JP2000003730A - Nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the energy quantity and cycle lifetime of a lithium secondary battery. SOLUTION: Transition metal oxide containing lithium is used as a positive electrode active material, and the compound containing silicon atom is used as a negative electrode material, and a material having a volume resistivity at 102 Ω.cm or less is used as the negative electrode conductive agent. One or more kinds of material is selected as the described material from among metals such as metal powder, metal flake, metal fiber and the carbon compound such as carbon black, graphite and carbon fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous secondary battery, and more particularly to a lithium secondary battery having a high capacity and a long cycle life.

[0002]

2. Description of the Related Art In a lithium secondary battery using a negative electrode material containing no lithium metal and a positive electrode active material containing lithium, first, lithium contained in the positive electrode active material is inserted into the negative electrode material to increase the activity of the negative electrode material. . This is the charging reaction, and the reverse reaction of inserting lithium ions from the negative electrode material into the positive electrode active material is the discharging reaction. Carbon is used as this type of lithium battery negative electrode material.
The theoretical capacity of carbon (C ₆ Li) is 372 mAh / g, and an even higher capacity negative electrode material is desired. The theoretical capacity of silicon forming an intermetallic compound with lithium is 400
It is well known that it exceeds 0 mAh / g and is larger than that of carbon. For example, Japanese Patent Application Laid-Open No. Hei 5-74463 discloses single-crystal silicon.
02 discloses amorphous silicon. Examples of alloys containing silicon include Li-Al alloys containing silicon as disclosed in JP-A-63-66369 (19% by weight of silicon),
63-174275 (0.05 to 1.0% by weight of silicon) and 63-285865 (1 to 5% by weight of silicon)
Is disclosed. However, since all of these alloy patent applications mainly use lithium, a compound containing no lithium was used as the positive electrode active material. Also,
In Japanese Patent Application Laid-Open No. 4-109562, 0.05 to 1.
A 0% by weight alloy is disclosed. However, none of them has a poor cycle life and has not been put to practical use. The reason why the cycle life of silicon is inferior is that the electron conductivity is low, the volume expands due to lithium insertion, and the electrical resistance increases due to the pulverization of particles. JP-A-60-124357 discloses a method of adding a metal powder to a metal or an alloy that occludes / releases an alkali metal ion. JP-A-62-226563 discloses a method of mixing a metal capable of alloying with lithium and graphite powder. A method has been disclosed, but the capacity is not yet sufficient. When using a silicon compound having a large capacity, it is important to ensure electron conductivity.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to increase the energy amount and the cycle life of a lithium secondary battery.

[0004]

