JPH11162511A - Non-aqueous electrolyte battery - Google Patents

Abstract

(57) [Problem] To provide a non-aqueous electrolyte battery excellent in low-temperature characteristics and long-term stability and excellent in cycle characteristics when used as a secondary battery. SOLUTION: In a non-aqueous electrolyte solution comprising a negative electrode, a positive electrode, a solute and an organic solvent, and a separator and an outer can using lithium as an active material, a compound having an SO bond as the organic solvent (For example, dimethyl sulfite, ethylene sulfite, sulfalane,
Sulfolene, 1,3-propane sultone, etc.)
A non-aqueous electrolyte battery, wherein a material of the current collector used for the positive electrode and a material of a portion of the outer can that comes into contact with the electrolyte on the positive electrode side are a valve metal or an alloy thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a non-aqueous electrolyte battery. In particular, the present invention relates to a high energy density non-aqueous electrolyte battery having excellent low-temperature characteristics and long-term stability and, in the case of a secondary battery, excellent cycle characteristics.

[0002]

2. Description of the Related Art With the recent reduction in the weight and size of electric appliances, lithium batteries having a high energy density have attracted attention. Further, with the expansion of the application field of lithium batteries, improvement of battery characteristics is also demanded. As a solvent for the electrolytic solution of such a lithium battery, for example, ethylene carbonate, propylene carbonate, diethyl carbonate,
Non-aqueous organic solvents such as carbonates and esters such as γ-butyrolactone are used.

[0003] Among them, propylene carbonate is a solvent having a high dielectric constant, dissolves a lithium salt-based solute (electrolyte) well, and has excellent performance as a main solvent of an electrolytic solution, such as exhibiting high electric conductivity even at a low temperature. ing. However, when propylene carbonate is used alone, the viscosity of the electrolytic solution becomes too high, and the discharge characteristics particularly at low temperatures are significantly reduced. For this reason, a mixed solvent obtained by mixing 1,2-dimethoxyethane with propylene carbonate is used. However, 1,2-dimethoxyethane has a low boiling point, and thus has problems in long-term stability and safety.

A secondary battery using propylene carbonate may have a problem such as gas generation depending on the type of electrode material. For example, when various graphite-based electrode materials are used alone, or when an electrode material capable of inserting and extracting lithium and a graphite-based electrode material are mixed and used as a negative electrode,
It is known that propylene carbonate decomposes violently on the graphite electrode surface, preventing the smooth insertion and extraction of lithium from the graphite electrode (7th International Sy
mposium on Li Batteries, P259, 1995).

[0005] Therefore, at present, ethylene carbonate, which has relatively little such decomposition reaction, is widely used as a solvent for the electrolytic solution. Ethylene carbonate is not used alone because it has a higher freezing point (36.4 ° C.) than propylene carbonate, and is mixed with a low-viscosity solvent such as dialkyl carbonate such as dimethyl carbonate or diethyl carbonate, dimethoxyethane, or dioxolane. ("Functional Materials", Vol. 15, April issue,
48, 1995). However, since a low-viscosity solvent generally has a low boiling point, when added in a large amount, the vapor pressure in the battery increases, and there is a concern that the safety may be reduced due to leakage of the solvent. At low temperatures, solidification of the electrolytic solution and low electrical conductivity often pose a problem. Under such circumstances, a mixed solvent of ethylene carbonate and diethyl carbonate or the like is used as the electrolyte for the lithium secondary battery. However, there is a problem that batteries using these electrolytic solutions have insufficient cycle characteristics and the like.

[0006] In order to solve these problems, it has been proposed to use a sulfite compound as a solvent (for example, Japanese Patent Application Laid-Open Nos. 6-302336 and 7-302).
122295, JP-A-8-96851, JP-A-9-120837, etc.). In these publications, it is reported that an electrolyte using a sulfite compound has high electric conductivity and low viscosity, and thus has good low-temperature characteristics and the like of a battery. It has also been proposed to use a sulfolane compound as a solvent from the viewpoint of improving the cycle characteristics in a secondary battery (for example, see JP-A-3-13-1).
No. 52879). However, it has been found that when a compound having an SO bond, such as a sulfite compound or a sulfolane compound, is used for the electrolyte, the battery does not operate normally. In particular, the cycle characteristics of the secondary battery are significantly reduced, and there is still room for improvement for practical use.

