JP5760665B2 - Non-aqueous electrolyte and non-aqueous electrolyte battery - Google Patents

Description

The present invention relates to a non-aqueous electrolyte solution and a non-aqueous electrolyte battery, and more specifically, a non-aqueous electrolyte solution containing a specific cyclic compound having a triple bond and a specific compound acting together with the cyclic compound, and the non-aqueous electrolysis The present invention relates to a non-aqueous electrolyte battery using a liquid.

  Practical use of non-aqueous electrolyte batteries such as lithium secondary batteries as a wide range of power sources from so-called power sources for portable electronic devices such as mobile phones and laptop computers to in-vehicle power sources for automobiles and large power sources for stationary applications It is being done. However, with the recent high performance of electronic devices and the application to in-vehicle power supplies for driving and large power supplies for stationary applications, the demand for applied secondary batteries is increasing, and the high performance of the battery characteristics of secondary batteries is increasing. For example, it is required to achieve high levels of improvement in capacity, for example, high capacity, high-temperature storage characteristics, and cycle characteristics.

  The electrolyte used for the non-aqueous electrolyte lithium secondary battery is usually composed mainly of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

In addition, various non-aqueous solvents, electrolytes , additives, and other additives are also proposed to improve battery characteristics such as load characteristics, cycle characteristics, storage characteristics, and low-temperature characteristics of batteries using these non-aqueous electrolytes. Has been. For example, in a nonaqueous electrolyte using a carbon material or lithium metal for the negative electrode, by using vinylene carbonate and its derivatives or vinyl ethylene carbonate derivatives, the cyclic carbonate having a double bond reacts preferentially with the negative electrode. Patent Documents 1 and 2 disclose that a good-quality film is formed on the surface of the negative electrode, thereby improving the storage characteristics and cycle characteristics of the battery.

JP-A-8-45545 JP-A-4-87156

As described above, in recent years, the demand for higher performance of secondary batteries is increasing, and thus the characteristics of lithium secondary batteries have been improved, that is, higher capacity, higher temperature storage characteristics, cycle characteristics and the like have been demanded.
In such a background, in the non-aqueous electrolyte battery using the electrolyte solution described in Patent Documents 1 and 2, if the charged battery is left at a high temperature or a continuous charge / discharge cycle is performed, it is not correct. There was a problem that the unsaturated cyclic carbonate or its derivative was oxidized and decomposed to generate carbon dioxide gas. If carbon dioxide gas is generated in such a use environment, the battery itself may become unusable due to, for example, activation of a battery safety valve or expansion of the battery.

In addition, the oxidative decomposition of unsaturated cyclic carbonate on the positive electrode causes a problem of generating a solid decomposition product in addition to the generation of carbon dioxide gas. Generation of such a solid decomposition product causes clogging of the electrode layer and the separator to inhibit the movement of lithium ions, or the solid decomposition product remains on the surface of the electrode active material and causes the lithium ion insertion / release reaction. May interfere. As a result, for example, the charge / discharge capacity may gradually decrease during the continuous charge / discharge cycle, the charge / discharge capacity may decrease from the initial stage after storage at a high temperature of the battery or after the continuous charge / discharge cycle, or the load characteristics may deteriorate.

  Also, the oxidative decomposition of unsaturated cyclic carbonate on the positive electrode becomes a particularly serious problem under the recent high performance secondary battery design. That is, this oxidative decomposition tends to become prominent when the potential at which the positive electrode active material inserts and desorbs lithium rises above the redox potential of lithium. For example, when an attempt is made to operate at a higher voltage than a battery of 4.2 V that is a battery voltage at the time of full charge of a secondary battery that is currently commercially available, these oxidation reactions are particularly prominent.

  In addition, as an alternative method for increasing the capacity of a non-aqueous electrolyte battery, it has been studied to pack as many active materials as possible in a limited battery volume. In batteries designed to increase the density or reduce the volume other than the active material in the battery as much as possible, the voids inside the battery are reduced, and the internal pressure of the battery increases significantly even when a small amount of gas is generated by oxidative decomposition. The battery itself may become unusable due to the operation of the safety valve or the expansion of the battery.

  Therefore, the present invention solves the above-mentioned various problems that occur when trying to achieve the performance required for secondary batteries in recent years, and in particular, durability and load characteristics such as cycle and storage are improved. The object is to provide a non-aqueous electrolyte battery.

As a result of intensive studies to solve the above-mentioned problems, the inventors have found that the non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery contains the compound represented by the following general formula (1) and the following: It has been found that by containing a specific lithium salt, a non-aqueous electrolyte secondary battery having improved durability characteristics such as cycle and storage can be realized, and the present invention has been completed.
That is, the gist of the present invention is as follows.

a) A non-aqueous electrolyte solution containing a lithium salt and a non-aqueous solvent for dissolving the lithium salt, wherein the non-aqueous electrolyte solution is a compound represented by the following general formula (1), and Li _α XO _n F _m (X = any element of Groups 13, 15 and 16 in the second or third period of the periodic table, α = 1 to 2, n = 1 to 3, m = 1 to 2), and the general formula (1 ) Is a compound represented by the following general formula (2), and the X is phosphorus or sulfur .

(In the above general formula (1), X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ¹ . Y may represent CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . In the general formula (1), R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other. R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group R ³ is a hydrocarbon group having 1 to 20 carbon atoms which may have Li, NR ⁴ ₄ or a functional group R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, and n and m represent an integer of 0 or more. Further, carbons in adjacent rings may form a further bond with each other, and R of the carbon may be reduced by one each, W is in the same range as R, and W is the same as R above. In the general formula (2), Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . R ² is a hydrocarbon group having 1 to 20 carbon atoms, R ³ is Li, NR ⁴ ₄ , or a hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ is a carbon group having 1 to 20 carbon atoms. It is a hydrogen group and may be the same or different from each other.)
b) The non-aqueous electrolyte solution according to a), wherein the compound represented by the general formula (1) is one or more of the compounds represented by the following formulas (3) to (7) .

c) The compound represented by the general formula (1) is a compound represented by the formula (3);
The non-aqueous electrolyte described.

d) The non-aqueous electrolyte according to c), wherein the Li _α XO _n F _m is LiPO ₂ F ₂ or LiSO ₃ F.
e) A non-aqueous electrolyte battery comprising a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is any one of a) to d). A non-aqueous electrolyte battery characterized by the above.

f) The nonaqueous electrolyte battery according to e), wherein the negative electrode capable of inserting and extracting lithium ions is a carbonaceous material.
g) The nonaqueous electrolyte battery according to e), wherein the negative electrode capable of inserting and extracting lithium ions is an alloy-based material.
h) The nonaqueous electrolyte battery according to e), wherein the negative electrode capable of inserting and extracting lithium ions is a Li-containing metal composite oxide material.

The present invention relates to a non-aqueous electrolyte battery comprising a non-aqueous electrolyte solution containing a compound in which a triple bond is bonded to a ring structure by a single bond without any other functional group or heteroelement, and the specific lithium salt. One of its features is the use. Usually, as typified by Patent Documents 1 and 2, many of the materials that protect the electrode surface and improve battery durability such as storage characteristics and cycle characteristics are compounds of a cyclic structure, and further have multiple bonding sites. Have. The present inventors pay attention to this point, and examine in detail the bonding sites of functional groups and hetero elements in the ring structure, the sites where multiple bonds are bonded to the ring structure, and the hybrid state of the electron orbits of the multiple bonds. As a result, for example, a compound in which a double bond is bonded to a ring structure is more stable with a positive electrode than a compound in which a part of the ring skeleton constituting the cyclic compound is a double bond, In addition, it was found that a carbon-carbon triple bond substituent bonded to the ring structure can form a more stable electrode protective film on the negative electrode surface than a carbon-carbon double bond. On the other hand, when the compound is a chain compound even if it is a compound having a carbon-carbon triple bond as described in Patent Document 3, the degree of polymerization is difficult to extend,
Since stability as an electrode protective film cannot be obtained, a significant effect of improving battery durability is not confirmed (see, for example, Comparative Example 3). Furthermore, the present inventors can obtain a synergistic effect excellent in battery durability characteristics by using the above-mentioned specific lithium salt in combination with the non-aqueous electrolyte in the compound represented by the general formula (1). Obtained knowledge. The reason for this is not clear at present, but the specific lithium salt is incorporated into the electrode protective film formed by the decomposition and polymerization of the general formula (1), and the durability of the electrode protective film is dramatic. As a result, the side decomposition reaction of the non-aqueous electrolyte is suppressed, and as a result, it is presumed that durability characteristics such as cycle and storage of the lithium secondary battery are greatly improved.

  That is, by using the present invention as described above, the non-aqueous electrolyte solution has improved battery load characteristics, durability characteristics such as cycle and storage, especially in the design of lithium secondary batteries with higher voltages and higher capacities. A battery is provided.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments, and can be arbitrarily modified and implemented.
1. Non-aqueous electrolyte 1-1. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, inorganic lithium salts LiTaF 6, LiWF ₇ and the like;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃
Sulfonic acid lithium salts such as SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , Lithium imide salts such as lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) ;
Lithium metide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ;
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalate phosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiBF 3 C 3} F 7, LiBF 2 (CF 3) 2, LiBF 2 (C 2 F 5) 2, LiBF 2 (CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2 Fluorine-containing organic lithium salts such as;

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane disulfonylimide, LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , lithium bisoxalatoborate , lithium difluoro oxalatoborate, lithium tetrafluoro-oxa Lato phosphate, lithium difluoro bis oxa Lato _{phosphate, LiC (C 2 F 5 SO} 2) 3, LiBF 3 CF 3, LiBF 3 C 2 F 5, LiPF 3 (CF 3 ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ etc. Is particularly preferable because it has the effect of improving output characteristics, high-rate charge / discharge characteristics, high-temperature storage characteristics, cycle characteristics, and the like.

The concentration of these lithium salts in the non-aqueous electrolyte and the specific lithium salt described below is not particularly limited as long as the effects of the present invention are not impaired, but the electrical conductivity of the electrolyte is in a good range. From the viewpoint of securing good battery performance, the total molar concentration of the lithium salt in the non-aqueous electrolyte is preferably 0.3 mol / L or more, more preferably 0.4 mol / L or more, and still more preferably 0.00. It is 5 mol / L or more, preferably 3 mol / L or less, more preferably 2.5 mol / L or less, and still more preferably 2.0 mol / L or less. If it is this range, effects, such as a low temperature characteristic, cycling characteristics, and a high temperature characteristic, will improve. On the other hand, if the total molar concentration of lithium is too low, the electrical conductivity of the electrolyte may be insufficient. On the other hand, if the concentration is too high, the electrical conductivity may decrease due to an increase in viscosity. May decrease.