An object of the present invention is to provide a non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material and a non-aqueous electrolyte, wherein the positive electrode active material is a transition metal oxide containing lithium. A compound containing a silicon atom is used as the negative electrode material, and the negative electrode mixture has a volume resistivity of 10 ² Ω · cm.
The problem was solved by mixing and using the following substances as conductive agents.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. (1) In a non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material, and a non-aqueous electrolyte, the positive electrode active material is a lithium-containing transition metal oxide, and the negative electrode material is a silicon atom capable of inserting and releasing lithium. A non-aqueous secondary battery characterized by comprising a compound having a volume resistivity of 10 ² Ω · cm or less in a negative electrode mixture as a conductive agent. (2) A non-aqueous secondary battery in which the silicon compound according to item (1) has an average particle size of 0.01 μm or more and 100 μm or less. (3) A non-aqueous secondary battery in which the silicon compound according to item (1) is an alloy. (4) A non-aqueous secondary battery in which the metal other than silicon of the alloy according to item (3) is at least one selected from alkaline earth metals, transition metals, and metalloids. (5) The metal other than silicon described in the item (3) or (4) is Ge, Be, Ag, Al, Au, Cd, Ga, or I.
A non-aqueous secondary battery that is at least one selected from n, Sb, Sn, and Zn. (6) A nonaqueous secondary battery in which the weight ratio of the metal other than silicon to silicon according to items (3) to (5) is 5 to 90%. (7) A non-aqueous secondary battery in which the silicon compound according to item (1) is silicon obtained by removing a metal from a metal silicide. (8) A nonaqueous secondary battery in which the metal silicide according to item (7) is a lithium silicide. (9) When the lithium content of the lithium silicide in the item (8) is
A non-aqueous secondary battery in which the content is 100 to 420 atomic% with respect to silicon. (10) A non-aqueous secondary battery in which the silicon compound according to item (1) is attached to a ceramic that does not react with lithium. (11) The ceramic described in (10) is made of Al ₂ O ₃ or Si.
A non-aqueous secondary battery that is O ₂ , TiO ₂ , SiC, or Si ₃ N ₄ . (12) A non-aqueous secondary battery in which the weight ratio of the ceramic to the silicon compound according to (10) or (11) is 2 to 50%. (13) A method for producing a negative electrode, wherein the method of attaching the ceramic to the silicon compound according to any one of the above items (10) to (12) comprises a step of heating to 300 to 1300 ° C. (14) As a conductive agent in the negative electrode mixture, the volume resistivity is 10 ²
A negative electrode for a non-aqueous secondary battery containing a substance of Ω · cm or less. (15) The conductive agent according to item (1) or (14) is a metal powder, a metal flake having a volume resistivity of 10 ² Ω · cm or less.
Non-aqueous secondary batteries that are metals selected from metals such as metal fibers. (16) A non-aqueous secondary battery in which the conductive agent is a carbon compound selected from carbon compounds having a volume resistivity of 10 ² Ω · cm or less, such as carbon black, graphite, and carbon fiber. (17) A non-aqueous secondary battery in which the conductive agent contains at least one substance of a metal powder and a carbon compound. (18) The conductive agent has a volume conversion ratio of 0.1 to the silicon compound.
Non-aqueous secondary batteries included in 01 to 10. (19) The conductive agent has a particle size of 0.01 μm or more,
A non-aqueous secondary battery having a size of 0 μm or less. (20) A non-aqueous secondary battery in which the metal powder used as the conductive agent is at least one selected from copper, nickel, aluminum, and silver. (21) The carbon compound used as the conductive agent is a natural graphite such as flaky graphite, flaky graphite, earthy graphite, a high-temperature fired body such as petroleum coke, coal coke, celluloses, sugars, mesophase pitch, and vapor phase growth. Graphites such as graphite, carbons such as acetylene black, furnace black, Ketjen black, channel black, lamp black, thermal black, asphalt pitch, coal tar, activated carbon, mesofused pitch, carbon such as polyacene A non-aqueous secondary battery that is at least one selected from materials. (22) A non-aqueous secondary battery, wherein the silicon compound according to item (1) is a silicon compound which is previously coated with a thermoplastic resin. (23) A non-aqueous secondary battery in which the thermoplastic resin described in (22) is polyvinylidene fluoride or polytetrafluoroethylene. (24) A non-aqueous secondary battery using a negative electrode in which the weight ratio of the thermoplastic resin to the silicon compound according to (22) or (23) is 2 to 30%. (25) A nonaqueous secondary battery using a negative electrode having a thermoplastic resin coverage of 5 to 100% according to any one of the above items (21) to (24). (26) The charge / discharge range of the silicon compound according to the item (1) is
As the equivalent ratio of lithium inserted and released into silicon, Li _x
A non-aqueous secondary battery in which x is in the range of 0 to 4.2 when represented by Si. (27) The charge / discharge range of the silicon compound according to item (1) is
A non-aqueous secondary battery in which x is in the range of 0 to 3.7 when represented by Li _x Si. (28) The positive electrode active material described in (1) is Li _y MO ₂ (M
= Co, Ni, Fe, at least one material having a Mn y = 0 to 1.2) material containing or _{Li z N 2 O 4 (N} = Mn z = 0~2) spinel structure represented by, Non-aqueous secondary battery using. (29) Non-aqueous water used in the paragraphs (3) to (27), wherein the average particle size of particles of a silicon-containing compound selected from a simple substance of silicon, a silicon alloy, and a silicide capable of reacting with lithium is 0.01 μm or more and 100 μm or less. Rechargeable battery.

The positive electrode (or negative electrode) used in the present invention
Applies the positive electrode mixture (or the negative electrode mixture) on the current collector,
It can be made by molding. The positive electrode mixture (or negative electrode mixture) may include a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives in addition to the positive electrode active material (or the negative electrode material). it can. These electrodes may be disk-shaped or plate-shaped, but are preferably in the form of a flexible sheet.