[0007]

In view of the situation in the prior art, the present invention selects a compound which is preferable as a solvent of a non-aqueous electrolyte and finds conditions under which the function is sufficiently exhibited in a battery. Was a problem to be solved. Specifically, an object of the present invention is to provide a high-energy-density nonaqueous electrolyte battery having excellent low-temperature characteristics and long-term stability and, in the case of a secondary battery, excellent cycle characteristics.

[0008]

Means for Solving the Problems As a result of intensive studies to solve such problems, the present inventors have selected a specific compound having an SO bond as a solvent for a non-aqueous electrolyte, Further, it has been found that a nonaqueous electrolyte battery having extremely excellent characteristics can be provided by specifying the materials of the positive electrode current collector and the outer can that come into contact with the electrolyte.

That is, the present invention relates to a non-aqueous electrolyte battery comprising a negative electrode containing lithium as an active material, a positive electrode, a solute and an organic solvent, a separator and an outer can. 1) containing at least one compound represented by formula (1), wherein the material of the current collector used for the positive electrode and the material of the portion of the outer can contacting the electrolyte on the positive electrode side are valve metals or alloys thereof. A non-aqueous electrolyte battery is provided.

[0010]

## STR1 _{R 1 -A-R 2 (1} ) ( wherein, R ₁ and R ₂ are each independently an alkyl group optionally substituted with an aryl group or a halogen atom,
Or an alkyl group or an aryl group optionally substituted with a halogen atom, or R ₁ and R ₂ are bonded to each other to form a cyclic structure which may contain an unsaturated bond together with -A-, Having a structure represented by any of formulas (2) to (5))

[0011]

Embedded image

The valve metal or alloy thereof used in the present invention is preferably Al, Ti, Zr, Hf, Nb, Ta or an alloy containing these metals.
More preferably, it is an alloy. The negative electrode material may be selected from carbonaceous materials such as graphite capable of occluding and releasing lithium, metal oxide materials capable of occluding and releasing lithium, lithium metal and lithium alloy. The positive electrode material can be selected from a lithium transition metal composite oxide material capable of inserting and extracting lithium, a transition metal oxide material, and a carbonaceous material. As the solute, LiClO ₄ , LiPF ₆ , L
iBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ )
₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (CF ₃
SO ₂ ) (C ₄ F ₉ SO ₂ ) and LiC (CF ₃ SO
₂ ) ₃ can be exemplified. Formula (1) in an organic solvent
The content of the compound represented by is 0.05 to 100 vol%
Is preferably set within the range. It is preferable that the solute concentration of the electrolytic solution is set to 0.5 to 2.0 mol / liter.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the non-aqueous electrolyte battery of the present invention will be described in detail. The non-aqueous electrolyte battery of the present invention has an essential requirement that it contains at least one compound represented by the formula (1) as an organic solvent of the electrolyte. R ₁ and R ₂ of the compound represented by the formula (1) each independently represent an aryl group or an alkyl group optionally substituted with a halogen atom, or an aryl group optionally substituted with an alkyl group or a halogen atom. Represents a group, or R ₁ and R ₂ combine with each other to form a cyclic structure which may contain an unsaturated bond together with -A-.

The alkyl group which R ₁ and R ₂ can have is
Preferably an alkyl group having 1 to 4 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group,
Butyl groups can be mentioned. Examples of the aryl group as a substituent of the alkyl group include a phenyl group, a naphthyl group, and an anthranyl group, and a phenyl group is preferable. Further, as the halogen atom serving as a substituent of the alkyl group, a fluorine atom, a chlorine atom and a bromine atom can be preferably used. A plurality of these substituents may be substituted on the alkyl group, or both the aryl group and the halogen atom may be substituted.

The cyclic structure formed by R ₁ and R ₂ together with -A- is a 4-membered ring or more, and may contain a double bond or a triple bond. As a bonding group formed by bonding R ₁ and R ₂ to each other, for example, -CH ₂ -,-
CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH ₂ C
_{H 2 CH 2 CH 2 -,} - CH 2 CH 2 CH 2 CH 2 CH
_{2 -, - CH = CH -} , - CH = CHCH 2 -, - CH
ＣＨCHCH ₂ CH ₂ —, —CH ₂ CH ＝ CHCH ₂ —,
—CH ₂ CH ₂ C≡CCH ₂ CH ₂ — can be exemplified. One or more of these hydrogen atoms may be substituted by an alkyl group, a halogen atom, an aryl group, and the like.

