferable. That is, among the above specific examples, LiMn2O4, LiMn 1.8 Al 0.2 O4, Li 1.1 Mn 1.9 Al 0.1 O4, LiMn 1.5 Ni 0.5 O4, etc. can also be cited as preferable specific examples.

[0142] As the transition metal of the lithium-containing transition metal phosphate compound, V, Ti, Cr, Mn, F e, Co, Ni, Cu, etc. are preferable. Specific examples of the phosphate compound include, for example, iron phosphates such as LiFePO4, Li3Fe2(PO4)3, LiFeP2O7, cobalt phosphates such as LiCoPO4, manganese phosphates such as LiMnPO4, and those in which a part of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are substituted with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W. As the transition metal of the lithium-containing transition metal silicate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable. Specific examples of the silicate compound include, for example, iron silicates such as Li2FeSiO4, cobalt silicates such as Li2CoSiO4, and those in which a part of the transition metal atoms that are the main components of these lithium transition metal silicate compounds are substituted with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W, etc. As the transition metal of the lithium-containing transition metal borate compound, V, Ti, Cr, Mn, Fe, Co, Ni, Cu, etc. are preferable. Specific examples of the borate compound include, for example, iron borates such as LiFeBO3, cobalt borates such as LiCoBO3, and those in which a part of the transition metal atoms that are the main components of these lithium transition metal borate compounds are substituted with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, W, etc.

[0143] (2) Method for producing the positive electrode active material The method for producing the positive electrode active material is not particularly limited as long as it does not exceed the gist of the present invention, and several methods can be mentioned. A general method as the method for producing an inorganic compound is used. In particular, various methods can be considered for producing spherical or ellipsoidal active materials. For example, as an example, a transition metal raw material substance such as a transition metal nitrate or sulfate, and, if necessary, a raw material substance of other elements are dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring to produce and recover a spherical precursor, which is dried if necessary, and then a Li source such as LiOH, Li2CO3, LiNO3, etc. is added and fired at a high temperature to obtain the active material. Also, as an example of another method, a transition metal raw material substance such as a transition metal nitrate, sulfate, hydroxide, oxide, etc., and, if necessary, a raw material substance of other elements are dissolved or pulverized and dispersed in a solvent such as water, and this is dried and molded with a spray dryer or the like to form a spherical or ellipsoidal precursor, and a Li source such as LiOH, Li2CO3, LiNO3, etc. is added thereto and fired at a high temperature to obtain the active material. As an example of still another method, a transition metal raw material substance such as a transition metal nitrate, sulfate, hydroxide, oxide, etc., a Li source such as LiOH, Li2CO3, LiNO3, etc., and, if necessary, raw material substances of other elements are dissolved or pulverized and dispersed in a solvent such as water, and then dried and formed with a spray dryer or the like to obtain a spherical or elliptical spherical precursor, which is fired at a high temperature to obtain an active material.

[0144] <3-1-4-2. Cathode Structure and Manufacturing Method> Hereinafter, the configuration of the cathode used in the present invention and its manufacturing method will be described. (Manufacturing Method of Cathode) The cathode is manufactured by forming a cathode active material layer containing cathode active material particles and a binder on a current collector. The manufacturing of the cathode using the cathode active material can be carried out by any known method. For example, the cathode active material, the binder, and, if necessary, a conductive material, a thickener, etc. are dry-mixed and formed into a sheet, which is then pressure-bonded to the cathode current collector, or these materials are dissolved or dispersed in a liquid medium to form a slurry, which is applied to the cathode current collector and dried, thereby forming a cathode active material layer on the current collector to obtain a cathode. The content of the cathode active material in the cathode active material layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 99.9% by mass or less, more preferably 99% by mass or less. When the content of the cathode active material is within the above range, sufficient capacitance can be ensured. Furthermore, the strength of the cathode will also be sufficient. The cathode active material powder in the present invention may be used alone, or two or more kinds having different compositions or different powder physical properties may be used in any combination and ratio. When two or more kinds of active materials are used in combination, it is preferable to use the composite oxide containing lithium and manganese as a component of the powder. As described above, cobalt or nickel is a metal with a small resource amount and high price. In a large battery that requires high capacity such as for automotive applications, the amount of active material used is large, so it is not preferable in terms of cost. Therefore, it is desirable to use manganese as the main component as a cheaper transition metal.