Hereinafter, the structure and material of the present invention will be described in detail. The compound containing a silicon atom capable of inserting and releasing lithium used in the negative electrode material of the present invention means a simple substance of silicon, a silicon alloy, or a silicide. As silicon alone,
Any of single crystal, polycrystal, and amorphous can be used. The purity of the simple substance is preferably 85% by weight or more,
It is preferably at least 5% by weight. Furthermore, 99% by weight or more is particularly preferable. The average particle size is 0.01-100μ
m is preferred. In particular, 0.01 to 50 μm is preferable.
Further, the thickness is preferably 0.01 to 5 μm.

The silicon alloy suppresses pulverization due to expansion and contraction of silicon generated when lithium is inserted and released,
It is considered to be effective in improving the low conductivity of silicon. As the alloy, an alloy with an alkaline earth metal, a transition metal or a metalloid is preferable. Particularly, a solid solution alloy or a eutectic alloy is preferable. A solid solution alloy is an alloy that forms a solid solution. The Ge alloy is a solid solution alloy. A eutectic alloy is an alloy that eutectic in any proportion with silicon, but the solid obtained upon cooling is a mixture of silicon and metal. Be, Ag, Al, Au, Cd, Ga, In, S
b, Sn, and Zn form a eutectic alloy. Among them, Ge, Be, Ag, Al, Au, Cd, Ga, I
An alloy of n, Sb, Sn, and Zn is preferable. Also, two or more of these alloys are preferable. In particular, Ge, Ag, Al,
An alloy containing Cd, In, Sb, Sn, and Zn is preferable.
The mixing ratio of these alloys is preferably 5 to 70% by weight with respect to silicon. Particularly, 10 to 60% by weight is preferable.
In this case, the electrical conductivity is improved, but the specific conductivity is one of the specific conductivity of silicon or silicon compound before alloying in terms of battery performance, particularly, discharge capacity, high rate characteristics, and cycle life.
It is preferably 0 times or more. The average particle size of the alloy is preferably 0.01 to 40 μm. In particular, 0.03 to 5
μm is preferred.

[0009] Silicide refers to a compound of silicon and a metal. As silicides, CaSi, CaSi ₂ , Mg ₂ S
i, BaSi ₂ , SrSi ₂ , Cu ₅ Si, FeSi, F
eSi ₂ , CoSi ₂ , Ni ₂ Si, NiSi ₂ , MnS
i, MnSi ₂ , MoSi ₂ , CrSi ₂ , TiSi ₂ , T
i ₅ Si ₃ , Cr ₃ Si, NbSi ₂ , NdSi ₂ , CeS
i ₂ , SmSi ₂ , DySi ₂ , ZrSi ₂ , WSi ₂ , W _{5
Si 3, TaSi 2, Ta 5} Si 3, TmSi 2, TbS
i ₂ , YbSi ₂ , YSi ₂ , YSi ₂ , ErSi, ErS
i ₂ , GdSi _2, PtSi, V ₃ Si, VSi ₂ , HfS
i ₂ , PdSi, PrSi ₂ , HoSi ₂ , EuSi ₂ , L
aSi, RuSi, ReSi, RhSi and the like are used.

As the silicon compound, silicon obtained by removing a metal from a metal silicide can be used. Regarding the shape of this silicon, the cavities are large and the silicon has a very fine shape like primary particles of silicon. It is thought that the reason for using silicon to improve the cycle life is that the silicon is hardly pulverized. The metal of the metal silicide is preferably an alkali metal or an alkaline earth metal. Among them, Li, Ca, and Mg are preferable. Particularly, Li is preferable. The lithium content of the lithium silicide is preferably 100 to 420 mol% based on silicon. Particularly, 200 to 420 is preferable. The method of removing an alkali metal or an alkaline earth metal from a silicide of an alkali metal or an alkaline earth metal is preferably performed by reacting with an alkali metal or an alkaline earth metal, and using a solvent in which a reaction product is dissolved. . As the solvent, water and alcohols are preferable. In particular, degassed and dehydrated alcohols are preferred. As alcohols, methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol,
2-butyl alcohol, t-butyl alcohol, 1-pentyl alcohol, 2-pentyl alcohol, and 3-pentyl alcohol are preferred. Particularly, 1-propyl alcohol, 2-propyl alcohol, 1-butyl alcohol, 2-butyl alcohol, and t-butyl alcohol are preferred. For removing Ca and Mg, water is preferable. In particular, it is preferable to use a pH buffer that keeps the pH around neutral.

