Non-aqueous electrolytes and non-aqueous electrolyte batteries

Abstract

The present invention provides a non-aqueous electrolyte that can suppress gas generation during the initial conditioning of a non-aqueous electrolyte battery, and a non-aqueous electrolyte battery in which gas generation during initial conditioning is suppressed. [Solution] A non-aqueous electrolyte for a non-aqueous electrolyte battery, characterized in that the non-aqueous electrolyte contains an alkali metal salt and a non-aqueous solvent, a compound represented by general formula (A), and a compound represented by general formula (α). TIFF2026113628000045.tif32170 TIFF2026113628000046.tif36170

Description

[Technical Field]

[0001] The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery, and more particularly to a non-aqueous electrolyte containing a specific compound and a non-aqueous electrolyte battery using this non-aqueous electrolyte. [Background technology]

[0002] Non-aqueous electrolyte batteries, such as lithium-ion secondary batteries, have been put into practical use in a wide range of applications, including power supplies for so-called consumer small devices such as smartphones and laptop computers, as well as on-board power supplies for electric vehicles.

[0003] Numerous studies have been conducted in the fields of active materials for positive and negative electrodes, and additives for non-aqueous electrolytes, as means of improving the battery characteristics of non-aqueous electrolyte batteries.

[0004] For example, Patent Document 1 discloses a study on improving the increase in resistance during high-temperature storage by adding fluoroethylene carbonate, methyl 3,3,3-trifluoropropionate, and a borate ester having a specific structure to a non-aqueous electrolyte. Patent Document 2 discloses studies on improving battery characteristics, such as suppressing the increase in interfacial resistance during initial charging and suppressing the increase in interfacial resistance after high-temperature storage, by adding a borate ester having a specific structure to a non-aqueous electrolyte. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-168375 [Patent Document 2] Japanese Patent Publication No. 2003-132946 [Overview of the project] [Problems that the invention aims to solve]

[0006] In recent years, there has been an acceleration in increasing the capacity of lithium batteries for use in electric vehicles and mobile phones such as smartphones, resulting in a smaller proportion of air voids within the battery compared to conventional batteries. Therefore, a large amount of gas generated during initial conditioning becomes a critical drawback. While the effects disclosed in Patent Documents 1 and 2 can be obtained by using the electrolytes described therein, there is room for improvement in gas generation during initial conditioning.

[0007] The present invention aims to provide a non-aqueous electrolyte that can suppress gas generation during the initial conditioning of a non-aqueous electrolyte battery. Furthermore, it aims to provide a non-aqueous electrolyte battery in which gas generation during initial conditioning is suppressed. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the inventors of the present invention conceived of suppressing gas generation during initial conditioning by using a non-aqueous electrolyte containing a compound represented by general formula (A) and a silicon compound represented by general formula (α), and thus completed the present invention.

[0009] [1] A non-aqueous electrolyte for a non-aqueous electrolyte battery having a positive electrode and a negative electrode capable of intercalating and releasing metal ions, characterized in that the non-aqueous electrolyte contains an alkali metal salt and a non-aqueous solvent, a compound represented by general formula (A), and a compound represented by general formula (α). [ka] (In formula (A), R 1 ~R 3 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have heteroatoms, or a trialkylsilyl group. Also, R 1 ~R 3 They may be bonded to each other, forming a ring. [ka] (In formula (α), R 89 represents a hydrogen atom or a silyl group represented by -SiR 6 R 7 R 8 ; R 6 ~R 8 each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent. R 9 represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or a silyl group represented by -SiR d R e R f ; R d ~R f each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent. Y represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, a group represented by -NR g -SiR h R i R j or a group represented by -NR g -H; R g represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent; R h ~R j each independently represents a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent; R 9 and R g may be bonded to each other to form a ring.) [2] The content of the compound represented by the general formula (A) is 1. 0×10 -3 mass% or more and 10 mass% or less based on the total amount of the non-aqueous electrolyte, the non-aqueous electrolyte according to [1]. [3] The non-aqueous electrolyte according to [1] or [2], wherein the content of the compound represented by the general formula (α) is 0.01 ppm by mass or more and 0.5% by mass or less relative to the total amount of the non-aqueous electrolyte. [4] The non-aqueous electrolyte according to any one of [1] to [3], wherein the ratio of the mass content of the compound represented by the general formula (A) to the content of the compound represented by the general formula (α) in the non-aqueous electrolyte is 1.0 or more and 10000 or less. [5] A non-aqueous electrolyte according to any one of [1] to [6], wherein the compound represented by general formula (A) is the compound represented by general formula (A') or the compound represented by general formula (A''). [ka] (In general formula (A'), R 12 ~R 14 Each of these is a carbon which may have substituents. This shows alkylene groups with prime numbers from 1 to 10, X a It is at least a trivalent or pentavalent heteroatom. [ka] (In the general formula (A''), R 1a ~R 3a Each of these independently represents a C1-C10 hydrocarbon group which may have a heteroatom, or a trialkylsilyl group which may have a substituent, and at least one of them is a C1-C10 hydrocarbon group which may have a heteroatom, or a trialkylsilyl group which may have a substituent. [6] The non-aqueous electrolyte according to any one of [1] to [5], wherein the compound represented by the general formula (A) is triethanolamine borate or tristrimethylsilylborate. [7] A non-aqueous electrolyte battery comprising a positive electrode and a negative electrode and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte described in any of [1] to [6]. [Effects of the Invention]

[0010] According to the present invention, a non-aqueous electrolyte that is excellent at suppressing gas generation during the initial conditioning of a non-aqueous electrolyte battery, and a non-aqueous electrolyte battery in which gas generation during initial conditioning is suppressed can be obtained. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described in detail below. The following embodiments are examples (representative examples) of the present invention, and the present invention is not limited thereto. Furthermore, the present invention can be modified and implemented as appropriate without departing from its spirit.

[0012] <1.Non-aqueous electrolyte> A non-aqueous electrolyte according to one embodiment of the present invention contains a compound having a BO structure represented by the general formula (A) described below, and a compound represented by the general formula (α). This non-aqueous electrolyte is preferably used as a non-aqueous electrolyte for a non-aqueous electrolyte battery equipped with a positive electrode and a negative electrode capable of intercalating and releasing metal ions, as described later. The mechanism by which gas generation during initial conditioning is suppressed by using a non-aqueous electrolyte containing a compound having a BO structure represented by general formula (A) and a compound represented by general formula (α) is not clear, but it is presumed to be as follows.

[0013] Compounds represented by general formula (A) have a polar structure (-BO-) within the molecule. Therefore, compounds represented by general formula (A) tend to interact with the surface of negative electrode active materials such as carbon and / or positive electrode active materials such as transition metal oxides, and localize near the surface. Compounds represented by general formula (α) have a nonpolar structure (-SiR 6 R 7 R 8), and / or polar structures (-NH-, -N-(C=O)-). Generally, silicon atoms have a large electron cloud and no steric hindrance when forming bonds, so they readily form bonds with π electrons and unpaired electrons via empty d orbitals. Also, since boron compounds represented by general formula (A) have empty orbitals, they can easily interact with polar structures. Furthermore, if general formula (α) has an -NH- structure, it can interact with the -BO- portion of the compound represented by general formula (A) via hydrogen bonding. Therefore, compounds represented by general formula (A) localized on the active material surface interact with compounds represented by general formula (α), which promotes the fixation of these compounds to the electrodes. As a result, during the initial charge, the compound represented by general formula (α) and the compound represented by general formula (A) electrochemically decompose, forming a composite insulating film. This composite film is presumed to suppress side reactions of the electrolyte during initial conditioning and reduce gas generation.

[0014] <1-1. Compounds represented by general formula (A)> A non-aqueous electrolyte according to one embodiment of the present invention is characterized by containing a compound having a BO structure represented by the following general formula (A).

[0015] [ka]

[0016] In general formula (A), R 1 ~R 3 Each independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have heteroatoms, or a trialkylsilyl group, which may have substituents. Also, R 1 ~R 3 They may be bonded to each other, forming a ring.

[0017] R related to general formula (A) 1 ~R 3Each of these independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have heteroatoms, or a trialkylsilyl group, which may have substituents. Among these, the trialkylsilyl group, which may have substituents, is preferred because it can suitably interact with the compound represented by general formula (α). Note that if a hydrocarbon group has substituents, the number of carbon atoms contained in the substituents is not included in this carbon count. A hydrocarbon group that may have heteroatoms means that it may have substituents containing monovalent heteroatoms that substitute for hydrogen atoms of the hydrocarbon group, or it may have divalent substituents containing heteroatoms that substitute for divalent groups (such as methylene groups) containing carbon atoms in the hydrocarbon group. Also, if one or more carbon atoms of a hydrocarbon group have an oxo group (=O) as a substituent, the carbon atoms with the oxo group become carbonyl groups {-C(=O)-}. The hydrocarbon group having 1 to 10 carbon atoms is preferably a hydrocarbon group having 1 to 6 carbon atoms, and particularly preferably a hydrocarbon group having 1 to 4 carbon atoms.