[0145] (Conductive material) As the conductive material, known conductive materials can be arbitrarily used. Specific examples include metal materials such as copper and nickel; graphite (graphite) such as natural graphite and artificial graphite; carbon black such as acetylene black; and carbonaceous materials such as amorphous carbon such as needle coke. These may be used alone or in combination of two or more in any combination and ratio. The content of the conductive material in the positive electrode active material layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 1% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass or less, and still more preferably 15% by mass or less. When the content is within the above range, sufficient conductivity can be ensured. Furthermore, it is easy to prevent a decrease in battery capacity.

[0146] (Binder) The binder used for manufacturing the positive electrode active material layer is not particularly limited as long as it is a material stable to the non-aqueous electrolyte and the solvent used during electrode manufacturing. When producing the positive electrode by the coating method, the binder is not particularly limited as long as it is a material that is dissolved or dispersed in the liquid medium used during electrode manufacturing. Specific examples thereof include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, and nitrocellulose; Rubbery polymers such as SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, isoprene rubber, butadiene rubber, and ethylene-propylene rubber; Thermoplastic elastomer-like polymers such as styrene-butadiene-styrene block copolymer or its hydrogenated product, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block copolymer or its hydrogenated product; Soft resin-like polymers such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene-vinyl acetate copolymer, and propylene-α-olefin copolymer; Fluorine-based polymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene-ethylene copolymer; Polymer compositions having ionic conductivity for alkali metal ions (especially lithium ions) And the like. These substances may be used alone or in combination of two or more in any combination and ratio.

[0147] The content of the binder in the positive electrode active material layer is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 80% by mass or less, more preferably 60% by mass or less, still more preferably 40% by mass or less, and particularly preferably 10% by mass or less. When the proportion of the binder is within the above range, the positive electrode active material can be sufficiently retained and the mechanical strength of the positive electrode can be ensured, so that the battery performance such as cycle characteristics is improved. Furthermore, it also helps to avoid a decrease in battery capacity and conductivity.

[0148] (Liquid medium) As the liquid medium used for preparing the slurry for forming the positive electrode active material layer, there is no particular limitation on the type as long as it is a solvent capable of dissolving or dispersing the positive electrode active material, the conductive material, the binder, and the thickener used as necessary, and either an aqueous solvent or an organic solvent may be used. Examples of the aqueous medium include, for example, water, a mixed solvent of alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; Aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; Heterocyclic compounds such as quinoline and pyridine; Ketones such as acetone, methyl ethyl ketone, and cyclohexanone; Esters such as methyl acetate and methyl acrylate; Amines such as diethylenetriamine and N,N-dimethylaminopropylamine; Ethers such as diethyl ether and tetrahydrofuran (THF); Amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide; Aprotic polar solvents such as hexamethylphosphoramide and dimethyl sulfoxide etc. can be mentioned. These may be used alone or in combination of two or more in any combination and ratio.

[0149] (Thickener) When an aqueous medium is used as the liquid medium for forming the slurry, it is preferable to form a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). The thickener is usually used to adjust the viscosity of the slurry. The thickener is not limited as long as the effects of the present invention are not significantly limited. Specifically, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof can be mentioned. These may be used alone or in combination of two or more in any combination and ratio. When using a thickener, the ratio of the thickener to the total mass of the positive electrode active material and the thickener is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.6% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 2% by mass or less. When within the above range, the coatability of the slurry is good, and furthermore, since the ratio of the active material in the positive electrode active material layer is sufficient, it is easy to avoid problems such as a decrease in the capacity of the secondary battery and an increase in the resistance between the positive electrode active materials.

[0150] (Consolidation) The positive electrode active material layer obtained by applying and drying the above slurry on the current collector is preferably consolidated by hand pressing, roller pressing, etc. to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1 g·cm -3 or more, more preferably 1.5 g·cm -3 or more, and still more preferably 2 g·cm -3The above is particularly preferable, and 4 g·cm -3 or less is preferable, 3.9 g·cm -3 or less is more preferable, 3.8 g·cm -3 or less is particularly preferable. When the density of the positive electrode active material layer is within the above range, the permeability of the non-aqueous electrolyte to the vicinity of the current collector / active material interface does not decrease, and particularly the charge / discharge characteristics at a high current density of the secondary battery are improved. Further, the conductivity between the active materials is less likely to decrease, and the battery resistance is less likely to increase.