It is considered that the ceramic adhered to the silicon compound is effective in suppressing the pulverization of silicon. As the ceramic, a compound that does not basically react with lithium is preferable. In particular, Al ₂ O ₃ , SiO ₂ , TiO ₂ , Si
C and Si ₃ N ₄ are preferred. As a method for attaching silicon and ceramic, mixing, heating, vapor deposition, and CVD are used, and particularly, a combination of mixing and heating is preferable. In particular, A
After l ₂ O ₃ or SiO ₂ sol and silicon are dispersed and mixed, the mixture is heated and the solid solution is pulverized to form silicon and Al ₂ O ₃ or S.
Deposits of iO ₂ can be obtained. In this case, Al ₂ O
_The deposits of ₃ and SiO ₂ refer to a state in which silicon powder is covered on their surfaces, they are trapped inside a mass of them, or they are covered on the surface of silicon. Mixing and dispersion can be achieved by mechanical stirring, ultrasonic waves, and kneading. Heating in inert gas at 300 ° C ~ 13
It is preferable to perform the reaction in the range of 00 ° C.,
1200 ° C. is preferred. Inert gases are argon, nitrogen,
Hydrogen is raised. These mixed gases are also used. As the pulverizing method, a well-known method such as a ball mill, a vibration mill, a planetary ball mill, and a jet mill is used. This pulverization is also preferably performed in an inert gas. The mixing ratio of the ceramic to silicon is preferably in the range of 2 to 50% by weight, and particularly preferably 3 to 40%. The average particle size determined from electron microscopic observation of silicon is 0.01 to 40 μm.
m is preferred. In particular, 0.03 to 5 μm is preferable.

It is preferable to coat the silicon compound used in the present invention with a thermoplastic resin. Thermoplastic resin is a fluorine-containing polymer compound, imide polymer, vinyl polymer,
An acrylate polymer, an ester polymer, polyacrylonitrile, or the like is used. In particular, the thermoplastic resin is preferably a resin that does not easily swell in the electrolytic solution. As a specific example,
Polyacrylic acid, Na polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyhydroxyethyl (meth) acrylate, styrene
Water-soluble polymers such as maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, (Meth) acrylic acid ester containing (meth) acrylic acid ester such as polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, and 2-ethylhexyl acrylate Coalescing,
(Meth) acrylate-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene, neoprene rubber, fluorine rubber, poly Emulsions (latex) or suspensions of ethylene oxide, polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin and the like can be given. In particular, polyacrylate latex, carboxymethylcellulose, polytetrafluoroethylene, and polyvinylidene fluoride are exemplified. These compounds can be used alone or as a mixture. Particularly, a fluorine-containing polymer compound is preferable. Among them, polytetrafluoroethylene and polyvinylidene fluoride are preferable. As a method of coating in advance, a thermoplastic resin is dissolved in a solvent, and a silicon compound is mixed and kneaded in the solution. A method of drying the solution and pulverizing the obtained solid is preferable. The use amount of the thermoplastic resin to the silicon compound is preferably 2 to 30% by weight. Particularly, 3 to 20% by weight is preferable. Coverage is 5
It is preferably from 100% to 100%, and particularly preferably from 5% to 90%. The average size of the coated particles is between 0.01 μm and 4 μm.
0 μm is preferred. In particular, 0.03 to 5 μm is preferable.

[0013] The charge / discharge range of the silicon compound negative electrode material is defined as the ratio of lithium and silicon atoms that can be inserted and released by Li _x
When represented by Si, x = 0 to 4.2 is preferable. As a result of intensive studies on the improvement of the cycle life of silicon, x = 0 to 3.7.
It has been found that the cycle life is greatly improved when it is within the range. The charging potential was 0.0 V including the overvoltage at x = 4.2 with respect to the lithium metal counter electrode, whereas the charging potential was about 0.05 V at x = 3.7. At this time, the shape of the discharge curve changes, and a flat discharge curve is obtained around 0.5 V (vs. lithium metal) at the return of 0.0 V charge, whereas it is 0.05 V or more, particularly 0.08 V or more.
Above V (x = 3.6), a smooth curve having an average voltage at about 0.4 V is obtained. That is, it is found that a specific phenomenon in which the discharge potential decreases as the charging end voltage is increased is found, and that the reversibility of the charge / discharge reaction is also improved.