1-2. Solvent As the non-aqueous solvent, a saturated cyclic carbonate, a cyclic carbonate having a fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, a sulfone compound, and the like can be used.
<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms. Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

A saturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
The blending amount of the saturated cyclic carbonate is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The lower limit of the blending amount when one kind is used alone is 5% in 100% by volume of the non-aqueous solvent. Volume% or more, more preferably 10 volume% or more. By setting this range, the decrease in electrical conductivity resulting from the decrease in the dielectric constant of the non-aqueous electrolyte is avoided, and the large current discharge characteristics, negative electrode stability, and cycle characteristics of the non-aqueous electrolyte secondary battery are good. It becomes easy to be in a range. Moreover, an upper limit is 95 volume% or less, More preferably, it is 90 volume% or less, More preferably, it is 85 volume% or less. By setting it as this range, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in ionic conductivity is suppressed, and as a result, the load characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

Also, one preferred combinations when using two or more saturated cyclic carbonate in any combination is a combination of ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 10:90, and particularly preferably 95: 5 to 10:60. Furthermore, the amount of propylene carbonate in the entire nonaqueous solvent is 0.1% by volume or more, preferably 1% by volume or more, more preferably 2% by volume or more, and the upper limit is usually 60% by volume or less, preferably 55% by volume. % Or less, more preferably 50% by volume or less. When propylene carbonate is contained within this range, it is preferable because the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

<Cyclic carbonate having a fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter also referred to as fluorinated cyclic carbonate) is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, 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-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ionic conductivity. It is more preferable in terms of imparting properties and suitably forming an interface protective film.
A fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios. The blending amount of the fluorinated cyclic carbonate is not particularly limited and may be arbitrary as long as the effects of the present invention are not significantly impaired, but in 100% by volume of the non-aqueous solvent, preferably 0.01% by volume or more, more preferably 0.8%. It is 1 volume% or more, More preferably, it is 0.2 volume% or more, Preferably it is 95 volume% or less, More preferably, it is 90 volume% or less. Within this range, the non-aqueous electrolyte secondary battery tends to exhibit a sufficient cycle characteristic improvement effect, and avoids a decrease in discharge capacity maintenance rate due to a decrease in high-temperature storage characteristics or an increase in the amount of gas generated. Cheap.

  In addition, the cyclic carbonate which has a fluorine atom is not only a solvent but the following 1-5. It also exhibits an effective function as an auxiliary described in 1. When a cyclic carbonate having a fluorine atom is used as a solvent and auxiliary agent, there is no clear boundary in the blending amount, and the blending amount described in the previous paragraph can be followed as it is.

<Chain carbonate>
As a chain carbonate, a C3-C7 thing is preferable.
Specifically, as the chain carbonate having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, Examples include n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, and methyl n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferable. is there.
Further, chain carbonates having a fluorine atom (hereinafter also referred to as fluorinated chain carbonate) can be suitably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily set to a favorable range. Become. Further, the chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is easy to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte and to make the large current discharge characteristics of the non-aqueous electrolyte secondary battery in a favorable range. .

The battery performance can be remarkably improved by combining ethylene carbonate at a specific blending amount with respect to the specific chain carbonate.
For example, when dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is selected as the specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 80% by volume or less, dimethyl carbonate, ethyl methyl carbonate, or diethyl It is preferable that the blending amount of carbonate is 20% by volume or more and 90% by volume or less. By selecting such a blending amount, the low-temperature deposition temperature of the electrolyte is lowered, the viscosity of the nonaqueous electrolytic solution is also lowered to improve the ionic conductivity, and a high output can be obtained even at a low temperature.

  It is also preferable to use two or more types of specific chain carbonates in combination. When dimethyl carbonate and ethyl methyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume or less. Particularly preferred are those in which the amount of ethyl methyl carbonate is 10% by volume or more and 80% by volume or less. When a specific chain carbonate is used in combination with dimethyl carbonate and diethyl carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, and the blending amount of dimethyl carbonate is 10% by volume or more and 70% by volume. Hereinafter, it is particularly preferable that the amount of diethyl carbonate is 10% by volume or more and 70% by volume or less. Further, when ethyl methyl carbonate and diethyl carbonate are used in combination with a specific chain carbonate, the blending amount of ethylene carbonate is 10% by volume or more and 60% by volume or less, the blending amount of ethyl methyl carbonate is 10% by volume or more, 80% Those having a volume% or less and a blending amount of diethyl carbonate of 10 vol% or more and 70 vol% or less are particularly preferable.

<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having 3 to 12 total carbon atoms in the structural formula. Specific examples include gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone, and the like. Among these, gamma butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.

Moreover, cyclic carboxylic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
The amount of the cyclic carboxylic acid ester is usually 5% by volume or more, more preferably 10% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this manner, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of cyclic carboxylic acid ester becomes like this. Preferably it is 50 volume% or less, More preferably, it is 40 volume% or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution is set to an appropriate range, a decrease in electrical conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. It becomes easy to make a characteristic into a favorable range.

<Chain carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having 3 to 7 carbon atoms in the structural formula. Specifically, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, acetic acid-t-butyl, methyl propionate, ethyl propionate, propionate-n-propyl, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid-n- Examples include propyl and isopropyl isobutyrate.

Among them, methyl acetate, ethyl acetate, acetate-n-propyl acetate-n-butyl acetate, methyl propionate, ethyl propionate, propionate-n-propyl, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. It is preferable from the viewpoint of improvement of ionic conductivity.
Moreover, chain | strand-shaped carboxylic acid ester may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The compounding amount of the chain carboxylic acid ester is usually 10% by volume or more, more preferably 15% by volume or more, in 100% by volume of the non-aqueous solvent. By setting the lower limit in this way, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery are easily improved. Moreover, the compounding quantity of chain | strand-shaped carboxylic acid ester is 60 volume% or less preferably in 100 volume% of nonaqueous solvents, More preferably, it is 50 volume% or less. By setting the upper limit in this manner, an increase in negative electrode resistance is suppressed, and the large current discharge characteristics and cycle characteristics of the non-aqueous electrolyte secondary battery are easily set in a favorable range.

<Ether compound>
As the ether compound, a chain ether having 3 to 10 carbon atoms in which part of hydrogen may be substituted with fluorine, and a cyclic ether having 3 to 6 carbon atoms are preferable.
Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl Ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2, 2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl -N-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro Olo-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2 , 2,3,3,3-pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3 -Fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) ) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) Ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3 , 3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, ( 3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3 3,3-triflu (Ro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-penta Fluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2,3 3,3-pentafluoro-n-propyl) ether, di (2,2,3,3)
3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1, 1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetra Fluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoro Ethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2-trif Oloethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2- Trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-Fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2, -Trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene Examples include glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvating ability to lithium ions and improve ion dissociation. Of these, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are preferable because they have low viscosity and give high ionic conductivity.
Moreover, an ether type compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The compounding amount of the ether compound is usually in 100% by volume of the non-aqueous solvent, preferably 5% by volume or more, more preferably 10% by volume or more, further preferably 15% by volume or more, and preferably 70% by volume or less. More preferably, it is 60 volume% or less, More preferably, it is 50 volume% or less. If it is this range, it is easy to ensure the improvement effect of the lithium ion dissociation degree of chain ether, and the improvement of the ionic conductivity derived from a viscosity fall, and when a negative electrode active material is a carbonaceous material, a chain ether with lithium ion It is easy to avoid a situation where the capacity is reduced due to co-insertion.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones that are monosulfone compounds; trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones that are disulfone compounds. Among these, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.

As sulfolanes, sulfolane and / or sulfolane derivatives (hereinafter also referred to as sulfolanes including sulfolane) are preferable. As the sulfolane derivative, one in which one or more hydrogen atoms bonded to the carbon atom constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable.
Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methyl Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane , 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in terms of high ionic conductivity and high input / output.

  As the chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trif Oromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di (trifluoroethyl) sulfone, perfluorodiethylsulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone Trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, Pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone Emissions, pentafluoroethyl -n- butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is preferred because a higher high output ionic conductivity.
Moreover, a sulfone type compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The compounding amount of the sulfone compound is usually 0.3% by volume or more, more preferably 0.5% by volume or more, and further preferably 1% by volume or more in 100% by volume of the nonaqueous solvent. Is 40% by volume or less, more preferably 35% by volume or less, and still more preferably 30% by volume or less. Within this range, durability improvement effects such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be set to an appropriate range to avoid a decrease in electrical conductivity. When charging / discharging an aqueous electrolyte secondary battery at a high current density, it is easy to avoid a situation in which the charge / discharge capacity retention rate decreases.
1-3. Compound Represented by General Formula (1) The present invention is characterized in that the non-aqueous electrolyte contains a compound represented by the following general formula (1).

In the general formula (1), X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ¹ , It may be the same or different. Y represents CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . In the general formula (1), R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other. . R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ³ is Li, NR ⁴ ₄ or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same as or different from each other. n and m represent an integer of 0 or more. W is a range having the same meaning as R, and W may be the same as or different from R.

In the general formula (1), X and Z is not particularly limited as long as the defined in the _{^{formula, CR 1 2, O, S}} , N-R 1 is more preferred. Although Y is not limited particularly as long as the defined in the _{formula, C = O, S = O} , S (= O) 2, P (= O) -R 2, P (= O) -OR ³ is more preferable.
R and R ¹ are not particularly limited as long as they are within the range defined in the formula, but preferably, hydrogen, fluorine, a saturated aliphatic hydrocarbon group which may have a substituent, or a substituent. Examples thereof include a good unsaturated aliphatic hydrocarbon group and an aromatic hydrocarbon group which may have a substituent.

R ² and R ⁴ are not particularly limited as long as they are within the range defined in the formula, but are preferably a saturated aliphatic hydrocarbon group that may have a substituent or an unsaturated group that may have a substituent. Examples thereof include an aliphatic hydrocarbon and an aromatic hydrocarbon / aromatic heterocycle which may have a substituent.
R ³ is not particularly limited as long as it is within the range defined in the formula, but preferably Li, a saturated aliphatic hydrocarbon which may have a substituent, or an unsaturated aliphatic which may have a substituent Examples thereof include hydrocarbons and optionally substituted aromatic hydrocarbons / aromatic heterocycles.

  As a saturated aliphatic hydrocarbon which may have a substituent, an unsaturated aliphatic hydrocarbon which may have a substituent, a substituent of an aromatic hydrocarbon / aromatic heterocycle which may have a substituent Is not particularly limited, but preferably has a saturated aliphatic hydrocarbon group, which may have a substituent such as halogen, carboxylic acid, carbonic acid, sulfonic acid, phosphoric acid, phosphorous acid, etc. And an unsaturated aliphatic hydrocarbon group which may be substituted, an ester of an aromatic hydrocarbon group which may have a substituent, and the like, more preferably halogen, and most preferably fluorine.

  Preferable saturated aliphatic hydrocarbons include, specifically, methyl group, ethyl group, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl group, 1,1-difluoroethyl. Group, 1,2-difluoroethyl group, 2,2-difluoroethyl group, 1,1,2-trifluoroethyl group, 1,2,2-trifluoroethyl group, 2,2,2-trifluoroethyl group Examples thereof include a phenyl group, a cyclopentyl group, and a cyclohexyl group.

Specific preferred unsaturated aliphatic hydrocarbons include ethenyl, 1-fluoroethenyl, 2-fluoroethenyl, 1-methylethenyl, 2-propenyl, and 2-fluoro-2-propenyl. , 3-fluoro-2-propenyl group, ethynyl group, 2-fluoroethynyl group, 2-propynyl group, and 3-fluoro-2propynyl group.
Preferred aromatic hydrocarbons include phenyl group, 2-fluorophenyl group, 3-fluorophenyl group, 2,4-difluorophenyl group, 2,6-difluorophenyl group, 3,5-difluorophenyl group, 2, 4 , 6-trifluorophenyl group.