As specific examples of the compound in which A has the structure represented by the formula (2), dimethyl sulfite, diethyl sulfite, ethyl methyl sulfite, methyl propyl sulfite, ethyl propyl sulfite, diphenyl sulfite, methyl Chain sulphite such as phenyl sulphite, ethyl sulphite, dibenzyl sulphite, benzyl methyl sulphite, benzyl ethyl sulphite; ethylene sulphite, propylene sulphite, butylene sulphite, vinylene sulphite, phenylethylene sulphite, 1-methyl-2
And cyclic sulfites such as -phenylethylene sulphite and 1-ethyl-2-phenylethylene sulphite; and their linear and cyclic sulphite halides.

Specific examples of the compound in which A has the structure represented by the formula (3) include dimethyl sulfone, diethyl sulfone, ethyl methyl sulfone, methyl propyl sulfone,
Chain sulfones such as ethyl propyl sulfone, diphenyl sulfone, methyl phenyl sulfone, ethyl phenyl sulfone, dibenzyl sulfone, benzyl methyl sulfone, and benzyl ethyl sulfone; sulfolane, 2-methyl sulfolane, 3-methyl sulfolane, 2-ethyl sulfone Cyclic sulfones such as folane, 3-ethylsulfolane, 2,4-dimethylsulfolane, sulfolene, 3-methylsulfolene, 2-phenylsulfolane, and 3-phenylsulfolane; And halides.

Specific examples of the compound in which A has the structure represented by the formula (4) include methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, methyl ethanesulfonate, ethyl ethanesulfonate and ethanesulfonic acid. Propyl, methyl benzenesulfonate, ethyl benzenesulfonate, propyl benzenesulfonate, phenyl methanesulfonate, phenyl ethanesulfonate, phenyl propanesulfonate, methyl benzylsulfonate, ethyl benzylsulfonate, propyl benzylsulfonate, methanesulfonate Chain sulfonic esters such as benzyl, benzyl ethanesulfonate and benzyl propanesulfonate: 1,3-propanesultone, 1,4-butanesultone, 3-phenyl-1,3-propanesultone, 4-phenyl- , Cyclic sulfonic acid esters such as 4-butane sultone; can be exemplified halides and the chain sulfonic acid esters and cyclic sulfonic ester.

Specific examples of the compound in which A has the structure represented by the formula (5) include dimethyl sulfate, diethyl sulfate, ethylmethyl sulfate, methylpropyl sulfate, ethylpropyl sulfate, methylphenyl sulfate, ethylphenyl sulfate, and phenylpropane sulfate. Chain sulfates such as toluene, benzylmethyl sulfate and benzylethyl sulfate; ethylene glycol sulfate, 1,2-propanediol sulfate,
3-propanediol sulfate, 1,2-butanediol sulfate, 1,3-butanediol sulfate, 2,3-butanediol sulfate, phenylethylene glycol sulfate, methylphenylethylene glycol sulfate, ethylphenylethylene Cyclic sulfates such as glycol sulfate; and halides of the above-mentioned chain sulfates and cyclic sulfates.

These compounds represented by the formula (1) may be used by selecting one kind alone or in combination of two or more kinds. When two or more compounds are used in combination, compounds having different structures of A may be used as a mixture. The amount of the compound of the formula (1) contained in the organic solvent in the non-aqueous electrolyte is 0.05 to 100 v.
ol%. Some of the compounds represented by the formula (1) are solid at room temperature. In such a case, the amount of the compound is not more than the saturated solubility in the organic solvent used, preferably not more than 60% by weight of the saturated solution, more preferably It is used within a range of 30% by weight or less of the saturated dissolution amount. When the content of the compound of the formula (1) is 0.05 vol% or less, the effects of the present invention tend not to be clearly exhibited. In this specification, the range described using “to” includes numerical values described before and after the range.

As the organic solvent in the non-aqueous electrolyte, a solvent other than the compound represented by the formula (1) can be used. For example, cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; linear carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; cyclic esters such as γ-butyrolactone and γ-valerolactone; methyl acetate and propion Chain esters such as methyl acid phosphate; cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran and tetrahydropyran; chain ethers such as dimethoxyethane and dimethoxymethane; cyclic phosphoric acids such as ethylene methyl phosphate and ethyl ethylene phosphate Esters; chain phosphate esters such as trimethyl phosphate and triethyl phosphate; halides of these compounds; and sulfur-containing organic solvents other than the compound represented by formula (1) can be used. You. One of these organic solvents may be selected and used, or two or more thereof may be used in combination.