[0151] (Current collector) The material of the positive electrode current collector is not particularly limited, and known materials can be arbitrarily used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbonaceous materials such as carbon cloth and carbon paper. Among them, metal materials, particularly aluminum, are preferable. As for the shape of the current collector, in the case of a metal material, metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, foamed metal, etc. can be mentioned, and in the case of a carbonaceous material, carbon plate, carbon thin film, carbon cylinder, etc. can be mentioned. Among these, a metal thin film is preferable. Note that the thin film may be appropriately formed in a mesh shape.

[0152] The thickness of the current collector is arbitrary, but preferably 1 μm or more, more preferably 3 μm or more, still more preferably 5 μm or more, and preferably 1 mm or less, more preferably 100 μm or less, still more preferably 50 μm or less. When the thickness of the current collector is within the above range, the strength required as a current collector can be sufficiently ensured. Further, the handleability is also good. The ratio of the thickness of the current collector to that of the positive electrode active material layer is not particularly limited, but (the thickness of the active material layer on one side immediately before injecting the non-aqueous electrolyte solution) / (the thickness of the current collector) is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, and preferably 0.1 or more, more preferably 0.4 or more, and particularly preferably 1 or more. When the ratio of the thickness of the current collector to that of the positive electrode active material layer is within the above range, it becomes difficult for the current collector to generate heat due to Joule heat during charge and discharge at a high current density of the secondary battery. Furthermore, it becomes difficult for the volume ratio of the current collector to the positive electrode active material to increase, and a decrease in battery capacity can be prevented.

[0153] (Electrode area) From the viewpoint of enhancing high output and stability at high temperatures, it is preferable that the area of the positive electrode active material layer is larger than the outer surface area of the battery exterior case. Specifically, it is preferable that the total electrode area of the positive electrode with respect to the surface area of the exterior of the non-aqueous electrolyte secondary battery is 20 times or more, more preferably 40 times or more, in terms of area ratio. The outer surface area of the exterior case means the total area calculated from the dimensions of the length, width, and thickness of the case portion filled with the power generation elements excluding the protruding portions of the terminals in the case of a bottomed rectangular shape. In the case of a bottomed cylindrical shape, it is the geometric surface area approximated by regarding the case portion filled with the power generation elements excluding the protruding portions of the terminals as a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode composite layer facing the composite layer containing the negative electrode active material. In a structure in which the positive electrode composite layers are formed on both sides via a current collector foil, it means the sum of the areas calculated separately for each surface.

[0154] (Discharge capacity) When using the non-aqueous electrolyte of the present invention, if the electric capacity of the battery element housed in one battery exterior of the non-aqueous electrolyte secondary battery (the electric capacity when the battery is discharged from a fully charged state to a discharged state) is 1 ampere-hour (Ah) or more, it is preferable because the effect of improving the low-temperature discharge characteristics becomes large. Therefore, the positive electrode plate is designed so that the discharge capacity is fully charged, preferably 3 Ah (ampere-hour), more preferably 4 Ah or more, and preferably 20 Ah or less, more preferably 10 Ah or less. Within the above range, when extracting a large current, the voltage drop due to the electrode reaction resistance does not become too large, and it is possible to prevent deterioration of the power efficiency. Further, the temperature distribution due to internal heat generation of the battery during pulse charge and discharge does not become too large, the durability of repeated charge and discharge is not inferior, and it is possible to avoid phenomena such as poor heat dissipation efficiency with respect to rapid heat generation during abnormal conditions such as overcharge and internal short circuit.

[0155] (Thickness of the positive electrode plate) The thickness of the positive electrode plate is not particularly limited. However, from the viewpoints of high capacity, high output, and high rate characteristics, the thickness of the positive electrode active material layer after subtracting the thickness of the current collector is preferably 10 μm or more, more preferably 20 μm or more, and preferably 200 μm or less, more preferably 150 μm or less, with respect to one side of the current collector.

[0156] <3-1-5. Separator> In the non-aqueous electrolyte secondary battery of the present invention, a separator is usually interposed between the positive electrode and the negative electrode in order to prevent short circuit. In this case, the non-aqueous electrolyte of the present invention is usually used by impregnating this separator. There are no particular restrictions on the material and shape of the separator, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, resins, glass fibers, inorganic substances, etc., formed of materials stable with respect to the non-aqueous electrolyte of the present invention are used, and it is preferable to use a porous sheet or a non-woven fabric form excellent in liquid retention. As materials for the resin and glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, aramid resins, polytetrafluoroethylene, polyethersulfone, glass filters, etc. can be used. Among them, glass filters and polyolefins are preferable, and polyolefins are more preferable. These materials may be used alone, or two or more kinds may be used in combination in any combination and ratio.