Although a method having an effect of improving the cycle life while maintaining a high capacity of the silicon compound has been individually described, a more preferred embodiment has been found to achieve a higher improvement effect by a combination of the above methods. . In the present invention, as the negative electrode material, in addition to the silicon compound of the present invention, a compound capable of inserting and releasing lithium such as a carbonaceous material, an oxide material, a nitride material, a sulfide material, a lithium metal, and a lithium alloy can be used.

The conductive agent in the negative electrode mixture of the present invention is not limited to metals and carbon compounds as long as the material has a volume resistivity of 10 ² Ω · cm or less, and many materials such as oxides can be used. , Carbon compounds are preferred. Volume resistivity is 10
Examples of the substance having a resistivity of ² Ω · cm or less include metals such as metal powder, metal flakes and metal fibers, and carbon compounds such as carbon black, graphite and carbon fibers. As the metal, a metal having low reactivity with lithium, that is, a metal that is unlikely to form a lithium alloy is preferable. Specifically, copper, nickel, iron, chromium, molybdenum, titanium, tungsten, gold, platinum, aluminum, silver, and the like are preferable. Is preferred. Among them, copper and nickel are preferable. The shape is preferably needle-like, column-like, plate-like, massive powder, scaly flake, or fibrous, but powder-like is preferred. Further, a metal substantially adhered to the surface is also possible, and more specifically, a metal or the like made of granular or fibrous resin or ceramic may be used. As a carbon compound,
Natural graphite such as flaky graphite, flaky graphite, earthy graphite, petroleum coke, coal coke, celluloses, sugars, high-temperature fired bodies such as mesophase pitch, graphite such as artificial graphite such as vapor-grown graphite, acetylene black, Furnace Black, Ketchen Black, Channel Black,
Carbon blacks such as lamp black and thermal black, asphalt pitch, coal tar, activated carbon, meso fuse pitch, carbon materials such as polyacene, and carbon fibers are preferable. Among the carbon compounds, graphite and acetylene black are preferred. These conductive agents may be used alone or as a mixture of two or more metals or carbon compounds, and may be used as a mixture of a metal and a carbon compound. The amount of the conductive agent in the negative electrode mixture is preferably from 0.01 to 10, preferably from 0.1 to 5, based on the volume of the silicon compound. If the amount is small, the effect of improving the conductivity is small. A preferred range of the particle size of the conductive agent is 0.01 μm to 20 μm, preferably 0.1 μm.
μm to 10 μm.

The cathode material used in the present invention is a lithium-containing transition metal oxide. Preferably Ti, V, Cr,
An oxide mainly containing lithium and at least one transition metal element selected from Mn, Fe, Co, Ni, Mo and W, and having a molar ratio of lithium to transition metal of 0.1.
3 to 2.2. More preferably, V, C
at least one selected from r, Mn, Fe, Co, and Ni
An oxide mainly containing various kinds of transition metal elements and lithium, and a compound in which the molar ratio of lithium to the transition metal is 0.3 to 2.2. It should be noted that Al, Ga, and I are present in a range of less than 30 mole percent based on the transition metal mainly present.
It may contain n, Ge, Sn, Pb, Sb, Bi, Si, P, B, and the like.