The solute used for the non-aqueous electrolyte is Li
Inorganic lithium salts such as ClO ₄ , LiPF ₆ and LiBF ₄ ; LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , L
iN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (CF ₃ S
O ₂ ) (C ₄ F ₉ SO ₂ ) and LiC (CF ₃ S
O ₂₎ fluorine-containing organic lithium salts such as ₃ can be mentioned. One of these solutes may be selected and used, or two or more may be used in combination.
The molar concentration of the solute lithium salt in the electrolyte is
It is desirable to be within the range of 0.5 to 2.0 mol / liter. When the molar concentration is less than 0.5 mol / L or more than 2.0 mol / L, the electric conductivity of the electrolytic solution tends to be low, and the performance of the battery tends to decrease.

The negative electrode constituting the nonaqueous electrolyte battery of the present invention is a negative electrode using lithium as an active material. In this specification, “using lithium as an active material” means that lithium metal, a lithium compound, or lithium ion participates in an electrode reaction. Examples of the material constituting the negative electrode include decomposition products obtained by thermally decomposing organic substances under various conditions, carbonaceous materials capable of occluding and releasing lithium, such as non-graphitizable carbon, artificial graphite, and natural graphite; tin oxide, oxide Metal oxide materials capable of occluding and releasing lithium such as silicon; lithium metal; and various lithium alloys can be used. One of these negative electrode materials may be selected and used, or two or more thereof may be used in combination.

A method for producing a negative electrode using these negative electrode materials is not particularly limited. For example, an electrode can be manufactured by adding a binder, a conductive material, a solvent, and the like to the negative electrode material as needed to form a slurry, applying the slurry to a current collector substrate, and drying. Further, the electrode material can be formed into a sheet by roll forming as it is, or can be formed into a pellet by compression molding or the like.

The type of the binder used in the production of the electrode is not particularly limited as long as it is a material that is stable with respect to the solvent and the electrolyte used in the production of the electrode. Specifically, resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, and cellulose; rubber-like polymers such as styrene-butadiene rubber, isoprene rubber, butadiene rubber, and ethylene-propylene rubber; styrene-butadiene. Thermoplastic elastomeric polymers such as styrene block copolymers and their hydrogenated products, styrene / ethylene / butadiene / styrene block copolymers and their hydrogenated products; styrene / isoprene / styrene block copolymers and their hydrogenated products Syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymer, propylene / α-olefin (C 2
12) Soft resinous polymers such as copolymers; and fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, and polytetrafluoroethylene / ethylene copolymer.

As the binder, a polymer composition having alkali metal ion conductivity such as lithium ions can be used. Examples of the polymer having such ion conductivity include polyether-based polymer compounds such as polyethylene oxide and polypropylene oxide, cross-linked polymer compounds of polyether, polyepichlorohydrin, polyphosphazene, polysiloxane, polyvinylpyrrolidone, and polyvinylidene. Carbonate, a high molecular compound such as polyacrylonitrile, a lithium salt or a complex of an alkali metal salt mainly composed of lithium, or a propylene carbonate, ethylene carbonate, an organic compound having a high dielectric constant such as γ-butyrolactone. A blended system can be used. These materials may be used in combination.

Various forms can be adopted as a mixed form of the negative electrode material and the above-mentioned binder. That is, a form in which both particles are mixed, a form in which a fibrous binder is entangled with the particles of the negative electrode material, a form in which a layer of the binder is attached to the particle surface, and the like are given. The mixing ratio of the binder to the negative electrode material powder is preferably 0.1 to 30% by weight, more preferably 0.5 to 1% by weight, based on the negative electrode material.
0% by weight. When the amount of the binder is more than 30% by weight, the internal resistance of the electrode tends to increase. On the other hand, when the amount of the binder is less than 0.1% by weight, the binding property between the current collector and the negative electrode material is reduced. It tends to be inferior.

When mixing the negative electrode material and the binder, a conductive material may be mixed together. The type of conductive material used is not particularly limited, and may be metal or non-metal. Examples of the metal conductive material include materials composed of metal elements such as Cu and Ni.
Examples of the nonmetallic conductive material include carbon materials such as graphite, carbon black, acetylene black, and Ketjen black. The average particle size of the conductive material is preferably 1 μm or less.

