Non-aqueous electrolyte and non-aqueous electrolyte battery using the same

Abstract

The present invention relates to: [1] a non-aqueous electrolyte comprising a compound (A) represented by general formula (1), and an anion (B) represented by general formula (2), the mass ratio [(A) / (B)] being 0.01-1.2, inclusive; and [2] a non-aqueous electrolyte battery provided with the non-aqueous electrolyte, a negative electrode, and a positive electrode having positive electrode active material that can store and release lithium ions.

Description

[Technical Field]

[0001] This invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery using the same. [Background technology]

[0002] Non-aqueous electrolyte batteries, such as lithium-ion secondary batteries, are being put into practical use in a wide range of applications, from power supplies for so-called consumer electronics such as mobile phones and laptop computers to on-board power supplies for automobiles. However, in recent years, the demand for higher performance in non-aqueous electrolyte batteries has been increasing, and in particular, there is a demand for improvements in various battery characteristics such as higher capacity, low-temperature operation characteristics, high-temperature storage characteristics, cycle characteristics, and overcharge safety. To date, numerous technologies have been investigated regarding the active materials of the positive and negative electrodes, as well as various battery components, including the non-aqueous electrolyte, as means of improving the high-temperature storage characteristics and cycle characteristics of non-aqueous electrolyte secondary batteries.

[0003] Patent Document 1 discloses a non-aqueous electrolyte containing specific amounts of vinylene carbonate and 2-propynylmethyl carbonate as a non-aqueous electrolyte for manufacturing lithium secondary batteries with excellent cycle characteristics. Patent Document 2 discloses a non-aqueous electrolyte that can improve electrochemical properties at high temperatures and reduce not only the discharge capacity retention rate but also the rate of increase in electrode thickness after high-temperature cycling tests. This non-aqueous electrolyte contains a specific diisocyanato compound and further contains a specific amount of at least one selected from a specific phosphate ester compound, a cyclic sulfonic acid ester compound, an isocyanate compound, and a triple bond-containing compound. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-101959 [Patent Document 2] International Publication No. 2017 / 061464 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the demand for higher performance in batteries has been increasing in recent years, requiring them to achieve high capacity, high-temperature storage characteristics, and high cycle characteristics at an advanced level. As a method to increase the capacity of non-aqueous electrolyte batteries, efforts are being made to pack as much electrode active material as possible into a limited battery volume. For example, methods such as pressurizing the electrode active material layer to increase its density, and designs that minimize the volume occupied by non-active material inside the battery (e.g., the amount of electrolyte), are being explored. However, increasing capacity reduces the void space inside the battery, which can lead to a problem where even a small amount of gas generated by the decomposition of the electrolyte can cause a significant increase in internal battery pressure. In particular, with non-aqueous electrolyte secondary batteries, when used as a backup power source during power outages or as a power source for portable devices, a weak current is constantly supplied to compensate for the battery's self-discharge, keeping it in a continuously charged state. In this continuous charging state, the activity of the electrode active material is always high, which can accelerate the decrease in battery capacity due to heat generated by the device, and can also cause the electrolyte to decompose and generate gas. In typical batteries, if the internal pressure rises abnormally due to an overcharge or other abnormality, a current cutoff valve is activated in response. However, if a large amount of gas is generated in a continuous charging state, the current cutoff valve, which should activate in the event of an overcharge or other abnormality, may malfunction, rendering the battery unusable. To reduce the malfunction of the current cutoff valve, it is necessary to widen the pressure difference between the internal pressure that rises in the event of an overcharge or other abnormality and the internal pressure that rises in a continuous charging state. Furthermore, increasing the battery capacity narrows the gap between the positive and negative electrodes through which lithium ions flow, leading to increased resistance and a decrease in discharge power capacity.

[0006] Therefore, the object of the present invention is to provide a non-aqueous electrolyte that can suppress malfunction of the current interruption valve under normal operating conditions in a non-aqueous electrolyte battery and improve the discharge power capacity, and a non-aqueous electrolyte battery using the non-aqueous electrolyte. [Means for solving the problem]

[0007] In view of the above circumstances, the inventors conducted diligent studies and found that the above problems can be solved by including a compound having a specific terminal alkyne skeleton and a specific anion in a specific mass ratio in a non-aqueous electrolyte, and thus completed the present invention. In other words, the gist of the present invention is as follows:

[0008] [1] A non-aqueous electrolyte containing a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2), wherein the mass ratio of the content of compound (A) to the content of anion (B) [(A) / (B)] is 0.01 or more and 1.2 or less.

[0009] [ka] [In formula (1), X 1 and X 2 Each of these independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms, which may be substituted with a hydrogen atom or a halogen atom. 1 This is a divalent atomic group selected from the structural group represented by the following formula (1-1). Z 1 This represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-3). [ka] [In formula (1-1), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).] [ka] [In formula (1-3), Z 2represents an alkyl group or an alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms which may be substituted with a halogen atom. X 3 and X 4 each independently represent a hydrogen atom or a halogen atom, and n represents an integer of 1 to 5. In the formula (1-3), ** represents Y in the formula (1) 1 and indicates the bonding position with Y in the formula (1). ]

[0010] [Chemical formula] [In the formula (2), Z 3 represents a fluorine atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms which may be substituted with a halogen atom, or an alkenyl group or an alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom. ]

[0011] [2] The non-aqueous electrolyte according to [1], wherein Y in the general formula (1) 1 is a divalent atomic group represented by the following formula (1-2). [Chemical formula] [In the formula (1-2), * indicates the bonding position with the oxygen atom in the formula (1). ]

[0012] [3] The non-aqueous electrolyte according to [1] or [2], wherein Z in the general formula (2) 3 is a fluorine atom. [4] The non-aqueous electrolyte according to any one of [1] to [3], further containing a chain carboxylic acid ester. [5] A non-aqueous electrolyte battery comprising a positive electrode having a positive electrode active material capable of occluding and releasing lithium ions, a negative electrode, and the non-aqueous electrolyte according to any one of [1] to [4]. [6] The non-aqueous electrolyte battery according to [5], wherein the positive electrode contains a lithium transition metal composite oxide represented by the following general formula (13) as a positive electrode active material. Li a1 Ni b1 M c1 O2(13) [In equation (13), a1, b1, and c1 are 0.90 ≤ a1 ≤ 1.10, 0.65 ≤ b1 ≤ 0.98, and 0 ≤ c1 ≤ 0.20, respectively, and b1 + c1 = 1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.] [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a non-aqueous electrolyte that can suppress malfunction of the current interruption valve under normal operating conditions in a non-aqueous electrolyte battery and improve the discharge power capacity, and a non-aqueous electrolyte battery using the non-aqueous electrolyte. [Modes for carrying out the invention]

[0014] [1. Non-aqueous electrolyte] The non-aqueous electrolyte of the present invention is a non-aqueous electrolyte for a non-aqueous electrolyte battery containing an electrolyte and a non-aqueous solvent, and is characterized in that it contains a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2), and the mass ratio of the content of compound (A) to the content of anion (B) [(A) / (B)] is 0.01 or more and 1.2 or less.

[0015] [ka] [In formula (1), X 1 and X 2 Each of these independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms, which may be substituted with a hydrogen atom or a halogen atom. 1 This is a divalent atomic group selected from the structural group represented by the following formula (1-1). Z 1 This represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-3).

[0016] [ka] [In formula (1-1), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).]

[0017] [ka] [In formula (1-3), Z 2 X represents an alkyl group or alkoxy group having 1 to 3 carbon atoms, which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms, which may be substituted with a halogen atom. 3 and X 4 Each of these independently represents either a hydrogen atom or a halogen atom, and n represents an integer between 1 and 5. Note that ** in equation (1-3) is the same as Y in equation (1). 1 This indicates the connection point.

[0018] [ka] [In formula (2), Z 3 This represents an alkyl or alkoxy group having 1 to 4 carbon atoms, which may be substituted with a fluorine atom or a halogen atom, or an alkenyl or alkenyloxy group having 2 to 4 carbon atoms, which may be substituted with a halogen atom.

[0019] A non-aqueous electrolyte battery manufactured using the non-aqueous electrolyte of the present invention can suppress malfunctions of the battery's current interruption valve and improve its discharge power capacity. While its operation and principle are not entirely clear, they are presumed to be as follows. However, the present invention is not limited to the operation and principle described below. Compound (A), represented by general formula (1), has terminal alkyne moieties with low steric hindrance, and therefore coordinates to the transition metal elements present at the positive electrode. As a result, contact of other electrolyte components with the positive electrode surface can be suppressed, and the oxidative decomposition reaction of the electrolyte can be suppressed. However, when the battery becomes overcharged and the positive electrode potential becomes nobler than the normal operating potential, compound (A) itself, which is coordinated to the positive electrode, undergoes oxidative decomposition, causing gas generation. Here, it is conceivable that by appropriately setting the pressure of the current cutoff valve, malfunctions of the current cutoff valve during normal use can be suppressed while still activating the current cutoff valve in the event of abnormalities such as overcharging. However, since compound (A) has a noble reduction potential, it is more easily reduced and decomposed at the negative electrode than it acts on the positive electrode. For this reason, even if only compound (A) is added to the electrolyte, it will hardly act appropriately on the positive electrode and will not be able to effectively suppress malfunctions of the battery's current cutoff valve.