Among the above-mentioned positive electrode active materials, the general formula Li_xM
O_Two(M = Co, Ni, Fe, Mnx = 0 to 1.2),
Or Li_yN_TwoO_Four(N = Mny = 0-2)
Using at least one kind of material having a spinel structure
This is good. Specifically, LixCoO_Two, Li_x
NiO_Two, Li_xMnO_Two, Li_xCo_aNi_1-aO_Two, Li
_xCo_bV_1-bO_z, Li_xCo_bFe_1-bO_Two, Li_xMn
_TwoO_Four, Li_xMn_cCo _2-cO_Four, Li_xMn_cNi
_2-cO_Four, Li_xMn_cV_2-cO_Four, Li_xMn_cFe_2-cO
_Four(Where x = 0.02 to 1.2, a = 0.1 to 0.
9, b = 0.8 to 0.98, c = 1.6 to 1.96, z
= 2.01-2.3). Most preferred lithium containing
Examples of transition metal oxides include Li_xCoO_Two, Li_xNi
O_Two, Li_xMnO_Two, Li_xCo_aNi_1-aO_Two, Li_x
Mn_TwoO_Four, Li_xCo_bV_1-bO_z(X = 0.02
1.2, a = 0.1 to 0.9, b = 0.9 to 0.98,
z = 2.01 to 2.3). Note that the value of x is
This is a value before the start of discharge, and increases or decreases due to charging and discharging.

The positive electrode active material used in the present invention can be synthesized by a method in which a lithium compound and a transition metal compound are mixed and fired, or a solution reaction, but the firing method is particularly preferred. Details of the firing are described in paragraph 35 of JP-A-6-60,867, JP-A-7-14,579 and the like, and these methods can be used. The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent. Further, as a method of chemically inserting lithium ions into the transition metal oxide, a method of synthesizing lithium metal, a lithium alloy, or butyllithium by reaction with the transition metal oxide may be used.

The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.1 to 50 μm. It is preferable that the volume of the particles of 0.5 to 30 μm is 95% or more. The volume occupied by the particle group having a particle size of 3 μm or less is 18% or less of the total volume, and 15 μm or more and 25 μm or more
More preferably, the volume occupied by the particle group of m or less is 18% or less of the total volume. No particular limitation is imposed on the specific surface area is preferably 0.01 to 50 m ² / g by the BET method, particularly preferably 0.2m ² / g~1m ² / g. Further, when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water, the pH of the supernatant is preferably 7 or more and 12 or less.

When the positive electrode active material of the present invention is obtained by firing, the firing temperature is preferably from 500 to 1500 ° C., more preferably from 700 to 1200 ° C., and particularly preferably from 750 to 1000 ° C. The firing time is preferably 4 to 30 hours, more preferably 6 to 20 hours, and particularly preferably 6 to 15 hours.

In the present invention, a binder is used to hold the electrode mixture. Examples of the binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Preferred binders include starch, carboxymethyl cellulose, cellulose, diacetyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, polyacrylic acid,
Water-soluble polymers such as sodium polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyhydroxyethyl (meth) acrylate, styrene-maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene , Polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EP
DM), sulfonated EPDM, polyvinyl acetal resin, (meth) acrylate copolymer containing (meth) acrylate such as methyl methacrylate, 2-ethylhexyl acrylate, and (meth) acrylate-acrylonitrile copolymer Copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene butadiene copolymer, acrylonitrile butadiene copolymer, polybutadiene, neoprene rubber, fluoro rubber, polyethylene oxide, polyester polyurethane resin, polyether polyurethane resin And emulsions (latex) or suspensions of polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin and the like. In particular, polyacrylate latex, carboxymethylcellulose, polytetrafluoroethylene, and polyvinylidene fluoride are exemplified. As these binders, it is preferable to use those in which fine powder is dispersed in water, and the average size of particles in the dispersion is 0.01 to 5%.
μm, more preferably 0.05 to 1 μm
It is particularly preferred to use m. These binders can be used alone or as a mixture. If the amount of the binder is small, the holding power and cohesive strength of the electrode mixture are weak. If it is too large, the electrode volume increases and the capacity per unit volume or unit weight of the electrode decreases. For these reasons, the amount of the binder added is preferably 1 to 30% by weight, particularly preferably 2 to 10% by weight.

As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. Usually, fibers such as olefin-based polymers such as polypropylene and polyethylene, glass, and carbon are used. Although the amount of the filler is not particularly limited,
30% by weight is preferred. As the ionic conductive agent, those known as inorganic and organic solid electrolytes can be used, and the details are described in the section of the electrolytic solution. The pressure booster is a compound for raising the internal pressure of the battery, and a carbonate such as lithium carbonate is a typical example.

In the current collector which can be used in the present invention, the positive electrode is aluminum, stainless steel, nickel, titanium or an alloy thereof, and the negative electrode is copper, stainless steel, nickel,
Titanium or their alloys. The form of the current collector is foil, expanded metal, punched metal, or wire mesh. In particular, an aluminum foil is preferable for the positive electrode, and a copper foil is preferable for the negative electrode.

