JP2008010414A - Non-aqueous electrolytic solution and non-aqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-aqueous electrolytic solution capable of fabricating a non-aqueous electrolyte battery featuring a high capacity and a good recycling property and a non-aqueous electrolyte battery fabricated thereby. <P>SOLUTION: A non-aqueous electrolytic solution contains (1) a cyclic carbonate with an unsaturated bond, (2) an aromatic compound whose total carbon number is 7-18, (3) a diethyl carbonate or (4) at least one kind selected from a group comprising a cyclic sulfonic acid ester compound, a disulfonic acid ester compound, a nitrile compound and a compound represented by the general formula (1). Furthermore, this solution contains a fluorinated cyclic carbonate with two or more fluorine atoms. Alternatively, (5) the non-aqueous electrolytic solution is an electrolytic solution which is used for a high voltage battery with a charge stop voltage of 4.3 V or more and contains a fluorinated cyclic carbonate with two or more fluorine atoms. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery using the same.

Non-aqueous electrolyte batteries such as lithium secondary batteries are being put to practical use in a wide range of applications from so-called consumer power sources such as mobile phones and laptop computers to in-vehicle power sources for automobiles and the like. However, the demand for higher performance for non-aqueous electrolyte batteries in recent years is increasing, and there is a demand for improvement in battery characteristics.
The electrolyte used for the non-aqueous electrolyte 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 order to improve battery characteristics such as load characteristics, cycle characteristics, and storage characteristics of such non-aqueous electrolyte batteries, various studies have been made on non-aqueous solvents and electrolytes.
Patent Document 1 proposes the use of ethyl methyl carbonate and dimethyl carbonate in order to suppress deterioration of overcharge characteristics caused by reaction of lithium with lithium by diethyl carbonate and deterioration when left in a high temperature environment. ing.

  In Patent Document 2, when a mixture of an asymmetric chain carbonate and a cyclic carbonate having a double bond is used as a non-aqueous solvent, the cyclic carbonate having a double bond reacts preferentially with the negative electrode and a good quality is formed on the negative electrode surface. It has been proposed that a film is formed, which suppresses the formation of a non-conductive film on the negative electrode surface due to the asymmetric chain carbonate, thereby improving storage characteristics and cycle characteristics.

  Patent Document 3 proposes to protect the battery by increasing the internal resistance of the battery by mixing an additive that polymerizes at a battery voltage equal to or higher than the maximum operating voltage of the battery in the electrolyte. 4. The internal electrical disconnection device provided for overcharge protection can be reliably obtained by mixing gas and an additive that generates pressure by polymerizing at a battery voltage higher than the maximum operating voltage of the battery in the electrolyte. And aromatic compounds such as biphenyl, thiophene, and furan are disclosed as additives.

Patent Document 5 discloses alkylene carbonates containing fluorine groups such as cis-4,5-difluoro-1,3-dioxolan-2-one and trans-4,5-difluoro-1,3-dioxolan-2-one. It is described that a lithium secondary battery having a high capacity and excellent cycle characteristics can be provided by using the electrolytic solution contained.
Japanese Patent Laid-Open No. 7-14607 Japanese Patent Laid-Open No. 11-185806 JP-A-9-106835 JP-A-9-171840 JP 2004-319317 A

However, the demand for higher performance of batteries in recent years is increasing, and it is required to achieve high capacity, high temperature storage characteristics, and cycle characteristics at a high level.
As a method for increasing the capacity, it has been studied to pack as many active materials as possible in a limited battery volume. Designs that occupy as little volume as possible are common. However, pressurizing the active material layer of the electrode to increase the density, or by reducing the amount of the electrolyte, it becomes impossible to use the active material uniformly, and some lithium precipitates due to non-uniform reaction, In the non-aqueous electrolyte secondary battery using the electrolytic solution described in Patent Documents 1 to 5, the deterioration of the active material is promoted and sufficient characteristics cannot be obtained. It was not yet satisfactory in terms of achieving both properties and high-temperature storage characteristics.
In addition, for the purpose of increasing the energy density, attempts have been made to increase the operating voltage of the battery by charging to a high voltage exceeding 4.2V. However, there is a problem that the higher the charging voltage, the more remarkable the deterioration of the battery characteristics.

As a result of various studies to achieve the above object, the present inventors have found that the above problems can be solved by incorporating a compound having a specific structure in a specific electrolyte. It came to complete.
That is, the gist of the present invention is shown below.
(1) In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution contains a cyclic carbonate having an unsaturated bond, and further has a fluorinated ring having two or more fluorine atoms. A non-aqueous electrolyte containing carbonate.
(2) In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution contains an aromatic compound having a total carbon number of 7 or more and 18 or less, and further contains two or more fluorine atoms. A non-aqueous electrolyte containing the fluorinated cyclic carbonate.
(3) A nonaqueous electrolytic solution containing an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous solvent contains diethyl carbonate, and further contains a fluorinated cyclic carbonate having 2 or more fluorine atoms. Non-aqueous electrolyte.
(4) In a non-aqueous electrolyte including an electrolyte and a non-aqueous solvent that dissolves the electrolyte, the non-aqueous electrolyte is represented by a cyclic sulfonate compound, a disulfonate compound, a nitrile compound, and the following general formula (1). A non-aqueous electrolytic solution comprising at least one compound selected from the group consisting of the following compounds, and further containing a fluorinated cyclic carbonate having two or more fluorine atoms.

(In General Formula (1), R ^{1 to} R ³ each independently represents an alkyl group having 1 to 12 carbon atoms which may be substituted with a fluorine atom, and n represents an integer of 0 to 6). .)
(5) The cyclic carbonate having an unsaturated bond is at least one compound selected from the group consisting of a vinylene carbonate compound, a vinyl ethylene carbonate compound, and a methylene ethylene carbonate compound. Non-aqueous electrolyte.
(6) The non-aqueous electrolyte according to (1) or (5) above, wherein the cyclic carbonate having an unsaturated bond is vinylene carbonate and / or vinyl ethylene carbonate.
(7) The ratio (1), (5) or (6) above, wherein the ratio of the cyclic carbonate having an unsaturated bond in the non-aqueous electrolyte is 0.001 wt% or more and 8 wt% or less. The non-aqueous electrolyte described.
(8) The non-aqueous electrolyte according to (2) above, wherein the aromatic compound has a total carbon number of 10 or more and 18 or less.
(9) Aromatic compounds having 7 to 18 carbon atoms in total are biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran The non-aqueous electrolyte according to (2) or (8) above, which is at least one compound selected from the group consisting of:
(10) The above (2), (8), wherein the ratio of the aromatic compound having a total carbon number of 7 or more and 18 or less in the non-aqueous electrolyte solution is 0.001 wt% or more and 5 wt% or less. ) Or (9).

(11) The nonaqueous electrolytic solution according to (3) above, wherein the proportion of diethyl carbonate in the total nonaqueous solvent is 10% by volume or more and 90% by volume or less.
(12) The cyclic sulfonate compound is at least one compound selected from the group consisting of 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, and 1,4-butene sultone. The nonaqueous electrolytic solution according to (4), which is characterized in that (13) The disulfonic acid ester compound is ethanediol disulfonates, 1,2-propanediol disulfonates, 1,3-propanediol disulfonates, 1,2-butanediol disulfonates, 1,3-butane. The non-aqueous electrolyte according to (4) above, which is at least one compound selected from the group consisting of diol disulfonates and 1,4-butanediol disulfonates.
(14) The nitrile compound is at least selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, and fumaronitrile. The non-aqueous electrolyte according to (4) above, which is a kind of compound.
(15) The nonaqueous electrolytic solution according to (4), wherein in general formula (1), R ^{1 to} R ³ have 2 to 8 carbon atoms.
(16) The nonaqueous electrolytic solution according to (4) or (15) above, wherein in the general formula (1), n is 0, 1 or 2.
(17) At least one compound selected from the group consisting of a cyclic sulfonic acid ester compound, a disulfonic acid ester compound, a nitrile compound, and a compound represented by the following general formula (1) in the nonaqueous electrolytic solution. The nonaqueous electrolytic solution according to any one of (4) and (12) to (16) above, wherein the content ratio is 0.001 wt% or more and 5 wt% or less in total.
(18) The fluorinated cyclic carbonate compound having two or more fluorine atoms is a fluorinated ethylene carbonate having two or more fluorine atoms, and is described in any one of (1) to (17) above Non-aqueous electrolyte.
(19) The fluorinated cyclic carbonate compound having two or more fluorine atoms is cis-4,5-difluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolane-2. Any one of the above-mentioned (1) to (18), which is at least one compound selected from the group consisting of -one and 4,4-difluoro-1,3-dioxolan-2-one The non-aqueous electrolyte described.
(20) The ratio of the fluorinated cyclic carbonate having two or more fluorine atoms in the non-aqueous electrolyte solution is 0.001 to 10% by weight, any one of (1) to (19) above The non-aqueous electrolyte solution according to one item.

(21) The ratio of the fluorinated cyclic carbonate having two or more fluorine atoms in the nonaqueous electrolytic solution is 0.01 to 4% by weight, and any one of (1) to (20) The non-aqueous electrolyte solution according to item.
(22) In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution is an electrolyte solution used for a high voltage battery having a charge end voltage of 4.3 V or more, and two or more A non-aqueous electrolyte containing a fluorinated cyclic carbonate having a fluorine atom.
(23) The nonaqueous electrolytic solution according to (22) above, wherein the nonaqueous electrolytic solution contains a cyclic carbonate having an unsaturated bond.
(24) The nonaqueous electrolytic solution according to (22), wherein the nonaqueous electrolytic solution contains an aromatic compound having a total carbon number of 7 or more and 18 or less.
(25) The non-aqueous electrolyte according to (22) above, wherein the non-aqueous electrolyte contains diethyl carbonate.
(26) The nonaqueous electrolytic solution contains at least one compound selected from the group consisting of a cyclic sulfonic acid ester compound, a disulfonic acid ester compound, a nitrile compound, and a compound represented by the following general formula (1). The nonaqueous electrolytic solution according to (22) above, wherein

(27) A non-aqueous electrolyte battery including 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 (1) to (26) above. A non-aqueous electrolyte battery characterized by being the non-aqueous electrolyte solution described.
(28) The non-aqueous electrolyte secondary battery according to (27), wherein the negative electrode includes a carbonaceous material and / or a metal compound capable of inserting and extracting lithium.
(29) The non-aqueous electrolyte secondary battery according to (27), wherein the positive electrode includes a lithium transition metal composite oxide material.

  ADVANTAGE OF THE INVENTION According to this invention, the non-aqueous electrolyte battery excellent in the storage capacity | capacitance and cycling characteristics with high capacity | capacitance can be provided, and size reduction and performance enhancement of a non-aqueous electrolyte battery can be achieved.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. However, the description of constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not specified by these contents. .