Preferred aromatic heterocycles include 2-furanyl group, 3-furanyl group, 2-thiophenyl group, 3-thiophenyl group, 1-methyl-2-pyrrolyl group, and 1-methyl-3-pyrrolyl group.
Among these, a methyl group, an ethyl group, a fluoromethyl group, a trifluoromethyl group, a 2-fluoroethyl group, a 2,2,2-trifluoroethyl group, an ethenyl group, an ethynyl group, and a phenyl group are more preferable. More preferred are a methyl group, an ethyl group, and an ethynyl group.

n and m are not particularly limited as long as they are in the range defined in the formula, but are preferably 0 or 1, more preferably n = m = 1 or n = 1, and m = 0.
Moreover, the molecular weight of the compound represented by the general formula (1) is preferably 50 or more and 500 or less. Within this range, it is easy to ensure the solubility of the cyclic carbonate having a carbon-carbon double bond in the non-aqueous electrolyte solution, and the effects of the present invention are sufficiently exhibited. Specific examples of these preferable compounds are shown below.

Among these, it is preferable that R is hydrogen, a fluorine, or an ethynyl group from both the reactivity and the stability. In the case of other substituents, the reactivity is lowered, and the expected properties may be lowered. Moreover, when it is halogen other than fluorine, there is a possibility that the reactivity is too high and the side reaction increases.
The number of fluorine or ethynyl groups in R is preferably within 2 in total. If the number is too large, the compatibility with the electrolytic solution may be deteriorated, and the reactivity may be too high to increase the side reaction.

Among these, n = 1 and m = 0 are preferable. When both are 0, stability deteriorates from the distortion of the ring, the reactivity becomes too high, and there is a possibility that side reactions increase. Further, even if n = 2 or more, or n = 1, when m = 1 or more, there is a possibility that the chain is more stable than the ring and the initial characteristics may not be exhibited.
Furthermore, wherein, X and Z are, ^CR _{1 2} or O are more preferred. In cases other than these, the reactivity may be too high and side reactions may increase.

The molecular weight is more preferably 100 or more, and more preferably 200 or less. If it is this range, the solubility of the compound represented by General formula (1) with respect to a non-aqueous electrolyte solution is further easy to be ensured, and the effect of this invention is fully further easily expressed.
Among these, specific examples of more preferable compounds are shown below.

More preferably, R is all hydrogen. In this case, the side reaction is most likely to be suppressed while maintaining the expected characteristics. In addition, when Y is C═O or S═O, one of X and Z is O, indicating that Y is S (═O) ₂ , P (═O) —R ² , P (═O In the case of —OR ³ , it is preferable that both X and Z are O or CH ₂ , or one of X and Z is O, and the other is CH ₂ . When Y is C═O or S═O, if both X and Z are CH ₂ , the reactivity may be too high and side reactions may increase.

  Specific examples of these compounds are shown below.

  On the other hand, among the compounds represented by the general formula (1), the compound represented by the following general formula (2) is preferable from the viewpoint of ease of industrial production.

In the general formula (2), Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ³ is Li, NR ⁴ ₄ , or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group. R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same as or different from each other. )
These compounds having preferable conditions are shown below.

  The compound represented by General formula (1) may be used individually by 1 type, or may have 2 or more types by arbitrary combinations and ratios. Moreover, the compounding quantity of the compound represented by General formula (1) is not restrict | limited in particular, As long as the effect of this invention is not impaired remarkably, it is arbitrary. The compounding amount of the compound represented by the general formula (1) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.2% in 100% by mass of the non-aqueous electrolyte solution. It is at least 30% by mass, preferably at most 30% by mass, more preferably at most 10% by mass, further preferably at most 5% by mass, particularly preferably at most 3% by mass. Within this range, the non-aqueous electrolyte battery is likely to exhibit a sufficient cycle characteristics improvement effect, and the high-temperature storage characteristics are reduced, and the amount of gas generation is increased, resulting in a decrease in discharge capacity maintenance rate. Easy to avoid the situation. In addition, the compound represented by General formula (1) may use what was synthesize | combined by the known method, or may use a commercially available thing.

1-4. Specific lithium salt The nonaqueous electrolytic solution of the present invention is characterized by containing the following specific lithium salt together with the compound represented by the general formula (1). By using this lithium salt in combination, a high-quality composite film having a high protective ability is formed on the electrode surface, and the cycle characteristics and storage characteristics of the non-aqueous electrolyte battery are greatly improved. In particular, the improvement effect is remarkable under high voltage conditions.

The non-aqueous electrolyte solution of the present invention only needs to include one or more of the following specific lithium salts, and may include, for example, a plurality of compounds belonging to the following specific lithium salt.
The specific lithium salt used in the present invention is a compound represented by Li _α XO _n F _m (X is an element of any of Groups 13, 15, 16 in the second or third period of the periodic table, and α = 1 -2, n = 1-3, m = 1-2).

X is preferably phosphorus or sulfur, and specific examples include Li ₂ PO ₃ F, LiPO ₂ F ₂ , and LiSO ₃ F. The specific compound is a lithium salt, but the lithium salt described in “1-1. Electrolyte” is not included.
There is no limitation on the amount of the specific compound to be added to the whole non-aqueous electrolyte solution of the present invention, and it is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 0.001 with respect to the non-aqueous electrolyte solution of the present invention. It is contained at a concentration of not less than mass%, preferably not less than 0.01 mass%, more preferably not less than 0.1 mass%, and usually not more than 15 mass%, preferably not more than 12 mass%, more preferably not more than 10 mass%. . When the above range is satisfied, effects such as output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics are further improved. On the other hand, if it is too much, it may be deposited at low temperature to deteriorate the battery characteristics, and if it is too little, the effect of improving the low-temperature characteristics, cycle characteristics, high-temperature storage characteristics, etc. may not be sufficiently exhibited.

When the specific lithium salt is contained in the electrolytic solution, the electrolytic solution is prepared by adding a specific lithium salt to the electrolytic solution containing a specific lithium salt synthesized by a known method, or by adding a specific lithium salt in the electrolytic solution. The method of generating is mentioned. For example, if the LiPO ₂ F _2, allowed to coexist water into cell components such as active material and the electrode plate to be described later, LiPO ₂ F in the system during the time of assembling a battery using the electrolytic solution containing LiPF _{6 2} can be generated.

The method for measuring the content of the specific lithium salt in the non-aqueous electrolyte and the non-aqueous electrolyte battery is not particularly limited, and any known method can be used. For example, LiPO _In the case of ₂ F ₂ , it can be measured using ion chromatography, F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR), and the like.

1-5. Auxiliary agent In the non-aqueous electrolyte battery of the present invention, an auxiliary agent may be appropriately used depending on the purpose in addition to the compound of the general formula (1). As an auxiliary agent, the following cyclic carbonate having a carbon-carbon unsaturated bond, chain carbonate having a carbon-carbon unsaturated bond, fluorinated carbonate, both a carbon-carbon unsaturated bond and a fluorine atom are included. Examples thereof include a cyclic carbonate, a chain carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter collectively referred to as carbonates), an overcharge inhibitor, and other auxiliary agents.

<Cyclic carbonate having a carbon-carbon unsaturated bond>
The cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated cyclic carbonate) has vinylene carbonates having an unsaturated bond in the skeleton of the cyclic carbonate, or has an aromatic ring or a carbon-carbon unsaturated bond. Examples thereof include ethylene carbonates substituted with a substituent, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates and the like.

  As vinylene carbonates, vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, phenyl vinylene carbonate, 4,5-diphenyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4 , 5-diallyl vinylene carbonate.

  Specific examples of ethylene carbonates substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5-vinyl ethylene carbonate, 4- Allyl-5-vinylethylene carbonate, phenylethylene carbonate, 4,5-diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene Examples thereof include carbonate and 4-methyl-5-allylethylene carbonate.

Examples of unsaturated cyclic carbonates include vinylene carbonate, methyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate Vinylene carbonate and vinyl ethylene carbonate are particularly preferred. Since these form a stable interface protective film, they are more preferably used.
Moreover, an unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<A chain carbonate having a carbon-carbon unsaturated bond>
The chain carbonate having a carbon-carbon unsaturated bond (hereinafter also referred to as an unsaturated chain carbonate) is a chain carbonate having a carbon-carbon unsaturated bond or a chain substituted with a substituent having an aromatic ring. And carbonated carbonates.

As chain carbonates having a chain hydrocarbon having a carbon-carbon unsaturated bond,
Methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, methyl-1-propenyl carbonate, ethyl-1-propenyl carbonate, di-1-propenyl carbonate, methyl (1-methylvinyl) carbonate, ethyl (1-methylvinyl) carbonate, Di (1-methylvinyl) carbonate, methyl-2-propenyl carbonate, ethyl-2-propenyl carbonate, di (2-propenyl) carbonate, 1-butenylmethyl carbonate, 1-butenylethyl carbonate, di (1-butenyl) ) Carbonate, methyl (1-methyl-1-propenyl) carbonate, ethyl (1-methyl-1-propenyl) carbonate, di (1-methyl-1-propenyl) carbonate, methyl-1-ethylvinyl -Bonate, ethyl-1-ethyl vinyl carbonate, di-1-ethyl vinyl carbonate, methyl (2-methyl-1-propenyl) carbonate, ethyl (2-methyl-1-propenyl) carbonate, di (2-methyl-1- Propenyl) carbonate, 2-butenyl methyl carbonate, 2-butenyl ethyl carbonate, di-2-butenyl carbonate, methyl (1-methyl-2-propenyl) carbonate, ethyl (1-methyl-2-propenyl) carbonate, Di (1-methyl-2-propenyl) carbonate, methyl (2-methyl-2-propenyl) carbonate, ethyl (2-methyl-2-propenyl) carbonate, di (2-methyl-2-propenyl) carbonate, methyl ( 1,2-dimethyl-1-propenyl) carbo , Ethyl (1,2-dimethyl-1-propenyl) carbonate, di (1,2-dimethyl-1-propenyl) carbonate, ethynyl methyl carbonate, ethyl ethynyl carbonate, diethynyl carbonate, methyl-1-propynyl carbonate, Ethyl-1-propynyl carbonate, di-1-propynyl carbonate, methyl-2-propynyl carbonate, ethyl-2-propynyl carbonate, di-2-propynyl carbonate, 1-butynylmethyl carbonate, 1-butynylethyl carbonate, di -1-butynyl carbonate, 2-butynyl methyl carbonate, 2-butynyl ethyl carbonate, di-2-butynyl carbonate, methyl (1-methyl-2-propynyl) carbonate, ethyl (1-methyl-2-propyl) Lopinyl) carbonate, di (1-methyl-2-propynyl) carbonate, 3-butynylmethyl carbonate, 3-butynylethyl carbonate, di-3-butynyl carbonate, methyl (1,1-dimethyl-2-propynyl) Carbonate, ethyl (1,1-dimethyl-2-propynyl) carbonate, dityl (1,1-dimethyl-2-propynyl) carbonate, methyl (1,3-dimethyl-2-propynyl) carbonate, ethyl (1,3- Dimethyl-2-propynyl) carbonate, dityl (1,3-dimethyl-2-propynyl) carbonate, methyl (1,2,3-trimethyl-2-propynyl) carbonate, ethyl (1,2,3-trimethyl-2- Propynyl) carbonate, dityl (1,2,3-trimethyl-2-propiyl) Le) carbonate, and the like.