[0157] The thickness of the separator is arbitrary, but preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less. When the thickness of the separator is within the above range, the insulation and mechanical strength are good. Furthermore, it is possible to prevent a decrease in battery performance such as rate characteristics, and it is also possible to prevent a decrease in the energy density of the non-aqueous electrolyte secondary battery as a whole. Furthermore, when using a porous material such as a porous sheet or non-woven fabric as the separator, the porosity of the separator is arbitrary, but preferably 20% or more, more preferably 35% or more, still more preferably 45% or more, and preferably 90% or less, more preferably 85% or less, still more preferably 75% or less. When the porosity is within the above range, the membrane resistance does not become too large, and deterioration of the rate characteristics of the secondary battery can be suppressed. Furthermore, the mechanical strength of the separator is also appropriate, and a decrease in insulation can be suppressed. Also, the average pore diameter of the separator is arbitrary, but preferably 0.5 μm or less, more preferably 0.2 μm or less, and preferably 0.05 μm or more. When the average pore diameter is within the above range, short circuit is less likely to occur. Furthermore, the membrane resistance does not become too large, and a decrease in the rate characteristics of the secondary battery can be prevented. On the other hand, as the inorganic material, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used, and those having a particle shape or a fiber shape are used. As the form of the separator, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. Among the thin film-shaped separators, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-mentioned independent thin film shape, a separator in which a composite porous layer containing the inorganic particles is formed on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, alumina particles with a particle size of less than 1 μm for 90% are used on both sides of the positive electrode, and a porous layer is formed using a fluororesin as a binder.

[0158] <3-1-6. Battery Design> (Electrode Group) The electrode group may be either a laminated structure formed by laminating the above-mentioned positive electrode plate and negative electrode plate via the above-mentioned separator, or a structure formed by winding the above-mentioned positive electrode plate and negative electrode plate in a spiral via the above-mentioned separator. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupancy rate) is preferably 40% or more, more preferably 50% or more, and preferably 95% or less, more preferably 90% or less. When the electrode group occupancy rate is within the above range, it is difficult for the battery capacity to become small. In addition, since an appropriate void space can be ensured, when the battery becomes hot, the members expand, the vapor pressure of the liquid component of the non-aqueous electrolyte increases, and the internal pressure rises, which may deteriorate various characteristics such as the charge-discharge cycle performance and high-temperature storage characteristics as a secondary battery. Furthermore, it is possible to avoid the case where a gas release valve for releasing the internal pressure to the outside operates.

[0159] (Current Collection Structure) The current collection structure is not particularly limited, but in order to more effectively improve the discharge characteristics of the non-aqueous electrolyte of the present invention, it is preferable to adopt a structure that reduces the resistance of the wiring portion and the joint portion. When the internal resistance is reduced in this way, the effect of using the non-aqueous electrolyte of the present invention is particularly well exhibited. When the electrode group has the above-mentioned laminated structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to the terminal is preferably used. When the area of one electrode becomes large, the internal resistance becomes large, so it is also preferably used to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the above-mentioned wound structure, a plurality of lead structures are provided for the positive electrode and the negative electrode respectively, and by bundling them to the terminal, the internal resistance can be lowered.

[0160] (Protection Element) Examples of protection elements include a PTC (Positive Temperature Coefficient) thermistor whose resistance increases when abnormal heat generation or excessive current flows, a temperature fuse, and a valve (current cutoff valve) that cuts off the current flowing through the circuit due to a rapid increase in the internal pressure or internal temperature of the battery during abnormal heat generation. It is preferable to select a protection element that does not operate under normal use conditions of high current, and it is more preferable to design the battery so that abnormal heat generation or thermal runaway does not occur even without a protection element.