<Non-aqueous electrolyte>
The non-aqueous electrolyte solution of the present invention contains an electrolyte and a non-aqueous solvent that dissolves the electrolyte, as is the case with conventional non-aqueous electrolyte solutions.
(Electrolytes)
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. Any lithium salt can be used, and specific examples include the following.
For example, inorganic lithium salts such as LiPF ₆ and LiBF ₄ ; LiCF ₃ SO ₃ , 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, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiPF ₄ (CF ₃ ) ₂ , Li
PF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , 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 S
And fluorine-containing organic lithium salts such as O ₂ ) ₂ and lithium bis (oxalate) borate.

Of these, LiPF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ or LiN (C ₂ F ₅ SO ₂ ) ₂ are preferable from the viewpoint of improving battery performance, and in particular, LiPF ₆ or LiB.
F ₄ is preferred.
These lithium salts may be used alone or in combination of two or more.
A preferred example in the case of using two or more types in combination is the combined use of LiPF ₆ and LiBF ₄ , which has an effect of improving cycle characteristics. In this case, the proportion of LiBF _{4 in} the total of both is preferably 0.01% by weight or more, particularly preferably 0.1% by weight or more, preferably 20% by weight or less, particularly preferably 5% by weight or less. is there. If the lower limit is not reached, it may be difficult to obtain a desired effect. If the upper limit is exceeded, battery characteristics after high-temperature storage may be deteriorated.

Another example is the combined use of an inorganic lithium salt and a fluorine-containing organic lithium salt. In this case, the proportion of the inorganic lithium salt in the total of both is 70% by weight or more and 99% by weight or less. It is desirable. Examples of the fluorine-containing organic lithium salt include LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropane. It is preferably any of disulfonylimide. The combined use of both has the effect of suppressing deterioration due to high temperature storage.

When the non-aqueous solvent contains 55% by volume or more of γ-butyrolactone, the lithium salt is preferably LiBF ₄ or LiBF ₄ in combination with another. In this case, LiBF ₄ preferably accounts for 40 mol% or more of the lithium salt. Particularly preferably, the proportion of LiBF _{4 in} the lithium salt is 40 mol% or more and 95 mol% or less, and the rest is LiP.
The combination is selected from the group consisting of F ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ and LiN (C ₂ F ₅ SO ₂ ) ₂ .

  The concentration of these electrolytes in the non-aqueous electrolyte solution is not particularly limited in order to exhibit the effects of the present invention, but is usually 0.5 mol / liter or more, preferably 0.6 mol / liter or more, more Preferably it is 0.7 mol / liter or more. The upper limit is usually 3 mol / liter or less, preferably 2 mol / liter or less, more preferably 1.8 mol / liter or less, and still more preferably 1.5 mol / liter or less. If the concentration is too low, the electric conductivity of the electrolyte solution may be insufficient. On the other hand, if the concentration is too high, the electric conductivity may decrease due to an increase in viscosity, and the battery performance may decrease. .

(Non-aqueous solvent)
The non-aqueous solvent can also be appropriately selected from conventionally known solvents for non-aqueous electrolyte solutions. Examples thereof include cyclic carbonates having no unsaturated bond, chain carbonates, cyclic ethers, chain ethers, cyclic carboxylic acid esters, chain carboxylic acid esters, and phosphorus-containing organic solvents.

  Examples of the cyclic carbonates having no carbon-carbon unsaturated bond include alkylene carbonates having an alkylene group having 2 to 4 carbon atoms such as ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate, From the viewpoint of improving battery characteristics, propylene carbonate is preferable, and ethylene carbonate is particularly preferable.

  As the chain carbonates, dialkyl carbonates are preferable, and the number of carbon atoms of the alkyl group constituting each is preferably 1 to 5, particularly preferably 1 to 4. Specifically, for example, symmetric chain alkyl carbonates such as dimethyl carbonate, diethyl carbonate, and di-n-propyl carbonate; asymmetric chain alkyls such as ethyl methyl carbonate, methyl-n-propyl carbonate, and ethyl-n-propyl carbonate Examples thereof include dialkyl carbonates such as carbonates. Among these, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are preferable from the viewpoint of improving battery characteristics (particularly, high load discharge characteristics).

Examples of cyclic ethers include tetrahydrofuran and 2-methyltetrahydrofuran.
Examples of chain ethers include dimethoxyethane and dimethoxymethane.
Examples of cyclic carboxylic acid esters include γ-butyrolactone and γ-valerolactone.

Examples of chain carboxylic acid esters include methyl acetate, methyl propionate, ethyl propionate, and methyl butyrate.
Examples of the phosphorus-containing organic solvent include trimethyl phosphate, triethyl phosphate, dimethyl ethyl phosphate, methyl diethyl phosphate, ethylene methyl phosphate, ethylene ethyl phosphate, and the like.

These may be used alone or in combination of two or more, but it is preferable to use in combination of two or more. For example, it is preferable to use a high dielectric constant solvent such as alkylene carbonates or cyclic carboxylic acid esters in combination with a low viscosity solvent such as dialkyl carbonates or chain carboxylic acid esters.
One preferred combination of non-aqueous solvents is a combination mainly composed of alkylene carbonates and dialkyl carbonates. Among them, the total of alkylene carbonates and dialkyl carbonates in the nonaqueous solvent is 70% by volume or more, preferably 80% by volume or more, more preferably 90% by volume or more, and the alkylene carbonates and dialkyl carbonates. The proportion of alkylene carbonate with respect to the total is 5% or more, preferably 10% or more, more preferably 15% or more, usually 50% or less, preferably 35% or less, more preferably 30% or less, still more preferably 25 % Or less. Use of a combination of these non-aqueous solvents is preferable because the balance between cycle characteristics and high-temperature storage characteristics (particularly, remaining capacity and high-load discharge capacity after high-temperature storage) of a battery produced using the non-aqueous solvent is improved.

  Specific examples of preferred combinations of alkylene carbonates and dialkyl carbonates include ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate, Examples include ethyl methyl carbonate, ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

A combination in which propylene carbonate is further added to a combination of these ethylene carbonate and dialkyl carbonates is also mentioned as a preferable combination.
In the case of containing propylene carbonate, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 40:60, particularly preferably 95: 5 to 50:50. Further, the proportion of propylene carbonate in the whole non-aqueous solvent is usually 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 20% by volume or less, preferably 8% by volume. The volume% or less, more preferably 5 volume% or less. It is preferable to contain propylene carbonate in this concentration range, since the low temperature characteristics are further excellent while maintaining the combination characteristics of ethylene carbonate and dialkyl carbonates.

  Among the combinations of ethylene carbonate and dialkyl carbonates, those containing asymmetric chain alkyl carbonates as dialkyl carbonates are more preferred, especially ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl. Methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, which contain ethylene carbonate, symmetric chain alkyl carbonates, and asymmetric chain alkyl carbonates, have a good balance between cycle characteristics and large current discharge characteristics. preferable. Among them, the asymmetric chain alkyl carbonate is preferably ethyl methyl carbonate, and the alkyl group of the alkyl carbonate preferably has 1 to 2 carbon atoms.

The proportion of dimethyl carbonate in the total non-aqueous solvent is usually 10% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, and further preferably 30% by volume or more. Usually, it is preferably contained in the range of 90% by volume or less, preferably 80% by volume or less, more preferably 75% by volume or less, and still more preferably 70% by volume or less, since the load characteristics of the battery are improved.
The proportion of ethyl methyl carbonate in the total non-aqueous solvent is usually 10% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, more preferably 30% by volume or more, and the upper limit is In general, when it is contained within the range of 90% by volume or less, preferably 80% by volume or less, more preferably 75% by volume or less, and further preferably 70% by volume or less, the balance between the cycle characteristics and storage characteristics of the battery is good. Therefore, it is preferable.
In addition, in the combination mainly composed of the alkylene carbonates and dialkyl carbonates, other solvents may be mixed, and in order to exhibit the effects of the present invention, there is no particular limitation, but load characteristics are emphasized. In some cases, it is preferable not to contain cyclic carboxylic acid esters.

Other examples of preferred non-aqueous solvents include one organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, γ-butyrolactone and γ-valerolactone, or two or more organic solvents selected from the group The mixed solvent becomes 60% by volume or more of the whole. The non-aqueous electrolyte using this mixed solvent is less likely to evaporate or leak when used at high temperatures. Among them, the total of ethylene carbonate and γ-butyrolactone in the nonaqueous solvent is preferably 80% by volume or more, more preferably 90% by volume or more, and the volume ratio of ethylene carbonate and γ-butyrolactone is 5: 95 to 45:55, or the total of ethylene carbonate and propylene carbonate in the nonaqueous solvent is preferably 80% by volume or more, more preferably 90% by volume or more, and the capacity of ethylene carbonate and propylene carbonate. When a material having a ratio of 30:70 to 60:40 is used, the balance between cycle characteristics and high-temperature storage characteristics is generally improved.
In this specification, the capacity of the non-aqueous solvent is a measured value at 25 ° C., but the measured value at the melting point is used for a solid at 25 ° C. such as ethylene carbonate.

(Fluorinated cyclic carbonate having 2 or more fluorine atoms)
The nonaqueous electrolytic solution according to the present invention contains the above-described electrolyte and a nonaqueous solvent, but contains a fluorinated cyclic carbonate having two or more fluorine atoms.
The number of fluorine atoms in the fluorinated cyclic carbonate having 2 or more fluorine atoms is not particularly limited, but in the case of fluorinated ethylene carbonate, the lower limit is usually 2 or more, and the upper limit is usually 4 or less, 3 or less is preferable.
In the case of fluorinated propylene carbonate, the lower limit is usually 2 or more, and the upper limit is usually 6 or less, preferably 5 or less. In particular, those in which two or more fluorine atoms are bonded to carbon forming the ring structure are preferable from the viewpoint of improving cycle characteristics and storage characteristics.

  Specific examples of the fluorinated cyclic carbonate having two or more fluorine atoms include cis-4,5-difluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolane-2. -One, fluorinated ethylene carbonate such as 4,4-difluoro-1,3-dioxolan-2-one, trifluoro-1,3-dioxolan-2-one, tetrafluoro-1,3-dioxolan-2-one 4,5-difluoro-4-methyl-1,3-dioxolan-2-one, 4,4-difluoro-5-methyl-1,3-dioxolan-2-one, 4,4,5-trifluoro Fluorinated propylene cars such as -5-methyl-1,3-dioxolan-2-one and 4,5-difluoro-4-trifluoromethyl-1,3-dioxolan-2-one Sulfonate, and the like. Among them, fluorinated ethylene carbonate having two or more fluorine atoms is preferable from the viewpoint of improving battery characteristics. Among them, cis-4,5-difluoro-1,3-dioxolan-2-one, trans-4,5-difluoro- 1,3-dioxolan-2-one and 4,4-difluoro-1,3-dioxolan-2-one are particularly preferred.