The thickness of the foil is preferably 7 μm to 100 μm, more preferably 7 μm to 50 μm, and particularly preferably 7 μm to 20 μm. Expanded metal, punching metal, wire mesh thickness is 7μm ~
200 μm is preferred, and more preferably 7 μm to 15 μm.
0 μm, particularly preferably 7 μm to 100 μm. The purity of the current collector is preferably 98% or more, more preferably 99% or more, and particularly preferably 99.
3% or more. The surface of the current collector may be washed with an acid, an alkali, an organic solvent, or the like.

In order to reduce the thickness of the current collector, it is more preferable that a metal layer is formed on both surfaces of a plastic sheet. The plastic is preferably excellent in stretchability and heat resistance, and is, for example, polyethylene terephthalate. Metals alone have little elasticity and are vulnerable to external forces. If a metal layer is formed on plastic, it will be resistant to impact. More specifically, the current collector may be a composite current collector in which a base material such as a synthetic resin film or paper is coated with an electron conductive material. As a synthetic resin film as a base material,
Examples include fluororesin, polyethylene terephthalate, polycarbonate, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polyimide, polyamide, cellulose dielectric, and polysulfone. Examples of the electron conductive material that coats the base material include carbonaceous materials such as graphite and carbon black, metal elements such as aluminum, copper, nickel, chromium, iron, molybdenum, gold, and silver and alloys thereof. it can. Particularly preferred electron conductive materials are metals, such as aluminum, copper, nickel and stainless steel. The composite current collector may be in a form in which a base sheet and a metal sheet are laminated, or a metal layer may be formed by vapor deposition or the like.

Next, the structure of the positive and negative electrodes according to the present invention will be described. The positive and negative electrodes preferably have a form in which an electrode mixture is applied to both surfaces of a current collector. In this case, the number of layers per side may be one or two or more. When the number of layers per side is two or more, the number of layers containing the positive electrode active material (or the negative electrode material) may be two or more. More preferably, the layer containing the positive electrode active material (or the negative electrode material) and the positive electrode active material (or the negative electrode material)
This is a case where it is composed of a layer containing no. The layer containing no positive electrode active material (or negative electrode material) includes a protective layer for protecting the layer containing the positive electrode active material (or negative electrode material), and a layer between the divided positive electrode active material (or negative electrode material) containing layer. Layer, positive electrode active material (or negative electrode material)
There is an undercoat layer between the containing layer and the current collector, and these are collectively referred to as an auxiliary layer in the present invention.

The protective layer is preferably on both the positive and negative electrodes or on either the positive or negative electrode. In the negative electrode, when lithium is inserted into the negative electrode material in the battery, the negative electrode preferably has a form having a protective layer. The protective layer is composed of at least one layer, and may be composed of a plurality of layers of the same type or different types. Further, the current collector may have a form in which the protective layer is provided only on one side of the mixture layer on both sides. These protective layers are composed of water-insoluble particles, a binder and the like. As the binder, the binder used when forming the above-mentioned electrode mixture can be used. As the water-insoluble particles, various kinds of conductive particles, organic and inorganic particles having substantially no conductivity can be used. The solubility of the water-insoluble particles in water is 100 ppm or less, and preferably the insoluble particles are insoluble. 2.5% by weight of particles contained in the protective layer
Not less than 96% by weight, preferably not less than 5% by weight and 95% by weight.
% By weight or less, more preferably 10% by weight or more and 93% by weight or less.

Examples of the water-insoluble conductive particles include metals, metal oxides, metal fibers, carbon fibers, and carbon particles such as carbon black and graphite. Among these water-insoluble conductive particles, those having low reactivity with alkali metals, particularly lithium, are preferable, and metal powder and carbon particles are more preferable. The electric resistivity at 20 ° C. of the elements constituting the particles is preferably 5 × 10 ⁹ Ω · m or less.