[0161] (Outer casing) The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the above non-aqueous electrolyte, negative electrode, positive electrode, separator, etc. in an outer casing (outer case). There is no limitation on this outer casing, and a known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. The material of the outer case is not particularly limited as long as it is a stable substance with respect to the non-aqueous electrolyte used. Specifically, metals such as nickel-plated steel sheets, stainless steel, aluminum or aluminum alloys, magnesium alloys, nickel, titanium, etc., or a laminated film (laminate film) of resin and aluminum foil are used. From the perspective of weight reduction, metals such as aluminum or aluminum alloys and laminate films are preferably used. In the case of an outer case using the above metals, those having a sealed structure by welding the metals together by laser welding, resistance welding, or ultrasonic welding, or those having a caulked structure using the above metals via a resin gasket can be mentioned. In the case of an outer case using the above laminate film, those having a sealed structure by heat-sealing the resin layers together can be mentioned. In order to improve the sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when heat-sealing the resin layer through a current collector terminal to form a sealed structure, since it is a joint between metal and resin, a resin having a polar group or a modified resin into which a polar group is introduced is preferably used as the interposed resin. Also, the shape of the outer case is arbitrary, and it may be, for example, cylindrical, rectangular, laminated, coin-shaped, large-sized, or the like.

[0162] <3-2. Non-aqueous electrolyte primary battery> In the non-aqueous electrolyte primary battery which is one embodiment of the present invention, for example, a material capable of occluding metal ions is used for the positive electrode, and a material capable of releasing metal ions is used for the negative electrode. As the positive electrode material, transition metal oxides such as graphite fluoride and manganese dioxide are preferable. As the negative electrode material, a simple metal such as zinc or lithium is preferable. For the non-aqueous electrolyte, the non-aqueous electrolyte of the present invention described above is used.

[0163] <3-3. Metal ion capacitor> In the metal ion capacitor which is one embodiment of the present invention, for example, a material capable of forming an electric double layer is used for the positive electrode and a material capable of occluding and releasing metal ions is used for the negative electrode. As the positive electrode material, activated carbon is preferable. Also, as the negative electrode material, a carbonaceous material is preferable. For the non-aqueous electrolyte, the non-aqueous electrolyte of the present invention described above is used.

[0164] <3-4. Electric double layer capacitor> In the electric double layer capacitor which is one embodiment of the present invention, for example, a material capable of forming an electric double layer is used for the electrode. As the electrode material, activated carbon is preferable. For the non-aqueous electrolyte, the non-aqueous electrolyte of the present invention described above is used.

Examples

[0165] Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

[0166] (Example 1) [Fabrication of negative electrode] To 98 parts by mass of a carbonaceous material, as a thickener and a binder, 1 part by mass of an aqueous dispersion of sodium carboxymethyl cellulose (concentration of sodium carboxymethyl cellulose: 1% by mass) and 1 part by mass of an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber: 50% by mass) were added, and the mixture was mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil with a thickness of 10 μm, dried, and rolled with a press machine, and then cut into a shape having an active material layer with a width of 30 mm, a length of 40 mm, and an uncoated portion with a width of 5 mm and a length of 9 mm as the negative electrode.

[0167] [Fabrication of Positive Electrode] As the positive electrode active material, 94% by mass of LiNi 0.6 Mn 0.2 Co 0.2 O2, 3% by mass of acetylene black as a conductive material, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in an N-methylpyrrolidone solvent to form a slurry. The obtained slurry was applied to one side of an aluminum foil with a thickness of 15 μm on which a conductive aid had been previously applied, dried, and roll-pressed with a press machine, and then cut into a shape having an active material layer with a width of 30 mm, a length of 40 mm, and an uncoated portion with a width of 5 mm and a length of 9 mm as the positive electrode.

[0168] [Preparation of Non-Aqueous Electrolyte] Under a dry argon atmosphere, 4.99% by mass of dried (FSO2)2NLi (hereinafter referred to as lithium bis(fluorosulfonyl)imide), 0.01% by mass of FSO3Li, and 8.8% by mass of LiPF6 were dissolved in a mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) (volume ratio 30:30:40) to prepare the non-aqueous electrolyte of Example 1.

[0169] [Manufacture of Non-Aqueous Electrolyte Secondary Battery] The above positive electrode, negative electrode, and separator made of polyethylene were laminated in the order of negative electrode, separator, and positive electrode to fabricate a battery element. This battery element was inserted into a bag made of a laminate film with both sides of aluminum (thickness 40 μm) coated with a resin layer so that the terminals of the positive and negative electrodes of the battery element protruded from the bag. Then, the above electrolytic solution was injected into the bag, vacuum-sealed, and a sheet-like non-aqueous electrolytic solution secondary battery of Example 1 that reached a fully charged state at 4.3 V was fabricated.