  The fluorinated cyclic carbonate having two or more fluorine atoms may be used alone or in combination of two or more. The ratio of the fluorinated cyclic carbonate compound having two or more fluorine atoms in the nonaqueous electrolytic solution is not particularly limited in order to exhibit the effect of the present invention, but is usually 0.001% by weight or more, preferably 0. 0.01% by weight or more, more preferably 0.1% by weight or more, particularly preferably 0.2% by weight or more, and most preferably 0.25% by weight. If the concentration is lower than this, the effects of the present invention may be difficult to express. Conversely, if the concentration is too high, the swelling of the battery may increase during high temperature storage, so the upper limit is usually 10% by weight or less, preferably 4% by weight or less, more preferably 2% by weight or less, and particularly preferably 1% by weight. % Or less, most preferably 0.5% by weight or less.

One of the present invention is a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution containing a cyclic carbonate having an unsaturated bond, and further containing two or more fluorine atoms. It contains the fluorinated cyclic carbonate which has.
Examples of cyclic carbonates having an unsaturated bond include vinylene carbonate compounds such as vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, 4,5-diethyl vinylene carbonate, and fluoro vinylene carbonate; Vinylethylene carbonate, 4-methyl-4-vinylethylene carbonate, 4-ethyl-4-vinylethylene carbonate, 4-n-propyl-4-vinylethylene carbonate, 5-methyl-4-vinylethylene carbonate, 4,4- Vinylethylene carbonate compounds such as divinylethylene carbonate and 4,5-divinylethylene carbonate; 4,4-dimethyl-5-methyleneethylene carbonate, 4,4-diethyl-5- Such as methylene ethylene carbonate compounds such as Chi Ren ethylene carbonate.
Among these, vinylene carbonate, vinyl ethylene carbonate, 4-methyl-4-vinyl ethylene carbonate or 4,5-divinyl ethylene carbonate is preferable from the viewpoint of improving cycle characteristics, and vinylene carbonate or vinyl ethylene carbonate is more preferable. These may be used alone or in combination of two or more.

When using 2 or more types together, it is preferable to use together vinylene carbonate and vinyl ethylene carbonate.
The ratio of the cyclic carbonate having an unsaturated bond in the non-aqueous electrolyte solution is not particularly limited in order to express the effect of the present invention, but is usually 0.001% by weight or more, preferably 0.1% by weight or more. Particularly preferred is 0.3% by weight or more, and most preferred is 0.5% by weight or more. If the content of the cyclic carbonate having an unsaturated bond in the molecule is too small, the effect of improving the cycle characteristics of the battery may not be sufficiently exhibited. However, if the content of the cyclic carbonate having an unsaturated bond is too large, the amount of gas generated during high-temperature storage tends to increase or the discharge characteristics at low temperatures tend to decrease, so the upper limit is usually 8% by weight or less. , Preferably 4% by weight or less, particularly preferably 3% by weight or less.

The reason why the nonaqueous electrolytic solution according to the present invention improves the high-temperature storage characteristics and cycle characteristics is not clear, and the present invention is not limited to the following principle of operation, but is presumed as follows.
First, cyclic carbonates having an unsaturated bond such as vinylene carbonate are reduced during initial charging, and a stable film containing a polymer component is formed on the negative electrode surface, so that storage characteristics and cycle characteristics can be improved. . However, the cyclic carbonate having an unsaturated bond easily reacts with the positive electrode material in a charged state, and particularly under a high temperature atmosphere, the reaction with the positive electrode material proceeds, the deterioration of the positive electrode active material is promoted, and the battery characteristics are deteriorated. There was a problem that gas generation increased. In contrast, when a fluorinated cyclic carbonate compound having two or more fluorine atoms is contained, the fluorinated cyclic carbonate compound having two or more fluorine atoms and the cyclic carbonate having an unsaturated bond are reduced by the reduction reaction. In this case, a part of the reduction product of the fluorinated cyclic carbonate compound having two or more fluorine atoms moves to the surface of the positive electrode to form a film on the surface of the positive electrode. It seems that contact between the cyclic carbonate having the positive electrode and the positive electrode can be prevented, and side reactions between the cyclic carbonate having an unsaturated bond and the positive electrode material can be suppressed.

Furthermore, since the fluorinated cyclic carbonate compound having 2 or more fluorine atoms has higher reduction reactivity than the fluorinated cyclic carbonate compound having less than 2 fluorine atoms, the film forming ability and the cathode protecting ability in the negative electrode are high. The side reaction occurring inside the battery can be suppressed.
Moreover, when it does not contain cyclic carbonates having an unsaturated bond, a film mainly composed of a reduced decomposition product of a fluorinated cyclic carbonate compound having two or more fluorine atoms is formed on the negative electrode surface. A composite film of a cyclic carbonate having an unsaturated bond and a fluorinated cyclic carbonate compound having two or more fluorine atoms contains a large amount of polymer components, is more stable, and is a secondary coating between the negative electrode material and other electrolyte components. It seems that the reaction can be suppressed.

Thus, the interaction between the cyclic carbonate having an unsaturated bond and the fluorinated cyclic carbonate compound having two or more fluorine atoms can improve the high-temperature storage characteristics and the cycle characteristics.
One aspect of the present invention is a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent that dissolves the electrolyte. The non-aqueous electrolyte solution contains an aromatic compound having a total carbon number of 7 to 18, and more than 2 It contains the fluorinated cyclic carbonate which has the following fluorine atom.
The carbon number of the aromatic compound having a total carbon number of 7 or more and 18 or less is usually 7 or more, preferably 8 or more, more preferably 10 or more as a lower limit, and usually 18 or less as an upper limit.
When this lower limit is exceeded, the overcharge prevention characteristics are good. Moreover, when it falls below this upper limit, the solubility in the electrolytic solution is good.

  Examples of the aromatic compound having a total carbon number of 7 to 18 include alkylbiphenyl such as biphenyl and 2-methylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclopentylbenzene, cyclohexylbenzene, t-butylbenzene, t- Aromatic compounds such as amylbenzene, diphenyl ether and dibenzofuran; Partially fluorinated products of the aromatic compounds such as 2-fluorobiphenyl, 3-fluorobiphenyl, 4-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene; 2 , 4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, fluorine-containing anisole compounds such as 3,5-difluoroanisole, and the like.

Of these, aromatic compounds such as biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran are preferable.
Two or more of these may be used in combination. When two or more types are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, terphenyl partially hydrogenated product, cyclohexylbenzene, t-butylbenzene The balance between overcharge prevention characteristics and high-temperature storage characteristics is obtained by using a combination selected from oxygen-free aromatic compounds such as t-amylbenzene and oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran. From the point of view, it is preferable.

The reason why the nonaqueous electrolytic solution according to the present invention is excellent in safety during overcharge and improves high-temperature storage characteristics and cycle characteristics is not clear, and the present invention is not limited to the following principle of operation. It is inferred as follows.
In general, aromatic compounds having a total carbon number of 7 or more and 18 or less have an effect of improving safety during overcharge, but these compounds are more easily reacted on the positive electrode and the negative electrode than the solvent components. Even when stored at high temperatures, it reacts at sites with high activity of the electrode, and when these compounds react, the internal resistance of the battery increases greatly, and gas generation can cause a significant decrease in discharge characteristics after storage at high temperatures. It was. By using an electrolytic solution containing a fluorinated cyclic carbonate having two or more fluorine atoms, a coating of the reduction reaction product derived from the fluorinated cyclic carbonate having two or more fluorine atoms is formed on the negative electrode surface from the initial charge. It is thought that it produces | generates efficiently and suppresses reaction with an aromatic compound with a total carbon number of 7-18, and a negative electrode. Furthermore, a part of the reduction product of the fluorinated cyclic carbonate compound having two or more fluorine atoms moves to the positive electrode surface to form a film on the positive electrode surface, and the aromatic compound having a total carbon number of 7 to 18 and It seems that contact with the positive electrode can be prevented, and side reactions between the aromatic compound having a total carbon number of 7 or more and 18 or less and the positive electrode material can be suppressed.

Thus, it is considered that by suppressing the side reaction between the aromatic compound having a total carbon number of 7 or more and 18 or less, and the negative electrode and the positive electrode, a significant decrease in discharge characteristics after high-temperature storage is suppressed.
The ratio of the aromatic compound having a total carbon number of 7 or more and 18 or less in the non-aqueous electrolyte solution is not particularly limited in order to exhibit the effect of the present invention, but is usually 0.001% by weight or more, preferably 0. 0.1% by weight or more, particularly preferably 0.3% by weight or more, most preferably 0.5% by weight or more, and the upper limit is usually 5% by weight or less, preferably 3% by weight or less, particularly preferably 2% by weight. It is as follows. If the concentration is lower than this lower limit, the effect of improving safety during overcharging may be difficult to express. Conversely, if the concentration is too high, battery characteristics such as high-temperature storage characteristics may deteriorate.

One aspect of the present invention is a nonaqueous electrolytic solution containing an electrolyte and a nonaqueous solvent for dissolving the electrolyte, wherein the nonaqueous solvent contains diethyl carbonate, and further contains a fluorinated cyclic carbonate having 2 or more fluorine atoms. It is characterized by that.
The ratio of diethyl carbonate in the total non-aqueous solvent is not particularly limited in order to exhibit the effects of the present invention, but is usually 10% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more. The upper limit is usually 90% by volume or less, preferably 80% by volume or less, more preferably 75% by volume or less, and still more preferably 70% by volume or less. Containing in this range is preferable because the swelling of the battery during high-temperature storage is suppressed.

The reason why the nonaqueous electrolytic solution according to the present invention improves the high-temperature storage characteristics and the cycle characteristics while suppressing the swelling of the battery during high-temperature storage is not clear, and the present invention is limited to the following principle of operation. However, it is guessed as follows.
Diethyl carbonate has a higher boiling point than dimethyl carbonate and ethyl methyl carbonate, and does not generate methane gas even when decomposed. Therefore, diethyl carbonate is a preferable solvent in terms of suppressing swelling of the battery during high temperature storage. However, diethyl carbonate has a tendency to react with lithium more easily than dimethyl carbonate or ethyl methyl carbonate. Particularly, in a battery in which lithium is likely to precipitate due to higher density, the battery characteristics are improved by reaction with precipitated lithium. It was the cause of the decline. By using an electrolytic solution containing a fluorinated cyclic carbonate having two or more fluorine atoms, a coating of the reduction reaction product derived from the fluorinated cyclic carbonate having two or more fluorine atoms is formed on the negative electrode surface from the initial charge. In addition to producing efficiently, some of the reduction products of these compounds move to the surface of the positive electrode to form a film on the surface of the positive electrode to suppress side reactions between other electrolyte components and the negative electrode and the positive electrode This is considered to be because the active material is uniformly used and the precipitation of lithium can be suppressed. Furthermore, even when lithium is deposited, it is considered that the fluorinated cyclic carbonate having two or more fluorine atoms forms a film on the lithium surface and suppresses the reaction with diethyl carbonate.