[0020] On the other hand, anion (B), represented by general formula (2), has an electron-withdrawing group and therefore undergoes a nucleophilic substitution reaction in the presence of a nucleophile. Since surface functional groups and anion compounds generated by the reductive decomposition of the electrolyte are present on the negative electrode surface, these and anion (B) undergo a nucleophilic substitution reaction and form a bond. As a result, the resulting negative electrode film component is in a very stable form and can suppress the continued decomposition of the electrolyte. Therefore, by using compound (A) and anion (B) in combination, the reduction and decomposition of compound (A) at the negative electrode is suppressed, and it can act effectively on the positive electrode. As a result, gas generation can be caused when the battery is overcharged, while gas generation during normal use can be suppressed. Furthermore, since compound (A) has the effect of suppressing the interfacial resistance of the positive electrode, and anion (B) has the effect of suppressing the interfacial resistance of the negative electrode, it is presumed that the discharge power capacity can be improved by using each in a specific mass ratio.

[0021] The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described below, and can be modified and implemented as desired without departing from the spirit of the invention. In this specification, when the expression "~" is used, it shall be used to include the numerical values ​​or physical properties before and after it. Furthermore, in this specification, the term "independently" used when describing two or more subjects together means that those two or more subjects may be the same or different.

[0022] [1-1. Compound (A) represented by general formula (1), and anion (B) represented by general formula (2)] The non-aqueous electrolyte of the present invention (hereinafter also simply referred to as "non-aqueous electrolyte") contains a compound (A) represented by general formula (1) and an anion (B) represented by general formula (2). The aforementioned non-aqueous electrolyte may contain an electrolyte and a non-aqueous solvent for dissolving it, similar to a general non-aqueous electrolyte.

[0023] [1-1-1. Compound represented by general formula (1) (A)] [ka]

[0024] X in general formula (1) 1 and X 2 Each of these independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms, which may be substituted with a hydrogen atom or a halogen atom. 1 and X 2 These are, from the viewpoint of reducing steric hindrance around the alkyne moiety and facilitating action on the positive electrode, aliphatic hydrocarbon groups having 1 or 2 carbon atoms, which may be independently substituted with hydrogen atoms or halogen atoms, and are particularly preferably hydrogen atoms. Examples of aliphatic hydrocarbon groups having 1 to 3 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, or isopropyl groups; alkenyl groups such as ethenyl or propenyl groups; and cycloalkyl groups such as cyclopropyl groups. Among these, alkyl groups are preferred from the viewpoint of suppressing reactivity at the negative electrode, methyl or ethyl groups are more preferred, and methyl groups are even more preferred.

[0025] Y in general formula (1) 1 This is a divalent atomic group selected from the structural group represented by the following formula (1-1).

[0026] [ka] [In formula (1-1), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).]

[0027] In the above formula (1-1), a divalent atomic group represented by the following formula (1-2) is preferred from the viewpoint of suppressing excessive oxidative decomposition at the positive electrode and decomposition at the negative electrode. [ka] [In formula (1-2), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).]

[0028] Z in general formula (1) 1 This represents an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or a monovalent substituent represented by the following formula (1-3). Here, "alkyl group" and "alkenyl group" refer to "unsubstituted alkyl group" and "unsubstituted alkenyl group," respectively.

[0029] [ka] [In formula (1-3), Z 2 X represents an alkyl group or alkoxy group having 1 to 3 carbon atoms, which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms, which may be substituted with a halogen atom. 3 and X 4 Each of these independently represents either a hydrogen atom or a halogen atom, and n represents an integer between 1 and 5. Note that ** in equation (1-3) is the same as Y in equation (1). 1 This indicates the connection point.

[0030] Z 1 Examples of alkyl groups having 1 to 5 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, and n-pentyl groups, while examples of alkenyl groups having 2 to 5 carbon atoms include ethenyl, propenyl, butenyl, and pentenyl groups. Among these, from the viewpoint of suppressing excessive oxidative decomposition, alkyl groups having 1 to 3 carbon atoms or alkenyl groups having 2 or 3 carbon atoms are preferred, methyl groups, ethyl groups, n-propyl groups, ethenyl groups, or propenyl groups are more preferred, and methyl groups are particularly preferred.

[0031] In equation (1-3) above, Z 2 This represents an alkyl or alkoxy group having 1 to 3 carbon atoms, which may be substituted with a halogen atom, or an alkoxyalkyl group having 2 to 4 carbon atoms. Z 2 Examples of alkyl groups having 1 to 3 carbon atoms include methyl, ethyl, n-propyl, and isopropyl groups. Examples of alkoxy groups having 1 to 3 carbon atoms include methoxy, ethoxy, n-propoxy, and isopropoxy groups. Examples of alkoxyalkyl groups having 2 to 6 carbon atoms include methoxymethyl, ethoxymethyl, n-propoxymethyl, and isopropoxymethyl groups. Among these, alkoxy groups having 1 to 3 carbon atoms are preferred, methoxy and ethoxy groups are more preferred, and ethoxy groups are even more preferred. X in equation (1-3) above 3 and X 4 A hydrogen atom is preferred as n, and 1 or 2 is preferred for n, with 1 being more preferred. Examples of compounds (A) represented by general formula (1) include the following:

[0032] [ka]

[0033] [ka]

[0034] Among the above compounds, the following compounds are preferred. [ka]

[0035] Among the compounds listed above, the following compounds are more preferred. [ka]

[0036] Among the above compounds, the following compounds are even more preferred. [ka]

[0037] Among the above compounds, 2-propynylmethyl carbonate represented by the following formula (1-4) is even more preferred. [ka]

[0038] Compound (A), represented by general formula (1), can be used alone or in combination of two or more compounds in any ratio. If the non-aqueous electrolyte contains two or more compounds (A), their total amount shall be considered the compound content. Furthermore, the content of compound (A) is not particularly limited and is arbitrary as long as it does not impair the effects of the present invention.

[0039] The content of compound (A) represented by general formula (1) is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and even more preferably 1% by mass or less, in 100% by mass of the non-aqueous electrolyte. The content of compound (A) represented by general formula (1) is usually 0.001% by mass or more and 10% by mass or less in 100% by mass of the non-aqueous electrolyte, preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.001% by mass or more and 2% by mass or less, more preferably 0.001% by mass or more and 1% by mass or less, and more preferably 0.01% by mass or more and 1% by mass or less. The identification and measurement of the content of compound (A) can be performed by nuclear magnetic resonance (NMR) spectroscopy.

[0040] [1-1-2. Anion represented by general formula (2) (B)] [ka]

[0041] In general formula (2), Z 3 This represents an alkyl or alkoxy group having 1 to 4 carbon atoms, which may be substituted with a fluorine atom or a halogen atom, or an alkenyl or alkenyloxy group having 2 to 4 carbon atoms, which may be substituted with a halogen atom. Z 3 From the viewpoint of increasing reactivity at the negative electrode, the element is preferably a fluorine atom, an alkoxy group which may be substituted with a halogen atom, or an alkenyloxy group, more preferably a fluorine atom, an unsubstituted alkyl group having 2 to 4 carbon atoms, or an unsubstituted alkoxy group having 2 to 4 carbon atoms, and more preferably a fluorine atom or an unsubstituted alkoxy group having 2 to 4 carbon atoms. From the viewpoint of oxidation resistance, alkyl groups and alkenyl groups which may be substituted with halogen atoms are preferably alkyl groups having 1 to 3 carbon atoms and alkenyl groups having 2 to 3 carbon atoms which may be substituted with halogen atoms, more preferably alkyl groups having 1 or 2 carbon atoms and alkenyl groups having 2 to 3 carbon atoms which may be substituted with halogen atoms, even more preferably methyl groups and ethyl groups which may be substituted with halogen atoms, even more preferably unsubstituted methyl groups and unsubstituted ethyl groups, and particularly preferably unsubstituted methyl groups.

[0042] Compounds containing the anion represented by general formula (2) are usually acids or salts. The compound containing the anion represented by general formula (2) is preferably a salt, and its countercation is preferably an alkali metal cation such as a lithium cation, sodium cation, or potassium cation, with a lithium cation being more preferred.

