JP5236875B2 - Nonaqueous electrolyte and nonaqueous electrolyte secondary battery using the same - Google Patents

Description

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

  Non-aqueous electrolyte lithium ion or lithium secondary batteries using carbon materials, oxides, lithium alloys, or lithium metals for the negative electrode are attracting attention as power sources for mobile phone notebook computers and the like because of their high energy density. In this secondary battery, it is known that a film called a surface film, a protective film, SEI (Solid Electrolyte Interface) or a film (hereinafter also referred to as a surface film) is formed on the surface of the negative electrode. . Since this surface film has a great influence on charge / discharge efficiency, cycle life and safety, it is known that control of the surface film is indispensable for improving the performance of the negative electrode. For carbon materials and oxide materials, it is necessary to reduce the irreversible capacity, and for lithium metal and alloy negative electrodes, it is necessary to solve the problem of safety due to the decrease in charge / discharge efficiency and the generation of dendrites (dendrites).

  In order to form a surface film on the negative electrode, various additives for electrolytic solutions have been proposed. For example, the cyclic monosulfonic acid esters as shown in Patent Documents 1 to 3 are often used because they have excellent surface film forming ability on the electrode surface and can improve battery characteristics. In addition, recently, since cycle characteristics and storage characteristics (suppression of resistance increase and capacity retention rate) can be improved as compared with those using cyclic monosulfonic acid esters, a proposal using cyclic disulfonic acid esters as shown in Patent Document 4 has been proposed. is there. The cyclic disulfonic acid ester can be synthesized by a method as disclosed in Patent Document 5, for example.

Japanese Patent No. 2597091 JP 2000-3724 A JP 11-339850 A JP 2004-281368 A Japanese Patent Publication No. 5-44946

The present invention, in a manufacturing process of disulfonic acid ester compound, as synthesized after finally is performed recrystallization and sublimation purification or the like, sufficient moisture content without drying process is large if, disulfonic acid It has been found that the ester undergoes a hydrolysis reaction to produce a by-product, which reacts with the supporting salt in the electrolytic solution to degrade the electrolytic solution, and the characteristics of the battery produced using this deteriorate. is there.

An object of the present invention, the electrolyte solution in the case of using the di-sulfonic acid ester as an electrolyte additive, the cycle life of the nonaqueous electrolyte secondary battery improve with obtaining long-term storage was stable electrolytes also, An object of the present invention is to provide a non-aqueous electrolyte that suppresses an increase in resistance and improves a capacity retention rate, and a non-aqueous electrolyte secondary battery using the same.

  The present inventors have found that the above-mentioned problems can be solved when the water content of the disulfonic acid ester is a predetermined concentration or less in the non-aqueous electrolyte containing the disulfonic acid ester, and have reached the present invention.

  That is, the nonaqueous electrolytic solution of the present invention is characterized in that in the nonaqueous electrolytic solution containing an aprotic solvent and a disulfonic acid ester, the water content of the disulfonic acid ester is less than 300 ppm.

The nonaqueous electrolytic solution of the present invention may contain a disulfonic acid ester represented by the formula (1) .

However, in Formula (1) , Q is an oxygen atom, a methylene group or a single bond, A is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms which may be branched, a carbonyl group, a sulfinyl group, a branched group. A substituted or unsubstituted perfluoroalkylene group having 1 to 5 carbon atoms, which may be branched, a substituted or unsubstituted fluoroalkylene group having 2 to 6 carbon atoms which may be branched, or a branched structure containing an ether bond A good substituted or unsubstituted alkylene group having 1 to 6 carbon atoms, which may be branched including an ether bond, a substituted or unsubstituted perfluoroalkylene group having 1 to 6 carbon atoms or a branched structure containing an ether bond A good substituted or unsubstituted fluoroalkylene group having 2 to 6 carbon atoms is shown. B represents a substituted or unsubstituted alkylene group , fluoromethylene group or oxygen atom which may be branched.

The nonaqueous electrolytic solution of the present invention may contain a disulfonic acid ester represented by the formula (2) .