  One of the present invention is an electrolyte and a non-aqueous electrolyte solution containing a non-aqueous solvent for dissolving the electrolyte, wherein the non-aqueous electrolyte solution is a cyclic sulfonate compound, a disulfonate compound, a nitrile compound, and the following general formula (1 And at least one compound selected from the group consisting of compounds represented by formula (2), and further containing a fluorinated cyclic carbonate having two or more fluorine atoms.

(In General Formula (1), R ^{1 to} R ³ each independently represents an alkyl group having 1 to 12 carbon atoms which may be substituted with a fluorine atom, and n represents an integer of 0 to 6). .)
[Cyclic sulfonic acid ester compound]
The type of the cyclic sulfonate compound is not particularly limited as long as it is a compound having a sulfonate structure in a part of the cyclic structure. Specific examples of the cyclic sulfonate compound include 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, 1,4-butene sultone, 1-methyl-1,3-propane sultone, 3- Examples include methyl-1,3-propane sultone, 1-fluoro-1,3-propane sultone, and 3-fluoro-1,3-propane sultone.
Of these, 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, and 1,4-butene sultone are preferable from the viewpoint of improving storage characteristics. -More preferred is propene sultone.

[Disulfonic acid ester compound]
The type of the disulfonic acid ester compound is not particularly limited as long as it is a compound having two sulfonic acid ester structures in the molecule. Specific examples of the disulfonic acid ester compound include, for example,
Ethanediol dimethanesulfonate, ethanediol diethanesulfonate, ethanediol dipropanesulfonate, ethanediol dibutanesulfonate, ethanediol bis (trifluoromethanesulfonate), ethanediol bis (pentafluoroethanesulfonate), ethanediol bis (heptafluoropropane) Sulfonate), ethanediol bis (perfluorobutanesulfonate), ethanediol di (fluoromethanesulfonate), ethanediol bis (difluoromethanesulfonate), ethanediol di (2-fluoroethanesulfonate), ethanediol bis (1,1- Difluoroethanesulfonate), ethanediol bis (1,2-difluoroethanesulfonate), ethanediol bis (2,2 Difluoroethanesulfonate), ethanediol bis (1,1,2-trifluoroethanesulfonate), ethanediol bis (1,2,2-trifluoroethanesulfonate), ethanediol bis (2,2,2-trifluoroethanesulfonate) ), Ethanediol bis (1,1,2,2-tetrafluoroethanesulfonate), ethanediol bis (1,2,2,2-tetrafluoroethanesulfonate), etc .;
1,2-propanediol dimethanesulfonate, 1,2-propanediol diethanesulfonate, 1,2-propanediol dipropanesulfonate, 1,2-propanediol dibutanesulfonate, 1,2-propanediol bis (trifluoromethane) Sulfonate), 1,2-propanediol bis (pentafluoroethane sulfonate), 1,2-propanediol bis (heptafluoropropane sulfonate), 1,2-propanediol bis (perfluorobutane sulfonate), 1,2-propane Diol di (fluoromethanesulfonate), 1,2-propanediol bis (difluoromethanesulfonate), 1,2-propanediol di (2-fluoroethanesulfonate), 1,2-propanediol bis (1,1 Difluoroethane sulfonate), 1,2-propanediol bis (1,2-difluoroethane sulfonate), 1,2-propanediol bis (2,2-difluoroethane sulfonate), 1,2-propanediol bis (1,1,2- Trifluoroethanesulfonate), 1,2-propanediol bis (1,2,2-trifluoroethanesulfonate), 1,2-propanediol bis (2,2,2-trifluoroethanesulfonate), 1,2- 1,2-propanediol disulfonate such as propanediol bis (1,1,2,2-tetrafluoroethanesulfonate), 1,2-propanediol bis (1,2,2,2-tetrafluoroethanesulfonate), etc. Kind;

  1,3-propanediol dimethanesulfonate, 1,3-propanediol diethanesulfonate, 1,3-propanediol dipropanesulfonate, 1,3-propanediol dibutanesulfonate, 1,3-propanediol bis (trifluoromethane) Sulfonate), 1,3-propanediol bis (pentafluoroethane sulfonate), 1,3-propanediol bis (heptafluoropropane sulfonate), 1,3-propanediol bis (perfluorobutane sulfonate), 1,3-propane Diol di (fluoromethanesulfonate), 1,3-propanediol bis (difluoromethanesulfonate), 1,3-propanediol di (2-fluoroethanesulfonate), 1,3-propanediol bis (1,1 Difluoroethanesulfonate), 1,3-propanediol bis (1,2-difluoroethanesulfonate), 1,3-propanediol bis (2,2-difluoroethanesulfonate), 1,3-propanediol bis (1,1,2- Trifluoroethanesulfonate), 1,3-propanediol bis (1,2,2-trifluoroethanesulfonate), 1,3-propanediol bis (2,2,2-trifluoroethanesulfonate), 1,3- 1,3-propanediol disulfonate such as propanediol bis (1,1,2,2-tetrafluoroethanesulfonate), 1,3-propanediol bis (1,2,2,2-tetrafluoroethanesulfonate), etc. 1,2-butanediol dimethanesulfonate, 1,2-but Diol diethanesulfonate, 1,2-butanediol bis (trifluoromethanesulfonate), 1,2-butanediol bis (pentafluoroethanesulfonate), 1,2-butanediol bis (heptafluoropropane sulfonate), 1,2 -Butanediol bis (perfluorobutane sulfonate), 1,2-butanediol di (fluoromethane sulfonate), 1,2-butanediol bis (difluoromethane sulfonate), 1,2-butanediol di (2-fluoroethane sulfonate) 1,2-butanediol bis (2,2-difluoroethanesulfonate), 1,2-butanediol bis (2,2,2-trifluoroethanesulfonate), and the like;

1,3-butanediol dimethanesulfonate, 1,3-butanediol diethanesulfonate, 1,3-butanediol bis (trifluoromethanesulfonate), 1,3-butanediol bis (pentafluoroethanesulfonate), 1,3 -Butanediol bis (heptafluoropropane sulfonate), 1,3-butanediol bis (perfluorobutane sulfonate), 1,3-butanediol di (fluoromethane sulfonate), 1,3-butanediol bis (difluoromethane sulfonate) 1,3-butanediol di (2-fluoroethanesulfonate), 1,3-butanediol bis (2,2-difluoroethanesulfonate), 1,3-butanediol bis (2,2,2-trifluoroethanesulfonate) 1) 3-butanediol di sulfonates;
1,4-butanediol dimethanesulfonate, 1,4-butanediol diethanesulfonate, 1,4-butanediol dipropanesulfonate, 1,4-butanediol dibutanesulfonate, 1,4-butanediol bis (trifluoromethane Sulfonate), 1,4-butanediol bis (pentafluoroethane sulfonate), 1,4-butanediol bis (heptafluoropropane sulfonate), 1,4-butanediol bis (perfluorobutane sulfonate), 1,4-butane Diol di (fluoromethanesulfonate), 1,4-butanediol bis (difluoromethanesulfonate), 1,4-butanediol di (2-fluoroethanesulfonate), 1,4-butanediol bis (1,1-difluoroethanesulfone) 1,4-butanediol bis (1,2-difluoroethanesulfonate), 1,4-butanediol bis (2,2-difluoroethanesulfonate), 1,4-butanediol bis (1,1,2- Trifluoroethanesulfonate), 1,4-butanediol bis (1,2,2-trifluoroethanesulfonate), 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate), 1,4- 1,4-butanediol disulfonate such as butanediol bis (1,1,2,2-tetrafluoroethanesulfonate), 1,4-butanediol bis (1,2,2,2-tetrafluoroethanesulfonate), etc. Kind;
Etc.

Of these,
Ethanediol dimethanesulfonate, ethanediol diethanesulfonate, ethanediol bis (trifluoromethanesulfonate), ethanediol bis (pentafluoroethanesulfonate), ethanediol di (fluoromethanesulfonate), ethanediol bis (difluoromethanesulfonate), ethane Ethanediol disulfonates such as diol di (2-fluoroethanesulfonate), ethanediol bis (2,2-difluoroethanesulfonate), ethanediol bis (2,2,2-trifluoroethanesulfonate);
1,2-propanediol dimethanesulfonate, 1,2-propanediol diethanesulfonate, 1,2-propanediol bis (trifluoromethanesulfonate), 1,2-propanediol bis (pentafluoroethanesulfonate), 1,2 -Propanediol di (fluoromethanesulfonate), 1,2-propanediol bis (difluoromethanesulfonate), 1,2-propanediol di (2-fluoroethanesulfonate), 1,2-propanediol bis (2,2- 1,2-propanediol disulfonates such as difluoroethanesulfonate) and 1,2-propanediol bis (2,2,2-trifluoroethanesulfonate);
1,3-propanediol dimethanesulfonate, 1,3-propanediol diethanesulfonate, 1,3-propanediol bis (trifluoromethanesulfonate), 1,3-propanediol bis (pentafluoroethanesulfonate), 1,3 -Propanediol di (fluoromethanesulfonate), 1,3-propanediol bis (difluoromethanesulfonate), 1,3-propanediol di (2-fluoroethanesulfonate), 1,3-propanediol bis (2,2- 1,3-propanediol disulfonates such as difluoroethanesulfonate) and 1,3-propanediol bis (2,2,2-trifluoroethanesulfonate);
1,2-butanediol dimethanesulfonate, 1,2-butanediol diethanesulfonate, 1,2-butanediol bis (trifluoromethanesulfonate), 1,2-butanediol bis (pentafluoroethanesulfonate), 1,2 -Butanediol di (fluoromethanesulfonate), 1,2-butanediol bis (difluoromethanesulfonate), 1,2-butanediol di (2-fluoroethanesulfonate), 1,2-butanediol bis (2,2- 1,2-butanediol disulfonates such as difluoroethanesulfonate) and 1,2-butanediol bis (2,2,2-trifluoroethanesulfonate);

1,3-butanediol dimethanesulfonate, 1,3-butanediol diethanesulfonate, 1,3-butanediol bis (trifluoromethanesulfonate), 1,3-butanediol bis (pentafluoroethanesulfonate), 1,3 -Butanediol di (fluoromethanesulfonate), 1,3-butanediol bis (difluoromethanesulfonate), 1,3-butanediol di (2-fluoroethanesulfonate), 1,3-butanediol bis (2,2- 1,3-butanediol disulfonates such as difluoroethanesulfonate) and 1,3-butanediol bis (2,2,2-trifluoroethanesulfonate);
1,4-butanediol dimethanesulfonate, 1,4-butanediol diethanesulfonate, 1,4-butanediol bis (trifluoromethanesulfonate), 1,4-butanediol bis (pentafluoroethanesulfonate), 1,4 -Butanediol di (fluoromethanesulfonate), 1,4-butanediol bis (difluoromethanesulfonate), 1,4-butanediol di (2-fluoroethanesulfonate), 1,4-butanediol bis (2,2- 1,4-butanediol disulfonates such as difluoroethanesulfonate) and 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate);
Etc. are preferable from the viewpoint of improving storage characteristics.