[0043] Specific examples of the anion (B) represented by general formula (2) include sulfate anions such as methyl sulfate anion, ethyl sulfate anion, and n-propyl sulfate anion; and sulfonic acid anions such as fluorosulfonate anion, methanesulfonate anion, ethanesulfonate anion, and n-propanesulfonate anion. Among these, one or more selected from fluorosulfonate anion, methyl sulfate anion, ethyl sulfate anion, and n-propyl sulfate anion are more preferred, one or more selected from fluorosulfonate anion and methyl sulfate anion are even more preferred, and fluorosulfonate anion is particularly preferred. The anion (B) represented by general formula (2) can be used alone or in combination of two or more in any ratio.

[0044] Furthermore, the content of the anion (B) represented by general formula (2) is not particularly limited and is arbitrary as long as it does not impair the effects of the present invention. It is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 2% by mass or less, and most preferably 1.5% by mass or less, in the total amount (100% by mass) of the non-aqueous electrolyte. The content of compound (B) represented by general formula (2) is usually 0.001% by mass or more and 10% by mass or less in 100% by mass of the non-aqueous electrolyte, preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.001% by mass or more and 3% by mass or less, more preferably 0.001% by mass or more and 2% by mass or less, more preferably 0.001% by mass or more and 1.5% by mass or less, and more preferably 0.01% by mass or more and 1.5% by mass or less. In a non-aqueous electrolyte, the mass ratio [(A) / (B)] of the content of compound (A) represented by general formula (1) to the content of anion (B) represented by general formula (2) is 0.01 or higher, preferably 0.05 or higher, more preferably 0.1 or higher, even more preferably 0.15 or higher, even more preferably 0.2 or higher, and also 1.2 or lower, preferably 1.0 or lower, more preferably 0.9 or lower, even more preferably 0.8 or lower, and even more preferably 0.7 or lower. The mass ratio [(A) / (B)] of the content of compound (A) represented by general formula (1) to the content of anion (B) represented by general formula (2) is 0.01 or more and 1.2 or less, preferably 0.01 or more and 1.0 or less, more preferably 0.01 or more and 0.9 or less, more preferably 0.01 or more and 0.8 or less, and more preferably 0.01 or more and 0.7 or less. The identification and measurement of the anion (B) content can be performed by nuclear magnetic resonance (NMR) spectroscopy.

[0045] [1-2. Electrolytes] <Lithium salts> In non-aqueous electrolytes, lithium salts are typically used as the electrolyte. There are no particular restrictions on the lithium salt used; any lithium salt can be used. However, lithium salts corresponding to the anion (B) represented by [1-1-2. General formula (2)] are excluded. Specific examples include lithium fluoroborate salts, lithium fluorophosphate salts, lithium tungstate salts, lithium carboxylate salts, lithium imide salts, lithium methide salts, lithium oxalate salts, and fluorine-containing organolithium salts.

[0046] Among these, from the viewpoint of improving low-temperature power characteristics, high-rate charge / discharge characteristics, impedance characteristics, high-temperature storage characteristics, and cycle characteristics, lithium fluoroborate salts such as LiBF4; lithium fluorophosphate salts such as LiPF6, Li2PO3F, and LiPO2F2; and lithium imide salts such as LiN(FSO2)2, LiN(FSO2)(CF3SO2), LiN(CF3SO2)2, LiN(C2F5SO2)2, lithium cyclic 1,2-perfluoroethanedisulfonyliimide, and lithium cyclic 1,3-perfluoropropanedisulfonyliimide; Preferred lithium methide salts include LiC(FSO2)3, LiC(CF3SO2)3, and LiC(C2F5SO2)3; preferred lithium oxalate salts include lithium difluorooxalate borate, lithium bis(oxalate) borate, lithium tetrafluorooxalate phosphate, lithium difluorobis(oxalate) phosphate, and lithium tris(oxalate) phosphate; more preferably one or more selected from LiPF6, LiN(FSO2)2, and lithium bis(oxalate) borate, with LiPF6 being particularly preferred.

[0047] The above electrolyte salts can be used individually or in combination of two or more in any ratio. There are no particular restrictions on the combination of two or more electrolyte salts, and examples include combinations of LiPF6 and LiN(FSO2)2, LiPF6 and LiBF4, LiPF6 and LiN(CF3SO2)2, LiBF4 and LiN(FSO2)2, and LiBF4, LiPF6 and LiN(FSO2)2. Among these, the combinations of LiPF6 and LiN(FSO2)2, LiPF6 and LiBF4, and LiBF4, LiPF6 and LiN(FSO2)2 are preferred.

[0048] While there are no particular restrictions on the total concentration of the electrolyte, from the viewpoint of ensuring proper electrical conductivity for battery operation and sufficient output characteristics, it is typically 8% by mass or more, preferably 8.5% by mass or more, more preferably 9% by mass or more, relative to the total amount of the non-aqueous electrolyte, and also typically 18% by mass or less, preferably 17% by mass or less, more preferably 16% by mass or less.

[0049] [1-3. Non-aqueous solvents] Non-aqueous electrolytes, like general non-aqueous electrolytes, usually contain a non-aqueous solvent as their main component that dissolves the electrolyte mentioned above. The non-aqueous solvent used is not particularly limited as long as it dissolves the electrolyte; any known organic solvent can be used. Examples of organic solvents include saturated cyclic carbonates, linear carbonates, linear carboxylic acid esters, cyclic carboxylic acid esters, ether compounds, and sulfone compounds, and are not particularly limited, but it is preferable that the organic solvent contains linear carboxylic acid esters.

[0050] Organic solvents can be used individually or in combination of two or more in any ratio. There are no particular restrictions on the combination of two or more organic solvents, but examples include combinations of saturated cyclic carbonates and linear carboxylic acid esters, combinations of cyclic carboxylic acid esters and linear carbonates, and combinations of saturated cyclic carbonates, linear carbonates and linear carboxylic acid esters. Among these, combinations of saturated cyclic carbonates and linear carbonates, and combinations of saturated cyclic carbonates, linear carbonates and linear carboxylic acid esters are preferred.

[0051] [1-3-1. Saturated Cyclic Carbonates] Examples of saturated cyclic carbonates include those having alkylene groups with 2 to 4 carbon atoms, and saturated cyclic carbonates with 2 to 3 carbon atoms are preferred from the viewpoint of improving battery characteristics due to an increased degree of lithium ion dissociation. Specific examples of saturated cyclic carbonates include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are preferred, and ethylene carbonate, which is less susceptible to oxidation and reduction, is more preferred. Saturated cyclic carbonates can be used individually or in combination of two or more in any ratio.

[0052] The content of saturated cyclic carbonate is not particularly limited and is arbitrary as long as it does not impair the effects of the invention according to this embodiment. The content of saturated cyclic carbonate is usually 3% by volume or more, preferably 5% by volume or more, relative to the total amount of non-aqueous solvent, while it is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By keeping it within this range, a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte is avoided, making it easier to achieve good high-current discharge characteristics, stability to the negative electrode, and cycle characteristics of the non-aqueous electrolyte secondary battery, improving the oxidation-reduction resistance of the non-aqueous electrolyte and tending to improve stability during high-temperature storage. In this specification, volume percent refers to volume percent at 25°C and 1 atmosphere.

[0053] [1-3-2. Chain-like carbonates] As for the chain-like carbonate, for example, those with 3 to 7 carbon atoms are usually used, and chain-like carbonates with 3 to 5 carbon atoms are preferably used in order to adjust the viscosity of the electrolyte to an appropriate range. Specific examples of chain-like carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethyl methyl carbonate, and methyl-n-propyl carbonate, and preferably one or more selected from dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Furthermore, chain-like carbonates containing fluorine atoms (hereinafter also referred to as "fluorinated chain-like carbonates") can also be suitably used. The number of fluorine atoms in a fluorinated chain-like carbonate is not particularly limited as long as it is one or more, but is usually six or less, preferably four or less. When a fluorinated chain-like carbonate has multiple fluorine atoms, these multiple fluorine atoms may be bonded to the same carbon or to different carbons. Examples of fluorinated chain carbonates include fluorinated dimethyl carbonate derivatives such as fluoromethylmethyl carbonate; fluorinated ethyl methyl carbonate derivatives such as 2-fluoroethylmethyl carbonate; and fluorinated diethyl carbonate derivatives such as ethyl-(2-fluoroethyl) carbonate. Chain-like carbonates can be used individually or in combination of two or more types in any ratio.

[0054] The content of chain-like carbonates is not particularly limited, but from the viewpoint of setting the viscosity of the non-aqueous electrolyte within an appropriate range, suppressing the decrease in ionic conductivity, and thereby improving the output characteristics of the non-aqueous electrolyte secondary battery, it is usually 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, and also usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte. Furthermore, by combining ethylene carbonate with specific chain-like carbonates in a specific amount, battery performance can be significantly improved. For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonates, the ethylene carbonate content is arbitrary as long as it does not impair the effects of the present invention, but from the viewpoint of improving high-temperature stability and suppressing gas generation, it is usually 15% by volume or more, preferably 20% by volume or more, and usually 45% by volume or less, preferably 40% by volume or less, relative to the total amount of solvent in the non-aqueous electrolyte. The dimethyl carbonate content is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte. The ethyl methyl carbonate content is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte.