As chain carbonates substituted with a substituent having an aromatic ring,
Methyl phenyl carbonate, ethyl phenyl carbonate, phenyl vinyl carbonate, allyl phenyl carbonate, enethyl phenyl carbonate, 2-propenyl phenyl carbonate, diphenyl carbonate, methyl (2-methylphenyl) carbonate, ethyl (2-methylphenyl) carbonate, (2 -Methylphenyl) vinyl carbonate, allyl (2-methylphenyl) carbonate, enethyl (2-methylphenyl) carbonate, 2-propenyl (2-methylphenyl) carbonate, di (2-methylphenyl) carbonate, methyl (3-methyl) Phenyl) carbonate, ethyl (3-methylphenyl) carbonate, (3-methylphenyl) vinyl carbonate, allyl (3-methylphenyl) carbonate , Enethyl (3-methylphenyl) carbonate, 2-propenyl (3-methylphenyl) carbonate, di (3-methylphenyl) carbonate, methyl (4-methylphenyl) carbonate, ethyl (4-methylphenyl) carbonate, (4 -Methylphenyl) vinyl carbonate, allyl (4-methylphenyl) carbonate, enethyl (4-methylphenyl) carbonate, 2-propenyl (4-methylphenyl) carbonate, di (4-methylphenyl) carbonate, benzylmethyl carbonate, benzyl Ethyl carbonate, benzyl phenyl carbonate, benzyl vinyl carbonate, benzyl-2-propenyl carbonate, benzyl ethynyl carbonate, benzyl-2-propynyl carbonate, dibenzyl -Bonate, methyl (2-cyclohexylphenyl) carbonate, methyl (3-cyclohexylphenyl) carbonate, methyl (4-cyclohexylphenyl) carbonate, ethyl (2-cyclohexylphenyl) carbonate, di (2-cyclohexylphenyl) carbonate, etc. It is done.

Among the above unsaturated chain carbonates, methyl vinyl carbonate, ethyl vinyl carbonate, divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 2-propynyl ethyl carbonate, 1-methyl- 2-propynylmethyl carbonate, 1-methyl-2-propynylethyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, dipropynyl carbonate, 2-butynylmethyl carbonate, 1-methyl-2-butynylmethyl carbonate, 1,1-dimethyl-2-butynylmethyl carbonate, dibutynyl carbonate, methylphenyl carbonate, ethylphenyl carbonate, phenyl vinyl carbonate, Ryl phenyl carbonate, diphenyl carbonate, benzyl methyl carbonate, benzyl ethyl carbonate, benzyl phenyl carbonate, allyl benzyl carbonate, dibenzyl carbonate, 2-propynyl phenyl carbonate, 2-butynyl phenyl carbonate are preferred, methyl vinyl carbonate, ethyl vinyl carbonate, Divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, diallyl carbonate, 2-propynyl methyl carbonate, 1-methyl-2-propynyl methyl carbonate, 1,1-dimethyl-2-propynyl methyl carbonate, dipropynyl carbonate, 2-butynyl Methyl carbonate, 1-methyl-2-butynyl methyl carbonate, 1,1-dimethyl 2-butynyl methyl carbonate, dibutyl alkenyl carbonate, methyl phenyl carbonate, ethyl phenyl carbonate, diphenyl carbonate is particularly preferred. Since these form a stable interface protective film, they are more preferably used.
Moreover, an unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.

<Fluorinated carbonate>
As the carbonate having a fluorine atom, both a chain carbonate having a fluorine atom (hereinafter also referred to as a fluorinated chain carbonate) and a cyclic carbonate having a fluorine atom (hereinafter also referred to as a fluorinated cyclic carbonate) can be used. .
In addition, although the linear or cyclic carbonate which has a fluorine atom is mentioned above as a solvent of nonaqueous electrolyte, it can also be used as an adjuvant.

  The number of fluorine atoms in the chain carbonate having fluorine atoms is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or may be bonded to different carbons. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethyl methyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

Examples of the fluorinated dimethyl carbonate derivative include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate, and the like.
Fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-trimethyl Examples include fluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, and ethyl trifluoromethyl carbonate.

  Fluorinated diethyl carbonate derivatives include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro). Ethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2,2, Examples include 2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, and the like.

As the fluorinated chain carbonate, 2,2,2-trifluoroethyl methyl carbonate is particularly preferable.
Moreover, a fluorinated chain carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
Examples of the fluorinated cyclic carbonate include derivatives of cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of the ethylene carbonate derivative include fluorinated products of ethylene carbonate or ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), and particularly those having 1 to 8 fluorine atoms. Is preferred.

  Specifically, 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-dimethyl Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

Examples of the fluorinated cyclic carbonate include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-
Particularly preferred is at least one selected from the group consisting of difluoro-4,5-dimethylethylene carbonate. These provide high ionic conductivity and preferably form an interface protective coating.

Moreover, a fluorinated cyclic carbonate may be used individually by 1 type, and may have 2 or more types together by arbitrary combinations and ratios.
<Cyclic carbonate having both a carbon-carbon unsaturated bond and a fluorine atom>
The cyclic carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as a fluorinated unsaturated cyclic carbonate) is a fluorinated vinylene carbonate derivative, an aromatic ring or a substituent having a carbon-carbon unsaturated bond. Examples thereof include substituted fluorinated ethylene carbonate derivatives.

  Fluorinated vinylene carbonate derivatives include 4-fluoro vinylene carbonate, 4-fluoro-5-methyl vinylene carbonate, 4-fluoro-5-phenyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, 4-fluoro-5- Examples include vinyl vinylene carbonate, 4-fluoro-5-vinyl vinylene carbonate, 4-allyl-5-fluoro vinylene carbonate, and the like.

Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5. -Vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate , 4,5-Diff Oro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4- Examples thereof include phenylethylene carbonate.

  Examples of the fluorinated unsaturated cyclic carbonate include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4 , 4-Difluoro-5-vinylethylene carbonate, 4,4-difluoro-5-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro -4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, 4,5-difluoro-4,5-diallylethylene carbonate are preferred. . Since these form a stable interface protective film, they are more preferably used.

Moreover, a fluorinated unsaturated cyclic carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
<Chain carbonate having both carbon-carbon unsaturated bond and fluorine atom>
Examples of the chain carbonate having both a carbon-carbon unsaturated bond and a fluorine atom (hereinafter also referred to as fluorinated unsaturated chain carbonate) include 1-fluorovinyl methyl carbonate, 2-fluorovinyl methyl carbonate, 1,2- Difluorovinylmethyl carbonate, ethyl-1-fluorovinyl carbonate, ethyl-2-fluorovinyl carbonate, ethyl-1,2-difluorovinyl carbonate, bis (1-fluorovinyl) carbonate, bis (2-fluorovinyl) carbonate, bis (1,2-difluorovinyl) carbonate, 1-fluoro-1-propenylmethyl carbonate, 2-fluoro-1-propenylmethyl carbonate, 3-fluoro-1-propenylmethyl carbonate, 1,2-difluoro-1-pro Nylmethyl carbonate, 1,3-difluoro-1-propenylmethyl carbonate, 2,3-difluoro-1-propenylmethyl carbonate, 3,3-difluoro-1-propenylmethyl carbonate, 1-fluoro-2-propenylmethyl carbonate, 2-fluoro-2-propenylmethyl carbonate, 3-fluoro-2-propenylmethyl carbonate, 1,1-difluoro-2-propenylmethyl carbonate, 1,2-difluoro-2-propenylmethyl carbonate, 1,3-difluoro- 2-propenylmethyl carbonate, 2,3-difluoro-2-propenylmethyl carbonate, fluoroethynylmethyl carbonate, 3-fluoro-1-propynylmethyl carbonate, 1-fluoro-2-propynylmethyl Boneto, 3-fluoro-2-propynyl methyl carbonate, and the like.

Moreover, a fluorinated unsaturated chain carbonate may be used individually by 1 type, and may have 2 or more types by arbitrary combinations and ratios.
The molecular weight of the carbonates is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired, but is preferably 50 or more and 250 or less. In the case of unsaturated cyclic carbonates, more preferably 80 or more and 150 or less, and in the case of fluorinated unsaturated cyclic carbonates, more preferably 100 or more and 200 or less. If it is this range, the solubility of the cyclic carbonate which has a carbon-carbon unsaturated bond with respect to a non-aqueous electrolyte solution will be easy to be ensured, and the effect of this invention will fully be expressed easily.

The above carbonates may be used alone or in combination of two or more in any combination and ratio.
The blending amount in the case of unsaturated cyclic carbonate is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more in 100% by mass of the non-aqueous solvent. Moreover, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.

The blending amount in the case of fluorinated chain carbonate or fluorinated cyclic carbonate can follow the blending amount described above as a solvent as it is, but is preferably less than 50% by mass in 100% by mass of the non-aqueous solvent.
The blending amount in the case of the fluorinated unsaturated cyclic carbonate is usually in 100% by mass of the non-aqueous electrolyte solution, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2%. It is at least 5% by mass, preferably at most 5% by mass, more preferably at most 4% by mass, even more preferably at most 3% by mass.

Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient cycle characteristics improvement effect, and the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity maintenance ratio decreases. Easy to avoid.
The proportion of the compound represented by the general formula (1) and the amount of the carbonate is not particularly limited, but when the carbonate is a carbonate having an unsaturated bond, the total content of the carbonate having an unsaturated bond is included. [M ₍₁₎ ] / [M _u ] is usually 100 to 0 when the mass is [M _u ] and the total content of the compound represented by the general formula (1) is [M ₍₁₎ ]. 0.01, more preferably 20 to 0.05, and even more preferably 10 to 0.1.

<Overcharge prevention agent>
In the non-aqueous electrolyte solution of the present invention, an overcharge inhibitor can be used in order to effectively prevent the battery from bursting or igniting when the non-aqueous electrolyte battery is overcharged.
As an overcharge inhibitor, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, dibenzofuran; 2-fluorobiphenyl, Partially fluorinated products of the above aromatic compounds such as o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene; 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like And a fluorine-containing anisole compound. Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, Using at least one selected from aromatic compounds not containing oxygen, such as t-amylbenzene, and at least one selected from oxygen-containing aromatic compounds such as diphenyl ether, dibenzofuran, and the like is an overcharge prevention property and a high temperature storage property. From the standpoint of balance.

The amount of the overcharge inhibitor is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is preferably 0.1% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. If it is this range, it will be easy to fully express the effect of an overcharge inhibiting agent, and it will be easy to avoid the situation where the battery characteristics, such as a high temperature storage characteristic, fall. The overcharge inhibitor is more preferably 0.2% by mass or more, further preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and more preferably 3% by mass or less, still more preferably. Is 2% by mass or less.