However, in Formula (2) , R < ₁ > and R < ₄ > are respectively independently a hydrogen atom, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C1-C5 alkoxy group. , Substituted or unsubstituted fluoroalkyl group having 1 to 5 carbon atoms, polyfluoroalkyl group having 1 to 5 carbon atoms, —SO ₂ X ₁ (X ₁ is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms) , -SY ₁ (Y ₁ is a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms), -COZ (Z is a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms), and a halogen atom An atom or group selected from R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted phenoxy group, substituted or An unsubstituted fluoroalkyl group having 1 to 5 carbon atoms, a polyfluoroalkyl group having 1 to 5 carbon atoms, a substituted or unsubstituted fluoroalkoxy group having 1 to 5 carbon atoms, a polyfluoroalkoxy group having 1 to 5 carbon atoms, a hydroxyl group, a halogen atom, -NX ₂ X ₃ (X ₂ and X ₃ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms), and -NY ₂ CONY ₃ Y ₄ (Y _{2 to} Y ₄ each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms).

Further, in the nonaqueous electrolytic solution of the present invention, the aprotic solvent is a cyclic carbonate, a chain carbonate, an aliphatic carboxylic acid ester, a γ-lactone, a cyclic ether, a chain ether, or a fluorine thereof. preferably contains at least one organic solvent selected from the group consisting of derivatives, said non-aqueous _{electrolyte, LiPF 6, LiBF 4, LiAsF} 6, LiSbF 6, LiClO 4, LiAlCl 4 as further lithium salt, Selected from the group consisting of LiN (C _k F _{2k + 1} SO ₂ ) ₂ and LiN (C _n F _{2n + 1} SO ₂ ) (C _m F _{2m + 1} SO ₂ ) (k, n and m are natural numbers) It is preferable to include at least one kind.

  The non-aqueous electrolyte secondary battery of the present invention preferably includes the non-aqueous electrolyte, at least a positive electrode, and a negative electrode, and includes a lithium-containing composite oxide as a positive electrode active material of the positive electrode. Preferably, the substance includes one or more substances selected from the group consisting of materials capable of inserting and extracting lithium, lithium metal, metal materials capable of forming an alloy with lithium, and oxide materials. The negative electrode active material preferably includes a carbon material, and the carbon material may be graphite, or the carbon material may be amorphous carbon.

  ADVANTAGE OF THE INVENTION According to this invention, decomposition | disassembly of the electrolyte solution of a nonaqueous electrolyte secondary battery can be suppressed by using the nonaqueous electrolyte solution containing an aprotic solvent and the disulfonic acid ester whose water content is 300 ppm or less. . Moreover, according to this invention, the charging / discharging efficiency and cycle life of a nonaqueous electrolyte secondary battery can be improved. Further, according to the present invention, it is possible to suppress an increase in resistance of the secondary battery. The nonaqueous electrolytic solution according to the present invention is simply and stably produced by a step of dissolving a disulfonic acid ester having a water content of 300 ppm or less in a solvent and a step of dissolving a lithium salt.

Hereinafter, the configuration of the non-aqueous electrolyte of the present invention will be described. The nonaqueous electrolytic solution contains an aprotic solvent, a lithium salt, and a disulfonic acid ester having a water content of 300 ppm or less. The disulfonic acid ester is preferably a compound represented by the following formula (1) or formula (2) .

Further, representative examples of the compound represented by the above formula (1) are specifically exemplified in Table 1, and typical examples of the compound represented by the formula (2) are specifically exemplified in Table 2, but the present invention is limited to these. is not.

The compound represented by the above formula (1) or formula (2) can be obtained, for example, using the production method described in Patent Document 5.

The proportion of the compound represented by formula (1) or formula (2) in the electrolytic solution is not particularly limited, but it is preferably included in 0.005 to 10% by mass of the entire electrolytic solution. By setting the concentration of the compound represented by the formula (1) or the formula (2) to 0.005% by mass or more, a sufficient surface film effect can be obtained. More preferably, the battery characteristics can be further improved by adding 0.01% by mass or more. Moreover, by setting it as 10 mass% or less, the raise of the viscosity of electrolyte solution and the increase in resistance accompanying it can be suppressed. More preferably, the battery characteristics can be further improved by adding 5% by mass or less.