[0170] [Evaluation of initial discharge capacity] The non-aqueous electrolytic solution secondary battery was charged to 4.3 V at a constant current corresponding to 0.2C at 25°C while being sandwiched between glass plates to enhance the adhesion between the electrodes, and then discharged to 2.8 V at a constant current of 0.2C. This was performed for 2 cycles to stabilize the battery. In the 3rd cycle, after charging to 4.3 V at a constant current of 0.2C, charging was carried out at a constant voltage of 4.3 V until the current value reached 0.05C, and then discharged to 2.8 V at a constant current of 0.2C. Thereafter, in the 4th cycle, after charging to 4.3 V at a constant current of 0.2C, charging was carried out at a constant voltage of 4.3 V until the current value reached 0.05C, and then discharged to 2.8 V at a constant current of 0.2C to obtain the initial discharge capacity.

[0171] [Evaluation of output characteristics] The battery after the evaluation of the initial discharge capacity was charged at 25°C at a constant current of 0.2C to a capacity that was half of the initial discharge capacity. This was discharged at 0.5C, 1.0C, 1.5C, 2.0C, and 2.5C at 25°C, respectively, and the voltage at 10 seconds was measured. The current value at 2.8V was obtained from the current-voltage straight line, and 2.8×(current value at 2.8V) was taken as the output (W). The results are shown in Table 1. In Table 1, the value of the output of Example 1 when the output in the case of Comparative Example 1 described later was taken as 100 was described as the relative output. The same applies hereinafter.

[0172] [Evaluation of input characteristics] The battery for which the evaluation of the initial discharge capacity had been completed was charged at 25°C at a constant current of 0.2C to a capacity that was half of the initial discharge capacity. This was then charged at 25°C at 0.5C, 1.0C, 1.5C, 2.0C, and 2.5C respectively, and the voltage at the 10th second was measured. The current value at 4.3V was obtained from the current-voltage straight line, and 4.3 × (the current value at 4.3V) was taken as the input (W). The results are shown in Table 1. In Table 1, the value of the input of Example 1 when the input in the case of Comparative Example 1 described later was taken as 100 was described as the relative input. The same applies hereinafter.

[0173] (Example 2) A sheet-like non-aqueous electrolyte secondary battery of Example 2 was produced and evaluated in the same manner as in Example 1, except that lithium bis(fluorosulfonyl)imide was dissolved to be 4.9% by mass and LiFSO3 was dissolved to be 0.1% by mass. The results are shown in Table 1. [Evaluation of cycle characteristics] The battery for which the evaluation of the initial discharge capacity had been completed was charged at 25°C at a constant current of 1C until 4.3V, and then discharged at a constant current of 0.2C until 2.8V. This was taken as 1 cycle and carried out for 100 cycles, and (the discharge capacity at 100 cycles) ÷ the initial discharge capacity × 100 was taken as the 25°C cycle capacity retention rate. The results are shown in Table 1. In Table 1, the value of the 25°C cycle capacity retention rate of Example 2 when the input in the case of Comparative Example 1 described later was taken as 100 was described as the relative value. The same applies hereinafter.

[0174] (Example 3) A sheet-like non-aqueous electrolyte secondary battery of Example 3 was produced and evaluated in the same manner as in Example 1, except that lithium bis(fluorosulfonyl)imide was dissolved to be 4.5% by mass and LiFSO3 was dissolved to be 0.5% by mass. The results are shown in Table 1.

[0175] (Example 4) A sheet-like non-aqueous electrolyte secondary battery of Example 4 was produced and evaluated in the same manner as in Example 1, except that lithium bis(fluorosulfonyl)imide was dissolved to be 4.0% by mass and LiFSO3 was dissolved to be 1.0% by mass. The results are shown in Table 1.

[0176] (Example 5) A sheet-like non-aqueous electrolyte secondary battery of Example 5 was fabricated and evaluated in the same manner as in Example 1, except that 3.0 mass% of lithium bis(fluorosulfonyl)imide and 2.0 mass% of FSO3Li were dissolved. The results are shown in Table 1.

[0177] (Example 6) A sheet-like non-aqueous electrolyte secondary battery of Example 6 was fabricated and evaluated in the same manner as in Example 1, except that 6.0 mass% of lithium bis(fluorosulfonyl)imide and 0.5 mass% of FSO3Li were dissolved. The results are shown in Table 1.

[0178] (Comparative Example 1) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 1 was fabricated and evaluated in the same manner as in Example 1, except that 5.0 mass% of lithium bis(fluorosulfonyl)imide was dissolved without dissolving FSO3Li. The results are shown in Table 1.