[0018] Specific examples of hydrocarbon groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, or aralkyl groups. Specific examples of alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, n-pentyl group, hexyl group, heptyl group, octyl group, nonyl group, or decyl group. Preferably, methyl group, ethyl group, n-propyl group, n-butyl group, tert-butyl group, n-pentyl group, or hexyl group; more preferably, methyl group, ethyl group, n-propyl group, n-butyl group, tert-butyl group, or n-pentyl group; and particularly preferably, methyl group, ethyl group, n-butyl group, or tert-butyl group. When the hydrocarbon group is an alkyl group as described above, it is preferable because the compound relating to general formula (A) tends to localize near the surface of the positive electrode active material and / or negative electrode active material.

[0019] Specific examples of alkenyl groups include vinyl groups, allyl groups, methallyl groups, 2-butenyl groups, 3-methyl-2-butenyl groups, 3-butenyl groups, or 4-pentenyl groups. Among these, vinyl groups, allyl groups, methallyl groups, or 2-butenyl groups are preferred, more preferably vinyl groups, allyl groups, or methallyl groups, and particularly preferably vinyl groups or allyl groups. The above-mentioned alkenyl groups are preferred because they tend to localize the compound relating to general formula (A) near the surface of the positive electrode active material and / or negative electrode active material.

[0020] Specific examples of alkynyl groups include ethynyl, 2-propynyl, 2-butynyl, 3-butynyl, 4-pentynyl, or 5-hexynyl groups. Among these, ethynyl, 2-propynyl, 2-butynyl, or 3-butynyl groups are preferred, more preferably 2-propynyl or 3-butynyl groups, and particularly preferably 2-propynyl groups. When the hydrocarbon group is an alkynyl group as described above, the compound relating to general formula (A) tends to localize near the surface of the positive electrode active material and / or negative electrode active material, which is preferable.

[0021] Specific examples of aryl groups include phenyl groups and tolyl groups. Among these, phenyl groups are preferred from the viewpoint that compounds relating to general formula (A) tend to localize near the surface of the positive electrode active material and / or negative electrode active material. Specific examples of aralkyl groups include phenylmethyl group (benzyl group), phenylethyl group (phenethyl group), phenylpropyl group, phenylbutyl group, or phenylisopropyl group. Among these, benzyl group or phenethyl group are more preferred, and benzyl group is particularly preferred, from the viewpoint that the compound represented by general formula (A) tends to localize near the surface of the positive electrode active material and / or negative electrode active material.

[0022] Examples of heteroatoms include oxygen atoms, sulfur atoms, nitrogen atoms, phosphorus atoms, or halogen atoms. Examples of monovalent substituents containing heteroatoms include cyano groups, isocyanate groups, and acyl groups (-(C=O)-R a), acyloxy group (-O(C=O)-R a ), alkoxycarbonyl group (-(C=O)OR a ), sulfonyl group (-SO2-R a ), sulfonyloxy group (-O(SO2)-R a ), alkoxysulfonyl group (-(SO2)-OR a ), alkoxysulfonyl oxy group (-O-(SO2)-OR a ), alkoxycarbonyloxy group (-O-(C=O)-OR a ), ether group (-OR a Examples include ), halogen atoms (preferably fluorine atoms), or trifluoromethyl groups. a R represents an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. a If it is an alkylene group, it may bond with some of the substituted hydrocarbon groups to form a ring. Among these substituents, cyano groups, isocyanate groups, and acyloxy groups (-O(C=O)-R a ), halogen atom (preferably a fluorine atom), or trifluoromethyl group, more preferably an isocyanate group, acyloxy group (-O(C=O)-R a ), a halogen atom (preferably a fluorine atom), or a trifluoromethyl group, and more preferably an acyloxy group (-O(C=O)-R a ), halogen atoms (preferably) It is a fluorine atom, or a trifluoromethyl group, and is particularly preferably a fluorine atom. Examples of heteroatoms in divalent substituents that substitute a divalent group containing a carbon atom in a hydrocarbon group (such as a methylene group) include oxygen, sulfur, nitrogen, or phosphorus. Preferably, a phosphorus atom or nitrogen atom, and especially preferably a nitrogen atom, is used from the viewpoint of strengthening the interaction with the compound represented by general formula (α). 1 ~R 3If any one of them has a heteroatom, the lone pair of electrons of the heteroatom may be coordinated to the boron atom.

[0023] Specific examples of trialkylsilyl groups include trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, triisopropylsilyl, or tert-butyldimethylsilyl. Among these, trimethylsilyl or triethylsilyl is preferred from the viewpoint of suitably interacting with the compound represented by general formula (α). The substituents that the trialkylsilyl group may have may be unsaturated hydrocarbon groups such as alkenyl groups, alkynyl groups, aryl groups, or aralkyl groups, or substituents that include a monovalent heteroatom that substitutes a hydrogen atom of an alkyl group bonded to the Si atom of the trialkylsilyl group. Examples of monovalent substituents containing heteroatoms include cyano groups, isocyanate groups, and acyl groups (-(C=O)-R b ), acyloxy group (-O(C=O)-R b ), alkoxycarbonyl group (-(C=O)OR b ), sulfonyl group (-SO2-R b ), sulfonyloxy group (-O(SO2)-R b ), alkoxysulfonyl group (-(SO2)-OR b ), alkoxysulfonyl oxy group (-O-(SO2)-OR a ), alkoxycarbonyloxy group (-O-(C=O)-OR b ), ether group (-OR b Examples include ), halogen atoms (preferably fluorine atoms), or trifluoromethyl groups. a R represents an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. a If it is an alkylene group, it may bond with some of the substituted hydrocarbon groups to form a ring. Among the substituents that these trialkylsilyl groups may have, preferably are alkenyl groups, alkynyl groups, cyano groups, isocyanate groups, and acyloxy groups (-O(C=O)-R a ), halogen atom (preferably a fluorine atom), or trifluoromethyl group, more preferably an isocyanate group, acyloxy group (-O(C=O)-R a ), halogen atom (preferably a fluorine atom), or trifluoromethyl group, and more preferably an alkenyl group, acyloxy group (-O(C=O)-R a ), a halogen atom (preferably a fluorine atom), or a trifluoromethyl group, particularly preferably a fluorine atom.

[0024] Also, R 1 ~R 3 They may be bonded to each other, forming a ring. 1 ~R 3 R is a term used to describe how they bond to each other and form a ring. 1 ~R 3 Two of them may be bonded to each other to form a ring, or R 1 ~R 3 All combinations of these may be coupled to one another.

[0025] R related to general formula (A) 1 ~R 3 These may be the same or different, but it is preferable that at least two or more are the same in terms of ease of compound synthesis, and it is even more preferable that all three are the same from the aforementioned viewpoint. Also, from the viewpoint of the compound represented by general formula (A) readily interacting with the compound represented by general formula (α), R 1 ~R 3 It is also preferable that at least two of them are bonded to each other to form a ring, R 1 ~R 3 It is more preferable that they are bonded to each other and form a ring, R 1 ~R 3 It is even more preferable that the atoms are bonded to each other via heteroatoms, forming a ring.

[0026] In the compound represented by the general formula (A), R 1 ~R 3 are bonded to each other via a hetero atom to form a ring, and the boron-containing cyclic compound is specifically a compound represented by the following general formula (A’). It is a compound represented by the following formula.

[0027] [Chemical formula]

[0028] R 12 ~R 14 in the general formula (A’) each independently represents an alkylene group having 1 to 10 carbon atoms which may have a substituent, preferably an alkylene group having 1 to 6 carbon atoms, and particularly preferably an alkylene group having 2 to 4 carbon atoms. Specifically, examples include those obtained by removing one hydrogen atom from the alkyl group exemplified by R 1 ~R 3 to form an alkylene group. For example, methylene group, methylmethylene group, ethylmethylene group, dimethylmethylene group, diethylmethylene group, methylethylene group, dimethylene group (ethylene group), trimethylene group (propylene group), or tetramethylene group (butylene group) can be mentioned. Specific examples of the substituent include the groups exemplified by the monovalent substituents containing the above-mentioned hetero atom.

[0029] X in the general formula (A’) is at least a trivalent or pentavalent hetero atom, and examples include a phosphorus atom (P), P=O, or a nitrogen atom (N). Particularly preferably, it is a nitrogen atom. The lone pair of electrons of the hetero atom X may be coordinated to boron. R 12 ~R 14 in the general formula (A’) may be the same or different, but it is preferable that at least two or more are the same from the viewpoint of easy synthesis of the compound, and it is more preferable that all three are the same from the above-mentioned viewpoint.

[0030] ​Here, among the compounds according to the general formula (A), preferred compounds are the compounds represented by the above general formula (A') or the following general formula (A''). [Chemical formula]

[0031] In the general formula (A''), R 1a’ ~R 3a’ each independently represents a hydrocarbon group having 1 to 10 carbon atoms which may have a hetero atom, or a trialkylsilyl group which may have a substituent, and at least one is a hydrocarbon group having 1 to 10 carbon atoms having a hetero atom, or a trialkylsilyl group which may have a substituent. R 1a ~R 3a corresponds to the above R 1 ~R 3 and the preferred conditions can also be applied in the same way. The compound represented by the above formula (A') is preferably triethanolamine borate described later, and the compound represented by the above formula (A'') is preferably tris(trimethylsilyl) borate described later.

[0032] In one embodiment of the present invention, a compound represented by the general formula (A) is used, and specific examples include compounds having the following structures.

[0033] [Chemical formula]

[0034] Preferably, the following compounds are included.