In addition to the compound represented by the above formula (1) or formula (2) , the electrolytic solution may further include one or more compounds having a sulfonyl group. For example, a sultone compound represented by the following formula (3) may be included.

However, in the above formula (3) , n is an integer of 0 or more and 2 or less. R _{8 to} R ₁₃ are independently selected from a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

In addition to the compound represented by Formula (1) or Formula (2) , by adding the compound having a sulfonyl group represented by Formula (3) , the viscosity of the electrolytic solution can be easily adjusted. Moreover, the stability of the surface film is improved by a synergistic effect by using a compound having a sulfonyl group in combination. Moreover, decomposition suppression of solvent molecules can be suppressed. In addition, the effect of removing moisture in the electrolytic solution is increased.

  Specific examples of the compound having a sulfonyl group include sulfolane (Japanese Patent Laid-Open No. 60-154478), 1,3-propane sultone and 1,4-butane sultone (Japanese Patent Laid-Open No. 62-1000094), Japanese Patent 63-102173, JP-A-11-339850, JP-A-2000-3724), alkanesulfonic anhydride (JP-A-10-189041), γ-sultone compound (JP-A 2000-235866). Gazette) and sulfolene derivatives (Japanese Patent Laid-Open No. 2000-294278), but are not limited thereto.

In addition to the formula (1) or the formula (2) , when a sulfonyl compound is further added to the electrolytic solution, it can be added to the electrolytic solution, for example, in an amount of 0.005 mass% to 10 mass%. By setting it as 0.005 mass% or more, a surface film can be effectively formed in the negative electrode surface. More preferably, it can be 0.01 mass% or more. Moreover, the solubility of a sulfonyl compound is maintained by setting it as 10 mass% or less, and the viscosity raise of electrolyte solution can be suppressed. More preferably, it can be 5 mass% or less.

The electrolytic solution can be obtained by dissolving or dispersing a compound represented by the formula (1) or the formula (2) , a compound having a sulfonyl group, a lithium salt, or other additives as necessary in an aprotic solvent. By mixing additives having different properties, a surface film having different properties is formed on the negative electrode surface, which is effective in improving battery characteristics.

  Further, by adding vinylene carbonate (VC) or a derivative thereof to the electrolytic solution, it is possible to improve the cycle characteristics and the resistance increase suppressing effect of the non-aqueous electrolyte secondary battery. Examples of vinylene carbonate or derivatives thereof include, for example, JP-A-4-16975, JP-A-7-122296, JP-A-8-45545, JP-A-5-82138, JP-A-5-74486, The compounds shown in JP-A-6-52887, JP-A-11-260401, JP-A-2000-208169, JP-A-2001-35530, and JP-A-2000-138071 can be used as appropriate.

  The addition amount of VC or a derivative thereof is preferably 0.01% by mass or more and 10% by mass or less of the entire electrolytic solution. By setting the content to 0.01% by mass or more, the cycle characteristics can be suitably exhibited, and further, it is possible to suppress an increase in resistance during storage at a high temperature. The resistance value of electrolyte solution can be made low by setting it as 10 mass% or less.

The electrolyte solution may further include a lithium salt as an electrolyte. In this way, since lithium ions can be used as a mobile substance, battery characteristics can be improved. Examples of lithium salts include LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , LiAlCl ₄ , LiN (C _k F _{2k + 1} SO ₂ ) ₂ and LiN (C _n F _{2n + 1} SO ₂ ) (C _m F _{2m + 1} SO ₂ ) (k, n, and m are natural numbers) may be included. In particular, it is preferable to use LiPF ₆ or LiBF ₄ . By using these, the electrical conductivity of the lithium salt can be increased, and the cycle characteristics of the nonaqueous electrolyte secondary battery can be further improved.

  The non-aqueous electrolyte includes, as an aprotic solvent, cyclic carbonates, chain carbonates, aliphatic carboxylic acid esters, γ-lactones, cyclic ethers, chain ethers, and fluorine derivatives of any of these, One or more solvents selected from the group consisting of can be included.