<Other auxiliaries>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other auxiliaries include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, anhydrous Carboxylic anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride and phenylsuccinic anhydride; 2,4,8,10-tetraoxaspiro [5.5 ] Spiro compounds such as undecane, 3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, 1,3-propane sultone, 1-fluoro-1,3- Propane sultone, 2-fluoro-1,3-propane sultone, 3-ph Oro-1,3-propane sultone, 1-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro -1-propene-1,3-sultone, 1,4-butanesultone, 1-butene-1,4-sultone, 3-butene-1,4-sultone, methyl fluorosulfonate, ethyl fluorosulfonate, methanesulfonic acid Sulfur-containing compounds such as methyl, ethyl methanesulfonate, busulfan, sulfolane, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl 2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidino And N- methyl succinimide nitrogen-containing compounds such as imides; acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methyl-butyronitrile, trimethyl acetonitrile, hexane nitrile, cyclopentanecarbonitrile Nitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitryl, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl 2-pentenenitrile, 2-hexenenitrile, fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile, 2-fluoropropionitrile, 3-fluoropropionitrile, , 2-difluoropropionitrile, 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropionitrile, 3,3,3-trifluoropropionitrile, 3, Cyano groups such as 3′-oxydipropionitrile, 3,3′-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5-pentanetricarbonitrile, pentafluoropropionitrile, etc. Compound having one: malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeonitrile, suberonitrile, azeronitrile, sebacononitrile, undecandinitrile, dodecandinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononito Ril, methylsuccinonitrile, 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, trimethylsuccinonitrile, tetramethylsuccinonitrile 3,3 ′-(ethylenedioxy) dipropionitrile, 3 , 3 ′-(ethylenedithio) dipropionitrile and other compounds having two cyano groups; 1,12-diisocyanatododecane, 1,11-diisocyanatoundecane, 1,10-diisocyanatodecane, 1, Compounds having two isocyanate groups such as 9-diisocyanatononane, 1,8-diisocyanatooctane, 1,7-isocyanatoheptane, 1,6-diisocyanatohexane; heptane, octane, nonane, decane, Hydrocarbon compounds such as cycloheptane, fluorobenzene, difluorobenzene, hexafluoro Benzene, fluorinated aromatic compounds such as benzotrifluoride, and the like. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved.

  The blending amount of other auxiliary agents is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte solution. Within this range, the effects of other auxiliaries can be sufficiently exhibited, and it is easy to avoid a situation in which battery characteristics such as high-load discharge characteristics deteriorate. The blending amount of other auxiliaries is more preferably 0.1% by mass or more, further preferably 0.2% by mass or more, more preferably 3% by mass or less, and further preferably 1% by mass or less. .

  The non-aqueous electrolyte solution described above includes those existing inside the non-aqueous electrolyte battery according to the present invention. Specifically, the components of the non-aqueous electrolyte solution such as lithium salt, solvent, and auxiliary agent are separately synthesized, and the non-aqueous electrolyte solution is prepared from what is substantially isolated by the method described below. In the case of a nonaqueous electrolyte solution in a nonaqueous electrolyte battery obtained by pouring into a separately assembled battery, the components of the nonaqueous electrolyte solution of the present invention are individually placed in the battery, In order to obtain the same composition as the non-aqueous electrolyte solution of the present invention by mixing in a non-aqueous electrolyte battery, the compound constituting the non-aqueous electrolyte solution of the present invention is further generated in the non-aqueous electrolyte battery. The case where the same composition as the aqueous electrolyte is obtained is also included.

2. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery, among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte secondary battery of the present invention can adopt a known structure. Typically, the negative electrode and the positive electrode capable of occluding and releasing ions (for example, lithium ions), and the non-aqueous electrolyte of the present invention described above. An aqueous electrolyte solution.

2-1. Negative electrode The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. Specific examples include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like. These may be used individually by 1 type, and may be used together combining 2 or more types arbitrarily.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like.
As a carbonaceous material used as a negative electrode active material,
(1) natural graphite,
(2) a carbonaceous material obtained by heat-treating an artificial carbonaceous material and an artificial graphite material at least once in the range of 400 to 3200 ° C;
(3) a carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different crystallinities and / or has an interface in contact with the different crystalline carbonaceous materials,
(4) A carbonaceous material in which the negative electrode active material layer is made of carbonaceous materials having at least two or more different orientations and / or has an interface in contact with the carbonaceous materials having different orientations,
Is preferably a good balance between initial irreversible capacity and high current density charge / discharge characteristics. Moreover, the carbonaceous materials (1) to (4) may be used alone or in combination of two or more in any combination and ratio.

  Examples of the artificial carbonaceous material and artificial graphite material of (2) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, those obtained by oxidizing these pitches, needle coke, pitch coke and Carbon materials that are partially graphitized, furnace black, acetylene black, organic pyrolysis products such as pitch-based carbon fibers, carbonizable organic materials and their carbides, or carbonizable organic materials are benzene, toluene, xylene, quinoline And a solution dissolved in a low-molecular organic solvent such as n-hexane, and carbides thereof.

  As an alloy material used as the negative electrode active material, as long as lithium can be occluded / released, lithium alone, simple metals and alloys forming lithium alloys, or oxides, carbides, nitrides, silicides, sulfides thereof Any of compounds such as products or phosphides may be used and is not particularly limited. The single metal and alloy forming the lithium alloy are preferably materials containing group 13 and group 14 metal / metalloid elements (that is, excluding carbon), more preferably aluminum, silicon and tin (hereinafter referred to as “ Simple metals) and alloys or compounds containing these atoms (sometimes abbreviated as “specific metal elements”). These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  As a negative electrode active material having at least one kind of atom selected from a specific metal element, a metal simple substance of any one specific metal element, an alloy composed of two or more specific metal elements, one type or two or more specific types Alloys comprising metal elements and one or more other metal elements, as well as compounds containing one or more specific metal elements, and oxides, carbides, nitrides and silicides of the compounds And composite compounds such as sulfides or phosphides. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

  In addition, a compound in which these complex compounds are complexly bonded to several kinds of elements such as a simple metal, an alloy, or a nonmetallic element is also included. Specifically, for example, in silicon and tin, an alloy of these elements and a metal that does not operate as a negative electrode can be used. For example, in the case of tin, a complex compound containing 5 to 6 kinds of elements in combination with a metal that acts as a negative electrode other than tin and silicon, a metal that does not operate as a negative electrode, and a nonmetallic element may be used. it can.

  Among these negative electrode active materials, since the capacity per unit mass is large when a battery is formed, any one simple metal of a specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element In particular, silicon and / or tin metal simple substance, alloy, oxide, carbide, nitride and the like are preferable from the viewpoint of capacity per unit mass and environmental load.

  The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium, but a material containing titanium and lithium is preferable from the viewpoint of high current density charge / discharge characteristics, A lithium-containing composite metal oxide material containing titanium is more preferable, and a composite oxide of lithium and titanium (hereinafter sometimes abbreviated as “lithium titanium composite oxide”). That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for a non-aqueous electrolyte secondary battery because the output resistance is greatly reduced.

In addition, lithium or titanium of the lithium titanium composite oxide is at least selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. Those substituted with one element are also preferred.
The metal oxide is a lithium titanium composite oxide represented by the general formula (A). In the general formula (A), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, It is preferable that 0 ≦ z ≦ 1.6 because the structure upon doping and dedoping of lithium ions is stable.

_{Li x Ti y M z O 4} (A)
[In General Formula (1), M represents at least one element selected from the group consisting of Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb. ]
Among the compositions represented by the general formula (A),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
This structure is particularly preferable because of a good balance of battery performance.

Particularly preferred representative compositions of the above compounds are Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), and Li _4/5 Ti _11/5 O in (c). ₄ . As for the structure of Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferable.
<Physical properties of carbonaceous materials>
When using a carbonaceous material as a negative electrode active material, it is desirable to have the following physical properties.

(Rhombohedral crystal ratio)
The rhombohedral crystal ratio can be determined from the ratio of the rhombohedral structure graphite layer (ABC stacking layer) and the hexagonal structure graphite layer (AB stacking layer) by the X-ray wide angle diffraction method (XRD) using the following formula.
Rhombohedral crystal ratio (%) = integrated intensity of ABC (101) peak of XRD ÷
XRD AB (101) peak integrated intensity × 100
Here, the rhombohedral crystal ratio of the carbonaceous material that can be used in the present invention is usually 0% or more, preferably more than 0%, more preferably 3% or more, and still more preferably 5% or more as a lower limit. Especially preferably, it is 12% or more. Moreover, as an upper limit, Preferably it is 35% or less, More preferably, it is 27% or less, More preferably, it is 24% or less, Most preferably, it is the range of 20% or less. Here, the rhombohedral crystal ratio of 0% indicates that no XRD peak derived from the ABC stacking layer is detected. On the other hand, “greater than 0%” means that even a slight XRD peak derived from the ABC stacking layer is detected.

If the rhombohedral crystal ratio is within the above range, for example, there are few defects in the crystal structure of the carbonaceous material, the reactivity with the electrolytic solution is small, the consumption of the electrolytic solution during the cycle is small, and the cycle characteristics are excellent.
The XRD measurement method for determining the rhombohedral crystal ratio is as follows: a 0.2 mm sample plate is filled so that the graphite powder is not oriented, and an X-ray diffractometer (for example, Cu using X'Pert Pro MPD manufactured by PANalytical) is used.
Measurement was performed with an Kα ray at an output of 45 kV and 40 mA. Using the obtained diffraction pattern, the peak integrated intensity is calculated by profile fitting using the asymmetric Pearson VII function using analysis software JADE5.0, and the rhombohedral crystal ratio is obtained from the above formula.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Solar slit 0.04 degree divergence slit 0.5 degree side divergence mask 15mm
Anti-scattering slit 1 degree ・ Measurement range and step angle / measurement time:
(101) plane: 41 ° ≦ 2θ ≦ 47.5 ° 0.3 ° / 60 seconds Background correction:
Connect 42.7 to 45.5 degrees with a straight line and subtract as background.
-Peak of rhombohedral-structure graphite particle layer: refers to a peak around 43.4 degrees.
-Peak of hexagonal structure graphite particle layer: It indicates a peak around 44.5 degrees.

  A method for obtaining graphite particles having a rhombohedral crystal ratio in the above range can employ a method of manufacturing using conventional techniques, and is not particularly limited, but the graphite particles are heat-treated at a temperature of 500 ° C. or higher. It is preferable to manufacture by this. In particular, mechanical effects such as compression, friction, shearing force, etc. including the interaction of particles are given to graphite particles mainly by impact force. In addition, the rhombohedral crystal ratio defined in the present invention can also be adjusted by changing the strength of mechanical action, processing time, presence / absence of repetition, and the like. Specifically, it has a rotor with a large number of blades installed inside the casing, and when the rotor rotates at high speed, mechanical action such as impact compression, friction, shearing force, etc. is applied to the carbon material introduced inside. An apparatus that provides a surface treatment is preferable. Moreover, it is preferable to have a mechanism that repeatedly gives a mechanical action by circulating a carbon material, or a mechanism that does not have a circulation mechanism but connects a plurality of apparatuses. As an example of a preferable apparatus, there can be mentioned a hybridization system manufactured by Nara Machinery Co., Ltd.