Above all,
Ethanediol bis (trifluoromethanesulfonate), ethanediol bis (pentafluoroethanesulfonate), ethanediol di (fluoromethanesulfonate), ethanediol di (2-fluoroethanesulfonate), ethanediol bis (2,2,2-trimethyl) Ethanediol disulfonates such as fluoroethanesulfonate);
1,2-propanediol bis (trifluoromethanesulfonate), 1,2-propanediol bis (pentafluoroethanesulfonate), 1,2-propanediol di (fluoromethanesulfonate), 1,2-propanediol di (2- 1,2-propanediol disulfonates such as (fluoroethanesulfonate), 1,2-propanediol bis (2,2,2-trifluoroethanesulfonate);
1,3-propanediol bis (trifluoromethanesulfonate), 1,3-propanediol bis (pentafluoroethanesulfonate), 1,3-propanediol di (fluoromethanesulfonate), 1,3-propanediol di (2- 1,3-propanediol disulfonates such as fluoroethanesulfonate) and 1,3-propanediol bis (2,2,2-trifluoroethanesulfonate);
1,2-butanediol bis (trifluoromethanesulfonate), 1,2-butanediol bis (pentafluoroethanesulfonate), 1,2-butanediol di (fluoromethanesulfonate), 1,2-butanediol di (2- 1,2-butanediol disulfonates such as fluoroethanesulfonate), 1,2-butanediol bis (2,2,2-trifluoroethanesulfonate);
1,3-butanediol bis (trifluoromethanesulfonate), 1,3-butanediol bis (pentafluoroethanesulfonate), 1,3-butanediol di (fluoromethanesulfonate), 1,3-butanediol di (2- 1,3-butanediol disulfonates such as fluoroethanesulfonate) and 1,3-butanediol bis (2,2,2-trifluoroethanesulfonate);
1,4-butanediol bis (trifluoromethanesulfonate), 1,4-butanediol bis (pentafluoroethanesulfonate), 1,4-butanediol di (fluoromethanesulfonate), 1,4-butanediol di (2- 1,4-butanediol disulfonates such as fluoroethanesulfonate) and 1,4-butanediol bis (2,2,2-trifluoroethanesulfonate);
Etc. are particularly preferred.

[Nitrile compound]
The type of nitrile compound is not particularly limited as long as it is a compound having a nitrile group in the molecule. Moreover, the compound which has two or more nitrile groups in 1 molecule may be sufficient.
Specific examples of nitrile compounds include
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotono Nitrile, 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, 2,2-difluoropropionitrile, 2,3-difluoropropionitrile, , 3-difluoro propionitrile, 2,2,3-trifluoropropyne propionitrile, 3,3,3 trifluoropropyne propionitrile, mononitrile compounds such as pentafluoro propionitrile;
Dinitrile compounds such as malononitrile, succinonitrile, 2-methylsuccinonitrile, tetramethylsuccinonitrile, glutaronitrile, 2-methylglutaronitrile, adiponitrile, fumaronitrile, 2-methyleneglutaronitrile;
Examples thereof include tetranitrile compounds such as tetracyanoethylene.
Among these,
Acetonitrile, propionitrile, butyronitrile, valeronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, fumaronitrile are preferable from the viewpoint of improving storage characteristics,
More preferred are dinitrile compounds such as malononitrile, succinonitrile, glutaronitrile, adiponitrile, fumaronitrile.

[Compound represented by general formula (1)]
In the general formula (1), examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl. And linear, branched or cyclic alkyl groups such as a group, tert-butyl group, pentyl group, cyclopentyl group and cyclohexyl group. The carbon number of R ^{1 to} R ³ is usually 1 or more as a lower limit, preferably 2 or more, and usually 12 or less as an upper limit, from the viewpoint of suppressing gas generation. Therefore, it is preferably 8 or less, more preferably 4 or less.
Furthermore, the alkyl group may be substituted with a fluorine atom, and examples of the group substituted with a fluorine atom include partial alkyl groups such as trifluoromethyl group, trifluoroethyl group, and pentafluoroethyl group. Alkyl group and perfluoroalkyl group.
Moreover, in said general formula, n shows the integer of 0-6.
Specific examples of the compound represented by the general formula (1) include
Trimethylphosphonoformate, methyldiethylphosphonoformate, methyldipropylphosphonoformate, methyldipeptylphosphonoformate, triethylphosphonoformate, ethyldimethylphosphonoformate, ethyldipropylphosphonoformate, Ethyl diptylphosphonoformate, tripropylphosphonoformate, propyldimethylphosphonoformate, propyldiethylphosphonoformate, propyldipeptylphosphonoformate, tributylphosphonoformate, butyldimethylphosphonoformate, Butyldiethylphosphonoformate, Butyldipropylphosphonoformate, Methylbis (2,2,2-trifluoroethyl) phosphonoformate, Ethylbis (2,2,2-to Trifluoroethyl) phosphonoacetate formate, propyl bis (2,2,2-trifluoroethyl) phosphonoacetate formate, butyl bis (2,2,2-trifluoroethyl) compound of n = 0, such as phosphono formate;
Trimethylphosphonoacetate, methyldiethylphosphonoacetate, methyldipropylphosphonoacetate, methyldipeptylphosphonoacetate, triethylphosphonoacetate, ethyldimethylphosphonoacetate, ethyldipropylphosphonoacetate, ethyldipeptylphosphonoacetate, Tripropylphosphonoacetate, propyldimethylphosphonoacetate, propyldiethylphosphonoacetate, propyldibutylphosphonoacetate, tributylphosphonoacetate, butyldimethylphosphonoacetate, butyldiethylphosphonoacetate, butyldipropylphosphonoacetate, methylbis (2,2,2-trifluoroethyl) phosphonoacetate, ethylbis (2,2,2-trifluoroethyl) phosphonoacetate , Propyl bis (2,2,2-trifluoroethyl) phosphonoacetate, butyl bis (2,2,2-trifluoroethyl) compound of n = 1, such as phosphonoacetate;

Trimethyl-3-phosphonopropionate, methyldiethyl-3-phosphonopropionate, methyldipropyl-3-phosphonopropionate, methyldipyl-3-phosphonopropionate, triethyl-3-phosphonopro Pionate, ethyldimethyl-3-phosphonopropionate, ethyldipropyl-3-phosphonopropionate, ethyldipeptyl-3-phosphonopropionate, tripropyl-3-phosphonopropionate, propyldimethyl- 3-phosphonopropionate, propyldiethyl-3-phosphonopropionate, propyldiptyl-3-phosphonopropionate, tributyl-3-phosphonopropionate, butyldimethyl-3-phosphonopropionate Butyl diethyl-3-phosphonopropionate, butyl dip Pyr-3-phosphonopropionate, methylbis (2,2,2-trifluoroethyl) -3-phosphonopropionate, ethylbis (2,2,2-trifluoroethyl) -3-phosphonopropio N = 2 such as nate, propylbis (2,2,2-trifluoroethyl) -3-phosphonopropionate, butylbis (2,2,2-trifluoroethyl) -3-phosphonopropionate Compound;
Trimethyl-4-phosphonobutyrate, methyldiethyl-4-phosphonobutyrate, methyldipropyl-4-phosphonobutyrate, methyldipyl-4-phosphonobutyrate, triethyl-4-phosphonobutyrate, ethyldimethyl -4-phosphonobutyrate, ethyldipropyl-4-phosphonobutyrate, ethyldiptyl-4-phosphonobutyrate, tripropyl-4-phosphonobutyrate, propyldimethyl-4-phosphonobutyrate, propyldiethyl -4-phosphonobutyrate, propyldipeptyl-4-phosphonobutyrate, tributyl-4-phosphonobutyrate, butyldimethyl-4-phosphonobutyrate, butyldiethyl-4-phosphonobutyrate, butyldi And n = 3 compounds such as propyl-4-phosphonobutyrate .

Among these, compounds with n = 0, 1, 2 are preferable from the viewpoint of improving battery characteristics after high-temperature storage, and compounds with n = 1, 2 are particularly preferable from the viewpoint of improving storage characteristics.
At least one compound selected from the group consisting of these cyclic sulfonic acid ester compounds, disulfonic acid ester compounds, nitrile compounds and compounds represented by the general formula (1) may be used alone. Two or more compounds may be used in any combination and ratio.
The content ratio of these compounds in the non-aqueous electrolyte solution is not particularly limited in order to exhibit the effects of the present invention, but is generally 0.001% by weight or more in total with respect to the entire non-aqueous electrolyte solution. , Preferably 0.01% by weight or more, more preferably 0.1% by weight or more. Further, the upper limit is generally 5% by weight or less, preferably 4% by weight or less, and more preferably 3% by weight or less. If the concentration of these compounds is too low, it may be difficult to obtain an improvement effect, while if the concentration is too high, the charge / discharge efficiency may be reduced.

The reason why the nonaqueous electrolytic solution according to the present invention improves the high-temperature storage characteristics is not clear, and the present invention is not limited to the following operation principle, but is presumed as follows.
The cyclic sulfonic acid ester compound, the disulfonic acid ester compound, the nitrile compound and the compound represented by the general formula (1) can suppress deterioration on the positive electrode side during high-temperature storage by adsorption onto the positive electrode surface or formation of a protective film. However, there is a tendency that reductive decomposition tends to occur on the negative electrode side, and side reactions on the negative electrode side increase, or resistance on the negative electrode side increases, and battery characteristics tend to deteriorate. When a fluorinated cyclic carbonate compound having two or more fluorine atoms is contained, the fluorinated cyclic carbonate compound having two or more fluorine atoms forms a film on the negative electrode surface at an earlier stage than these compounds react, It is thought that excessive reaction of these compounds can be suppressed.
One aspect of the present invention is an electrolyte used for a high-voltage battery having an end-of-charge voltage of 4.3 V or more in a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte. And a fluorinated cyclic carbonate having two or more fluorine atoms.