  Specifically, for example, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), chain carbonates such as dipropyl carbonate (DPC), aliphatic carboxylic acid esters such as methyl formate, methyl acetate and ethyl propionate, γ-lactones such as γ-butyrolactone, 1,2-ethoxy Chain ethers such as ethane (DEE) and ethoxymethoxyethane (EME), cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylphenol Rumamide, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, Propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, N-methylpyrrolidone, fluorinated carboxylic acid ester, methyl-2,2,2-trifluoroethyl carbonate, methyl-2,2,3,3,3-pentafluoropropyl carbonate , Trifluoromethyl ethylene carbonate, monofluoromethyl ethylene carbonate, difluoromethyl ethylene carbonate, 4,5-difluoro-1,3-dioxolan-2-one, monofluoroe Of such alkylene carbonate, it can be used by mixing one or two or more.

  Hereinafter, the configuration of the nonaqueous electrolyte secondary battery of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a non-aqueous electrolyte secondary battery of the present invention.

  The battery according to the present invention has a structure as shown in FIG. The positive electrode is formed by forming a layer 12 containing a positive electrode active material on the positive electrode current collector 11. The negative electrode is formed by forming a layer 13 containing a negative electrode active material on a negative electrode current collector 14. The positive electrode and the negative electrode are disposed to face each other with a non-aqueous electrolyte and a porous separator 16 in the non-aqueous electrolyte. The porous separator 16 is disposed substantially parallel to the layer 13 containing the negative electrode active material.

  In the non-aqueous electrolyte secondary battery of FIG. 1, the negative electrode active material used for the layer 13 containing the negative electrode active material is selected from the group consisting of, for example, lithium metal, lithium alloy, and a material capable of inserting and extracting lithium. One or more substances can be used. As a material for inserting and extracting lithium ions, a carbon material or an oxide can be used.

  As the carbon material, graphite that absorbs lithium, amorphous carbon, diamond-like carbon, carbon nanotube, and the like can be used. Of these, graphite material or amorphous carbon is particularly preferable. In particular, the graphite material has high electron conductivity, excellent adhesion to a current collector made of a metal such as copper, and voltage flatness, and is formed at a high processing temperature, so it contains few impurities and has negative electrode performance. It is advantageous for improvement and is preferable.

  Further, as the oxide, any of silicon oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, phosphoric acid, boric acid, or a composite thereof may be used, and it is particularly preferable to include silicon oxide. . The structure is preferably in an amorphous state. This is because silicon oxide is stable and does not cause a reaction with other compounds, and the amorphous structure does not lead to deterioration due to nonuniformity such as crystal grain boundaries and defects. As a film forming method, a vapor deposition method, a CVD method, a sputtering method, or the like can be used.

  The lithium alloy is composed of lithium and a metal capable of forming an alloy with lithium. For example, it is composed of a binary or ternary alloy of a metal such as Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, and lithium. . As the lithium metal or lithium alloy, an amorphous one is particularly preferable. This is because the amorphous structure hardly causes deterioration due to non-uniformity such as crystal grain boundaries and defects.

  Lithium metal or lithium alloy is formed by an appropriate method such as a melt cooling method, a liquid quenching method, an atomizing method, a vacuum deposition method, a sputtering method, a plasma CVD method, a photo CVD method, a thermal CVD method, or a sol-gel method. can do.

  In the negative electrode of the non-aqueous electrolyte secondary battery in FIG. 1, when a complex composed of a transition metal cation and an imide anion is present at the interface with the electrolyte, the negative electrode is flexible with respect to volume changes of metal and alloy phases, and ion distribution. This is preferable because of excellent uniformity and physical / chemical stability. As a result, dendrite formation and lithium atomization can be effectively prevented, and cycle efficiency and life are improved.

  Further, when a carbon material or an oxide material is used as the negative electrode, dangling bonds existing on the surface have high chemical activity, and the solvent is easily decomposed. By adsorbing a complex composed of a transition metal cation and an imide anion on this surface, the decomposition of the solvent is suppressed and the irreversible capacity is greatly reduced, so that the charge / discharge efficiency can be kept high.