The mixing ratio of the conductive material is preferably 0.1 to 30% by weight, more preferably 0.5 to 30% by weight, based on the negative electrode material.
15% by weight. By setting the mixing ratio of the conductive material to 30% by weight or less, the charge / discharge capacity of the electrode per unit volume can be relatively increased. Further, by setting the mixing ratio of the conductive material to 0.1% by weight or more, a conductive path between the conductive materials can be sufficiently formed in the electrode.

The above-mentioned mixture containing at least the negative electrode material and the binder is applied on the current collector according to the purpose of use of the electrode.
The shape of the current collector to be applied is not particularly limited, and can be appropriately determined according to the usage of the negative electrode and the like. For example, a columnar, plate-like, or coil-like current collector can be used. The material of the current collector is preferably a metal such as copper, nickel, and stainless steel. Among these, copper foil is more preferable because it can be easily formed into a thin film and is inexpensive.

The application to the current collector can be performed by means known to those skilled in the art. When the mixture is in the form of a slurry, it can be applied to the current collector using, for example, a die coater or a doctor blade. When the mixture is in the form of a paste, it can be applied onto the current collector by roller coating or the like. When a solvent is used, the electrode can be manufactured by drying and removing the solvent.

The positive electrode constituting the non-aqueous electrolyte battery of the present invention includes, for example, a lithium transition metal composite oxide material such as lithium cobalt oxide, lithium nickel oxide, and lithium manganese oxide; Oxide materials; materials that can occlude and release lithium, such as carbonaceous materials such as fluorinated graphite, can be used. Specifically, LiFeO ₂ , LiCoO ₂ , LiNiO ₂ , Li
Mn ₂ O ₄ and these non-stoichiometric compounds, MnO ₂ , T
iS ₂ , FeS ₂ , Nb ₃ S ₄ , Mo ₃ S ₄ , Co
S ₂ , V ₂ O ₅ , P ₂ O ₅ , CrO ₃ , V ₃ O ₃ , Te
O ₂ , GeO ₂ or the like can be used. The method for manufacturing the positive electrode is not particularly limited, and the positive electrode can be manufactured by the same method as the above-described method for manufacturing the negative electrode.

As the positive electrode current collector used in the present invention, a valve metal or an alloy thereof is used. As used herein, the term “valve metal” has the same meaning as a known term, that is, a metal that forms a passive film on its surface by anodic oxidation in an electrolytic solution. As valve metals, IIIa, IVa, Va group (3
B, 4B, and 5B) and alloys thereof. Specifically, Al, Ti, Z
Examples thereof include r, Hf, Nb, Ta and alloys containing these metals, and Al, Ti, Ta and alloys containing these metals can be preferably used.
In particular, Al and its alloys are desirable because of their light weight and high energy density.

Since the surface of the valve metal is covered with an oxide film, it is possible to effectively prevent the compound represented by the formula (1) from being oxidatively decomposed at a portion in contact with the electrolytic solution.
On the other hand, when a metal material other than a valve metal such as stainless steel is used, the oxidative decomposition reaction of a compound having an SO bond cannot be prevented. Therefore, according to the present invention, it is possible to effectively improve the long-term storage property of the primary battery and the cycle characteristics of the secondary battery.

As in the case of the positive electrode current collector, a valve metal or an alloy thereof is used for the portion of the outer can that is in contact with the electrolyte on the positive electrode side. The entire outer can may be made of a valve metal or an alloy thereof, or only the liquid contact portion may be protected by the valve metal or an alloy thereof. As an example of the former, there can be cited an example in which Al or an Al alloy is used as the outer can. Further, as the latter example, there can be cited an example in which a wetted portion of stainless steel, which is suitably used as an outer can of a battery, is protected with Al or an Al alloy. As a method of protecting with valve metal, a method of protecting with plating or foil can be exemplified. The term “outer can” used in the present specification includes a lead wire housed inside the battery and a part such as a safety valve that operates when the internal pressure inside the battery rises.

The material and shape of the separator used in the battery of the present invention are not particularly limited. The separator separates the positive electrode and the negative electrode so that they do not come into physical contact with each other, and preferably has high ion permeability and low electric resistance. Preferably, the separator is selected from materials that are stable with respect to the electrolytic solution and have excellent liquid retention properties. Specifically, the above electrolytic solution can be impregnated using a porous sheet or nonwoven fabric made of a polyolefin such as polyethylene or polypropylene as a raw material.