[0055] [1-3-3. Chain-like carboxylic acid esters] Examples of linear carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, methyl valerate, methyl isobutyrate, ethyl isobutyrate, and methyl pivalate. Among these, methyl acetate, ethyl acetate, propyl acetate, and butyl acetate are preferred from the viewpoint of improving battery characteristics. Linear carboxylic acid esters in which some of the hydrogen atoms of the above compounds are substituted with fluorine (for example, methyl trifluoroacetate, ethyl trifluoroacetate, etc.) can also be suitably used. The amount of chain-like carboxylic acid ester added is usually 1 volume% or more, preferably 5 volume% or more, and more preferably 15 volume% or more, relative to the total amount of non-aqueous solvent, from the viewpoint of improving the electrical conductivity of the non-aqueous electrolyte and improving the high-current discharge characteristics of the non-aqueous electrolyte battery. Furthermore, the upper limit of the amount added is usually 70 volume% or less, preferably 50 volume% or less, and more preferably 40 volume% or less, from the viewpoint of keeping the viscosity of the non-aqueous electrolyte within an appropriate range, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and keeping the high-current discharge characteristics of the non-aqueous electrolyte secondary battery within a good range.

[0056] [1-3-4. Cyclic carboxylic acid esters] Examples of cyclic carboxylic acid esters include γ-butyrolactone and γ-valerolactone. Of these, γ-butyrolactone is more preferred. Cyclic carboxylic acid esters obtained by substituting some of the hydrogen atoms of the above-mentioned compounds with fluorine can also be suitably used. The amount of cyclic carboxylic acid ester added is typically 1% by volume or more, preferably 5% by volume or more, and more preferably 15% by volume or more, relative to the total amount of non-aqueous solvent, from the viewpoint of improving the electrical conductivity of the non-aqueous electrolyte and enhancing the high-current discharge characteristics of non-aqueous electrolyte batteries. Furthermore, the upper limit of the amount added is typically 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoint of keeping the viscosity of the non-aqueous electrolyte within an appropriate range, avoiding a decrease in electrical conductivity, suppressing an increase in negative electrode resistance, and keeping the high-current discharge characteristics of non-aqueous electrolyte secondary batteries within a good range.

[0057] [1-3-5. Ether compounds] Preferred ether compounds include chain ethers having 3 to 10 carbon atoms, such as dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether, as well as cyclic ethers having 3 to 6 carbon atoms, such as tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, and 1,4-dioxane. Some of the hydrogen atoms in the ether compounds may be substituted with fluorine atoms. Among these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferred as chain ethers having 3 to 10 carbon atoms, from the viewpoint of high solvation ability to lithium ions, improved ion dissociation, low viscosity, and high ionic conductivity. As cyclic ethers having 3 to 6 carbon atoms, tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, etc. are preferred from the viewpoint of providing high ionic conductivity.

[0058] The content of the ether compound is arbitrary as long as it does not impair the effects of the present invention, but is usually 1% by volume or more, preferably 2% by volume or more, more preferably 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte. If the content of the ether compound is within the above range, it is easy to ensure the improvement in the degree of lithium ion dissociation by the ether compound and the improvement in ionic conductivity derived from the reduction in viscosity of the non-aqueous electrolyte. Furthermore, when the negative electrode active material is a carbon-based material, the phenomenon of chain-like ether being co-inserted together with lithium ions can be suppressed, so that the input / output characteristics and charge / discharge rate characteristics can be set within an appropriate range.

[0059] [1-3-6. Sulfone compounds] The sulfone compound is not particularly limited and may be a cyclic sulfone or a linear sulfone. In the case of a cyclic sulfone, the number of carbon atoms is usually 3 to 6, preferably 3 to 5, and in the case of a linear sulfone, the number of carbon atoms is usually 2 to 6, preferably 2 to 5. Furthermore, the number of sulfonyl groups in one molecule of the sulfone compound is not particularly limited, but is usually 1 or 2. Examples of cyclic sulfones include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones; and disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones. Among these, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferred from the viewpoint of dielectric constant and viscosity, and tetramethylene sulfones (sulfolanes) are even more preferred. Sulfolanes and sulfolane derivatives are preferred as sulforanes. Sulfolane derivatives are preferred in which one or more hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring are substituted with fluorine atoms, alkyl groups, or fluorine-substituted alkyl groups. Among these, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, and 3-trifluoromethylsulfolane are preferred because they have high ionic conductivity and high input / output capabilities.

[0060] Furthermore, examples of chain-like sulfones include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, and pentafluoroethyl methyl sulfone. Among these, dimethyl sulfone, ethyl methyl sulfone, and monofluoromethyl methyl sulfone are preferred because they improve the high-temperature storage stability of the electrolyte. The content of the sulfone compound is arbitrary as long as it does not impair the effects of the present invention, but from the viewpoint of improving high-temperature storage stability, it is usually 0.3% by volume or more, preferably 0.5% by volume or more, more preferably 1% by volume or more, relative to the total amount of non-aqueous solvent in the non-aqueous electrolyte, and is also usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less.

[0061] [1-4. Auxiliary Agents] The non-aqueous electrolyte of the present invention may contain various auxiliary agents, as long as they do not impair the effects of the present invention. Conventionally known auxiliary agents can be used as desired. The auxiliary agents can be used individually or in combination of two or more agents in any ratio. Examples of additives include cyclic carbonates having carbon-carbon unsaturated bonds, fluorine-containing cyclic carbonates, compounds having isocyanate groups, compounds having isocyanuric acid skeletons, compounds having cyano groups, sulfur-containing organic compounds, phosphorus-containing organic compounds, silicon-containing compounds, aromatic compounds, fluorine-free carboxylic acid esters, cyclic compounds having ether bonds, carboxylic acid anhydrides, borates, oxalates, monofluorophosphates, difluorophosphates, and the like. For example, compounds described in International Publication No. 2015 / 111676 can be cited. The content of the auxiliary agent is not particularly limited and is arbitrary as long as it does not 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, relative to the total amount of the non-aqueous electrolyte, and is also usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably less than 1% by mass.

[0062] Cyclic compounds containing ether bonds can be used as additives in non-aqueous electrolytes, and some can also be used as non-aqueous solvents, as shown in [1-3. Non-aqueous Solvents]. When using cyclic compounds having ether bonds as additives, it is preferable to use them in an amount of less than 4% by mass. Borates, oxalates, monofluorophosphates, and difluorophosphates can also be used as additives in non-aqueous electrolytes, and some can be used as electrolytes as shown in [1-2. Electrolytes]. When using these compounds as additives, it is preferable to use them in an amount of less than 3% by mass. Among these, fluorine-containing cyclic carbonates and cyclic carbonates having carbon-carbon unsaturated bonds are preferred, and fluorine-containing cyclic carbonates are more preferred from the viewpoint of easily forming a stable interfacial protective film.

[0063] [1-4-1. Fluorine-containing cyclic carbonates] Fluorine-containing cyclic carbonates are not particularly limited as long as they have a cyclic carbonate structure and contain fluorine atoms. Examples of fluorine-containing cyclic carbonates include fluorinated cyclic carbonates having alkylene groups with 2 to 6 carbon atoms, and their derivatives. Examples include fluorinated ethylene carbonates (hereinafter also referred to as "fluorinated ethylene carbonates") and their derivatives. Examples of derivatives of fluorinated ethylene carbonates include fluorinated ethylene carbonates substituted with alkyl groups (for example, alkyl groups with 1 to 4 carbon atoms). Among these, fluorinated ethylene carbonates with 1 to 8 fluorine atoms and their derivatives are preferred.

[0064] Examples of fluorinated ethylene carbonates and their derivatives having 1 to 8 fluorines 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, and 4,4-difluoro-5,5-dimethylethylene carbonate. Among these, one or more selected from monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate are preferred from the viewpoint of providing high ionic conductivity to the electrolyte and facilitating the formation of a stable interfacial protective film. Fluorine-containing cyclic carbonates can be used individually or in combination of two or more in any ratio.

[0065] The content of fluorine-containing cyclic carbonates (total amount if there are two or more types) is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and also preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less. Furthermore, when fluorine-containing cyclic carbonate is used as a non-aqueous solvent, its content is preferably 1% by volume or more, more preferably 5% by volume or more, even more preferably 10% by volume or more, and also preferably 50% by volume or less, more preferably 35% by volume or less, and even more preferably 25% by volume or less, based on 100% by volume of the non-aqueous solvent.