Further, it is more preferable to apply a heat treatment after applying the mechanical action.
Further, it is particularly preferable that after applying the mechanical action, it is combined with a carbon precursor and subjected to heat treatment at a temperature of 700 ° C. or higher.
(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction by the Gakushin method of carbonaceous materials is preferably 0.335 nm or more, and is usually 0.360 nm or less. 350 nm or less is preferable, and 0.345 nm or less is more preferable. Further, the crystallite size (Lc) of the carbonaceous material obtained by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more, and more preferably 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) obtained by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and 7 μm. The above is particularly preferable, and is usually 100 μm or less, preferably 50 μm or less, more preferably 40 μm or less, further preferably 30 μm or less, and particularly preferably 25 μm or less.

If the volume-based average particle size is below the above range, the irreversible capacity may increase, leading to loss of initial battery capacity. On the other hand, when the above range is exceeded, when an electrode is produced by coating, it tends to be a non-uniform coating surface, which may be undesirable in the battery manufacturing process.
The volume-based average particle size is measured by dispersing carbon powder in a 0.2% by weight aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate, which is a surfactant, and laser diffraction / scattering particle size distribution. This is carried out using a meter (LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(Raman R value, Raman half width)
The Raman R value of the carbonaceous material is a value measured using an argon ion laser Raman spectrum method, and is usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and particularly preferably 0.5 or less.

  When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge / discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. In particular, when a negative electrode active material having a Raman R value of 0.1 or more and a compound described in the general formula (1) are used in combination, the film forms a good network on the negative electrode surface and has a suitable film density. And cycle characteristics and load characteristics can be dramatically improved.

On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.
Further, the Raman half-width in the vicinity of 1580 cm ^{−1 of the} carbonaceous material is not particularly limited, but is usually 10 cm ⁻¹ or more, preferably 15 cm ⁻¹ or more, and usually 100 cm ⁻¹ or less, and 80 cm ⁻¹ or less. Preferably, 60 cm ⁻¹ or less is more preferable, and 40 cm ⁻¹ or less is particularly preferable.

  If the Raman half width is less than the above range, the crystallinity of the particle surface becomes too high, and there are cases where the number of sites where Li enters between layers decreases with charge and discharge. That is, charge acceptance may be reduced. In addition, when the negative electrode is densified by applying it to the current collector and then pressing it, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if it exceeds the above range, the crystallinity of the particle surface is lowered, the reactivity with the non-aqueous electrolyte is increased, and the efficiency may be lowered and the gas generation may be increased.

The measurement of the Raman spectrum, using a Raman spectrometer (manufactured by JASCO Corporation Raman spectrometer), the sample is naturally dropped into the measurement cell and filled, and while irradiating the sample surface in the cell with argon ion laser light, This is done by rotating the cell in a plane perpendicular to the laser beam. The resulting Raman spectrum, the intensity _{I A} of the peak _{P A} in the vicinity of 1580 cm ^-1, and measuring the intensity _{I B} of a peak _{P B} in the vicinity of 1360 cm ^-1, the intensity ratio _{R (R = I B / I} A) Is calculated. The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention. Further, the half width of the peak P _A in the vicinity of 1580 cm ^-1 of the resulting Raman spectrum was measured, which is defined as the Raman half-value width of the carbonaceous material of the present invention.

Moreover, said Raman measurement conditions are as follows.
Argon ion laser wavelength: 514.5nm
・ Laser power on the sample: 15-25mW
・ Resolution: 10-20cm ^-1
Measurement range: 1100 cm ^{−1 to} 1730 cm ⁻¹
・ Raman R value, Raman half width analysis: background processing,
-Smoothing processing: Simple average, 5 points of convolution

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high-density charge / discharge characteristics may deteriorate. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. Set the molding obtained by filling 0.47 g of the sample into a molding machine with a diameter of 17 mm and compressing it with 58.8 MN · m ^{-2 so} that it is flush with the surface of the sample holder for measurement. X-ray diffraction is measured. From the (110) diffraction and (004) diffraction peak intensities of the obtained carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated. The orientation ratio calculated by the measurement is defined as the orientation ratio of the carbonaceous material of the present invention.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree / measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(Aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more and usually 10 or less, preferably 8 or less, and more preferably 5 or less. If the aspect ratio exceeds the above range, streaking or a uniform coated surface cannot be obtained when forming an electrode plate, and the high current density charge / discharge characteristics may deteriorate. The lower limit of the above range is the theoretical lower limit value of the aspect ratio of the carbonaceous material.

  The aspect ratio is measured by magnifying and observing the carbonaceous material particles with a scanning electron microscope. Carbonaceous material particles when three-dimensional observation is performed by selecting arbitrary 50 graphite particles fixed to the end face of a metal having a thickness of 50 μm or less and rotating and tilting the stage on which the sample is fixed. The longest diameter a and the shortest diameter b orthogonal to it are measured, and the average value of a / b is obtained. The aspect ratio (a / b) obtained by the measurement is defined as the aspect ratio of the carbonaceous material of the present invention.

<Configuration and production method of negative electrode>
Any known method can be used for producing the electrode as long as the effects of the present invention are not significantly impaired. For example, it is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, which is applied to a current collector, dried and then pressed. Can do.
In the case of using an alloy-based material, a method of forming a thin film layer (negative electrode active material layer) containing the above-described negative electrode active material by a technique such as vapor deposition, sputtering, or plating is also used.

(Current collector)
As the current collector for holding the negative electrode active material, a known material can be arbitrarily used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable from the viewpoint of ease of processing and cost.

In addition, the shape of the current collector may be, for example, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punch metal, a foam metal, or the like when the current collector is a metal material. Among these, a metal thin film is preferable, a copper foil is more preferable, and a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method are more preferable.
The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and is usually 100 μm or less, preferably 50 μm or less. This is because if the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low, and conversely if it is too thin, handling may be difficult.

(Binder)
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolyte solution and the solvent used in manufacturing the electrode.
Specific examples include resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, and nitrocellulose; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluorine rubber, Rubber polymers such as NBR (acrylonitrile / butadiene rubber) and ethylene / propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof; EPDM (ethylene / propylene / diene terpolymer), styrene / Thermoplastic elastomeric polymers such as ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate , Soft resinous polymers such as ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, etc. And a polymer composition having ion conductivity of alkali metal ions (particularly lithium ions). These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass. The following is more preferable, 10% by mass or less is further preferable, and 8% by mass or less is particularly preferable. When the ratio of the binder with respect to a negative electrode active material exceeds the said range, the binder ratio from which the amount of binders does not contribute to battery capacity may increase, and the fall of battery capacity may be caused. On the other hand, below the above range, the strength of the negative electrode may be reduced.

  In particular, when a rubbery polymer typified by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 .6% by mass or more is more preferable, and is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the main component contains a fluorine-based polymer typified by polyvinylidene fluoride, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

(Thickener)
A thickener is normally used in order to adjust the viscosity of the slurry at the time of producing a negative electrode active material layer. The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.

  Further, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is more preferable.

(Electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. When the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases or non-aqueous system near the current collector / negative electrode active material interface. There is a case where high current density charge / discharge characteristics are deteriorated due to a decrease in permeability of the electrolytic solution. On the other hand, if the amount is less than the above range, the conductivity between the negative electrode active materials decreases, the battery resistance increases, and the capacity per unit volume may decrease.

(Thickness of negative electrode plate)
The thickness of the negative electrode plate is designed according to the positive electrode plate to be used, and is not particularly limited. However, the thickness of the negative electrode active material layer obtained by subtracting the thickness of the metal foil (current collector) from the negative electrode plate is usually 15 μm. Above, preferably 20 μm or more, more preferably 30 μm or more, and usually 300 μm or less, preferably 280 μm or less, more preferably 250 μm or less.

(Surface coating of negative electrode plate)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said negative electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

2-2. Positive electrode <Positive electrode active material>
The positive electrode active material used for the positive electrode is described below.
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. For example, a material containing lithium and at least one transition metal is preferable. Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

V, Ti, Cr, Mn, Fe, Co, Ni, Cu and the like are preferable as the transition metal of the lithium transition metal composite oxide, and specific examples include lithium-cobalt composite oxides such as LiCoO ₂ , LiMnO ₂ , Examples thereof include lithium / manganese composite oxides such as LiMn ₂ O ₄ and Li ₂ MnO ₄ , lithium / nickel composite oxides such as LiNiO ₂ , and the like. Further, some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and Si. Specific examples include lithium-nickel-cobalt-aluminum composite oxides, lithium-cobalt-nickel composite oxides, lithium-cobalt-manganese composite oxides, lithium- Nickel / manganese composite oxide, lithium / nickel / cobalt / manganese composite oxide, and the like can be given. Among these, lithium / nickel / manganese composite oxide and lithium / nickel / cobalt / manganese composite oxide are preferable because of good battery characteristics.

Specific examples of the substituted ones include, for example, Li _{1 + a} Ni _0.5 Mn _0.5 O ₂ , Li _{1 + a} Ni _0.8 Co _0.2 O ₂ , Li _{1 + a} Ni _0.85 Co _0.10 Al _{0. 05} O ₂ , Li _{1 + a} Ni _0.33 Co _0.33 Mn _0.33 O ₂ , Li _{1 + a} Ni _0.45 Mn _0.45 Co _0.1 O ₂ , Li _{1 + a} Ni _0.475 Mn _0.475 Co _{0 .05} O ₂ , Li _{1 + a} Mn _1.8 Al _0.2 O ₄ , Li _{1 + a} Mn ₂ O ₄ , Li _{1 + a} Mn _1.5 Ni _0.5 O ₄ , xLi ₂ MnO _3. (1-x) Li _{1 + a} MO ₂ (M = transition metal, for example, a metal selected from the group consisting of Li, Ni, Mn and Co) (a; 0 <a ≦ 3.0). The ratio of these substituted metal elements in the composition formula is appropriately adjusted depending on the relationship between the battery characteristics of the battery using the element and the cost of the material.

The lithium-containing transition metal phosphate compound is LixMPO ₄ (M = a kind of element selected from the group consisting of Group 4 to Group 11 transition metals in the periodic table, x is 0 <x <1.2). As the transition metal (M), V, Ti, Cr, Mg, Zn, Ca, Cd, Sr, Ba, Co, Ni,
It is preferably at least one element selected from the group consisting of Fe, Mn and Cu, and more preferably at least one element selected from the group consisting of Co, Ni, Fe and Mn. For _{example, LiFePO 4, Li 3 Fe 2} (PO 4) 3, LiFeP 2 O 7 , etc. of phosphorus Santetsurui, cobalt phosphate such as LiCoPO _4, manganese phosphate such as LiMnPO _4, phosphoric acids such as LiNiPO ₄ Nickel, a part of transition metal atoms that are the main components of these lithium transition metal phosphate compounds are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Examples include those substituted with other metals such as Nb and Si.

Among these, iron phosphates such as LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , and LiFeP ₂ O ₇ are preferably used because they are less likely to cause metal elution at high temperatures and charged states and are inexpensive. It is done.
The above-mentioned “LixMPO ₄ is a basic composition” includes not only the composition represented by the composition formula but also a material in which part of sites such as Fe in the crystal structure is replaced with other elements. Means that. Furthermore, it means that not only a stoichiometric composition but also a non-stoichiometric composition in which some elements are deficient or the like is included. Other elements to be substituted are preferably elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, and Si. When the substitution of other elements is performed, the content is preferably 0.1 mol% or more and 5 mol% or less, more preferably 0.2 mol% or more and 2.5 mol% or less.