The method for producing a non-aqueous electrolyte battery using the non-aqueous electrolyte, the negative electrode, the positive electrode, the outer can and the separator is not particularly limited, and may be appropriately selected from commonly employed methods. it can. For the non-aqueous electrolyte battery of the present invention, a gasket, a sealing plate, a cell case, and the like can be used as necessary in addition to the non-aqueous electrolyte, the negative electrode, the positive electrode, the outer can, and the separator. The manufacturing method is, for example, placing the negative electrode on the outer can, providing an electrolytic solution and a separator thereon,
Furthermore, the positive electrode is placed so as to face the negative electrode, and the battery can be caulked together with the gasket and the sealing plate. The shape of the battery is not particularly limited, and may be a cylinder type in which a sheet electrode and a separator are spirally formed, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, a coin type in which a pellet electrode and a separator are stacked, and the like. .

[0038]

The present invention will be described more specifically with reference to the following examples. The materials, usage amounts, ratios, operations, and the like shown below can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

Examples 1 to 13 LiC as a positive electrode material
oO ₂ (90 parts by weight) and carbon black (6 parts by weight)
And polyvinylidene fluoride (4 parts by weight) were added, mixed, and dispersed with N-methyl-2-pyrrolidone to form a slurry. This slurry was used to form a positive electrode current collector having a thickness of 20 μm.
Was uniformly applied on an Al foil, dried, and punched into a predetermined shape to obtain a positive electrode.

Polyvinylidene fluoride (10 parts by weight) was mixed with a negative electrode material artificial graphite powder (manufactured by Timcal Co., trade name: KS-44) (90 parts by weight), and N-methyl-2 was added.
-Dispersed with pyrrolidone to form a slurry. This slurry was uniformly applied on a copper foil having a thickness of 18 μm as a negative electrode current collector, dried, and punched into a predetermined shape to obtain a negative electrode.

As for the electrolyte, ethylene sulfite (ES), dimethyl sulfite (DMS), sulfolane (SLA), sulfolene (SLE), 1,3-propane sultone (PSL), and ethylene carbonate (EC) which is a cyclic carbonate ), Diethyl carbonate (DEC) as a chain carbonate, γ-butyrolactone (GBL) as a cyclic ester, methyl propionate (MP) as a chain ester, tetrahydrofuran (THF) as a cyclic ether, and chain ether. In a solvent in which dimethoxyethane (DME) is mixed with the composition shown in Table 1, sufficiently dried lithium hexafluorophosphate (LiPF ₆ ) is dissolved as a solute in a dry argon atmosphere so as to have a concentration of 1 mol / liter. Prepared by

Using these positive electrode, negative electrode and electrolyte, a coin-type non-aqueous electrolyte battery shown in FIG. 1 was produced in a dry argon atmosphere. That is, the positive electrode 1 and the negative electrode 2 were accommodated in a stainless steel positive electrode can (outer can) 3 and a sealing plate 4, respectively, and were laminated via a separator 5 made of a polyethylene microporous film impregnated with an electrolytic solution. . At this time, in order to use a valve metal as the material of the liquid contact portion on the positive electrode side, a material in which the inside of the positive electrode can 3 was previously covered with an Al foil 6 was used. Subsequently, the positive electrode can 3 and the sealing plate 4 were caulked and sealed via the gasket 7 to produce a coin-type battery.

(Comparative Examples 1 to 9) Coin-type batteries were prepared in the same manner as in Examples 1 to 5 and 10 to 13 except that a positive electrode can whose inner side was not covered with the Al foil 6 was used.
Each of the batteries of Examples 1 to 13 and Comparative Examples 1 to 9 was charged at a constant current of 0.5 mA at 25 ° C. with a final charge voltage of 4.2 V,
A charge / discharge test was performed at a discharge end voltage of 2.5 V. Table 1 shows the charge capacity and the discharge capacity per negative electrode weight in the first cycle in each battery. FIG. 2 shows the change in the discharge capacity per negative electrode weight according to the charge / discharge cycle in Example 2 and Comparative Example 2, and the change in the discharge capacity per negative electrode weight according to the charge / discharge cycle in Example 13 and Comparative Example 9. Is shown in FIG.