[0066] When a non-aqueous electrolyte contains LiPF6, the mass ratio of the total content of fluorine-containing cyclic carbonate to the LiPF6 content (fluorine-containing cyclic carbonate / LiPF6) is usually 0.00005 or higher, preferably 0.001 or higher, more preferably 0.01 or higher, even more preferably 0.02 or higher, and even more preferably 0.025 or higher, and also usually 0.5 or lower, preferably 0.45 or lower, more preferably 0.4 or lower, and even more preferably 0.35 or lower, from the viewpoint of improving energy device characteristics, especially durability characteristics, and minimizing the decomposition side reactions of LiPF6 within the energy device system.

[0067] [2.Nonaqueous electrolyte battery] The non-aqueous electrolyte battery of the present invention comprises a positive electrode having a positive electrode active material capable of intercalating and releasing metal ions, a negative electrode, and the non-aqueous electrolyte of the present invention, with lithium batteries being preferred. Within the scope of the present invention, it is also possible to use a mixture of other non-aqueous electrolytes with the non-aqueous electrolyte of the present invention.

[0068] [2-1. Lithium Batteries] The lithium battery according to the present invention comprises a positive electrode having a current collector and a positive electrode active material layer provided on the current collector, a negative electrode having a current collector and a negative electrode active material layer provided on the current collector, and capable of intercalating and releasing lithium ions, and the non-aqueous electrolyte of the present invention. In this invention, the term "lithium battery" refers collectively to lithium-ion primary batteries and lithium-ion secondary batteries. The lithium battery is similar to conventionally known lithium batteries in its configuration, except for the non-aqueous electrolyte of the present invention. Typically, the positive electrode and the negative electrode are stacked via a porous membrane (separator) impregnated with the non-aqueous electrolyte, and these are housed in a case (outer casing).

[0069] [2-2. Positive electrode] The positive electrode has a positive electrode active material capable of intercalating and releasing lithium ions on at least a portion of the current collector surface. The positive electrode active material preferably contains a lithium transition metal compound. [2-2-1. Positive electrode active material]

[0070] [2-2-1-1. Lithium transition metal compounds] Lithium transition metal compounds are compounds having a structure that allows for the removal and insertion of lithium ions. Examples include sulfides, phosphate compounds, silicate compounds, borate compounds, and lithium transition metal composite oxides. Among these, phosphate compounds and lithium transition metal composite oxides are preferred, and lithium transition metal composite oxides are more preferred. Examples of lithium transition metal composite oxides include those with a spinel structure that allows for three-dimensional diffusion, and those with a layered structure that enables two-dimensional diffusion of lithium ions.

[0071] Lithium transition metal composite oxides having a spinel structure are generally represented by the following formula (11). Li x M2O4(11) [In equation (11), x is 1 ≤ x ≤ 1.5, and M represents one or more transition metal elements.] Specific examples of oxides represented by formula (11) include LiMn2O4, LiCoMnO4, and LiNi 0.5 Mn 1.5 Examples include O4 and LiCoVO4.

[0072] Lithium transition metal composite oxides having a layered structure are generally represented by the following compositional formula (12). Li 1+x MO2(12) [In equation (12), x is -0.1 ≤ x ≤ 0.5, and M represents one or more transition metal elements.] Specific examples of oxides represented by formula (12) include LiCoO2, LiNiO2, and LiNi 0.85 Co 0.10 Al 0.05 O2, LiLiLi 0.80 Co 0.15 Al 0.05 O2, LiLiLi 0.33 Co 0.33 Mn 0.33 O2, Li 1.05 Ni 0.33 Co 0.33 Mn 0.33 O2, LiLiLi 0.5 Co 0.2 Mn 0.3 O2, Li 1.05 Ni 0.5 Co 0.2 Mn 0.3 O2, LiLiLi 0.6 Co 0.2 Mn 0.2 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2, LiLiLi 0.91 Co 0.06 Mn 0.03 O2, LiLiLi 0.91 Co 0.06 Al 0.03 O2, LiLiLi 0.90 Co 0.03 Al 0.07 Examples include O2.

[0073] Among these, lithium transition metal composite oxides having a layered structure are preferred from the viewpoint of improving battery capacity, and lithium transition metal composite oxides represented by the following formula (13) are more preferred. Li a1 Ni b1 M c1 O2(13) [In equation (13), a1, b1, and c1 are 0.90 ≤ a1 ≤ 1.10, 0.65 ≤ b1 ≤ 0.98, and 0 ≤ c1 ≤ 0.20, respectively, and b1 + c1 = 1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.] Preferred examples of the lithium transition metal composite oxide represented by the above formula (13) include LiNi 0.7 Mn 1.3 O4, LiNi 0.85 Co 0.10 Al 0.05 O2, LiNi 0.80 Co 0.15 Al 0.05 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.91 Co 0.06 Mn 0.03 O2, LiNi 0.91 Co 0.06 Al 0.03 O2, LiNi 0.90 Co 0.03 Al 0.07 O2 and the like. In the formula (13), b1 is preferably 0.70 ≦ b1 ≦ 0.98, more preferably 0.80 ≦ b1 ≦ 0.98, and still more preferably 0.90 ≦ b1 ≦ 0.98. In the above formulas (11) to (13), from the viewpoint of enhancing the structural stability of the lithium transition metal oxide and suppressing the structural deterioration during repeated charge and discharge, M preferably contains Mn or Al, and more preferably contains Mn.

[0074] In particular, from the viewpoint of the structural stability of the lithium transition metal composite oxide, it is preferably a lithium transition metal composite oxide represented by the following formula (14). Li a2 Ni b2 Co c2 M d2 O2(14) 〔In the formula (14), a2, b2, c2 and d2 are respectively 0.90 ≦ a2 ≦ 1.10, 0.65 ≦ b2 ≦ 0.98, 0.01 ≦ c2 ≦ 0.06, and 0.01 ≦ d2 ≦ 0.04, and b2 + c2 + d2 = 1. M represents at least one element selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti and Er.〕 Preferred examples of the lithium transition metal composite oxide represented by the above formula (14) include LiNi 0.85 Co0.10 Al 0.05 O2, LiLiLi 0.80 Co 0.15 Al 0.05 O2, LiLiLi 0.8 Co 0.1 Mn 0.1 O2, LiLiLi 0.91 Co 0.06 Mn 0.03 O2, LiLiLi 0.91 Co 0.06 Al 0.03 O2, LiLiLi 0.90 Co 0.03 Al 0.07 Examples include O2. In equation (14), b2 is preferably 0.70 ≤ b2 ≤ 0.98, more preferably 0.80 ≤ b2 ≤ 0.98, and even more preferably 0.90 ≤ b2 ≤ 0.98. In the above formula (14), it is preferable that M contains Mn or Al, from the viewpoint of improving the structural stability of the lithium transition metal oxide and suppressing structural degradation when repeatedly charged and discharged. The positive electrode active material is identified by ICP emission spectroscopy after wet decomposition of the sample.

[0075] [2-2-1-2. Introduction of different elements] Furthermore, lithium transition metal composite oxides may contain elements other than those included in any of the above formulas (11) to (14) (other elements).

[0076] [2-2-1-3. Surface coating] As the positive electrode, a positive electrode active material may be used in which a substance with a different composition from the positive electrode active material (surface-adhered substance) is attached to its surface. Examples of surface-adhering substances include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate. These surface-adhering substances can be attached to the surface of the positive electrode active material by, for example, dissolving or suspending them in a solvent, impregnating them into the positive electrode active material, and then drying them. The amount of surface-adhering material is preferably 1 μmol / g or more, more preferably 10 μmol / g or more, and usually 1 mmol / g or less, relative to the positive electrode active material. In this specification, a positive electrode active material with the above-mentioned surface-adhered substance attached to its surface is also referred to as a "positive electrode active material."

[0077] [2-2-1-4. Blend] The positive electrode active material can be used alone or in combination of two or more materials in any ratio. ru.

[0078] [2-2-2. Configuration and Manufacturing Method of the Positive Electrode] The positive electrode using positive electrode active material can be manufactured by conventional methods. Specifically, the positive electrode can be obtained by a coating method in which the positive electrode active material, binder, and optionally conductive material and thickener are dry-mixed to form a sheet, which is then pressed onto the positive electrode current collector, or by dissolving or dispersing these materials in a liquid medium such as an aqueous solvent or an organic solvent to form a slurry, which is then applied to the positive electrode current collector and dried to form a positive electrode active material layer on the current collector. Alternatively, for example, the above-mentioned positive electrode active material may be roll-molded to form a sheet electrode, or it may be compressed to form a pellet electrode. The following describes the process of sequentially applying and drying the slurry onto the positive electrode current collector.

[0079] [2-2-2-1. Content of positive electrode active material] The content of the positive electrode active material in the positive electrode active material layer is typically between 80% by mass and 99.5% by mass.