[0035] [Chemical formula]

[0036] More preferably, the following compounds are included.

[0037] [ka]

[0038] Particularly preferred are the following compounds.

[0039] [ka]

[0040] In particular, the boron-containing cyclic compound is triethanolamine borate, or the borate ester compound having a trialkylsilyl group is tristrimethylsilylborate.

[0041] The compound represented by general formula (A) may be used alone or in combination of two or more. The total content of the compound represented by general formula (A) relative to the total amount of the non-aqueous electrolyte according to one embodiment of the present invention is usually 1.0 × 10⁻⁶ -3 Mass% or more, preferably 0.01% by mass or more, Preferably, it is 0.1% by mass or more, and usually 10% by mass or less, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass or less, and particularly preferably 1.0% by mass or less. If the total amount of the compound represented by general formula (A) relative to the total amount of non-aqueous electrolyte is within the above range, the concentration of the compound into the active material proceeds favorably, making it possible to manufacture a battery with less gas generation during initial conditioning. The identification and measurement of the content of compounds represented by general formula (A) in non-aqueous electrolytes are performed by nuclear magnetic resonance (NMR) spectroscopy.

[0042] <1-2. Compounds represented by general formula (α)> A non-aqueous electrolyte according to one embodiment of the present invention is characterized by containing a compound represented by the following general formula (α).

[0043] [ka]

[0044] In formula (α), R 89 is a hydrogen atom or -SiR 6 R 7 R 8 The silyl group represented by R is shown; 6 ~R 8 Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. 9 This is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have substituents, or -SiR d R e R f This represents a silyl group represented by R. d ~R f Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. Y represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents A good alkoxy group with 1 to 12 carbon atoms, -NR g -SiR h R i R j A base represented by -NR g R indicates a group represented by -H. g R represents a hydrocarbon group having 1 to 12 carbon atoms, which may have a hydrogen atom or substituents. h ~R j Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. 9 and R g They may be bonded to each other, forming a ring.

[0045] R related to general formula (α) 89 is a hydrogen atom or -SiR 6 R 7 R 8 The silyl group represented by R 6 ~R8 Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. Among these, a C1-C12 hydrocarbon group which may have substituents and a C1-C12 alkoxy group which may have substituents are preferred, and a C1-C12 hydrocarbon group which may have substituents is particularly preferred. If the hydrocarbon group has substituents, the number of carbon atoms in the substituents is not included in this C1 count. Also, R 6 ~R 8 It is preferable that at least one of the atoms is an alkyl group having 1 to 12 carbon atoms, from the viewpoint that the compound relating to general formula (α) tends to be suitably localized on the electrode surface. Particularly preferable is R 6 ~R 8 All of them are alkyl groups with 1 to 12 carbon atoms. R related to general formula (α) 6 ~R 8 These may be the same or different, but it is preferable that at least two or more are the same in terms of facilitating the synthesis of the compound, and it is even more preferable from the aforementioned viewpoint that all three are the same. Examples of halogen atoms include fluorine atoms, chlorine atoms, or bromine atoms. Preferably, fluorine atoms are used because they have fewer electrochemical side reactions. The hydrocarbon group having 1 to 12 carbon atoms is preferably a hydrocarbon having 1 to 6 carbon atoms, and particularly preferably a hydrocarbon having 1 to 4 carbon atoms. Specific examples of hydrocarbon groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, or aralkyl groups. Specific examples of alkyl groups include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, tert-butyl group, n-pentyl group, hexyl group, heptyl group, octyl group, nonyl group, or decyl group. Preferably, methyl group, ethyl group, n-propyl group, n-butyl group, tert-butyl group, n-pentyl group, or hexyl group; more preferably, methyl group, ethyl group, n-propyl group, n-butyl group, tert-butyl group, or n-pentyl group; and particularly preferably, methyl group, ethyl group, n-butyl group, or tert-butyl group. The above alkyl groups are preferred because they tend to localize the compound relating to general formula (α) near the surface of the positive electrode active material and / or negative electrode active material.

[0046] Specific examples of alkenyl groups include vinyl groups, allyl groups, methallyl groups, 2-butenyl groups, 3-methyl2-butenyl groups, 3-butenyl groups, or 4-pentenyl groups. Preferably, vinyl groups, allyl groups, methallyl groups, or 2-butenyl groups are used; more preferably, vinyl groups, allyl groups, or methallyl groups are used; and most preferably, vinyl groups or allyl groups are used. The aforementioned alkenyl group is preferable because it tends to localize the compound relating to general formula (α) near the surface of the positive electrode active material and / or the negative electrode active material.

[0047] Specific examples of alkynyl groups include ethynyl, 2-propynyl, 2-butynyl, 3-butynyl, 4-pentynyl, or 5-hexynyl groups. Among these, ethynyl, 2-propynyl, 2-butynyl, or 3-butynyl groups are preferred, more preferably 2-propynyl or 3-butynyl groups, and particularly preferably 2-propynyl groups. The above-mentioned alkynyl groups are preferred because they tend to localize the compound relating to general formula (α) near the surface of the positive electrode active material and / or negative electrode active material.

[0048] Specific examples of aryl groups include phenyl groups and tolyl groups. Among these, the phenyl group is preferred from the viewpoint that the compound relating to general formula (α) tends to localize near the surface of the positive electrode active material and / or the negative electrode active material. Specific examples of aralkyl groups include phenylmethyl group (benzyl group), phenylethyl group (phenethyl group), phenylpropyl group, phenylbutyl group, or phenylisopropyl group. Among these, benzyl and phenethyl groups are more preferred, and benzyl groups are particularly preferred, from the viewpoint that the compound represented by general formula (α) tends to localize near the surface of the positive electrode active material and / or negative electrode active material.

[0049] The alkoxy group having 1 to 12 carbon atoms is preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably an alkoxy group having 1 to 4 carbon atoms. Specific examples of alkoxy groups having 1 to 12 carbon atoms include methoxy, ethoxy, propoxy, butoxy, or isopropoxy groups. Among these, methoxy or ethoxy groups are preferred because they have less steric hindrance to the compound and are suitably concentrated on the active material surface.

[0050] Here, the substituents are a cyano group, an isocyanate group, and an acyl group (-(C=O)-R b ), acyloxy group (-O(C=O)-R b ), alkoxycarbonyl group (-(C=O)OR b ), sulfonyl group (-SO2-R b ), sulfonyloxy group (-O(SO2)-Rb), alkoxysulfonyl group (-(SO2)-OR b ), alkoxysulfonyl oxy group (-O-(SO2)-OR b ), alkoxycarbonyloxy group (-O-(C=O)-OR b ), ether group (-OR b Examples include acrylic groups, methacrylic groups, halogens (preferably fluorine), or trifluoromethyl groups. bR represents an alkyl group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms. b If it is an alkylene group, it may bond with some of the substituted hydrocarbon groups to form a ring. Among these substituents, preferred are a cyano group, an isocyanate group, an acyloxy group (-O(C=O)-Rb), a halogen (preferably fluorine), or a trifluoromethyl group, and more preferably an isocyanate group, an acyloxy group (-O(C=O)-Rb). b ), halogen (preferably fluorine), or trifluoromethyl group, and particularly preferably an acyloxy group (-O(C=O)-R b ), halogen (preferably fluorine), or trifluoromethyl group.

[0051] R related to general formula (α) 9 This is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have substituents, or -SiR d R e R f This represents a silyl group represented by -SiR. In particular, a hydrocarbon group having 1 to 12 carbon atoms which may have substituents. d R e R f A silyl group represented by is preferred. Here, R is an example of a hydrocarbon group having 1 to 12 carbon atoms that may have substituents. 6 ~R 8 It is equivalent to what is defined in [the relevant section].

[0052] Also, -SiR d R e R f R in the silyl group represented by d ~R f Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. Here, any of the halogen atom, the C1-C12 hydrocarbon group which may have substituents, and the C1-C12 alkoxy group which may have substituents are R. 6 ~R 8 This is equivalent to what is defined in [the relevant section].

[0053] Y in general formula (α) is a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, a C1-C12 alkoxy group which may have substituents, or -NR g -SiR h R i R j , or -NR g -H represents the group, R g R represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, which may have substituents. h ~R j Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. Here, the halogen atom, the C1-C12 hydrocarbon group which may have substituents, and the C1-C12 alkoxy group which may have substituents are all R 6 ~R 8 It is equivalent to what is defined in [the relevant section]. -NR g -SiR h R i R j In a base represented by R g R 9 This is equivalent to what is defined by -SiR. h R i R j The group represented by -SiR d R e R f It is synonymous with the base represented by . -NR g In a group represented by -H, R g R is a hydrocarbon group having 1 to 12 carbon atoms, which may have a hydrogen atom or a substituent. Here, the hydrocarbon group having 1 to 12 carbon atoms, which may have a substituent, is R11 This is equivalent to what is defined in [the relevant section]. Among these, hydrogen atoms or hydrocarbon groups having 1 to 12 carbon atoms, which may have substituents, are preferred, hydrogen atoms or hydrocarbon groups having 1 to 12 carbon atoms are more preferred, hydrogen atoms or hydrocarbon groups having 1 to 6 carbon atoms are even more preferred, and hydrogen atoms or hydrocarbon groups having 1 to 4 carbon atoms are particularly preferred.