The said positive electrode active material may be used independently and may use 2 or more types together.
Further, foreign elements may be introduced into the lithium transition metal-based compound powder of the present invention. Different elements include B, Na, Mg, Al, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Ru, Rh, Pd, Ag, In, Sn, Sb. Te, Ba, Ta, Mo, W, Re, Os, Ir, Pt, Au, Pb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu , Bi, N, F, Cl, Br, or I. These foreign elements may be incorporated into the crystal structure of the lithium transition metal compound, or may not be incorporated into the crystal structure of the lithium transition metal compound, and may be a single element or compound on the particle surface or grain boundary. May be unevenly distributed.

(Surface coating)
Moreover, you may use what the substance of the composition different from this adhered to the surface of the said positive electrode active material. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

  For example, these surface adhering substances are dissolved or suspended in a solvent, impregnated and added to the positive electrode active material, and dried. After the surface adhering substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material, It can be made to adhere to the surface of the positive electrode active material by a method of reacting by heating or the like, a method of adding to the positive electrode active material precursor and firing simultaneously. In addition, when making carbon adhere, the method of making carbonaceous adhere mechanically later in the form of activated carbon etc. can also be used, for example.

The amount of the surface adhering substance is by mass with respect to the positive electrode active material, preferably 0.1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit, preferably 20% or less, more preferably, as the lower limit. Is used at 10% or less, more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the electrolyte solution on the surface of the positive electrode active material and can improve the battery life. However, when the amount of the adhering quantity is too small, the effect is not sufficiently manifested. In the case where it is too high, the resistance may increase in order to inhibit the entry and exit of lithium ions, so this composition range is preferable.
In the present invention, a material in which a material having a different composition is attached to the surface of the positive electrode active material is also referred to as “positive electrode active material”.

(shape)
Examples of the shape of the positive electrode active material particles include a lump shape, a polyhedron shape, a sphere shape, an oval sphere shape, a plate shape, a needle shape, and a column shape, which are conventionally used. It is preferable that the secondary particles have a spherical shape or an elliptical shape. In general, an electrochemical element expands and contracts as the active material in the electrode expands and contracts as it is charged and discharged. Therefore, the active material is easily damaged due to the stress or the conductive path is broken. Therefore, it is preferable that the primary particles are aggregated to form secondary particles, rather than a single particle active material having only primary particles, in order to relieve expansion and contraction stress and prevent deterioration. In addition, spherical or oval spherical particles are less oriented during molding of the electrode than plate-like equiaxed particles, so that the expansion and contraction of the electrode during charging and discharging is small, and the electrode is produced. The mixing with the conductive material is also preferable because it is easy to mix uniformly.

(Median diameter d ₅₀ )
The median diameter d ₅₀ of the positive electrode active material particles (secondary particle diameter when primary particles aggregate to form secondary particles) is preferably 0.1 μm or more, more preferably 0.5 μm or more, The upper limit is preferably 20 μm or less, more preferably 18 μm or less, still more preferably 16 μm or less, and most preferably 15 μm or less. If the lower limit is not reached, a high tap density product may not be obtained. If the upper limit is exceeded, it takes time to diffuse lithium in the particles. When a conductive material, a binder, or the like is slurried with a solvent and applied as a thin film, problems such as streaking may occur. Here, by mixing two or more kinds of the positive electrode active materials having different median diameters d ₅₀ , the filling property at the time of forming the positive electrode can be further improved.

In the present invention, the median diameter d ₅₀ is measured by a known laser diffraction / scattering particle size distribution measuring apparatus. When LA-920 manufactured by HORIBA is used as a particle size distribution meter, a 0.1% by mass sodium hexametaphosphate aqueous solution is used as a dispersion medium used for measurement, and a measurement refractive index of 1.24 is set after ultrasonic dispersion for 5 minutes. Measured.

(Average primary particle size)
When primary particles are aggregated to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.03 μm or more, more preferably 0.05 μm or more, and still more preferably 0.8. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, still more preferably 3 μm or less, and most preferably 2 μm or less. If the above upper limit is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder filling property, or the specific surface area is greatly reduced, so that there is a high possibility that battery performance such as output characteristics will deteriorate. is there. On the other hand, when the value falls below the lower limit, there is a case where problems such as inferior reversibility of charge / discharge are usually caused because crystals are not developed.

  In the present invention, the primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000 times, the longest value of the intercept by the left and right boundary lines of the primary particles with respect to the horizontal straight line is obtained for any 50 primary particles and obtained by taking the average value. It is done.

<Configuration and manufacturing method of positive electrode>
The structure of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. The production of the positive electrode using the positive electrode active material can be performed by a conventional method. That is, a positive electrode active material, a binder, and, if necessary, a conductive material and a thickener mixed in a dry form into a sheet form are pressure-bonded to the positive electrode current collector, or these materials are liquid media A positive electrode can be obtained by forming a positive electrode active material layer on the current collector by applying it to a positive electrode current collector and drying it as a slurry by dissolving or dispersing in a slurry.

  The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. Moreover, an upper limit becomes like this. Preferably it is 95 mass% or less, More preferably, it is 93 mass% or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electric capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1.5 g / cm ³ or more as a lower limit, more preferably 2 g / cm ³ , further preferably 2.2 g / cm ³ or more, and preferably 4.0 g as an upper limit. / cm ³ or less, more preferably 3.8 g / cm ³ or less, more preferably 3.6 g / cm ³ or less. If it exceeds this range, the permeability of the electrolyte solution to the vicinity of the current collector / active material interface decreases, and the charge / discharge characteristics particularly at a high current density decrease, and a high output may not be obtained. On the other hand, if it is lower, the conductivity between the active materials is lowered, the battery resistance is increased, and a high output may not be obtained.

(Conductive material)
A known conductive material can be arbitrarily used as the conductive material. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more in the positive electrode active material layer, and the upper limit is usually 50% by mass or less, preferably It is used so as to contain 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

(Binder)
The binder used for manufacturing the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that can be dissolved or dispersed in a liquid medium used during electrode manufacturing may be used. Resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluorine rubber, isoprene rubber , Rubber polymers such as butadiene rubber and ethylene-propylene rubber; styrene / butadiene / styrene block copolymer or hydrogenated product thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / Ethylene copolymer, styrene Thermoplastic elastomeric polymer such as isoprene / styrene block copolymer or hydrogenated product thereof; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer Soft resinous polymers such as polymers; Fluoropolymers such as polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymers; alkali metal ions (especially lithium ions) And a polymer composition having ion conductivity. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and the upper limit is usually 80% by mass or less, preferably 60%. It is not more than mass%, more preferably not more than 40 mass%, most preferably not more than 10 mass%. If the ratio of the binder is too low, the positive electrode active material cannot be sufficiently retained, and the mechanical strength of the positive electrode is insufficient, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, battery capacity and conductivity may be reduced.

(Thickener)
A thickener can be used normally in order to adjust the viscosity of the slurry used for manufacture of a positive electrode active material layer. In particular, when an aqueous medium is used, it is preferable to make a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). The thickener is not particularly limited, and specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios. When a thickener is further added, the ratio of the thickener to the active material is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more. The upper limit is 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. Below this range, applicability may be significantly reduced. If it exceeds, the ratio of the active material in the positive electrode active material layer may decrease, and there may be a problem that the capacity of the battery decreases and a problem that the resistance between the positive electrode active materials increases.

(Current collector)
The material of the positive electrode current collector is not particularly limited, and a known material can be arbitrarily used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; and carbon materials such as carbon cloth and carbon paper. Of these, metal materials, particularly aluminum, are preferred.

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, and foam metal in the case of a metal material. A thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. In addition, you may form a thin film suitably in mesh shape. Although the thickness of the thin film is arbitrary, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less, preferably 100 μm or less, more preferably 50 μm or less. If the thin film is thinner than this range, the strength required for the current collector may be insufficient. Conversely, if the thin film is thicker than this range, the handleability may be impaired.

Moreover, it is also preferable from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer that a conductive additive is applied to the surface of the current collector. Examples of the conductive assistant include noble metals such as carbon, gold, platinum, and silver.
(Thickness of positive 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 metal foil (current collector) from the positive electrode plate is set on one side of the current collector. On the other hand, the lower limit is preferably 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Positive electrode surface coating)
Moreover, you may use what adhered the substance of the composition different from this to the surface of the said positive electrode plate. Surface adhering substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate And sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

2-3. Separator Normally, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the nonaqueous electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Among them, a resin, glass fiber, inorganic material, etc. formed of a material that is stable with respect to the non-aqueous electrolyte solution of the present invention is used, and a porous sheet or a nonwoven fabric-like material having excellent liquid retention properties is used. Is preferred.

  As materials for the resin and glass fiber separator, for example, polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone, glass filters and the like can be used. Of these, glass filters and polyolefins are preferred, and polyolefins are more preferred. These materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less. If the separator is too thin than the above range, the insulating properties and mechanical strength may decrease. On the other hand, if it is thicker than the above range, not only the battery performance such as the rate characteristic may be lowered, but also the energy density of the whole non-aqueous electrolyte secondary battery may be lowered.

  Furthermore, when using a porous material such as a porous sheet or nonwoven fabric as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. If the porosity is too smaller than the above range, the membrane resistance tends to increase and the rate characteristics tend to deteriorate. Moreover, when larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

Moreover, although the average pore diameter of a separator is also arbitrary, it is 0.5 micrometer or less normally, 0.2 micrometer or less is preferable, and it is 0.05 micrometer or more normally. If the average pore diameter exceeds the above range, a short circuit tends to occur. On the other hand, below the above range, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as inorganic materials, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Used.

  As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used. In addition to the above-described independent thin film shape, a separator formed by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, a porous layer may be formed by using alumina particles having a 90% particle size of less than 1 μm on both surfaces of the positive electrode and using a fluororesin as a binder.

The Gurley value of the separator represents the difficulty of air passage in the film thickness direction, and is expressed as the number of seconds required for 100 ml of air to pass through the film. Means that it is difficult to get through. That is, a smaller value means better communication in the thickness direction of the film, and a larger value means lower communication in the thickness direction of the film. Communication is the degree of connection of holes in the film thickness direction. If the Gurley value of the separator of the present invention is low, it can be used for various purposes. For example, when used as a separator for a non-aqueous lithium secondary battery, a low Gurley value means that lithium ions can be easily transferred and is preferable because of excellent battery performance. Although the Gurley value of a separator is arbitrary, Preferably it is 10-1000 second / 100ml, More preferably, it is 15-800 second / 100ml, More preferably, it is 20-500 second / 100ml. If the Gurley value is 1000 seconds / 100 ml or less, the electrical resistance is substantially low, which is preferable as a separator.

2-4. Battery design <Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are interposed through the separator, and a structure in which the positive electrode plate and the negative electrode plate are wound in a spiral shape through the separator. Either is acceptable. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupation ratio) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less. .