[0080] [2-2-2-2. Electrode density] The positive electrode active material layer obtained by coating and drying is preferably compacted by hand pressing, roller pressing, or the like to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer present on the current collector is typically 1.5 g / cm³. 3 The above is more preferable, or 2.0 g / cm³. 3 The above is the most preferred, and is particularly preferably 3.0 g / cm³. 3 The above is the standard, and the usual value is 4.5 g / cm³. 3 The following, and more preferably 4.0 g / cm³ 3 The following, and particularly preferably 3.5 g / cm³ 3The following applies: The density of the positive electrode active material layer is measured by measuring its thickness and weight.

[0081] [2-2-2-3. Conductive materials] Any known conductive material can be used as the conductive material. Specific examples include metallic materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; and carbon-based materials such as amorphous carbon such as needle coke. The conductive material can be used alone or in combination of two or more materials in any ratio. The conductive material is usually contained in the positive electrode active material layer in an amount of 0.01% by mass or more and 50% by mass or less.

[0082] [2-2-2-4. Binding agent] When forming the positive electrode active material layer by a coating method, the type of binder used is not particularly limited as long as it is a material that can be dissolved or dispersed in the liquid medium for the slurry. For example, fluororesins such as polyvinyl fluoride, polyvinylidene fluoride, and polytetrafluoroethylene are preferred due to their weather resistance, chemical resistance, heat resistance, and flame retardancy; CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide are preferred. Furthermore, mixtures of the above polymers, modified products, derivatives, random copolymers, alternating copolymers, graft copolymers, block copolymers, etc., can also be used. The binder can be used alone or in combination of two or more types in any ratio. Furthermore, when a resin is used as a binder, the weight-average molecular weight of the resin can be arbitrary as long as it does not impair the effects of the present invention, and is usually between 10,000 and 3,000,000. When the molecular weight is within this range, the strength of the electrode is improved, and the electrode can be formed suitably. The proportion of binder in the positive electrode active material layer is typically between 0.1% by mass and 80% by mass.

[0083] [2-2-2-5. Current Collector] The material of the positive electrode current collector is not particularly limited, and any known material can be used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, with aluminum being preferred. Examples of current collector shapes include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, metal foil or metal thin film is preferred. The metal thin film may be formed in a mesh shape as appropriate. When the shape of the positive electrode current collector is plate-shaped or film-shaped, the thickness of the current collector can be arbitrary, but is usually between 1 μm and 1 mm.

[0084] [2-2-2-6. Thickness of the positive electrode plate] The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the positive electrode active material layer, obtained by subtracting the thickness of the current collector from the thickness of the positive electrode plate, is usually between 10 μm and 500 μm on one side of the current collector.

[0085] [2-2-2-7. Surface coating of the positive electrode plate] The positive electrode plate may be one on which a substance with a different composition from the positive electrode plate is attached to its surface, and the substance used may be the same as the surface-attached substance that may be attached to the surface of the positive electrode active material.

[0086] [2-3. Negative electrode] The negative electrode has negative electrode active material on at least a portion of the current collector surface. [2-3-1. Negative electrode active material] There are no particular restrictions on the negative electrode active material used in the negative electrode, as long as it is capable of electrochemically intercepting and releasing metal ions. Specific examples include (i) carbon-based materials, (ii) particles containing metals that can alloy with Li, (iii) lithium-containing metal composite oxide materials, and (iv) mixtures thereof. Among these, (i) carbon-based materials, (ii) particles containing metals that can alloy with Li, and (v) mixtures of particles containing metals that can alloy with Li and graphite particles are used because they offer good cycle characteristics, safety, and excellent continuous charging characteristics. It is preferable to do so. These can be used individually or in combination of two or more in any ratio. The identification and content measurement of the negative electrode active material are performed by ICP emission spectroscopy after alkali fusion of the sample.

[0087] [2-3-1-1. Carbon-based materials] (i) Examples of carbon-based materials include natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, and resin-coated graphite. Among these, natural graphite is preferred. Carbon-based materials can be used individually or in combination of two or more in any ratio. Examples of natural graphite include scaly graphite, flake graphite, and / or graphite particles obtained by treating these graphites, such as spheroidization or densification. Among these, spherical or ellipsoidal graphite particles obtained by spheroidization treatment are 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.

[0088] [2-3-1-2. Physical Properties of Carbon-Based Materials] The carbon-based material used as the negative electrode active material preferably satisfies at least one of the following physical properties and characteristics such as shape, as shown in (1) to (4), and more preferably satisfies multiple items simultaneously. (1) X-ray diffraction parameters The d-value (interlayer distance) of the lattice plane (002 plane) of carbon-based materials, as determined by X-ray diffraction using the JSPS method, is typically between 0.335 nm and 0.360 nm. Furthermore, the crystallite size (Lc) of carbon-based materials, as determined by X-ray diffraction using the JSPS method, is 1.0 nm or greater. (2) Volume-based average particle size The volume-based average particle size of carbon-based materials is the volume-based average particle size (median diameter) determined by laser diffraction and scattering, and is typically between 1 μm and 100 μm. (3) Raman R value, Raman half-width The Raman R value of carbon-based materials is measured using argon ion laser Raman spectroscopy and is typically between 0.01 and 1.5. Also, 1580 cm² of carbon-based materials -1 The Raman width at half maximum in the vicinity is not particularly restricted, but is usually 10 cm. -1 More than 100cm -1 The following applies: (4) BET specific surface area The BET specific surface area of ​​carbon-based materials is the value of the specific surface area measured using the BET method, and is typically 0.1 m². 2 ·g -1 Over 100m 2 ·g -1 The following applies: The negative electrode active material may contain two or more carbon-based materials with different properties. The properties referred to here are one or more characteristics selected from the group consisting of X-ray diffraction parameters, volume-based average particle size, Raman R value, Raman full width at half maximum, and BET specific surface area. Examples of materials containing two or more carbon-based materials with different properties include those in which the volume-based particle size distribution is not symmetrical when centered on the median diameter, those containing two or more carbon-based materials with different Raman R values, and those with different X-ray diffraction parameters.

[0089] [2-3-1-3. Particles containing metals that can be alloyed with Li] (ii) Any conventionally known particles containing a metal that can be alloyed with Li may be used, but from the viewpoint of capacity and cycle life, it is preferable that the particles be a metal or compound thereof selected from the group consisting of Sb, Si, Sn, Al, As, and Zn. Furthermore, if the particles containing a metal that can be alloyed with Li contain two or more types of metals, the particles may be alloy particles made of an alloy of these metals. Furthermore, examples of metal compounds that can alloy with Li include metal oxides, metal nitrides, and metal carbides. These compounds may contain two or more metals that can alloy with Li. Among these, metallic Si (hereinafter also referred to as "Si") or Si-containing inorganic compounds are preferred in terms of increasing capacity. Furthermore, the metal compound that can be alloyed with Li may already be alloyed with Li during the production of the negative electrode, as described later. Si or a Si-containing inorganic compound is preferred as the compound in terms of increasing capacity. In this specification, Si or Si-containing inorganic compounds are collectively referred to as Si compounds. Examples of Si compounds include SiO x (0 ≦ x ≦ 2), etc. Examples of metal compounds alloyed with Li include Li y Si(0 < y ≦ 4.4), Li 2z SiO 2+z (0 < z ≦ 2), etc. Examples of Si compounds include Si metal oxides (SiO x1 , 0 < x1 ≦ 2), which are 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 being able to obtain a high capacity. The average particle diameter (d 50 ) of particles containing a metal alloyable with Li is usually 0.01 μm or more and 10 μm or less from the viewpoint of cycle life.

[0090] [2-3-1-4. Mixture of Particles Containing a Metal Alloyable with Li and Graphite Particles] (v) The mixture of particles containing a metal alloyable with Li and graphite particles may be a mixture in which the particles containing a metal alloyable with Li and the graphite particles are mixed in a state of independent particles, or a composite in which the particles containing a metal alloyable with Li are present on the surface or inside of the graphite particles. The content ratio of the particles containing a metal alloyable with Li to the total of the particles containing a metal alloyable with Li and the graphite particles is usually 1 mass% or more and 99 mass% or less.

[0091] [2-3-1-5. Lithium-Containing Metal Composite Oxide Material] (iii) The lithium-containing metal composite oxide material is not particularly limited as long as it is capable of intercalating and releasing lithium ions. Specifically, from the viewpoint of high current density charge / discharge characteristics, lithium-containing metal composite oxide materials containing titanium are preferred, lithium-titanium composite oxides (hereinafter also referred to as "lithium titanium composite oxides") are more preferred, and lithium titanium composite oxides having a spinel structure are even more preferred because they significantly reduce output resistance. Furthermore, the lithium and / or titanium in the lithium-titanium composite oxide may be substituted with other metallic elements, such as at least one element selected from the group consisting of Al, Ga, Cu, and Zn. As a lithium titanium composite oxide, Li 4 / 3 Ti 5 / 3 O4, Li1Ti2O4 and Li 4 / 5 Ti 11 / 5 O4 is preferred. Also, lithium titanium composite oxides in which part of lithium and / or titanium is substituted with other elements are preferred, for example, Li 4 / 3 Ti 4 / 3 Al 1 / 3 O4 is also preferable.