[0179] (Comparative Example 2) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 2 was fabricated and evaluated in the same manner as in Example 1, except that 2.0 mass% of lithium bis(fluorosulfonyl)imide and 3.0 mass% of FSO3Li were dissolved. The results are shown in Table 1.

[0180] (Comparative Example 3) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 3 was fabricated and evaluated in the same manner as in Example 1, except that 1.0 mass% of lithium bis(fluorosulfonyl)imide and 4.0 mass% of FSO3Li were dissolved. The results are shown in Table 1.

[0181] (Comparative Example 4) 4.0 mass% of lithium bis(fluorosulfonyl)imide and 1.0 mass% of lithium methyl sulfate were mixed and attempted to be dissolved in a non-aqueous electrolyte. However, since lithium methyl sulfate could not be dissolved and a sheet-like non-aqueous electrolyte secondary battery could not be fabricated, the evaluation was aborted.

[0182] (Comparative Example 5) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 5 was produced and evaluated in the same manner as in Example 1, except that 14.4% by mass of lithium bis(fluorosulfonyl)imide and 0.5% by mass of FSO3Li were dissolved and LiPF6 was not dissolved. The results are shown in Table 1.

[0183] [Table 1]

[0184] As is clear from Table 1, it can be seen that Examples 1 to 6 are superior to Comparative Examples 1 to 3 in input / output characteristics and cycle capacity retention rate. That is, when the ratio of the content mass of the fluorosulfonate (B) to the content mass of lithium bis(fluorosulfonyl)imide, which is a compound belonging to group (A), is 1 or less, a good effect is exhibited on the input / output characteristics and the cycle capacity retention rate. Further, Examples 1 to 6 show good relative output and relative input with respect to Comparative Example 5 in which the content mass of lithium bis(fluorosulfonyl)imide, which is a compound belonging to group (A), exceeds 8% by mass. It is also clear. In addition, when 1.0% by mass of lithium methyl sulfate, which has a structure relatively close to that of the fluorosulfonate (B), was used, the lithium methyl sulfate did not dissolve and a uniform non-aqueous electrolyte could not be prepared. From this, it can be seen that even a compound having a structure similar to that of the fluorosulfonate (B) is essential for exerting the effect by using the fluorosulfonate (B) as described in this specification.

[0185] (Example 7) A sheet-like non-aqueous electrolyte secondary battery of Example 7 was produced and evaluated in the same manner as in Example 1, except that 1.25% by mass of 1,2-ethylene sulfate, 0.75% by mass of FSO3Li, and 13.6% by mass of LiPF6 were dissolved and lithium bis(fluorosulfonyl)imide was not dissolved. The results are shown in Table 2. Table 2 shows the relative values when the values in the case of Comparative Example 6 described later are taken as 100.

[0186] (Comparative Example 6) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 6 was produced and evaluated in the same manner as in Example 1, except that 1,2-ethylene sulfate was dissolved to a concentration of 2% by mass and LiPF6 was dissolved to a concentration of 13.6% by mass, and lithium bis(fluorosulfonyl)imide and FSO3Li were not dissolved. The results are shown in Table 2.

[0187] [Table 2]

[0188] As is clear from Table 2, it can be seen that Example 7 is superior to Comparative Example 6 in input / output characteristics and cycle capacity retention rate. That is, when the ratio of the content mass of the fluorosulfonate (B) to the content mass of 1,2-ethylene sulfate, which is a compound belonging to Group (A), is 1 or less, a good effect is exhibited on the input / output characteristics and the cycle capacity retention rate.

[0189] (Example 8) A sheet-like non-aqueous electrolyte secondary battery of Example 8 was produced and evaluated in the same manner as in Example 1, except that 1,3-propene sultone was dissolved to a concentration of 1.25% by mass, FSO3Li was dissolved to a concentration of 0.75% by mass, and lithium bis(fluorosulfonyl)imide was not dissolved. LiPF6 was dissolved to a concentration of 13.6% by mass. The results are shown in Table 3. Table 3 shows the relative values when the values in the case of Comparative Example 7 described later are set to 100.

[0190] (Comparative Example 7) A sheet-like non-aqueous electrolyte secondary battery of Comparative Example 7 was produced and evaluated in the same manner as in Example 1, except that 1,3-propene sultone was dissolved to a concentration of 2% by mass and LiPF6 was dissolved to a concentration of 13.6% by mass, and lithium bis(fluorosulfonyl)imide and FSO3Li were not dissolved. The results are shown in Table 3.