[0044]

[Table 1]

As is clear from Table 1, FIGS. 2 and 3, when the material of the liquid contact portion on the positive electrode side is stainless steel or the like, the compound represented by the formula (1) contained in the electrolytic solution is removed. A sufficient discharge capacity cannot be obtained because the oxidative decomposition reaction proceeds. On the other hand, when the material of the liquid contact portion on the positive electrode side is Al, the oxidative decomposition is suppressed, and the discharge capacity and cycle characteristics are significantly improved.

[0046]

The compound represented by the formula (1) is selected as the organic solvent of the electrolytic solution, and a valve metal or an alloy thereof is used for a portion of the positive electrode current collector and the outer can of the positive electrode which is in contact with the electrolytic solution. This makes it possible to provide a nonaqueous electrolyte battery having excellent low-temperature characteristics and long-term stability and, in the case of a secondary battery, excellent cycle characteristics. This non-aqueous electrolyte battery can be widely applied to electric products, energy storage equipment, and the like.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structural example of a coin-type battery.

FIG. 2 is a diagram showing a relationship between a charge / discharge cycle and a discharge capacity of the nonaqueous electrolyte batteries of Example 2 and Comparative Example 2 of the present invention.

FIG. 3 is a diagram showing a relationship between a charge / discharge cycle and a discharge capacity of the nonaqueous electrolyte batteries of Example 13 and Comparative Example 9 of the present invention.

[Description of sign]

 1: Positive electrode 2: Negative electrode 3: Positive electrode can (outer can) 4: Sealing plate 5: Separator 6: Al foil 7: Gasket 8: Positive electrode current collector 9: Negative electrode current collector

 ──────────────────────────────────────────────────の Continuing from the front page (72) Noriko Shima, Inventor, Tsukuba Research Laboratory, Mitsubishi Chemical Co., Ltd. 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Prefecture

Claims (9)

[Claims] 1. A non-aqueous electrolyte solution comprising a negative electrode, a positive electrode, a solute and an organic solvent comprising lithium as an active material, a separator and an outer can, wherein the organic solvent is represented by the formula (1). Including at least one compound represented by the formula, wherein the material of the current collector used for the positive electrode and the material of the liquid contacting part with the electrolytic solution on the positive electrode side of the outer can are a valve metal or an alloy thereof. Non-aqueous electrolyte battery. ## STR1 _{R 1 -A-R 2 (1} ) ( wherein, R ₁ and R ₂ are each independently an alkyl group optionally substituted with an aryl group or a halogen atom,
Or an alkyl group or an aryl group optionally substituted with a halogen atom, or R ₁ and R ₂ are bonded to each other to form a cyclic structure which may contain an unsaturated bond together with -A-, Having a structure represented by any of formulas (2) to (5): 2. In the above formula (1), R ₁ and R ₂
Are each independently a phenyl group or an alkyl group having 1 to 4 carbon atoms which may be substituted with a halogen atom, or a phenyl group which may be substituted with a halogen atom, or R ₁ and R ₂ are The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery forms a cyclic structure which may combine with -A- to include an unsaturated bond. 3. The valve metal or its alloy is made of Al, T
3. The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery is selected from the group consisting of i, Zr, Hf, Nb, Ta, and an alloy containing these metals. 4. The non-aqueous electrolyte battery according to claim 3, wherein the valve metal or an alloy thereof is Al or an Al alloy. 5. The negative electrode includes one or more materials selected from the group consisting of a carbonaceous material capable of occluding and releasing lithium, a metal oxide material capable of occluding and releasing lithium, lithium metal and a lithium alloy. The non-aqueous electrolyte battery according to claim 1, wherein: 6. The cathode according to claim 1, wherein the positive electrode is at least one selected from the group consisting of a lithium transition metal composite oxide material capable of inserting and extracting lithium, a transition metal oxide material capable of inserting and extracting lithium, and a carbonaceous material. The nonaqueous electrolyte battery according to claim 1, further comprising a material. 7. The method according to claim 1, wherein the solute is LiClO ₄ , LiP
F ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃
SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN
(CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) and LiC (C
Nonaqueous electrolyte battery according to claim 1, characterized in that it is a F ₃ SO ₂₎ 1 or more lithium salts selected from the group consisting of _3. 8. The non-aqueous system according to claim 1, wherein the content of the compound represented by the formula (1) in the organic solvent is 0.05 to 100 vol%. Electrolyte battery. 9. The non-aqueous electrolytic solution having a solute concentration of 0.
The non-aqueous electrolyte battery according to any one of claims 1 to 8, wherein the amount is 5 to 2.0 mol / liter.