[0092] [2-3-2. Negative electrode configuration and manufacturing method] The negative electrode may be manufactured using any known method, as long as it does not impair the effects of the present invention. For example, it can be manufactured by adding a binder, a liquid medium such as an aqueous solvent or an organic solvent, and optionally a thickener, a conductive material, a filler, etc., to the negative electrode active material to form a slurry, applying this slurry to a current collector, drying it, and then pressing it to form a negative electrode active material layer.

[0093] [2-3-2-1. Content of negative electrode active material] The content of the negative electrode active material in the negative electrode active material layer is typically between 80% by mass and 99.5% by mass.

[0094] [2-3-2-2. Electrode density] The negative electrode active material layer obtained by coating and drying is preferably compacted using a hand press, roller press, or the like to increase the packing density of the negative electrode active material. The electrode structure when the negative electrode active material is used as an electrode is not particularly limited, but the density of the negative electrode active material layer present on the current collector is usually 1 g·cm³. -3 More than 2.2g cm -3 The following is the result: 1.2 g·cm -3 More than 2.0g cm -3 The following is preferable: 1.4 g·cm -3 More than 1.8g cm -3 The following are preferable. The density of the negative electrode active material layer is measured by measuring the thickness and weight of the negative electrode active material layer.

[0095] [2-3-2-3. Thickening agents] Thickening agents are typically used to adjust the viscosity of slurries. While not particularly limited, examples of thickening agents include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, and polyvinyl alcohol. These can be used individually or in combination of two or more in any ratio. When a thickening agent is used, the ratio of the thickening agent to the negative electrode active material is usually between 0.1% by mass and 5% by mass.

[0096] [2-3-2-4. Binding agent] The binder used to bind the negative electrode active material can be any material that is stable with non-aqueous electrolytes or liquid media used during electrode manufacturing, and is not particularly limited. Specific examples include rubbery polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), ethylene-propylene rubber, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and tetrafluoroethylene-ethylene copolymers. These can be used individually or in combination of two or more in any ratio. The ratio of binder to negative electrode active material is usually between 0.1% by mass and 20% by mass. In particular, when the binder contains a rubbery polymer such as SBR as its main component, the ratio of the binder to the negative electrode active material is usually between 0.1% by mass and 5% by mass. Furthermore, when the binder contains a fluorine-based polymer such as polyvinylidene fluoride as its main component, the ratio of the binder to the negative electrode active material is usually between 1% by mass and 15% by mass.

[0097] [2-3-2-5. Current Collector] Any known material can be used as the current collector for holding the negative electrode active material. Examples of negative electrode current collectors include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel, but copper is particularly preferred in terms of ease of processing and cost. Examples of the negative electrode current collector shape include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, metal foil or metal thin film is preferred. The metal thin film may be formed in a mesh shape as appropriate. When the negative electrode current collector is plate-shaped or film-shaped, the thickness of the current collector can be arbitrary, but is usually between 1 μm and 1 mm.

[0098] [2-3-2-6. Thickness of the negative electrode plate] The thickness of the negative electrode (negative electrode plate) is designed to match the positive electrode (positive electrode plate) used and is not particularly limited; however, the thickness of the negative electrode active material layer, obtained by subtracting the thickness of the current collector from the thickness of the negative electrode material, is usually between 15 μm and 300 μm.

[0099] [2-3-2-7. Surface coating of the negative electrode plate] Furthermore, the negative electrode plate may also be one in which a substance with a different composition from the negative electrode active material is attached to its surface (surface-attached substance). Examples of surface-attached substances include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate.

[0100] [2-4. Separator] A separator is usually placed between the positive and negative electrodes to prevent short circuits. In this case, the non-aqueous electrolyte is typically used by impregnating this separator. There are no particular restrictions on the material or shape of the separator; any known material or shape can be used as long as it does not impair the effects of the present invention.

[0101] [2-5.Battery design] [2-5-1. Electrode group] The electrode group may be either a laminated structure in which the positive electrode plate and the negative electrode plate are separated by the separator, or a structure in which the positive electrode plate and the negative electrode plate are spirally wound around the separator. The proportion of the electrode group's volume to the battery's internal volume (electrode group occupancy rate) is usually between 40% and 90%.

[0102] [2-5-2. Current collection structure] In the case of electrode groups with the aforementioned laminated structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to a terminal is preferably used. A structure that reduces resistance by providing multiple terminals within the electrode is also preferably used. In the case of electrode groups with the aforementioned wound structure, the internal resistance can be reduced by providing multiple lead structures in both the positive and negative electrodes and bundling them to a terminal.

[0103] [2-5-3. Protective Elements] As protective elements, PTC (Positive Temperature Coefficient) elements whose resistance increases with heat generation due to excessive current, thermal fuses, thermistors, and valves (current interruption valves) that interrupt the current flowing through the circuit due to a rapid rise in internal pressure or temperature of the battery in the event of abnormal heat generation can be used. It is preferable to select the above protective elements that do not operate under normal high-current use, and it is even more preferable to design the system so that abnormal heat generation or thermal runaway does not occur even without protective elements.

[0104] [2-5-4. Exterior] Non-aqueous electrolyte batteries are typically constructed by housing the non-aqueous electrolyte, negative electrode, positive electrode, separator, etc., of the present invention within an outer casing (outer case). There are no restrictions on this outer casing; any known material can be used as long as it does not impair the effects of the present invention. The material of the outer casing can be any substance that is stable with respect to the non-aqueous electrolyte used, and is not particularly limited. However, from the viewpoint of weight reduction and cost, metals such as iron, aluminum, aluminum alloys, or laminated films are preferably used. Iron is particularly preferred due to its pressure resistance required to operate the current interruption valve. Outer cases using the above-mentioned metals include those that create a sealed structure by welding the metals together using laser welding, resistance welding, or ultrasonic welding, or those that create a crimped structure using the above-mentioned metals via a resin gasket.

[0105] [2-5-5. Shape] Furthermore, the shape of the outer casing is arbitrary and can be cylindrical, rectangular, laminated, coin-shaped, large, or any other shape. In particular, a cylindrical shape is most preferable from the viewpoint of mounting the current interruption valve. [Examples]

[0106] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0107] <Example 1> [Preparation of non-aqueous electrolytes] Under a dry argon atmosphere, a mixed solvent consisting of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate (mixing volume ratio 30:30:40) was prepared by dissolving thoroughly dried LiPF6 as an electrolyte at a concentration of 1.0 mol / L. Furthermore, 1.0% by mass of monofluoroethylene carbonate was added as an auxiliary agent to the total electrolyte to create the standard electrolyte. Furthermore, a non-aqueous electrolyte was prepared by adding 0.4% by mass of 2-propynylmethyl carbonate and 1.0% by mass of lithium fluorosulfonate (LiFSO3) to the standard electrolyte.

[0108] [Fabrication of the positive electrode] Nickel-containing transition metal oxide (LiNi) is used as the positive electrode active material. 0.91 Co 0.06 Mn 0.0397 parts by mass of O2, 1.5 parts by mass of acetylene black as a conductive material, and 1.5 parts by mass of polyvinylidene fluoride as a binder were mixed in an N-methylpyrrolidone solvent using a disperser to form a slurry. This slurry was uniformly coated onto both sides of a 21 μm thick aluminum foil, dried, and then the density was 3.3 g / cm³. 3 It was pressed in this manner to form the positive electrode.

[0109] [Fabrication of the negative electrode] Natural graphite powder was used as the negative electrode active material, an aqueous dispersion of sodium carboxymethylcellulose (1% by mass) as a thickener, and an aqueous dispersion of styrene-butadiene rubber (50% by mass) as a binder. These were mixed in a disperser to form a slurry. This slurry was uniformly applied to one side of a 12 μm thick copper foil, dried, and then the density was 1.5 g / cm³. 3 The negative electrode was formed by pressing it in this manner. Furthermore, the dried negative electrode was manufactured with a mass ratio of natural graphite:sodium carboxymethylcellulose:styrene-butadiene rubber = 98:1:1.