(High-voltage battery with end-of-charge voltage of 4.3V or higher)
The non-aqueous electrolyte solution according to the present invention is used for a high-voltage battery having a charge end voltage of 4.3 V or more.
The lower limit of the voltage of a high voltage battery having a charge end voltage of 4.3 V or higher is usually 4.3 V or higher, preferably 4.35 V or higher. The upper limit is not particularly limited, but is 6 V or less, preferably 5 V or less, particularly preferably 4.8 V or less. When this lower limit is exceeded, the energy density improvement effect and cycle characteristics are good, which is preferable.
In order to set the battery at a high voltage, it can be achieved by configuring the battery by appropriately selecting the type of active material and the balance between the positive and negative electrodes.
Details of the configuration will be described later.
Since the battery of the present invention has the end-of-charge voltage of 4.3 V or higher, the battery has experienced a voltage of 4.3 V or higher at least once. In general, a battery that has experienced a voltage of 4.3 V or more at least once has a problem that the deterioration of battery characteristics, which may be caused by a side reaction between the positive electrode and the electrolyte, becomes remarkable.

On the other hand, since the battery of the present invention hardly decomposes the positive electrode, the negative electrode and the electrolyte under high voltage, the battery can be repeatedly charged and discharged while maintaining high battery characteristics.
The nonaqueous electrolytic solutions according to the present invention may be used in combination.
For example, in a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent that dissolves the electrolyte, the non-aqueous electrolyte solution includes a cyclic carbonate having an unsaturated bond and / or an aromatic compound having a total carbon number of 7 to 18 and And / or the non-aqueous solvent contains diethyl carbonate, and / or at least one selected from the group consisting of cyclic sulfonic acid ester compounds, disulfonic acid ester compounds, nitrile compounds, and compounds represented by the general formula (1) And a non-aqueous electrolyte containing a fluorinated cyclic carbonate having two or more fluorine atoms, or the non-aqueous electrolyte is used for a high voltage battery having a charge end voltage of 4.3 V or more. It may be a non-aqueous electrolyte solution.

(Other compounds)
The non-aqueous electrolyte solution according to the present invention may contain various other compounds as auxiliary agents within a range not impairing the effects of the present invention.
As other auxiliaries,
Carbonate compounds such as fluoroethylene carbonate, erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate;
Succinic anhydride, glutaric anhydride, maleic anhydride, itaconic anhydride, citraconic anhydride, glutaconic anhydride, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, phenyl succinic anhydride, etc. Carboxylic acid anhydrides of
Spiro compounds such as 2,4,8,10-tetraoxaspiro [5.5] undecane, 1,9-divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane;
Ethylene sulfite, propylene sulfite, methyl methanesulfonate, ethylmethanesulfonate, methyl-methoxymethanesulfonate, methyl-2-methoxyethanesulfonate, sulfolane, sulfolene, dimethylsulfone, diphenylsulfone, N, N-dimethylmethanesulfonamide, N Sulfur-containing compounds such as N-diethylmethanesulfonamide;

Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 3-dimethyl-2-imidazolidinone, N-methylsuccinimide;
Hydrocarbon compounds such as heptane, octane, nonane, decane, cycloheptane, methylcyclohexane, ethylcyclohexane, propylcyclohexane, n-butylcyclohexane, t-butylcyclohexane, dicyclohexyl,
Fluorobenzene, difluorobenzene, hexafluorobenzene fluorinated benzene, and the like.
Two or more of these may be used in combination.

  The ratio of these auxiliaries in the non-aqueous electrolyte solution is not particularly limited in order to exhibit the effects of the present invention, but is usually 0.01% by weight or more, preferably 0.1% by weight or more, particularly preferably. Is 0.2% by weight or more, and the upper limit is usually 5% by weight or less, preferably 3% by weight or less, and particularly preferably 1% by weight or less. By adding these auxiliaries, capacity maintenance characteristics and cycle characteristics after high temperature storage can be improved. If the concentration is lower than this lower limit, the effect of the auxiliary agent may be hardly exhibited. On the other hand, if the concentration is too high, battery characteristics such as high load discharge characteristics may deteriorate.

(Preparation of electrolyte)
The nonaqueous electrolytic solution according to the present invention dissolves an electrolyte, at least one compound selected from the group consisting of a fluorinated cyclic carbonate compound having two or more fluorine atoms, and, if necessary, other compounds in a nonaqueous solvent. Can be prepared. In preparing the non-aqueous electrolyte solution, each raw material is preferably dehydrated in advance in order to reduce the water content when the electrolyte solution is used. Usually, it is good to dehydrate to 50 ppm or less, preferably 30 ppm or less, particularly preferably 10 ppm or less. Moreover, you may implement dehydration, a deoxidation process, etc. after electrolyte solution preparation.
The non-aqueous electrolyte of the present invention is suitable for use as a secondary battery among non-aqueous electrolyte batteries, that is, as an electrolyte for a non-aqueous electrolyte secondary battery, for example, a lithium secondary battery. Hereinafter, a non-aqueous electrolyte secondary battery using the electrolyte of the present invention will be described.

<Non-aqueous electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present invention is a non-aqueous electrolyte battery including a negative electrode and a positive electrode capable of inserting and extracting lithium ions, and a non-aqueous electrolyte, and the non-aqueous electrolyte is the above-described electrolyte. It is characterized by being.
(Battery configuration)
A non-aqueous electrolyte secondary battery according to the present invention is similar to a conventionally known non-aqueous electrolyte secondary battery except that it is prepared using the above-described electrolyte of the present invention. A non-aqueous electrolyte battery including a positive electrode and a non-aqueous electrolyte, usually obtained by housing the positive electrode and the negative electrode in a case through a porous membrane impregnated with the non-aqueous electrolyte according to the present invention. . Therefore, the shape of the secondary battery according to the present invention is not particularly limited, and may be any of a cylindrical shape, a square shape, a laminate shape, a coin shape, a large size, and the like.

(Negative electrode)
As the negative electrode active material, a carbonaceous material or metal compound capable of inserting and extracting lithium, a lithium metal, a lithium alloy, or the like can be used. These negative electrode active materials may be used alone or in combination of two or more. Among these, preferred are carbonaceous materials and metal compounds capable of occluding and releasing lithium.

Among the carbonaceous materials, graphite and graphite whose surface is coated with amorphous carbon as compared with graphite are particularly preferable.
The graphite preferably has a lattice plane (002 plane) d value (interlayer distance) of 0.335 to 0.338 nm, particularly 0.335 to 0.337 nm, as determined by X-ray diffraction using the Gakushin method. The crystallite size (Lc) determined by X-ray diffraction by the Gakushin method is usually 30 nm or more, preferably 50 nm or more, and particularly preferably 100 nm or more. The ash content is usually 1% by weight or less, preferably 0.5% by weight or less, particularly preferably 0.1% by weight or less.

  The graphite surface coated with amorphous carbon is preferably graphite having a d-value of 0.335 to 0.338 nm on the lattice plane (002 plane) in X-ray diffraction as a core material. A carbonaceous material having a larger d-value on the lattice plane (002 plane) in X-ray diffraction than the core material is attached, and the d-value on the lattice plane (002 plane) in X-ray diffraction is greater than that of the core material and the core material. The ratio with respect to the carbonaceous material having a large is 99/1 to 80/20 by weight. When this is used, a negative electrode having a high capacity and hardly reacting with the electrolytic solution can be produced.

The particle size of the carbonaceous material is a median diameter by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, most preferably 7 μm or more, and usually 100 μm or less, preferably 50 μm or less, More preferably, it is 40 micrometers or less, Most preferably, it is 30 micrometers or less.
The specific surface area of the carbonaceous material by the BET method is usually 0.3 m ² / g or more, preferably 0.5
m ² / g or more, more preferably 0.7 m ² / g or more, and most preferably 0.8 m ² / g or more and usually 25.0 m ² / g or less, preferably 20.0 m ² / g, more Preferably it is 15.0 m < ² > / g or less, Most preferably, it is 10.0 m < ² > / g or less.

Further, the carbonaceous material is analyzed by Raman spectrum using argon ion laser light, the peak is the peak intensity of the peak P _A in the range of 1570~1620cm ^-1 I _A, in the range of 1300~1400cm ^-1 P If the peak intensity of the _B was I _B, R value represented by the ratio of I _B and _{I a (= I B / I} a) is what is preferably in the range of 0.01 to 0.7. Further, the half width of the peak in the range of 1570～1620Cm ^-1 is typically 26cm ^-1 or less, are preferred in particular 25 cm ^-1 or less.

  Examples of metal compounds capable of inserting and extracting lithium include compounds containing metals such as Ag, Zn, Al, Ga, In, Si, Ge, Sn, Pb, P, Sb, Bi, Cu, Ni, Sr, and Ba. These metals are used as simple substances, oxides, alloys with lithium, and the like. In the present invention, those containing an element selected from Si, Sn, Ge and Al are preferred, and oxides or lithium alloys of metals selected from Si, Sn and Al are more preferred. These may be in the form of powder or thin film, and may be crystalline or amorphous.

Lithium is a metal compound that can occlude and release lithium, or its oxides and alloys with lithium generally have higher capacity per unit weight than carbonaceous materials typified by graphite. It is suitable for a secondary battery.
The average particle system of the metal compound capable of occluding and releasing lithium or the oxide or an alloy thereof with lithium is not particularly limited in order to exhibit the effect of the present invention, but is usually 50 μm or less, preferably 20 μm or less, Particularly preferably, it is 10 μm or less, usually 0.1 μm or more, preferably 1 μm or more, particularly preferably 2 μm or more. When this upper limit is exceeded, the expansion of the electrode increases, and the cycle characteristics may deteriorate. Moreover, when less than this minimum, it becomes difficult to collect current and there is a possibility that the capacity is not sufficiently developed.

(Positive electrode)
Examples of the positive electrode active material include materials capable of inserting and extracting lithium, such as lithium transition metal composite oxide materials such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide. These compounds are Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _{1 -y My} O ₂ , Li _x Ni _{1 -y My} O ₂ , Li _x Mn _{1 -y My} O ₂ etc., where M is usually at least one selected from Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, V, Sr, Ti, 0.4 and what is ≦ x ≦ 1.2,0 ≦ y ≦ 0.6 , Li X Mn a Ni b Co c O 2 ( where, 0.4 ≦ x ≦ 1.2, a + b + c = 1) is Can be mentioned.

Especially represented by _{Li X Co 1-y M y} O 2, Li X Ni 1-y M y O 2, Li X Mn 1-y M y O 2 , etc., cobalt, nickel, and other part of manganese Replaced with metal or Li _X Mn _a Ni _b C
Those represented by o _c O ₂ (0.4 ≦ x ≦ 1.2, a + b + c = 1, | ab | <0.1) are preferable because the structure can be stabilized.
The positive electrode active materials may be used alone or in combination.

  In addition, a material in which a substance having a composition different from that of the substance constituting the main cathode active material is attached to the surface of the cathode active material can be used. 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.

  The amount of the surface adhering substance is not particularly limited in order to exhibit the effects of the present invention, but is preferably 0.1 ppm or more, more preferably 1 ppm or more as a lower limit in terms of mass with respect to the positive electrode active material. The upper limit is preferably 10 ppm or more, preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less. The surface adhering substance can suppress the oxidation reaction of the non-aqueous 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 exhibited. If the amount is too large, the resistance may increase in order to inhibit the entry and exit of lithium ions.