[0054] Furthermore, the compound represented by general formula (α) is preferably the compound represented by general formula (α1) or general formula (α2), as described later.

[0055] (Compounds represented by the general formula (α1))

[0056] [ka]

[0057] In general formula (α1), R 6a ~R 8a Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. 9a This is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have substituents, or -SiR da R ea R fa This represents a silyl group represented by R. da ~R fa Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. a This includes a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, a C1-C12 alkoxy group which may have substituents, and -NR ga -SiR ha R ia R ja A base represented by -NR ga R indicates a group represented by -H. gaR represents a hydrocarbon group having 1 to 12 carbon atoms, which may have a hydrogen atom or substituents. ha ~R ja Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. 9a and R ga They may be bonded to each other, forming a ring. In the above general formula (α1), R 6a ~R 9a , Y a , and R da ~R ja This is R of the general formula (α) mentioned above. 6 ~R 9 , Y, and R d ~R j Each corresponds to a different condition, and the favorable conditions can be applied similarly.

[0058] (Compounds represented by the general formula (α2))

[0059] [ka]

[0060] In general formula (α2), R 9b This is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have substituents, or -SiR db R eb R fb This represents a silyl group represented by R. db ~R fb Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. b This includes a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, a C1-C12 alkoxy group which may have substituents, and -NR gb -SiR hb R ib R jb A base represented by -NR ga R indicates a group represented by -H.gb R represents a hydrocarbon group having 1 to 12 carbon atoms, which may have a hydrogen atom or substituents. hb ~R jb Each of these independently represents a hydrogen atom, a halogen atom, a C1-C12 hydrocarbon group which may have substituents, or a C1-C12 alkoxy group which may have substituents. 9 and R g They may be bonded to each other, forming a ring. In the above general formula (α2), R 9b , Y b , and R db ~R jb R is the R of the general formula (α) described above. 9 , Y, and R d ~R j Each corresponds to a different condition, and the favorable conditions can be applied similarly.

[0061] Specific examples of compounds represented by the general formula (α) according to this embodiment include the following compounds.

[0062] [ka]

[0063] [ka]

[0064] Preferably, the following compounds are mentioned.

[0065] [ka]

[0066] [ka]

[0067] More preferably, the following compounds are mentioned.

[0068] [ka]

[0069] [ka]

[0070] Particularly preferred are the following compounds.

[0071] [ka]

[0072] [ka]

[0073] One compound represented by general formula (α) may be used, or two or more compounds may be used. When two or more compounds are used, it is preferable to include one or more compounds represented by general formula (α1) and one or more compounds represented by general formula (α2) in order to increase the adhesion rate to the electrode. There are no particular restrictions on the ratio (mass) of the content of the compound represented by general formula (α1) to the compound represented by general formula (α2), but it is usually in the range of 10000:1 to 1:10000. The total content of the compound represented by general formula (α) relative to the total amount of the non-aqueous electrolyte according to one embodiment of the present invention is not particularly limited, but is preferably 0.01 ppm by mass or more, more preferably 0.1 ppm by mass or more, even more preferably 1.0 ppm by mass or more, particularly preferably 10 ppm by mass or more, and also preferably 0.5% by mass or less, more preferably less than 0.5% by mass, more preferably 0.4% by mass or less, more preferably 0.3% by mass or less, more preferably 0.2% by mass or less, more preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and more preferably 0.03% by mass or less. If the total amount of the compound represented by general formula (α) relative to the total amount of non-aqueous electrolyte is within the above range, the concentration of the compound represented by general formula (α) into the active material proceeds favorably, making it possible to manufacture a battery with less gas generation during initial conditioning. Furthermore, if two or more compounds represented by general formula (α) are used, their total amount shall be considered as the content of the compound represented by general formula (α). The ratio of the mass content of the compound represented by general formula (A) to the mass content of the compound represented by general formula (α) in the non-aqueous electrolyte is not particularly limited, but is usually 1.0 or more, preferably 2.0 or more, and especially preferably 3.0 or more. On the other hand, it is usually 10,000 or less, preferably 7,000 or less, more preferably 4,000 or less, even more preferably 2,000 or less, especially preferably 1,000 or less, and particularly preferably 500 or less.

[0074] The total content of the compound represented by general formula (α1) relative to the total amount of the non-aqueous electrolyte according to one embodiment of the present invention is not particularly limited, but is preferably 0.01 ppm by mass or more, more preferably 0.1 ppm by mass or more, even more preferably 1.0 ppm by mass or more, particularly preferably 10 ppm by mass or more, and usually 0.5% by mass or less, preferably less than 0.5% by mass, more preferably 0.4% by mass or less, even more preferably 0.3% by mass or less, especially preferably 0.2% by mass or less, and particularly preferably 0.1% by mass or less. If the total amount of the compound represented by general formula (α1) relative to the total amount of non-aqueous electrolyte is within the above range, the concentration of the compound represented by general formula (α1) into the active material proceeds favorably, making it possible to produce a battery with less gas generation during initial conditioning. The ratio of the mass content of the compound represented by general formula (A) to the content of the compound represented by general formula (α1) in the non-aqueous electrolyte is not particularly limited, but is usually 1.0 or more, preferably 2.0 or more, and especially preferably 3.0 or more. On the other hand, it is usually 10,000 or less, preferably 7,000 or less, more preferably 4,000 or less, even more preferably 2,000 or less, especially preferably 1,000 or less, and particularly preferably 500 or less.

[0075] The total amount of the compound represented by general formula (α2) relative to the total amount of the non-aqueous electrolyte according to one embodiment of the present invention is not particularly limited, but is preferably 0.01 ppm by mass or more. More preferably 0.1 ppm by mass or more, even more preferably 1.0 ppm by mass or more, particularly preferably 10 ppm by mass or more, and also preferably 0.50% by mass or less, more preferably 0.2% by mass or less, even more preferably 0.1% by mass or less, especially preferably 0.05% by mass or less, particularly preferably 0.03% by mass or less. If the total amount of the compound represented by general formula (α2) relative to the total amount of non-aqueous electrolyte is within the above range, the concentration of the compound represented by general formula (α2) into the active material proceeds favorably, making it possible to produce a battery with low gas generation during initial conditioning. The ratio of the mass content of the compound represented by general formula (A) to the content of the compound represented by general formula (α2) in the non-aqueous electrolyte is not particularly limited, but is usually 1.0 or more, preferably 2.0 or more, and especially preferably 3.0 or more. On the other hand, it is usually 10,000 or less, preferably 7,000 or less, more preferably 4,000 or less, even more preferably 2,000 or less, especially preferably 1,000 or less, and particularly preferably 500 or less.

[0076] The identification and measurement of the content of compounds represented by general formula (α) in non-aqueous electrolytes are performed by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography. Furthermore, there are no particular limitations on the method of incorporating the compound represented by general formula (α) into the electrolyte, or the method of incorporating the compound represented by the general formula. In addition to the method of directly adding the above compound to the electrolyte, there are also methods of generating the above compound inside the battery or in the electrolyte.

[0077] In this specification, the compound content refers to the content at the time of manufacturing the non-aqueous electrolyte, at the time the non-aqueous electrolyte is injected into the battery, or at any of the following points in time when the battery is shipped.

[0078] <1-3. Electrolytes> The non-aqueous electrolyte of this embodiment, like general non-aqueous electrolytes, usually contains an electrolyte as a component. The electrolyte used in the non-aqueous electrolyte of this embodiment is not particularly limited as long as it is an alkali metal salt, and lithium salts such as LiBF4, LiPF6, LiN(FSO2)2, LiN(CF3SO2)2, or lithium difluorooxalatoborate can be suitably used. Furthermore, these lithium salts can be used individually or in combination of two or more.

[0079] The total concentration of alkali metal 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, and more preferably 9% by mass or more, relative to the total volume of the non-aqueous electrolyte. The upper limit is usually 18% by mass or less, preferably 17% by mass or less, and more preferably 16% by mass or less. When the total concentration of alkali metal salts, which are the electrolyte, is within the above range, the electrical conductivity becomes appropriate for battery operation, and sufficient output characteristics tend to be obtained. Identification and measurement of alkali metal salt content in non-aqueous electrolytes are performed by nuclear magnetic resonance (NMR) spectroscopy or ion chromatography.

[0080] <1-4. Non-aqueous solvents> The non-aqueous electrolyte of this embodiment, like general non-aqueous electrolytes, usually contains a non-aqueous solvent that dissolves the electrolyte as described above as its main component. There are no particular restrictions on the non-aqueous solvent, and known organic solvents can be used. Examples of organic solvents include saturated cyclic carbonates such as ethylene carbonate, propylene carbonate, or butylene carbonate; linear carbonates such as dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate; carboxylic acid esters such as methyl acetate, ethyl acetate, propyl acetate, or butyl acetate; ether compounds such as dimethoxymethane, diethoxymethane, ethoxymethoxymethane, tetrahydrofuran, 1,3-dioxane, or 1,4-dioxane; sulfone compounds such as 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, dimethyl sulfone, ethyl methylsulfone, or monofluoromethylmethylsulfone; and the like. Preferably saturated cyclic carbonates and linear carbonates. Alternatively, it may be a carboxylic acid ester, more preferably a saturated cyclic carbonate or a linear carbonate. These non-aqueous solvents can be used individually or in combination of two or more.