[0110] [Manufacturing of non-aqueous electrolyte batteries (pouch type)] The positive electrode, negative electrode, and polypropylene separator described above were stacked in the order of negative electrode, separator, and positive electrode to create a battery element. The battery elements were inserted into a bag made of laminate film, which consists of aluminum (40 μm thick) coated on both sides with a resin layer, so that the positive and negative electrode terminals protruded from the bag. Then, the non-aqueous electrolyte obtained above was injected into the bag, and it was vacuum-sealed to produce a pouch-type battery, which was then made into a non-aqueous electrolyte battery.

[0111] <Examples 2-5> In Example 1, a non-aqueous electrolyte battery was prepared in the same manner as in Example 1, except that the conditions shown in Table 1 were changed.

[0112] <Example 6> A non-aqueous electrolyte battery was prepared in the same manner as in Example 1, except that a mixed solvent consisting of ethylene carbonate, ethyl methyl carbonate, and methyl acetate (volume ratio 30:50:20) was used as the non-aqueous solvent.

[0113] <Comparative Examples 1-10> In Example 1, a non-aqueous electrolyte battery was prepared in the same manner as in Example 1, except that the conditions shown in Table 1 were changed. In addition, as auxiliary agents, 3.0% by mass of vinylene carbonate (VC) was added in Comparative Example 6, 3.0% by mass of lithium bisfluorosulfonylimide (LiFSI) in Comparative Example 7, 1.0% by mass of lithium difluorophosphate (LiPO2F2) in Comparative Example 8, 0.4% by mass of dipropynyl carbonate (DPC) in Comparative Example 9, and 0.4% by mass of ethynylethylene carbonate (EEC) in Comparative Example 10.

[0114] <Evaluation of non-aqueous electrolyte batteries> [Pre-test charge / discharge and discharge power capacity] Each non-aqueous electrolyte battery obtained in the examples and comparative examples was charged at 25°C for 4 hours with a constant current equivalent to 0.05C while sandwiched between glass plates to improve adhesion between electrodes, and then discharged to 2.5V with a constant current of 0.2C. Here, 1C represents the current value that discharges the battery's standard capacity in 1 hour, 0.5C represents a current value that is half that of 1C, and 0.2C represents a current value that is one-fifth that of 1C. Next, it was charged to 4.1V with a constant current equivalent to 0.1C, discharged to 2.5V with a constant current of 0.2C, then charged again with a constant current-constant voltage of 0.2C to 4.1V (0.05C cut), and then discharged to 2.5V with a constant current of 0.2C. After that, it was charged with a constant current-constant voltage of 0.2C to 4.2V (0.05C cut), and then discharged to 2.5V with a constant current of 0.2C. After that, it was charged with a constant current-constant voltage of 0.2C to 4.2V (0.05C cut), and then discharged to 2.5V with a constant current of 1.0C. The power capacity at 1.0C discharge was defined as the discharge power capacity. The results are shown in Table 1. Table 1 shows relative values ​​normalized to 100 for the discharge power capacity of Comparative Example 1. After that, it was charged at 0.2C with constant current and constant voltage up to 4.2V (0.05C cut-off).

[0115] [Failure suppression rate of battery current cutoff valve] The amount of gas generated during overcharging and during high-temperature continuous charging was measured using the method described below, and the difference between the two was defined as the malfunction suppression rate of the battery current cutoff valve. The results are shown in Table 1. Table 1 shows relative values ​​normalized to 100 for the malfunction suppression rate of the battery current cutoff valve in Comparative Example 1.

[0116] (Measurement of gas amount generated during overcharging) Before the test, the volume of each non-aqueous electrolyte battery after charging and discharging was measured using Archimedes' principle. Then, with the batteries again sandwiched between glass plates, they were charged to 5.0V at 45°C with a constant current equivalent to 0.5C. After removing the glass plates, the volume of each non-aqueous electrolyte battery was measured again using Archimedes' principle. The change in volume before and after the test was defined as the amount of gas generated during overcharging.

[0117] (Measurement of gas generation during continuous high-temperature charging) Before the test, the volume of each non-aqueous electrolyte battery after charge and discharge was measured using Archimedes' principle. Then, with the batteries again sandwiched between glass plates, they were charged at 45°C at 0.2C to 4.25V with constant current and constant voltage (72-hour cut-off). After removing the glass plates, the volume of each non-aqueous electrolyte battery was measured again using Archimedes' principle. The volume change before and after the test was defined as the amount of gas generated during high-temperature continuous charging.

[0118] [Table 1]

[0119] Table 1 shows that the non-aqueous electrolyte batteries of Examples 1 to 6, which contain an electrolyte containing compound (A) represented by general formula (1) and anion (B) represented by general formula (2), and have a mass ratio [(A) / (B)] of 0.01 or more and 1.2 or less, showed improved discharge power capacity and reduced malfunction rate of the current interruption valve compared to the non-aqueous electrolyte battery of Comparative Example 1, which has an electrolyte that does not contain compound (A) and anion (B); the non-aqueous electrolyte batteries of Comparative Examples 2 to 4, which have an electrolyte that does not contain compound (A) or anion (B); and the non-aqueous electrolyte battery of Comparative Example 5, which contains compound (A) and anion (B) but does not satisfy the predetermined mass ratio [(A) / (B)]. In other words, the synergistic effect of containing compound (A), compound (B), and satisfying the predetermined mass ratio [(A) / (B)] was confirmed. Furthermore, Examples 1 to 6 showed improved discharge power capacity and reduced malfunction rate of the current interruption valve compared to Comparative Example 6's non-aqueous electrolyte battery, which contained vinylene carbonate instead of anion (B); Comparative Example 7's non-aqueous electrolyte battery, which contained bisfluorosulfonylimide anion instead of anion (B); Comparative Example 8's non-aqueous electrolyte battery, which contained difluorophosphate anion instead of anion (B); Comparative Example 9's battery, which contained dipropynyl carbonate instead of compound (A); and Comparative Example 10's non-aqueous electrolyte battery, which contained ethynylethylene carbonate instead of compound (A). In other words, it can be seen that the effects of the present invention are achieved by including a combination of compound (A) and anion (B) among the triple-bond-containing compounds and anions used in the prior art. [Industrial applicability]

[0120] By using the non-aqueous electrolyte of the present invention as the electrolyte in a non-aqueous electrolyte battery, malfunctions of the current cutoff valve under normal operating conditions can be suppressed and the discharge power capacity can be improved. Therefore, the non-aqueous electrolyte of the present invention can be suitably used in all fields of electronic equipment and other devices in which non-aqueous electrolyte batteries are used. Specific examples of applications for the non-aqueous electrolyte secondary battery of the present invention include, for example, notebook computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, portable audio players, small video cameras, headphone stereos, video movies, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, strobes, cameras, household backup power supplies, business backup power supplies, load leveling power supplies, and natural energy storage power supplies.

Claims

1. A non-aqueous electrolyte containing a compound (A) represented by the following general formula (1) and an anion (B) represented by the following general formula (2), wherein the mass ratio of the compound (A) to the anion (B) content [(A) / (B)] is 0.01 or more and 1.2 or less. 【Chemistry 1】 [In formula (1), X １ and X ２ Each of these independently represents an aliphatic hydrocarbon group having 1 to 3 carbon atoms, which may be substituted with a hydrogen atom or a halogen atom. １ This is a divalent atomic group selected from the group of structures represented by the following formula (1-1). Z １ This represents an alkyl group with 1 to 5 carbon atoms. 【Chemistry 2】 [In formula (1-1), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).] 【Transformation 3】 [In formula (2), Z ３ This represents an alkyl or alkoxy group having 1 to 4 carbon atoms, which may be substituted with a fluorine atom or a halogen atom, or an alkenyl or alkenyloxy group having 2 to 4 carbon atoms, which may be substituted with a halogen atom.

2. Y in general formula (1) １ The non-aqueous electrolyte according to claim 1, wherein the atom is a divalent group represented by the following formula (1-2). 【Chemistry 4】 [In formula (1-2), the asterisk (*) indicates the bonding site with the oxygen atom in formula (1).]

3. Z in general formula (2) ３ The non-aqueous electrolyte according to claim 1 or 2, wherein the atom is a fluorine atom.

4. The non-aqueous electrolyte according to any one of claims 1 to 3, further containing a chain-like carboxylic acid ester.

5. A non-aqueous electrolyte battery characterized by comprising a positive electrode having a positive electrode active material capable of intercalating and releasing lithium ions, a negative electrode, and a non-aqueous electrolyte according to any one of claims 1 to 4.

6. The non-aqueous electrolyte battery according to claim 5, wherein the positive electrode contains a lithium transition metal composite oxide represented by the following general formula (13) as the positive electrode active material. Li ａ１ Ni ｂ１ M ｃ１ O ２ (13) [In equation (13), a1, b1, and c1 are 0.90 ≤ a1 ≤ 1.10, 0.65 ≤ b1 ≤ 0.98, and 0 ≤ c1 ≤ 0.20, respectively, and b1 + c1 = 1. M represents at least one element selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti, and Er.]

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