  Furthermore, when the surface film is mechanically broken, lithium fluoride, which is a reactive product of lithium on the negative electrode surface and the imide anion adsorbed on the negative electrode surface, repairs the surface film. And has the effect of leading to the formation of a stable surface compound even after the surface film is destroyed.

In the non-aqueous electrolyte secondary battery of FIG. 1, examples of the positive electrode active material used for the layer 12 containing the positive electrode active material include lithium-containing composite oxides such as LiCoO ₂ , LiNiO ₂ , and LiMn ₂ O _4. . In addition, the transition metal portion of these lithium-containing composite oxides may be replaced with another element.

Alternatively, a lithium-containing composite oxide having a plateau at 4.5 V or more at the metal lithium counter electrode potential can be used. Examples of the lithium-containing composite oxide include spinel-type lithium manganese composite oxide, olivine-type lithium-containing composite oxide, and reverse spinel-type lithium-containing composite oxide. The lithium-containing composite oxide is, for example, Li _a (M _x Mn _2−x ) O ₄ (where 0 <x <2 and 0 <a <1.2. M is Ni, And at least one selected from the group consisting of Co, Fe, Cr, and Cu.

  The positive electrode is obtained by dispersing and kneading these active materials in a solvent such as N-methyl-2-pyrrolidone (NMP) together with a conductive material such as carbon black and a binder such as polyvinylidene fluoride (PVDF). Can be obtained by coating on a substrate such as an aluminum foil.

The non-aqueous electrolyte secondary battery of FIG. 1 has a negative electrode and a positive electrode laminated via a porous separator 16 in a dry air or inert gas atmosphere. It accommodates in exterior bodies, such as a flexible film which consists of a laminated body of resin and metal foil, and impregnates the electrolyte solution containing the compound shown by said Formula (1) . And a surface film | membrane can be formed on a negative electrode by charging a nonaqueous electrolyte secondary battery after sealing or sealing an exterior body. In addition, as the porous separator 16, porous films, such as polyolefin, such as a polypropylene and polyethylene, a fluororesin, are used.

  The shape of the nonaqueous electrolyte secondary battery according to the present embodiment is not particularly limited, and examples thereof include a cylindrical shape, a square shape, a laminate outer shape, and a coin shape.

(Synthesis and drying of disulfonic acid ester)
Compound No. 1 was synthesized according to the method described in Patent Document 5. The crude product was purified by silica gel column chromatography using a mixed solvent of hexane: ethyl acetate = 1: 1. When the water content of 1 was measured by the Karl Fischer method, it was 3000 ppm. The moisture content after drying this compound at 40 ° C. under reduced pressure for 12 hours was 500 ppm, the moisture content after drying for 18 hours was 300 ppm, and after drying for 24 hours, it was 250 ppm.

(Production of battery)
The production of the battery of this example will be described. An aluminum foil having a thickness of 20 μm was used as the positive electrode current collector, and LiM n ₂ O ₄ was used as the positive electrode active material. Further, a copper foil having a thickness of 10 μm was used as the negative electrode current collector, and a negative electrode active material obtained by vapor deposition of 20 μm thick lithium metal was used as the negative electrode. In addition, a mixed solvent of EC and DEC (volume ratio: 30/70) is used as the solvent of the electrolytic solution, and LiN (C ₂ F ₅ SO ₂ ) ₂ (hereinafter abbreviated as LiBETI) is used as ¹ mol L ⁻¹ as the supporting electrolyte. Further, the compound No. 1 described in Table 1 above was dissolved. 1, Compound No. 1 obtained by performing the drying time under reduced pressure for 24 hours. 1 was added so that 1 mass% was contained in electrolyte solution. And the negative electrode and the positive electrode were laminated | stacked through the separator which consists of polyethylene, and the nonaqueous electrolyte secondary battery of a present Example was produced.