[0081] <1-5. Auxiliary Agents> In the non-aqueous electrolyte of this embodiment, auxiliary agents may be included to the extent that the effects of the present invention are achieved. As an auxiliary agent, Fluorinated salts such as difluorophosphates, fluorosulfonates, fluoroboronates, or fluoroimide salts; Unsaturated cyclic carbonates such as vinylene carbonate, vinylethylene carbonate, or ethynylethylene carbonate; Fluorinated cyclic carbonates such as monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, or 4,5-difluoro-4,5-dimethylethylene carbonate; Oxalate salts such as lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, or lithium tris(oxalato)phosphate; Carbonate compounds such as methoxyethyl-methyl carbonate; Spiro compounds such as methyl-2-propynyl oxalate; Sulfur-containing compounds such as ethylene sulfite; Diisocyanates having a cycloalkylene group, such as 1,3-bis(isocyanatomethyl)cyclohexane; trimer compounds derived from compounds having at least two isocyanate groups in the molecule, such as triallyl isocyanurate, or isocyanate compounds such as aliphatic polyisocyanates obtained by adding a polyhydric alcohol thereto; Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone; Hydrocarbon compounds such as cycloheptane; Fluorine-containing aromatic compounds such as fluorobenzene; Fluorosilane compounds such as fluorotrimethylsilane, fluorodimethylvinylsilane, difluorodimethylsilane, or difluorovinylmethylsilane; Ester compounds such as 2-propynyl 2-(methanesulfonyloxy)propionic acid; Lithium salts such as lithium ethylmethyloxycarbonylphosphonate; These are some examples. These can be used individually or in combination of two or more. By adding these auxiliary agents, it is possible to suppress gas generation during initial conditioning, suppress initial resistance, improve volume retention characteristics after high-temperature storage, or improve cycle characteristics.

[0082] In particular, in the non-aqueous electrolyte according to one embodiment of the present invention, it is preferable to use in combination one or more selected from fluorinated salts, unsaturated cyclic carbonates, cyclic carbonates having fluorine atoms, fluorosilane compounds, and oxalate salts, as this further suppresses gas generation during initial conditioning, resulting in a battery that is less prone to swelling, or lowers the initial resistance of the battery. More preferably, the material contains at least an unsaturated cyclic carbonate or a cyclic carbonate having a fluorine atom, and even more preferably, an unsaturated cyclic carbonate and a cyclic carbonate having a fluorine atom. Furthermore, it is preferable to include at least an unsaturated cyclic carbonate or a cyclic carbonate having a fluorine atom, and to include one or more selected from fluorinated salts, fluorosilane compounds, and oxalate salts, as this further suppresses gas generation during initial conditioning, resulting in a battery that is less prone to swelling, or lowers the initial resistance of the battery. It is more preferable to include, and particularly preferable to include, one or more selected from unsaturated cyclic carbonates, cyclic carbonates having fluorine atoms, fluorinated salts, and fluorosilane compounds. The content of the auxiliary agent is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, and more preferably 5% by mass or less, based on 100% by mass of the non-aqueous electrolyte. When two or more auxiliary agents are used in combination, it is preferable that the total content meets the above range. The identification and measurement of the content of auxiliary agents in non-aqueous electrolytes are performed using nuclear magnetic resonance (NMR) spectroscopy. The following provides a detailed explanation of "fluorinated salts," "fluorosilane compounds," "unsaturated cyclic carbonates," "fluorinated cyclic carbonates," and "oxalate salts."

[0083] (Fluorinated salt) The non-aqueous electrolyte according to this embodiment may contain a fluorinated salt. There are no particular restrictions on the fluorinated salt, but difluorophosphates, fluorosulfonates, fluoroboronates, or fluoroimide salts are preferred because they have a highly detachable fluorine atom in their structure, react suitably with decomposition products of compounds represented by general formula (A) or (α), form a composite film, and reduce initial battery resistance. Fluoroboronates, fluorosulfonates, or difluorophosphates are more preferred because they have particularly high fluorine detachability and react suitably with nucleophiles, fluorosulfonates or difluorophosphates are particularly preferred, and fluorosulfonates are most preferred due to their high fluorine detachability. Furthermore, fluorinated lithium salts are preferred as the fluorinated salt. The fluorinated salt may be used alone or in combination of two or more types in any combination and ratio. Furthermore, the content of the fluorinated salt relative to the total amount of the non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 less than 8% by mass, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less. The following describes these various types of salts.

[0084] <Difluorophosphate> There are no particular limitations on the countercation of difluorophosphate, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, or NR 27 R 28 R 29 R 30 (In the formula, R 27 ~R 30 Each of these independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. Examples include ammonium compounds represented by ( ). Lithium is preferred among these.

[0085] The above ammonium R 27 ~R30 There are no particular limitations on the organic group having 1 to 12 carbon atoms represented by , but examples include alkyl groups which may be substituted with a halogen atom, cycloalkyl groups which may be substituted with a halogen atom or an alkyl group, aryl groups which may be substituted with a halogen atom or an alkyl group, or nitrogen atom-containing heterocyclic groups which may have substituents. Among these, R 27 ~R 30 However, each is preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

[0086] Specific examples of difluorophosphates include lithium difluorophosphate, sodium difluorophosphate, or potassium difluorophosphate, with lithium difluorophosphate being preferred. Difluorophosphates can be used individually or in any combination and ratio of two or more types. It may be used in combination with the other. Furthermore, the content of difluorophosphate relative to the total amount of non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 less than 8% by mass, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less. If the difluorophosphate content is within this range, non-aqueous electrolyte secondary batteries are more likely to exhibit sufficient improvement in cycle characteristics, and it is easier to avoid situations such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0087] <Fluorosulfonate> The counter cation of the fluorosulfonate is not particularly limited, but may include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, or NR. 17 R 18 R 19 R 20 (In the formula, R 17 ~R 20Each of these independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. Examples include ammonium compounds represented by ( ). Lithium is preferred among these.

[0088] The above ammonium R 17 ~R 20 There are no particular limitations on the organic group having 1 to 12 carbon atoms represented by , but examples include alkyl groups which may be substituted with a halogen atom, cycloalkyl groups which may be substituted with a halogen atom or an alkyl group, aryl groups which may be substituted with a halogen atom or an alkyl group, or nitrogen atom-containing heterocyclic groups which may have substituents. Among these, R 17 ~R 20 However, each is preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group. Specific examples of fluorosulfonates include: Examples include lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, or cesium fluorosulfonate, with lithium fluorosulfonate being preferred.

[0089] Fluorosulfonates may be used individually or in any combination and ratio of two or more types. Furthermore, the content of fluorosulfonates relative to the total amount of non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 less than 8% by mass, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less. If the fluorosulfonate content is within this range, non-aqueous electrolyte secondary batteries are more likely to exhibit sufficient improvement in cycle characteristics, and it is easier to avoid situations such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0090] <Fluoroboro salts> The counter cation of the fluoroboron salt is not particularly limited, but may be lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, or NR. 21 R 22 R 23 R 24 (In the formula, R 21 ~R 24 Each of these independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. Examples include ammonium compounds represented by ( ). Lithium is preferred among these.

[0091] The above ammonium R 21 ~R 24 There are no particular limitations on the organic group having 1 to 12 carbon atoms represented by , but examples include alkyl groups which may be substituted with a halogen atom, cycloalkyl groups which may be substituted with a halogen atom or an alkyl group, aryl groups which may be substituted with a halogen atom or an alkyl group, or nitrogen atom-containing heterocyclic groups which may have substituents. Among these, R 21 ~R 24 However, each is preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

[0092] Specific examples of fluoroboron salts include: LiBF4, LiB(C) i F 2i+1 ) j (F) 4-j Examples include the above, with LiBF4 being preferred. Note that i represents an integer from 1 to 10, and j represents an integer from 1 to 4. Fluoroboro salts may be used individually or in combination of two or more types in any combination and ratio. Furthermore, the content of fluoroboro salts relative to the total amount of non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 3% by mass or less, preferably 1% by mass or less, more preferably 0.8% by mass or less, even more preferably 0.5% by mass or less, and most preferably 0.3% by mass or less. If the fluoroboron salt content is within this range, non-aqueous electrolyte secondary batteries are more likely to exhibit sufficient improvement in cycle characteristics, and it is easier to avoid situations such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0093] <Fluoroimide salts> The counter cation of the fluoroimide salt is not particularly limited, but may include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, or NR. 31 R 32 R 33 R 34 (In the formula, R 31 ~R 34 Each of these independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. Examples include ammonium compounds represented by ( ). Lithium is preferred among these.

[0094] The above ammonium R 31 ~R 34 There are no particular limitations on the organic group having 1 to 12 carbon atoms represented by , but examples include alkyl groups which may be substituted with halogen atoms, cycloalkyl groups which may be substituted with halogen atoms or alkyl groups, aryl groups which may be substituted with halogen atoms or alkyl groups, or nitrogen atom-containing heterocyclic groups which may have substituents. Among these, R 31 ~R 34 However, each is preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

[0095] Specific examples of fluoroimide salts include LiN(FCO)2, LiN(FCO)(FSO2), LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, or LiN(CF3SO2)(C4F9SO2), with LiN(FSO2)2, LiN(CF3SO2)2, or LiN(C2F5SO2)2 being preferred.