(electrode)
As the binder for binding the active material, any material can be used as long as it is a material that is stable with respect to the solvent and the electrolyte used in manufacturing the electrode. For example, fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, polyolefins such as polyethylene and polypropylene, polymers having unsaturated bonds such as styrene / butadiene rubber, isoprene rubber and butadiene rubber, and copolymers thereof, ethylene / acrylic Examples thereof include acrylic acid polymers such as acid copolymers and ethylene / methacrylic acid copolymers, and copolymers thereof.

The electrode may contain a thickener, a conductive material, a filler, etc. in order to increase mechanical strength and electrical conductivity.
Examples of the thickener include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein.

Examples of the conductive material include a metal material such as copper or nickel, and a carbon material such as graphite or carbon black.
The electrode may be manufactured by a conventional method. For example, it can be formed by adding a binder, a thickener, a conductive material, a solvent or the like to a negative electrode or a positive electrode active material to form a slurry, applying the slurry to a current collector, drying it, and then pressing it.

In addition, a material obtained by adding a binder or a conductive material to an active material is roll-formed as it is to form a sheet electrode, a pellet electrode is formed by compression molding, and an electrode is formed on the current collector by a technique such as vapor deposition, sputtering, or plating. A thin film of material can also be formed.
When graphite is used as the negative electrode active material, the density of the negative electrode active material layer after drying and pressing is usually 1.45 g / cm ³ or more, preferably 1.55 g / cm ³ or more, more preferably 1.60 g. / Cm ³ or more, particularly preferably 1.65 g / cm ³ or more.

The density of the positive electrode active material layer after drying and pressing is usually 2.0 g / cm ³ or more, preferably 2.5 g / cm ³ or more, more preferably 3.0 g / cm ³ or more.
Various types of current collectors can be used, but metals and alloys are usually used. Examples of the current collector for the negative electrode include copper, nickel, and stainless steel, with copper being preferred. Examples of the positive electrode current collector include metals such as aluminum, titanium, and tantalum, and alloys thereof, and aluminum or an alloy thereof is preferable.

(Separator, exterior body)
A porous film (separator) is interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the electrolytic solution is used by impregnating the porous membrane. The material and shape of the porous film are not particularly limited as long as it is stable to the electrolytic solution and excellent in liquid retention, and a porous sheet or nonwoven fabric made of polyolefin such as polyethylene and polypropylene is preferable.
The material of the battery casing used in the battery according to the present invention is also arbitrary, and nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium, a laminate film, or the like is used.
The operating voltage of the non-aqueous electrolyte secondary battery of the present invention described above is usually in the range of 2V to 6V.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.
In addition, each evaluation method of the battery obtained by the following Example and the comparative example is shown below.
[Capacity evaluation]
The non-aqueous electrolyte secondary battery is charged to 4.2 V at a constant current corresponding to 0.2 C at 25 ° C. in a state of being sandwiched between glass plates in order to enhance the adhesion between the electrodes, and then 0.2 C The battery was discharged to 3 V at a constant current of. This is done for 3 cycles to stabilize the battery. In the 4th cycle, after charging to 4.2V with a constant current of 0.5C, charging is carried out until the current value reaches 0.05C with a constant voltage of 4.2V. The initial discharge capacity was determined by discharging to 3 V at a constant current of 0.2C.
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.

[Evaluation of cycle characteristics]
After the capacity evaluation test is completed, the battery is charged at a constant current of 0.5 C to 4.2 V at 45 ° C., and then charged at a constant voltage of 4.2 V until the current value becomes 0.05 C. A constant current of 1 C A cycle test was conducted to discharge to 3V. The discharge capacity (%) after 300 cycles when the discharge capacity at the first cycle was 100 was determined.

[Evaluation of high voltage cycle characteristics]
After the capacity evaluation test was completed, the battery was charged to 4.35 V at a constant current of 0.5 C at 45 ° C., and then charged to a current value of 0.05 C at a constant voltage of 4.35 V. A cycle test for discharging to 3V was conducted. The discharge capacity (%) after 50 cycles when the discharge capacity at the first cycle was 100 was determined.

[Evaluation of discharge storage characteristics]
The battery for which the capacity evaluation test was completed was stored at 60 ° C., and the change in voltage was measured. The time required for the voltage to change from 3 V to 2.5 V was defined as the discharge storage time. As the discharge storage time is longer, deterioration during storage (deterioration due to side reactions inside the battery, mainly due to side reactions on the negative electrode side) is suppressed, indicating that the battery is more stable.

[Evaluation of continuous charging characteristics]
After the capacity evaluation test was completed, the volume was measured by immersing the battery in an ethanol bath. Then, constant current charging was performed at a constant current of 0.5 C at 60 ° C., and after reaching 4.25 V, constant voltage charging was performed. Switching was performed continuously for one week.
After the battery was cooled, it was immersed in an ethanol bath to measure the volume, and the amount of gas generated from the volume change before and after continuous charging was determined.
After measuring the amount of gas generated, discharge to 3 V at a constant current of 0.2 C at 25 ° C., measure the remaining capacity after the continuous charge test, and determine the ratio of the discharge capacity after the continuous charge test to the initial discharge capacity. Is the remaining capacity (%) after continuous charging.

(Example 1)
[Manufacture of negative electrode]
The d value of the lattice plane (002 plane) in X-ray diffraction is 0.336 nm, the crystallite size (Lc) is 652 nm, the ash content is 0.07 wt%, the median diameter by laser diffraction / scattering method is 12 μm, and the ratio by BET method The surface area is 7.5 m ² / g, and the R value (= I _B / I _A ) obtained from Raman spectrum analysis using argon ion laser light is 0.12, half of the peak in the range of 1570 to 1620 cm ^−1. 94 parts by weight of natural graphite powder having a value range of 19.9 cm ⁻¹ and 6 parts by weight of polyvinylidene fluoride were mixed, and N-methyl-2-pyrrolidone was added to form a slurry. This slurry was uniformly applied to one side of a 12 μm thick copper foil, dried, and then pressed so that the density of the negative electrode active material layer was 1.65 g / cm ³ to obtain a negative electrode.

[Production of positive electrode]
90 parts by weight of LiCoO ₂ , 4 parts by weight of carbon black and 6 parts by weight of polyvinylidene fluoride (manufactured by Kureha Chemical Co., Ltd., trade name “KF-1000”) are mixed, and N-methyl-2-pyrrolidone is added to form a slurry. After uniformly applying and drying on both surfaces of a 15 μm thick aluminum foil, the positive electrode active material layer was pressed to a density of 3.0 g / cm ³ to obtain a positive electrode.

[Manufacture of electrolyte]
Under a dry argon atmosphere, 97 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7), 2 parts by weight of vinylene carbonate and cis-4,5-difluoro-1,3-dioxolan-2-one 1 Next, parts by weight were mixed, and then sufficiently dried LiPF ₆ was dissolved at a rate of 1.0 mol / liter to obtain an electrolytic solution.

[Manufacture of lithium secondary batteries]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator, the positive electrode, the separator, and the negative electrode to produce 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 then the electrolyte was poured into the bag and vacuum sealed. The sheet-like battery was manufactured and the cycle characteristics and the discharge storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Example 2)
97.5 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7), 2 parts by weight of vinylene carbonate and 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one A lithium secondary battery in the same manner as in Example 1 except that an electrolytic solution prepared by mixing parts and then dissolving sufficiently dried LiPF ₆ at a ratio of 1.0 mol / liter was used. And the cycle characteristics and the discharge storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Example 3)
97.5 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7), 1.5 parts by weight of vinylene carbonate, 0.5 parts by weight of vinyl ethylene carbonate and cis-4,5-difluoro-1, Except for using an electrolyte prepared by mixing 0.5 parts by weight of 3-dioxolan-2-one and then dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / liter. In the same manner as in Example 1, a sheet-like lithium secondary battery was produced and the cycle characteristics were evaluated. The evaluation results are shown in Table 1.

Example 4
In the electrolyte solution of Example 1, trans-4,5-difluoro-1,3-dioxolan-2-one was used instead of cis-4,5-difluoro-1,3-dioxolan-2-one In the same manner as in Example 1, a sheet-like lithium secondary battery was produced, and the cycle characteristics were evaluated. The evaluation results are shown in Table 1.

(Example 5)
97 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (volume ratio 2: 4: 4), 2 parts by weight of vinylene carbonate and cis-4,5-difluoro-1,3-dioxolan-2-one 1 In the same manner as in Example 1, except that an electrolytic solution prepared by dissolving parts by weight and then dissolving sufficiently dried LiPF ₆ at a ratio of 1.0 mol / liter was used. A secondary battery was prepared and the cycle characteristics were evaluated. The evaluation results are shown in Table 1.

(Comparative Example 1)
98 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7) was mixed with 2 parts by weight of vinylene carbonate, and then 1 part of fully dried LiPF ₆ was mixed.
. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving at a rate of 0 mol / liter was used, and cycle characteristics and discharge storage characteristics were evaluated. . The evaluation results are shown in Table 1.

(Comparative Example 2)
98 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7) was mixed with 2 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and then thoroughly dried. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving LiPF ₆ to a ratio of 1.0 mol / liter was used, and cycle characteristics and discharge storage characteristics were obtained. Was evaluated. The evaluation results are shown in Table 1.

(Comparative Example 3)
Except for using an electrolyte prepared by dissolving LiPF ₆ sufficiently dried in a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7) to a ratio of 1.0 mol / liter. In the same manner as in Example 1, a sheet-like lithium secondary battery was produced, and the cycle characteristics and the discharge storage characteristics were evaluated. The evaluation results are shown in Table 1.

(Comparative Example 4)
97 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7) was mixed with 2 parts by weight of vinylene carbonate and 1 part of 4-fluoro-1,3-dioxolan-2-one, and then fully A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving dried LiPF ₆ at a ratio of 1.0 mol / liter was used, and evaluation of cycle characteristics was performed. Went. The evaluation results are shown in Table 1.

As is apparent from Table 1, the battery according to the present invention is excellent in cycle characteristics and storage characteristics.
(Example 6)
96.5 parts by weight of a mixture of ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate (volume ratio 2: 4: 4), 2 parts by weight of vinylene carbonate, cis-4,5-difluoro-1,3-dioxolane-2- This was carried out except that 0.5 parts by weight of ON and 1 part by weight of cyclohexylbenzene were mixed, and then an electrolyte prepared by dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / liter was used. A sheet-like lithium secondary battery was produced in the same manner as in Example 1, and the continuous charge characteristics were evaluated. The evaluation results are shown in Table 2.

(Example 7)
A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that 2,4-difluoroaniol was used in place of cyclohexylbenzene in the electrolytic solution of Example 6, and continuous charge characteristics were evaluated. . The evaluation results are shown in Table 2.