  When the electrode group occupancy is below the above range, the battery capacity decreases. Also, if the above range is exceeded, the void space is small, the battery expands, and the member expands or the vapor pressure of the electrolyte liquid component increases and the internal pressure rises. In some cases, the gas release valve that lowers various characteristics such as storage at high temperature and the like, or releases the internal pressure to the outside is activated.

<Exterior case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, stainless steel, aluminum, an aluminum alloy, a metal such as a magnesium alloy, or a laminated film (laminate film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, an aluminum or aluminum alloy metal or a laminate film is preferably used.

  In an exterior case using metals, the metal is welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed sealed structure, or a caulking structure using the above metals via a resin gasket. Things. Examples of the outer case using the laminate film include a case where a resin-sealed structure is formed by heat-sealing resin layers. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a sealed structure, a metal and a resin are joined, so that a resin having a polar group or a modified group having a polar group introduced as an intervening resin is used. Resins are preferably used.

<Protective element>
As a protective element, PTC (Positive Temperature Coefficient), thermal fuse, thermistor, whose resistance increases when abnormal heat or excessive current flows, cut off current flowing in the circuit due to sudden rise in battery internal pressure or internal temperature at abnormal heat generation A valve (current cutoff valve) or the like can be used. It is preferable to select a protective element that does not operate under normal use at a high current, and it is more preferable that the protective element is designed so as not to cause abnormal heat generation or thermal runaway even without the protective element.

<Exterior body>
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body. This exterior body is not particularly limited, and any known one can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired. Specifically, the material of the exterior body is arbitrary, but usually, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, or the like is used.

  The shape of the exterior body is also arbitrary, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

EXAMPLES 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.
The compound of the general formula (1) used in this example was synthesized by the following method.
[Compound A]
The raw material 1) was synthesized according to the method of non-patent literature (JOC 56 (3), 1083-8, 1991). Then, Eur. J. et al. O. C. Compound A was obtained by a method according to 2009 (20), 2836-2844.

<Example A>
[Production of negative electrode]
98 parts by mass of a carbonaceous material, 100 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of carboxymethylcellulose sodium) and an aqueous dispersion of styrene-butadiene rubber (styrene-butadiene, respectively) as a thickener and a binder 2 parts by mass of rubber (50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry was applied to a copper foil having a thickness of 10 μm, dried, and rolled with a press. The active material layer was 30 mm wide, 40 mm long, 5 mm wide, and 9 mm long uncoated. It cut out into the shape which has a part, and it was set as the negative electrode used for Examples 1-4, Comparative Examples 1-3, and Reference Example 1.

[Production of positive electrode]
90% by mass of Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) 5 as a binder % By mass was mixed in N-methylpyrrolidone solvent to make a slurry. The obtained slurry was applied to a 15 μm-thick aluminum foil previously coated with a conductive additive, dried, and rolled with a press machine. The active material layer size was 30 mm wide, 40 mm long, and 5 mm wide. The positive electrode used in Examples 1 to 4, Comparative Examples 1 to 3, and Reference Example 1 was cut into a shape having an uncoated part with a length of 9 mm.

[Preparation of electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and diethyl carbonate (EMC) (volume ratio 30:30:40) was dissolved to a ratio of 1 mol / L. Thus, a basic electrolyte solution was prepared. The basic electrolyte solution was mixed with the compounds described in Table 1 to obtain electrolyte solutions used in Examples 1 to 4, Comparative Examples 1 to 3, and Reference Example 1.

[Production of lithium secondary battery]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, and the positive electrode to prepare a battery element. The battery element was inserted into a bag made of a laminate film in which both surfaces of aluminum (thickness: 40 μm) were coated with a resin layer while projecting positive and negative terminals, and each of the electrolyte solutions shown in Table 1 was placed in the bag. The battery was sealed in a vacuum, and a sheet-like battery was produced. The batteries used in Examples 1 to 4, Comparative Examples 1 to 3, and Reference Example 1 were obtained.

[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been run-in is charged at a constant current-constant voltage (0.05 C cut) up to 4.1 V at a current corresponding to 0.2 C at 25 ° C., and then 3.0 V at a current corresponding to 0.2 C. The initial discharge capacity was determined by carrying out constant current discharge. Here, 1C represents a current value for discharging the reference capacity of the battery in one hour, and 0.2C represents a current value of 1/5 thereof.

[Analysis of battery electrolyte]
The electrolyte used for the battery used in Reference Example 1 was extracted from the lithium secondary battery in which the break-in operation was completed, and quantitative analysis of LiPO ₂ F ₂ was performed by ion chromatography.
[Evaluation of cycle characteristics]
A lithium secondary battery that has been subjected to a break-in operation is charged at 60 ° C. with a constant current of 2 C up to 4.1 V, and then discharged with a constant current of 2 C up to 3.0 V as one cycle. The discharge capacity at the cycle was determined.

  As is clear from Table 1, the batteries using the non-aqueous electrolyte solution according to the present invention (Examples 1 to 4) are the batteries using the non-aqueous electrolyte solution according to the present invention (Comparative Examples 1 to 3, Compared to Reference Example 1), the cycle capacity retention rate is excellent. When a specific lithium salt is introduced together with the compound of the general formula (1), the specific lithium salt is taken into the electrode protective layer formed by the compound of the general formula (1), and the electrode surface durability is remarkably improved. It is presumed that the above-mentioned remarkable battery durability performance is improved. On the other hand, even if it was a compound which has a triple bond, the remarkable effect was not seen except the compound represented by General formula (1) (comparative example 3).

<Example B>
[Preparation of electrolyte]
In a dry argon atmosphere, LiPF ₆ dried in a mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and diethyl carbonate (EMC) (volume ratio 30:30:40) was dissolved to a ratio of 1 mol / L. Thus, a basic electrolyte solution was prepared. The basic electrolyte solution was mixed with the compounds shown in Table 2 to obtain electrolyte solutions used in Examples 5 and 6, Comparative Examples 4 and 5, and Reference Example 2.

[Production of lithium secondary battery]
A sheet battery was prepared in the same manner as in Example A except that the basic electrolyte was used.
[Evaluation of initial discharge capacity]
The lithium secondary battery was conditioned with a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to improve the adhesion between the electrodes. A battery that has been conditioned is charged at a constant current-constant voltage (0.05 C cut) up to 4.4 V at a current corresponding to 0.2 C at 25 ° C. and then 3.0 V at a current corresponding to 0.2 C. The initial discharge capacity was determined by carrying out constant current discharge.

[Evaluation of high-temperature storage characteristics]
The battery for which the evaluation of the initial discharge capacity was completed was charged at a constant current-constant voltage (0.05 C cut) to 4.4 V at a current corresponding to 0.2 C, and stored at 75 ° C. for 120 hours. After cooling the battery to room temperature, discharge at a constant current up to 3.0 V at a current equivalent to 0.2 C to obtain the discharge capacity, and the calculation formula of (discharge capacity after storage) ÷ (initial discharge capacity) × 100 From this, the discharge capacity retention rate was determined.

  As is clear from Table 2, the batteries using the non-aqueous electrolyte solution according to the present invention (Examples 5 and 6) were the batteries using the non-aqueous electrolyte solution according to the present invention (Comparative Examples 4, 5, Compared with Reference Example 2), the cycle capacity retention rate is excellent. When a specific lithium salt is introduced together with the compound of the general formula (1), the specific lithium salt is taken into the electrode protective layer formed by the compound of the general formula (1), and the electrode surface durability is remarkably improved. It is presumed that the above-mentioned remarkable battery durability performance is improved. It can also be seen that the effect of the present invention is maintained even when the battery voltage is higher than in Example (A).

  According to the non-aqueous electrolyte solution of the present invention, the non-aqueous electrolyte battery using the non-aqueous electrolyte solution of the present invention is extremely useful because it has a high capacity retention rate even after a durability test such as a high temperature storage test or a cycle test. is there. Therefore, the non-aqueous electrolyte solution of the present invention and the non-aqueous electrolyte battery using the same can be used for various known applications. Specific examples include notebook computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile faxes, mobile copy, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, etc. , Walkie Talkie, Electronic Notebook, Calculator, Memory Card, Portable Tape Recorder, Radio, Backup Power Supply, Motor, Automobile, Motorbike, Motorbike, Bicycle, Lighting Equipment, Toy, Game Equipment, Clock, Electric Tool, Strobe, Camera, etc. Examples include a household backup power source, an energy storage system for collective housing, a business backup power source for offices and factories, a load leveling power source, and a natural energy storage power source.

Claims (8)

A non-aqueous electrolyte solution comprising a lithium salt and a non-aqueous solvent for dissolving the lithium salt, wherein the non-aqueous electrolyte solution comprises a compound represented by the following general formula (1), and Li _α XO _n F _m (X = Element of Group 13, 15, 16 of 2nd or 3rd period of periodic table, α = 1-2, n = 1-3, m = 1-2), and in the general formula (1) The non-aqueous electrolyte solution characterized by the compound represented by following General formula (2) being said, and said X being phosphorus or sulfur .

(In the above general formula (1), X and Z represent CR ¹ ₂ , C═O, C═N—R ¹ , C═P—R ¹ , O, S, N—R ¹ , P—R ¹ . Y may represent CR ¹ ₂ , C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ³ . In the general formula (1), R and R ¹ are hydrogen, halogen, or a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other. R ² is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group R ³ is a hydrocarbon group having 1 to 20 carbon atoms which may have Li, NR ⁴ ₄ or a functional group R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms which may have a functional group, and may be the same or different from each other, and n and m represent an integer of 0 or more. Further, carbons in adjacent rings may form a further bond with each other, and R of the carbon may be reduced by one each, W is in the same range as R, and W is the same as R above. May be different.)

(In the general formula (2), Y represents C═O, S═O, S (═O) ₂ , P (═O) —R ² , P (═O) —OR ^3. R ² represents carbon. R ³ is a hydrocarbon group having 1 to 20 carbon atoms , R ³ is Li, NR ⁴ ₄ , or a hydrocarbon group having 1 to 20 carbon atoms, R ⁴ is a hydrocarbon group having 1 to 20 carbon atoms, and They may be the same or different.) The non-aqueous electrolyte solution according to claim 1, wherein the compound represented by the general formula (1) is at least one of the compounds represented by the following formulas (3) to (7) .

  The non-aqueous electrolyte solution according to claim 2, wherein the compound represented by the general formula (1) is a compound represented by the formula (3). The non-aqueous electrolyte solution according to claim 1 , wherein the Li _α XO _n F _m is LiPO ₂ F ₂ or LiSO ₃ F. 5. A non-aqueous electrolyte battery comprising a negative electrode and a positive electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte solution, wherein the non-aqueous electrolyte solution is a non-aqueous electrolyte solution according to claim 1. A non-aqueous electrolyte battery characterized by the above.   The non-aqueous electrolyte battery according to claim 5, wherein the negative electrode capable of inserting and extracting lithium ions is a carbonaceous material.   The non-aqueous electrolyte battery according to claim 5, wherein the negative electrode capable of inserting and extracting lithium ions is an alloy-based material.   The nonaqueous electrolyte battery according to claim 5, wherein the negative electrode capable of inserting and extracting lithium ions is a Li-containing metal composite oxide material.