[0096] Fluoroimide salts may be used individually or in combination of two or more types in any combination and ratio. Furthermore, the content of fluoroimide salts relative to the total amount of non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 less than 8% by mass, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less. If the fluoroimide salt content is within this range, non-aqueous electrolyte secondary batteries are more likely to exhibit sufficient improvement in cycle characteristics, and it is easier to avoid situations such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0097] (Oxalate salt) Oxalate salts react suitably with decomposition products of compounds represented by general formula (A) or (α), forming a composite film, which is preferable because it can reduce the initial battery resistance. There are no particular limitations on the countercation of the oxalate salt, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, or N R 35 R 36 R 37 R 38 (In the formula, R 35 ~R 38 Each of these independently represents a hydrogen atom or an organic group having 1 to 12 carbon atoms. Examples include ammonium compounds represented by ( ). Lithium is preferred among these.

[0098] The above ammonium R 35 ~R 38There are no particular limitations on the organic group having 1 to 12 carbon atoms represented by , but examples include alkyl groups which may be substituted with halogen atoms, cycloalkyl groups which may be substituted with halogen atoms or alkyl groups, aryl groups which may be substituted with halogen atoms or alkyl groups, or nitrogen atom-containing heterocyclic groups which may have substituents. Among these, R 35 ~R 38 However, each is preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, or a nitrogen atom-containing heterocyclic group.

[0099] Specific examples of oxalate salts include lithium bis(oxalato)borate, lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, or lithium tris(oxalato)phosphate, with lithium bis(oxalato)borate or lithium difluorobis(oxalato)phosphate being preferred, and lithium bis(oxalato)borate being particularly preferred.

[0100] The oxalate salt may be used alone or in combination of two or more types in any combination and ratio. Furthermore, the content of the oxalate salt relative to the total amount of the non-aqueous electrolyte is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention, but 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 less than 8% by mass, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1% by mass or less. If the oxalate salt content is within this range, it enhances the initial effect of reducing battery resistance, makes it easier for non-aqueous electrolyte secondary batteries to exhibit sufficient improvement in cycle characteristics, and helps avoid situations such as decreased high-temperature storage characteristics, increased gas generation, and reduced discharge capacity retention.

[0101] (Fluorosilane compounds) Fluorosilane compounds react suitably with decomposition products of compounds represented by general formula (A) or (α), forming a composite film, which is preferable because it can reduce the initial battery resistance. The non-aqueous electrolyte according to this embodiment may contain a fluorosilane compound. The fluorosilane compound is not particularly limited as long as it is a compound having at least one silicon-fluorine bond (Si-F bond) in its molecule. Examples of fluorosilane compounds include fluorotrimethylsilane, dimethyl(fluoro)(vinyl)silane, (allyl)dimethyl(fluoro)silane, dimethyl(fluoro)(propargyl)silane, divinylfluoro(methyl)silane, fluorotrivinylsilane, ethinyldimethylfluorosilane, difluorodimethylsilane, difluorodivinylsilane, methyltrifluorosilane, trifluorovinylsilane, fluorotriethylsilane, diethyl(fluoro)(methyl)silane, diethyl(fluoro)(vinyl)silane, ethyldivinylfluorosilane, diethyl(fluoro)(ethynyl)silane, (allyl)diethyl(fluoro)silane, diethyl(fluoro)(propargyl)silane, and difluorodi Ethylsilane, ethyldifluorovinylsilane, trifluoroethylsilane, fluorotripropylsilane, trifluoropropylsilane, fluorotributylsilane, trifluorobutylsilane, fluorotripentylsilane, trifluoropentylsilane, fluorotrihexylsilane, trifluorohexylsilane, fluorotricyclohexylsilane, trifluorocyclohexylsilane, fluorotriphenylsilane, fluorotritriylsilane, fluorotribenzylsilane, difluorodinaphthylsilane, naphthyltrifluorosilane, dibiphenyldifluorosilane, biphenyltrifluorosilane, (cyclohexylphenyl)trifluorosilane, di(cyclohexylphenyl)difluoro Examples of compounds include rosilane, fluorotri(biphenyl)silane, or fluorotri(cyclohexylphenyl)silane.

[0102] Of these, fluorotrimethylsilane, dimethyl(fluoro)(vinyl)silane, dimethyldifluorosilane, or methyl(difluoro)(vinyl)silane are preferred.

[0103] Fluorosilane compounds may be used individually or in any combination and ratio of two or more. The content of fluorosilane compounds (total amount if two or more are used) 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 3% by mass or less, preferably 1% by mass or less, and more preferably 0.5% by mass or less, relative to the total amount of non-aqueous electrolyte. Within this range, the initial battery resistance reduction effect is enhanced, and output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, high-temperature storage characteristics, etc., can be easily controlled.

[0104] (Unsaturated cyclic carbonate) In this specification, "unsaturated cyclic carbonate" refers to a cyclic carbonate having carbon-carbon unsaturated bonds, and is not particularly limited to carbonates having carbon-carbon unsaturated bonds such as carbon-carbon double bonds or carbon-carbon triple bonds; any unsaturated cyclic carbonate can be used. Examples of unsaturated cyclic carbonates include vinylene carbonates, or ethylene carbonates substituted with substituents having carbon-carbon unsaturated bonds. Specific examples of vinylene carbonates include vinylene carbonate, methylvinylene carbonate, or 4,5-dimethylvinylene carbonate. Specific examples of ethylene carbonates substituted with substituents having carbon-carbon unsaturated bonds include vinylethylene carbonate, 4,5-divinylethylene carbonate, ethynylethylene carbonate, and propargylethylene carbonate. Among these, vinylene carbonate, vinylethylene carbonate, or ethynylethylene carbonate are preferred, and vinylene carbonate is particularly preferred because it can contribute to the formation of a stable film-like structure. The molecular weight of the unsaturated cyclic carbonate is not particularly limited and can be any as long as it does not significantly impair the effects of the present invention, but 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 non-aqueous electrolytes, and the effects of the present invention are easily expressed. Unsaturated cyclic carbonates may be used individually or in any combination and ratio of two or more types. Furthermore, the content of unsaturated cyclic carbonates is not particularly limited and is arbitrary as long as it does not significantly impair the effects of the present invention. However, the content of unsaturated cyclic carbonates is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, and more preferably 5% by mass or less, relative to the total amount of non-aqueous electrolyte. If the content of unsaturated cyclic carbonates is within the above range, the effect of reducing the initial resistance of non-aqueous electrolyte secondary batteries is enhanced, and furthermore, sufficient high-temperature storage characteristics and improved cycle characteristics are easily achieved.

[0105] (Fluorinated cyclic carbonate) In this specification, "fluorinated cyclic carbonate" refers to a cyclic carbonate having a fluorine atom. Examples of fluorinated cyclic carbonates include derivatives of cyclic carbonates having alkylene groups with 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of ethylene carbonate derivatives include ethylene carbonate or alkyl groups (for example, carbon Examples include fluorinated ethylene carbonates substituted with alkyl groups having 1 to 4 elementary atoms, with those having 1 to 8 fluorine atoms being preferred. Specifically, examples include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene 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-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, or 4,4-difluoro-5,5-dimethylethylene carbonate. Among these, 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-dimethylethylene carbonate is more preferable in that it provides high ionic conductivity and forms a suitable interfacial protective film. Fluorinated cyclic carbonates may be used individually or in combination of two or more types in any combination and ratio. Furthermore, fluorinated cyclic carbonate may be used as an additive to the non-aqueous electrolyte or as a non-aqueous solvent. When used as a non-aqueous solvent, the content of fluorinated cyclic carbonate is usually 8% by mass or more, preferably 10% by mass or more, more preferably 12% by mass or more, and usually 85% by mass or less, preferably 80% by mass or less, and more preferably 75% by mass or less, relative to the total amount of the non-aqueous electrolyte. Within this range, the effect of reducing the initial resistance of the non-aqueous electrolyte secondary battery is enhanced, and a sufficient improvement in cycle characteristics is easily achieved, while it is easy to avoid a decrease in the discharge capacity retention rate. In a non-aqueous electrolyte according to one embodiment of the present invention, it is preferable that the unsaturated cyclic carbonate or fluorinated cyclic carbonate is at least one selected from the group consisting of vinylene carbonate, vinylethylene carbonate, ethynylethylene carbonate, and fluoroethylene carbonate.

[0106] As the fluorinated cyclic carbonate, a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as "fluorinated unsaturated cyclic carbonate") can be used. The fluorinated unsaturated cyclic carbonate is not particularly limited. Among them, those with one or two fluorine atoms are preferred. The method for producing the fluorinated unsaturated cyclic carbonate is not particularly limited, and it can be produced by arbitrarily selecting a known method. Examples of fluorinated unsaturated cyclic carbonates include vinylene carbonate derivatives, or ethylene carbonate derivatives substituted with substituents having an aromatic ring or a carbon-carbon unsaturated bond. Examples of vinylene carbonate derivatives include 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-phenylvinylene carbonate, or 4,5-difluoroethylene carbonate. Examples of ethylene carbonate derivatives substituted with substituents having an aromatic ring or a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, or 4,5-difluoro-4-phenylethylene carbonate. The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited, and the effects of the present invention are significantly reduced. Although it is arbitrary as long as it is not impaired, it 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. The fluorinated unsaturated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio. Further, the blending amount 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. However, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, based on the total amount of the non-aqueous electrolyte. Within this range, the effect of reducing the initial resistance of the non-aqueous electrolyte secondary battery is enhanced, and further, a sufficient cycle characteristic improvement effect is likely to be exhibited.