[0191] [Table 3]

[0192] As is clear from Table 3, it can be seen that Example 8 is superior to Comparative Example 7 in input / output characteristics and cycle capacity retention rate. That is, when the ratio of the content mass of the fluorosulfonate (B) to the content mass of 1,3-propanesultone, which is a compound belonging to Group (A), is 1 or less, a good effect is exhibited on the input / output characteristics and the cycle capacity retention rate.

Industrial Applicability

[0193] According to the non-aqueous electrolyte of the present invention, it is possible to improve the cycle capacity retention rate during durability such as cycle operation or high-temperature storage of the non-aqueous electrolyte secondary battery, the input / output characteristics (input / output retention rate) after the cycle, and battery swelling, which is useful. Therefore, the non-aqueous electrolyte of the present invention and energy devices such as non-aqueous electrolyte secondary batteries using the same can be used for various known applications. Specific examples include, for example, notebook computers, pen input computers, mobile computers, e-book readers, mobile phones, mobile faxes, mobile copiers, mobile printers, headphone stereos, video movies, liquid crystal TVs, handy cleaners, portable CDs, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, motorized bicycles, bicycles, lighting fixtures, toys, game devices, watches, power tools, strobes, cameras, household backup power supplies, industrial backup power supplies, load leveling power supplies, natural energy storage power supplies, and the like.

Claims

1. One or more compounds selected from the group (A) consisting of 1,3-propane sultone and 1,3-propene sultone, The following formula (2): (FSO ３ ) ｘ M (2) [In formula (2), M is a metal atom, and x is the valence of the metal atom M and is an integer of 1 or more] and a fluorosulfonate (B) represented by the formula: the ratio of the mass content of the fluorosulfonate (B) to the mass content of the compound belonging to group (A) in the nonaqueous electrolyte solution is 0.250 or more and 1 or less, the content of the compound belonging to group (A) in the nonaqueous electrolyte solution is 0.01% by mass or more and 8% by mass or less, The energy device includes a positive electrode, the positive electrode includes a lithium-nickel-cobalt-manganese composite oxide, and the lithium-nickel-cobalt-manganese composite oxide has a nickel content of 50 atomic % or more relative to a total of 100 atomic % of nickel, cobalt, and manganese (however, this does not include a nonaqueous electrolyte solution containing a compound having a structure represented by the following formula (8)): 【Chemical 1】 (In formula (8), R １ ~R ３ represents an organic group having 1 to 20 carbon atoms which may have a substituent.

2. The nonaqueous electrolyte solution according to claim 1, wherein the compound belonging to group (A) includes 1,3-propane sultone.

3. The nonaqueous electrolyte solution according to claim 1, wherein the compound belonging to group (A) includes 1,3-propene sultone.

4. A non-aqueous electrolyte solution according to any one of claims 1 to 3, wherein the metal salt other than the fluorosulfonate (B) is one type.

5. A non-aqueous electrolyte solution described in any one of claims 1 to 4, wherein the ratio of the mass content of the fluorosulfonate (B) to the mass content of the compound belonging to group (A) in the non-aqueous electrolyte solution is 0.7 or less.

6. The non-aqueous electrolyte solution according to claim 1 , wherein the content of the fluorosulfonate (B) in the non-aqueous electrolyte solution is 2 mass % or less.

7. The fluorosulfonic acid salt (B) is FSO ３ The nonaqueous electrolyte solution according to claim 1 , further comprising Li.

8. The non-aqueous electrolyte solution is LiPF ６ The non-aqueous electrolyte solution according to claim 1 , comprising:

9. 9. An energy device comprising: a plurality of electrodes capable of absorbing and desorbing metal ions; and the nonaqueous electrolyte solution according to claim 1 , wherein the plurality of electrodes capable of absorbing and desorbing metal ions are a positive electrode and a negative electrode, the positive electrode contains a lithium-nickel-cobalt-manganese composite oxide, and a nickel content of the lithium-nickel-cobalt-manganese composite oxide is 50 atomic % or more relative to a total of 100 atomic % of nickel, cobalt, and manganese.

10. 10. The energy device according to claim 9, wherein the plurality of electrodes capable of absorbing and desorbing metal ions are a positive electrode and a negative electrode, and the negative electrode contains a carbonaceous material or a material containing silicon.

Images