(Comparative Example 5)
97 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (volume ratio 2: 4: 4) was mixed with 2 parts by weight of vinylene carbonate and 1 part by weight of cyclohexylbenzene, and then LiPF ₆ sufficiently dried was mixed. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving at a rate of 1.0 mol / liter was used, and the continuous charge characteristics were evaluated. The evaluation results are shown in Table 1.

(Comparative Example 6)
In the electrolytic solution of Comparative Example 5, a sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that 2,4-difluoroaniol was used instead of cyclohexylbenzene, and the continuous charge characteristics were evaluated. . The evaluation results are shown in Table 2.

  As is clear from Table 2, the battery according to the present invention generates gas after high-temperature storage (after continuous charge test) despite containing an aromatic compound having a total carbon number of 7 or more and 18 or less in the electrolytic solution. And a significant decrease in discharge characteristics can be suppressed.

(Example 8)
99.5 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one And then using an electrolyte prepared by dissolving LiPF ₆ sufficiently dried at a ratio of 1.0 mol / liter, a sheet-like lithium secondary battery was prepared in the same manner as in Example 1. The high voltage cycle characteristic and the continuous charge characteristic were evaluated. The evaluation results are shown in Table 3.

(Comparative Example 7)
Example 1 was used except that an electrolyte prepared by dissolving LiPF ₆ in ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7) at a ratio of 1.0 mol / liter was used. Similarly, a sheet-like lithium secondary battery was produced, and the high voltage cycle characteristics and the continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

(Comparative Example 8)
An electrolytic solution prepared by dissolving LiPF ₆ sufficiently dried in a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6) at a ratio of 1.0 mol / liter. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that it was used, and high voltage cycle characteristics and continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

Example 9
99 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and 1 , 3-propane sultone mixed with 0.5 parts by weight, and then an electrolyte prepared by dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / liter was used. Similarly, a sheet-like lithium secondary battery was produced, and high voltage cycle characteristics and continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

(Example 10)
99 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and 1 , 4-butanediol bis (2,2,2-trifluoroethanesulfonate) 0.5 parts by weight, and then sufficiently dried LiPF ₆ was dissolved at a ratio of 1.0 mol / liter. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that the prepared electrolytic solution was used, and high voltage cycle characteristics and continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

(Example 11)
99 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and Example 1 was used except that 0.5 parts by weight of sinonitrile was mixed and then an electrolyte prepared by dissolving LiPF ₆ sufficiently dried at a ratio of 1.0 mol / liter was used. A sheet-like lithium secondary battery was prepared and evaluated for high voltage cycle characteristics and continuous charge characteristics. The evaluation results are shown in Table 3.

Example 12
99 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and triethyl Example 1 was used except that 0.5 parts by weight of phosphonoacetate was mixed, and then an electrolyte prepared by dissolving LiPF ₆ sufficiently dried at a ratio of 1.0 mol / liter was used. Then, a sheet-like lithium secondary battery was prepared, and the high voltage cycle characteristics and the continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

(Example 13)
98.5 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one An electrolyte prepared by mixing 0.5 parts by weight of vinylene carbonate and 0.5 parts by weight of triethylphosphonoacetate and then dissolving LiPF ₆ sufficiently dried to a ratio of 1.0 mol / liter. A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that it was used, and high voltage cycle characteristics and continuous charge characteristics were evaluated. The evaluation results are shown in Table 3.

(Example 14)
99 parts by weight of a mixture of ethylene carbonate and ethyl methyl carbonate (volume ratio 3: 7), 0.5 parts by weight of cis-4,5-difluoro-1,3-dioxolan-2-one and 0.5 parts of triethylphosphonoacetate In the same manner as in Example 1 except that an electrolytic solution prepared by mixing parts by weight and then dissolving sufficiently dried LiPF ₆ at a ratio of 1.0 mol / liter was used. Batteries were prepared and evaluated for high voltage cycle characteristics and continuous charge characteristics. The evaluation results are shown in Table 3.

(Comparative Example 9)
99.5 parts by weight of a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 1: 6) was mixed with 0.5 part by weight of succinonitrile, and then LiPF ₆ which was sufficiently dried was mixed with 1. A sheet-like lithium secondary battery was prepared in the same manner as in Example 1 except that an electrolytic solution prepared by dissolving so as to have a ratio of 0 mol / liter was used, and evaluation of high voltage cycle characteristics and continuous charge characteristics was performed. went. The evaluation results are shown in Table 3.

  As is apparent from Table 3, the battery according to the present invention has excellent cycle characteristics, can suppress gas generation after high-temperature storage (after a continuous charge test), and improve discharge characteristics.

Claims (29)

  In a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte contains a cyclic carbonate having an unsaturated bond, and further contains a fluorinated cyclic carbonate having two or more fluorine atoms. A non-aqueous electrolyte solution characterized by that.   In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution contains an aromatic compound having a total carbon number of 7 or more and 18 or less, and further has two or more fluorine atoms. A non-aqueous electrolyte containing a cyclic carbonate.   A non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, wherein the non-aqueous solvent contains diethyl carbonate, and further contains a fluorinated cyclic carbonate having two or more fluorine atoms Electrolytic solution. In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent that dissolves the electrolyte, the non-aqueous electrolyte solution includes a cyclic sulfonate compound, a disulfonate compound, a nitrile compound, and a compound represented by the following general formula (1). A non-aqueous electrolyte containing at least one compound selected from the group consisting of fluorinated cyclic carbonates having two or more fluorine atoms.

(In General Formula (1), R ^{1 to} R ³ each independently represents an alkyl group having 1 to 12 carbon atoms which may be substituted with a fluorine atom, and n represents an integer of 0 to 6). .)   The non-aqueous electrolytic solution according to claim 1, wherein the cyclic carbonate having an unsaturated bond is at least one compound selected from the group consisting of vinylene carbonate compounds, vinyl ethylene carbonate compounds, and methylene ethylene carbonate compounds. .   6. The non-aqueous electrolyte solution according to claim 1, wherein the cyclic carbonate having an unsaturated bond is vinylene carbonate and / or vinyl ethylene carbonate.   The non-aqueous electrolyte solution according to claim 1, 5 or 6, wherein the ratio of the cyclic carbonate having an unsaturated bond in the non-aqueous electrolyte solution is 0.001 wt% or more and 8 wt% or less.   The non-aqueous electrolyte solution according to claim 2, wherein the aromatic compound has a total carbon number of 10 or more and 18 or less.   The aromatic compound having a total carbon number of 7 or more and 18 or less is a group consisting of biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenyl ether, and dibenzofuran The non-aqueous electrolyte solution according to claim 2, wherein the non-aqueous electrolyte solution is at least one compound selected from the group consisting of:   10. The non-aqueous electrolyte solution according to claim 2, wherein the ratio of the aromatic compound having a total carbon number of 7 to 18 is 0.001 to 5% by weight. Aqueous electrolyte.   The nonaqueous electrolytic solution according to claim 3, wherein the proportion of diethyl carbonate in the total nonaqueous solvent is 10% by volume or more and 90% by volume or less.   The cyclic sulfonic acid ester compound is at least one compound selected from the group consisting of 1,3-propane sultone, 1,4-butane sultone, 1,3-propene sultone, and 1,4-butene sultone. The non-aqueous electrolyte solution according to claim 4.   Disulfonic acid ester compounds are ethanediol disulfonates, 1,2-propanediol disulfonates, 1,3-propanediol disulfonates, 1,2-butanediol disulfonates, 1,3-butanediol disulfonate And at least one compound selected from the group consisting of 1,4-butanediol disulfonates.   The nitrile compound is at least one compound selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, crotononitrile, 3-methylcrotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, and fumaronitrile. The non-aqueous electrolyte solution according to claim 4, wherein The non-aqueous electrolyte solution according to claim 4, wherein in general formula (1), R ^{1 to} R ³ have 2 to 8 carbon atoms.   In the general formula (1), n is 0, 1 or 2, The non-aqueous electrolyte solution according to claim 4 or 15 characterized by things.   The content ratio of at least one compound selected from the group consisting of a cyclic sulfonic acid ester compound, a disulfonic acid ester compound, a nitrile compound, and a compound represented by the following general formula (1) in the nonaqueous electrolytic solution is: The total amount is 0.001 wt% or more and 5 wt% or less, and the nonaqueous electrolytic solution according to claim 4 or any one of claims 12 to 16.   The non-aqueous electrolyte solution according to any one of claims 1 to 17, wherein the fluorinated cyclic carbonate compound having two or more fluorine atoms is a fluorinated ethylene carbonate having two or more fluorine atoms.   A fluorinated cyclic carbonate compound having two or more fluorine atoms is cis-4,5-difluoro-1,3-dioxolan-2-one, trans-4,5-difluoro-1,3-dioxolan-2-one, And at least one compound selected from the group consisting of 4,4-difluoro-1,3-dioxolan-2-one and the nonaqueous electrolytic solution according to any one of claims 1 to 18 .   The ratio of the fluorinated cyclic carbonate having two or more fluorine atoms in the non-aqueous electrolyte solution is 0.001 to 10% by weight, according to any one of claims 1 to 19, Aqueous electrolyte.   The ratio of the fluorinated cyclic carbonate having two or more fluorine atoms in the non-aqueous electrolyte solution is 0.01 to 4% by weight, according to any one of claims 1 to 20, Aqueous electrolyte. In a non-aqueous electrolyte solution containing an electrolyte and a non-aqueous solvent for dissolving the electrolyte, the non-aqueous electrolyte solution is an electrolyte solution used for a high-voltage battery having a charge end voltage of 4.3 V or more, and two or more fluorine atoms A non-aqueous electrolyte containing a fluorinated cyclic carbonate having   The non-aqueous electrolyte solution according to claim 22, wherein the non-aqueous electrolyte solution contains a cyclic carbonate having an unsaturated bond.   The non-aqueous electrolyte solution according to claim 22, wherein the non-aqueous electrolyte solution contains an aromatic compound having a total carbon number of 7 or more and 18 or less.   The non-aqueous electrolyte solution according to claim 22, wherein the non-aqueous electrolyte solution contains diethyl carbonate. The non-aqueous electrolyte contains at least one compound selected from the group consisting of a cyclic sulfonic acid ester compound, a disulfonic acid ester compound, a nitrile compound, and a compound represented by the following general formula (1). The non-aqueous electrolyte solution according to claim 22.

  27. 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, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to any one of claims 1 to 26. A non-aqueous electrolyte battery characterized by the above.   The non-aqueous electrolyte secondary battery according to claim 27, wherein the negative electrode includes a carbonaceous material and / or a metal compound capable of inserting and extracting lithium.   The non-aqueous electrolyte secondary battery according to claim 27, wherein the positive electrode contains a lithium transition metal composite oxide material.