[0107] Auxiliary agents other than the fluorinated salt, fluorosilane compound, unsaturated cyclic carbonate, fluorinated cyclic carbonate, and oxalate salt (content of other auxiliary agents) are not particularly limited and are arbitrary as long as the effects of the present invention are not significantly impaired. However, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, based on the total amount of the non-aqueous electrolyte. Within this range, the effects of other auxiliary agents are likely to be sufficiently exhibited, and the high-temperature storage stability tends to improve. When two or more other auxiliary agents are used in combination, the total amount of the other auxiliary agents should satisfy the above range.

[0108] <2. Non-aqueous electrolyte battery> The non-aqueous electrolyte battery according to an embodiment of the present invention is a non-aqueous electrolyte battery including a positive electrode, a negative electrode, and a non-aqueous electrolyte, and includes the non-aqueous electrolyte according to an embodiment of the present invention described above. More specifically, a positive electrode having a current collector and a positive electrode active material layer on at least a part of the surface of the current collector and capable of occluding and releasing metal ions, a negative electrode having a current collector and a negative electrode active material layer on at least a part of the surface of the current collector and capable of occluding and releasing metal ions, and the non-aqueous electrolyte includes a non-aqueous electrolyte containing an alkali metal salt, a non-aqueous solvent, a compound represented by the above general formula (1), and a compound represented by general formula (α).

[0109] <2-1. Battery configuration> For the non-aqueous electrolyte battery of this embodiment, the configurations other than the above non-aqueous electrolyte are the same as those of a conventionally known non-aqueous electrolyte battery. Usually, the positive electrode and the negative electrode are laminated through a porous membrane (separator) impregnated with the above non-aqueous electrolyte, and they are housed in a case (outer package). The shape of the non-aqueous electrolyte battery of this embodiment is not particularly limited, and it may be any of a cylindrical shape, a rectangular shape, a laminate shape, a coin shape, or a large size.

[0110] <2-2. Non-aqueous electrolyte> As the non-aqueous electrolyte, the non-aqueous electrolyte according to an embodiment of the present invention described above is used. In addition, 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 above non-aqueous electrolyte.

[0111] <2-3. Positive electrode> The positive electrode refers to a current collector and a positive electrode active material on at least a part of the surface of the current collector. Other configurations can be those conventionally known.

[0112] The positive electrode active material is not particularly limited as long as it is lithium cobalt oxide or a transition metal oxide containing at least Ni and Co, with at least 50 mol% of the transition metal being Ni and Co, and capable of electrochemically intercepting and releasing metal ions. However, for example, a material capable of electrochemically intercepting and releasing lithium ions is preferred, and it contains lithium and at least Ni and Co. A transition metal oxide in which 60 mol% or more of the transition metals are Ni and Co is preferred. This is because Ni and Co have oxidation-reduction potentials that are suitable for use as positive electrode materials in secondary batteries and are suitable for high-capacity applications.

[0113] In particular, an embodiment in which the transition metal oxide is represented by the following compositional formula (11) is preferred. Li a1 Ni b1 Co c1 M d1 O2···(11) In equation (11) above, a1, b1, c1, and d1 are values ​​such that 0.90 ≤ a1 ≤ 1.10, 0.50 ≤ b1 ≤ 0.98, 0.01 ≤ c1 < 0.50, and 0.01 ≤ d1 < 0.50, satisfying b1 + c1 + d1 = 1. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti, and Er. In the composition formula (11), it is preferable that the value is 0.1 ≤ d1 < 0.5. By setting the composition ratios of Ni, Co, and other metal species within the above range, transition metals are less likely to leach from the positive electrode, and even if they do leach, Ni and Co have the advantage of having little adverse effect within a non-aqueous secondary battery. A suitable example is LiNi 0.85 Co 0.10 Al 0.05 O2, LiLiLi 0.80 Co 0.15 Al 0.05 O2, LiLiLi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.50 Co 0.20 Mn 0.30 O2, LiLiLi 0.6 Co0.2 Mn 0.2 O2, or LiNi 0.8 Co 0.1 Mn 0.1 Examples include O2.

[0114] <2-4. Negative electrode> The negative electrode refers to a current collector and a current collector having a negative electrode active material on at least a portion of its surface. Other components can be those that are conventionally known.

[0115] The negative electrode active material is not particularly limited as long as it is capable of electrochemically intercalating and releasing metal ions. Specific examples include carbon-based materials, materials containing metal elements and / or metalloid elements that can alloy with Li, lithium-containing metal composite oxide materials, and mixtures thereof. These may be used individually or in any combination of two or more. It is preferable to use a mixture of carbon-based materials, materials containing metal particles that can alloy with Li and / or metalloid elements that can alloy with Li, and graphite particles, as these offer good cycle characteristics, safety, and excellent continuous charging characteristics.

[0116] Examples of carbon-based materials include natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, or resin-coated graphite. Among these, natural graphite is preferred.

[0117] Examples of natural graphite include scaly graphite, flake graphite, and / or graphite particles obtained by processing these graphites as raw materials, such as spheroidization or densification. Among these, spherical or ellipsoidal graphite particles that have undergone spheroidization processing are particularly preferred from the viewpoint of particle packing properties or charge / discharge rate characteristics. The average particle size (d50) of graphite particles is typically between 1 μm and 100 μm.

[0118] As a material containing a metal element and / or a metalloid element that can be alloyed with Li, any conventionally known material can be used. However, from the viewpoints of capacity and cycle life, the metal particles are preferably a material containing a metal element and / or a metalloid element selected from the group consisting of, for example, Sb, Si, Sn, Al, As, and Zn. Further, when the material containing a metal element and / or a metalloid element that can be alloyed with Li contains two or more metal elements and / or metalloid elements, the material may be a material composed of an alloy of these metal elements and / or metalloid elements. In addition, examples of the material containing a metal element and / or a metalloid element that can be alloyed with Li include metal oxides, metal nitrides, metal carbides, or Si-containing inorganic compounds. The compound may contain two or more materials containing a metal element and / or a metalloid element that can be alloyed with Li. It may be. Among them, metallic Si (hereinafter sometimes referred to as Si) or a Si-containing inorganic compound is preferable in terms of achieving a high capacity. In addition, the material containing a metal element and / or a metalloid element that can be alloyed with Li may already be alloyed with Li at the time of manufacturing the negative electrode described later. Si or a Si-containing inorganic compound is preferable in terms of achieving a high capacity.

[0119] In this specification, Si or a Si-containing inorganic compound is collectively referred to as a Si compound. Specific examples of the Si compound include SiO x (0 ≦ x ≦ 2), etc. Specific examples of the material containing a metal element and / or a metalloid element that can be alloyed with Li include Li y Si (0 < y ≦ 4.4), Li 2z SiO 2+z (0 < z ≦ 2), etc. As the Si compound, a Si oxide (SiO x、 0 < x ≦ 2) is preferable in terms of having a larger theoretical capacity compared to graphite, and amorphous Si or nano-sized Si crystals are preferable in terms of allowing easy entry and exit of alkali ions such as lithium ions and enabling the achievement of a high capacity. The mixture of a material containing a metal element and / or a metalloid element capable of alloying with Li used as the negative electrode active material and graphite particles may be a mixture in which the material containing the metal element and / or the metalloid element capable of alloying with Li and the aforementioned graphite particles are mixed in the state of independent particles, or may be a composite in which the material containing the metal element and / or the metalloid element capable of alloying with Li is present on the surface or inside of the graphite particles. The content ratio of the material containing the metal element and / or the metalloid element capable of alloying with Li to the total of the material containing the metal element and / or the metalloid element capable of alloying with Li and the graphite particles is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, still more preferably 2.0% by mass or more. Also, it is usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, even more preferably 25% by mass or less, even more preferably 20% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less.

[0120] <2-5. Separator> A separator is usually interposed between the positive electrode and the negative electrode to prevent short circuit. In this case, the non-aqueous electrolyte according to one embodiment of the present invention is usually used by impregnating this separator. A conventionally known separator can be used.

Examples

[0121] 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 it does not exceed the gist thereof.

[0122] The compounds used in the present Examples and Comparative Examples are shown below.

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Chemical formula

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[0140] <Examples 1-23, Comparative Examples 1-21> [Fabrication of the positive electrode] Lithium nickel cobalt manganese composite oxide (Li) is used as the positive electrode active material. 1.0 Ni 0.5 Co 0.2 Mn 0.3 90 parts by mass of O2, 7 parts by mass of acetylene black as a conductive material, and 3 parts by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in an N-methylpyrrolidone solvent using a disperser to form a slurry. This slurry was uniformly applied to both sides of a 15 μm thick aluminum foil, dried, and then pressed to form the positive electrode.

[0141] [Fabrication of the negative electrode] 98 parts by mass of natural graphite were mixed with 1 part by mass of aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose 1% by mass) and 1 part by mass of aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber 50% by mass) as thickeners and binders, and mixed in a disperser to form a slurry. The resulting slurry was applied to one side of a 10 μm thick copper foil, dried, and then pressed to form the negative electrode.