(Battery characteristics evaluation test)
The obtained battery is charged once, discharged in a depth of 50%, placed in a constant temperature bath at 60 ° C., left for one month, then returned to room temperature and discharged, and then charged and discharged again. The discharge capacity was the recovery capacity, and the ratio to the initial capacity was the capacity recovery rate. The resistance of the battery is based on the 10 second value of the current and voltage when charging and discharging for 10 seconds at each current value of 1C, 3C, 5C, and 7C, assuming that the current value when the initial discharge capacity is discharged in 1 hour is 1C. Calculated. The cycle capacity retention rate (%) is a value obtained by dividing the discharge capacity (mAh) after 400 cycles by the discharge capacity (mAh) at the 10th cycle. These results are shown in Table 3.

(Comparative Example 1)
Compound No. obtained by drying under reduced pressure for 18 hours. A non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in the example except that the electrolyte solution using No. 1 was used. The results are shown in Table 3.

(Comparative Example 2)
Compound No. obtained by drying under reduced pressure for 12 hours. A non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in the example except that the electrolyte solution using No. 1 was used. The results are shown in Table 3.

(Comparative Example 3)
Compound No. obtained without drying under reduced pressure. A non-aqueous electrolyte secondary battery was produced and evaluated in the same manner as in the example except that the electrolyte solution using No. 1 was used. The results are shown in Table 3.

  As shown in Table 3, when the water content is 300 ppm or more, the capacity recovery rate is extremely reduced to 90% or less, and the resistance increase ratio and the cycle capacity retention rate are also extremely deteriorated.

The schematic block diagram of the nonaqueous electrolyte secondary battery of this invention.

Explanation of symbols

11 Positive Electrode Current Collector 12 Layer Containing Positive Electrode Active Material 13 Layer Containing Negative Electrode Active Material 14 Negative Electrode Current Collector 15 Nonaqueous Electrolytic Solution 16 Porous Separator

Claims (10)

A non-aqueous electrolyte solution containing an aprotic solvent, a lithium salt, and a disulfonic acid ester,
Ri said 300ppm less der water content of disulfonic acid ester before being added to the nonaqueous electrolytic solution,
The proportion of the disulfonic acid ester in the entire non-aqueous electrolyte is 0.005 to 10% by mass,
The disulfonic acid ester has the following compound No. 1-22 and the following compound No. A non-aqueous electrolyte , which is at least one compound selected from the group consisting of compounds represented by 101 to 120 .
 2. The non-aqueous electrolyte according to claim 1, wherein a ratio of the disulfonic acid ester to the entire non-aqueous electrolyte is 0.005 to 5 mass%. The aprotic solvent is at least selected from the group consisting of cyclic carbonates, chain carbonates, aliphatic carboxylic acid esters, γ-lactones, cyclic ethers, chain ethers, and fluorinated derivatives thereof. The nonaqueous electrolytic solution according to claim 1 or 2 , comprising one type of organic solvent. The lithium salt is LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , LiAlCl ₄ , LiN (C _k F _{2k + 1} SO ₂ ) ₂ and LiN (C _n F _{2n + 1} SO ₂ ) (C _m F _{2m + 1 SO 2) (k} , n, m are non-aqueous electrolyte according to any one of claims 1 to 3, characterized in that at least one member selected from the group consisting of natural numbers). A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte is the non-aqueous electrolyte according to any one of claims 1 to 4. Non-aqueous electrolyte secondary battery characterized. The non-aqueous electrolyte secondary battery according to claim 5 , wherein the positive electrode includes a lithium-containing composite oxide as a positive electrode active material. The negative electrode includes at least one selected from the group consisting of a material capable of inserting and extracting lithium as a negative electrode active material, a lithium metal, a metal material capable of forming an alloy with lithium, and an oxide material. The nonaqueous electrolyte secondary battery according to claim 5 or 6 . The nonaqueous electrolyte secondary battery according to any one of claims 5 to 7 , wherein the negative electrode has carbon as a negative electrode active material. The non-aqueous electrolyte secondary battery according to claim 8 , wherein the carbon is graphite. The non-aqueous electrolyte secondary battery according to claim 8 , wherein the carbon is amorphous carbon.