[0142] [Preparation of non-aqueous electrolytes] Under a dry argon atmosphere, a mixture of ethylene carbonate (EC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) (volume ratio EC:DEC:EMC = 3:3:4) was dissolved with 1.2 mol / L (14.8% by mass, as the concentration in the non-aqueous electrolyte) of thoroughly dried LiPF6 as the electrolyte. Furthermore, vinylene carbonate (VC) and fluoroethylene carbonate (FEC) were each added at 2.0% by mass (as the concentration in the non-aqueous electrolyte) (hereinafter referred to as standard electrolyte 1). Compounds 1 to 17 were added to standard electrolyte 1 in the amounts listed in Table 1 below to prepare the non-aqueous electrolytes of Examples 1 to 17 and Comparative Examples 2 to 18. The non-aqueous electrolyte of Comparative Example 1 was standard electrolyte 1 itself. Note that the "Content (mass%)" in the table represents the content when the total amount of each non-aqueous electrolyte is considered as 100% by mass.

[0143] [Manufacturing of non-aqueous electrolyte batteries] The positive electrode, negative electrode, and polyethylene separator described above were stacked in the order of negative electrode, separator, and positive electrode to create a battery element. This battery element was inserted into a bag made of laminate film, which consisted of aluminum (40 μm thick) coated on both sides with a resin layer, with the terminals of the positive and negative electrodes protruding from the bag. Then, the prepared non-aqueous electrolyte was injected into the bag, and it was vacuum-sealed to create a laminate-type non-aqueous electrolyte battery.

[0144] <Evaluation of non-aqueous electrolyte batteries> [Initial Conditioning] The battery was charged with a constant current equivalent to 0.05C for 6 hours in a 25°C constant temperature bath, then discharged to 3.0V at 0.2C. CC-CV charging was then performed to 4.1V at 0.2C. Afterward, aging was performed at 45°C for 72 hours. Following this, the laminated battery was discharged to 3.0V at 0.2C to stabilize it. Furthermore, CC-CV charging was performed to 4.2V at 0.2C. Afterward, the battery was discharged to 3.0V at 0.2C to perform initial conditioning. [Initial conditioning gas generation measurement] The battery, after initial conditioning, was immersed in an ethanol bath and its volume was measured. The amount of gas generated was determined from the volume change before and after initial conditioning, and this was defined as the "initial gas amount." [Initial resistance] After initial conditioning, the batteries were charged using CC-CV charging at 0.2C to half of their initial discharge capacity. These batteries were then discharged at 1.0C, 2.0C, and 3.0C at 25°C, and the voltage was measured after 5 seconds. The average of the slopes of the current-voltage lines obtained at 1.0C, 2.0C, and 3.0C was defined as the initial resistance. Table 1 below shows the initial gas volume values ​​when the initial gas volume of Comparative Example 1 is set to 100, and the initial resistance values ​​when the initial resistance of Comparative Example 1 is set to 100. Compound (A) refers to the compound represented by general formula (A), compound (α) refers to the compound represented by general formula (α), compound (α1) refers to the compound represented by general formula (α1), compound (α2) refers to the compound represented by general formula (α2), and other compounds refer to compounds different from those represented by general formula (A) and general formula (α).

[0145] [Table 1]

[0146] Table 1 shows that the batteries produced in Examples 1 to 23 are similar to the batteries produced in Comparative Examples 1 to 21. In contrast, it can be seen that the initial gas volume is small and the initial resistance is also small. A comparison of Comparative Example 1 with Comparative Examples 2, 7, 8, 9, and 13 shows that when a non-aqueous electrolyte containing only the compound having the BO structure represented by formula (A) and not the compound represented by formula (α) is used, the initial gas volume tends to be higher than in Comparative Example 1, and the initial resistance tends to be higher than in Comparative Example 1. Furthermore, a comparison of Comparative Examples 1 with Comparative Examples 3-6, 10-12, and 14-19 shows that when a non-aqueous electrolyte containing only the compound represented by formula (α) and not the compound having the BO structure represented by formula (A) is used, the initial gas volume and initial resistance tend to be higher than in Comparative Example 1. From these findings, it is expected that using a non-aqueous electrolyte containing both the compound having the BO structure represented by formula (A) and the compound represented by formula (α) would increase the initial gas volume of the battery. However, the initial gas volume and initial resistance in Examples 1-23 are reduced, which is an unexpectedly significant effect. Furthermore, in Comparative Examples 7 and 8, which used a compound having the BO structure represented by formula (A) in combination with a compound not corresponding to the compound represented by formula (α), the initial gas volume increased by 15 to 62% compared to Comparative Example 1. Furthermore, it can be seen that the batteries produced in Comparative Examples 10 to 12, which used a compound represented by formula (α) in combination with compound (A) and other compounds other than compound (α), did not achieve the improvement in initial gas volume and initial resistance seen in the battery of the example. In addition, the batteries produced in Comparative Examples 14 and 15, which used a compound having a BO structure other than compound (A) in combination with the compound represented by formula (α), also did not achieve the improvement in initial gas volume and initial resistance seen in the battery of the example. Comparing Examples 19, 20, and 22 with Comparative Example 1, it can be seen that improvements in initial gas volume and initial resistance can be obtained by having compounds (A), (α1), and (α2). Furthermore, it can be seen that an even greater improvement in initial resistance can be obtained in the case of boron-containing chain compounds such as compound 3. Comparing Examples 5 and 7 with Examples 8-11, it can be seen that the inclusion of fluorinated salts such as compounds 14 and 15 further improves the initial resistance. This is an unexpectedly significant effect, considering the results of Comparative Examples 20 or 21, which contained neither compound (A) nor compound (α) but included compound 14 or 15. Comparing Example 17 and Example 18, it can be seen that including a fluorosilane compound such as compound 17 further improves the initial gas amount and initial resistance. In the example battery, the amount of adsorption of the compound represented by general formula (α) and the compound having a BO structure represented by general formula (A) onto the positive electrode active material and / or negative electrode active material is large after the electrolyte is injected. Therefore, it is presumed that during the first charge, the compounds localized on the electrodes decompose electrochemically, forming a complex insulating film on the surface of the positive electrode active material and / or negative electrode active material. Therefore, by combining a compound having a structure represented by general formula (α) with a compound having a BO structure represented by general formula (A), the adsorption of the compound onto the electrode can be controlled, and the generation of initial gas and the increase in battery resistance can be suitably controlled.

Claims

1. A non-aqueous electrolyte for a non-aqueous electrolyte battery having a positive electrode and a negative electrode capable of intercalating and releasing metal ions, characterized in that the non-aqueous electrolyte contains, together with an alkali metal salt and a non-aqueous solvent, a compound represented by general formula (A) and a compound represented by general formula (α), wherein the content of the compound represented by general formula (α) is 0.01 ppm by mass or more and 0.5% by mass or less of the total amount of the non-aqueous electrolyte. 【Chemistry 1】 (In formula (A), R １ ~R ３ Each independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have heteroatoms, or a trialkylsilyl group. Also, R １ ~R ３ They may be bonded to each other, forming a ring. 【Chemistry 2】 (In formula (α), R ８９ represents a hydrogen atom or a silyl group represented by -SiR ６ R ７ R ８ ; R ６ to R ８ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent. R ９ represents a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or a silyl group represented by -SiR ｄ R ｅ R ｆ ; R ｄ to R ｆ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent. Y represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, an alkoxy group having 1 to 12 carbon atoms which may have a substituent, a group represented by -NR ｇ -SiR ｈ R ｉ R ｊ , or a group represented by -NR ｇ -H; R ｇ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent; R ｈ to R ｊ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, or an alkoxy group having 1 to 12 carbon atoms which may have a substituent; R ９ and R ｇ may be bonded to each other to form a ring.)

2. The content of the compound represented by the general formula (A) is 1.0 × 1 in relation to the total volume of the non-aqueous electrolyte. 0 －３ The non-aqueous electrolyte according to claim 1, wherein the concentration is 10% by mass or more and 10% by mass or less.

3. The non-aqueous electrolyte according to claim 1 or 2, wherein the ratio of the mass content of the compound represented by general formula (A) to the content of the compound represented by general formula (α) in the non-aqueous electrolyte is 1.0 or more and 10,000 or less.

4. The compound represented by the general formula (A) is a compound represented by the general formula (A') or the general formula (A A non-aqueous electrolyte according to any one of claims 1 to 3, wherein the compound is represented by ''). 【Transformation 3】 (In general formula (A'), R １２ ~R １４ Each independently represents an alkylene group having 1 to 10 carbon atoms, which may have substituents, and X ａ It is at least a trivalent or pentavalent heteroatom. 【Chemistry 4】 (In the general formula (A''), R １ａ ~R ３ａ Each of these independently represents a C1-C10 hydrocarbon group which may have a heteroatom, or a trialkylsilyl group which may have a substituent, and at least one of them is a C1-C10 hydrocarbon group which has a heteroatom, or a trialkylsilyl group which may have a substituent.

5. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein the compound represented by the general formula (A) is triethanolamine borate or tritrimethylsilylborate.

6. A non-aqueous electrolyte battery comprising a positive electrode and a negative electrode and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte described in any one of claims 1 to 5.

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