As the metal powder, a metal having low reactivity with lithium, that is, a metal which is unlikely to form a lithium alloy is preferable, and specifically, copper, nickel, iron, chromium, molybdenum, titanium, tungsten, and tantalum are preferable. The shape of these metal powders may be any of a needle shape, a column shape, a plate shape, and a lump shape, and the maximum diameter is preferably 0.02 μm or more and 20 μm or less, more preferably 0.1 μm or more and 10 μm or less. It is preferable that the surface of these metal powders is not excessively oxidized. When the surfaces are oxidized, it is preferable to perform heat treatment in a reducing atmosphere.

As the carbon particles, known carbon materials which are conventionally used as a conductive material when the electrode active material is not conductive can be used. Specifically, a conductive agent used when preparing an electrode mixture is used.

Examples of the water-insoluble particles having substantially no conductivity include fine powder of Teflon, SiC, aluminum nitride, alumina, zirconia, magnesia, mullite, forsterite, and steatite.
These particles may be used in combination with the conductive particles, and are preferably used in an amount of 0.01 to 10 times the conductive particles.

The positive (negative) electrode sheet can be prepared by applying a positive (negative) electrode mixture on a current collector, drying and compressing. To prepare the mixture, a positive electrode active material (or a negative electrode material) and a conductive agent are mixed, a binder (a solution or a suspension or an emulsion of resin powder) and a dispersion medium are added, and the mixture is kneaded and mixed. Subsequently, the dispersion can be carried out by using a mixer, a homogenizer, a dissolver, a planetary mixer, a paint shaker, a stirring mixer such as a sand mill, or a disperser. Water or an organic solvent is used as the dispersion medium, but water is preferred.
In addition, additives such as a filler, an ion conductive agent, and a pressure enhancer may be appropriately added. The pH of the dispersion is 5 to 5 at the negative electrode.
10, 7 to 12 is preferable for the positive electrode.

The coating can be performed by various methods.
Examples of the method include a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion method, a slide method, a curtain method, a gravure method, a bar method, a dip method, and a squeeze method. A method using an extrusion die and a method using a slide coater are particularly preferable. The coating is preferably performed at a speed of 0.1 to 100 m / min. At this time, by selecting the above-mentioned coating method in accordance with the liquid physical properties and drying properties of the mixture paste, a good surface state of the coating layer can be obtained.
When the electrode layer has a plurality of layers, it is preferable to apply the plurality of layers simultaneously from the viewpoint of uniform electrode production, production cost, and the like. The thickness, length and width of the coating layer are determined by the size of the battery. A typical thickness of the coating layer is 10 to 1000 μm in a compressed state after drying. The electrode sheet after application is hot air, vacuum, infrared, far infrared,
It is dried and dehydrated by the action of electron beams and low humidity air. These methods can be used alone or in combination. The drying temperature is preferably in the range of 80 to 350C, particularly preferably in the range of 100 to 260C. The water content after drying is preferably 2000 ppm or less, more preferably 500 ppm or less. The compression of the electrode sheet can be performed by a commonly used pressing method, but a die pressing method and a calendar pressing method are particularly preferable. The press pressure is not particularly limited, but is preferably 10 kg / cm ^{2 to 3} t / cm ² . The press speed of the calendar press method is 0.1 ~
50 m / min is preferred. Press temperature is from room temperature to 200 ℃
Is preferred.

The separator which can be used in the present invention is not limited as long as it has a high ion permeability, a predetermined mechanical strength, and an insulating thin film.
Fluorine polymer, cellulose polymer, polyimide, nylon, glass fiber, alumina fiber is used,
As the form, a nonwoven fabric, a woven fabric, or a microporous film is used. In particular, the material is preferably polypropylene, polyethylene, a mixture of polypropylene and polyethylene, a mixture of polypropylene and Teflon, a mixture of polyethylene and Teflon, and the form is preferably a microporous film. In particular, a microporous film having a pore size of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferable. These microporous films may be a single film or a composite film composed of two or more layers having different properties such as the shape, density, and material of the micropores. For example, a composite film obtained by laminating a polyethylene film and a polypropylene film can be used.

The electrolyte generally comprises a supporting salt and a solvent. As a supporting salt in a lithium secondary battery, a lithium salt is mainly used. Examples of the lithium salt that can be used in the present invention include LiClO ₄ , LiBF ₄ , LiPF ₆ ,
_{LiCF 3 CO 2, LiAsF 6,} LiSbF 6, LiB 10
Cl ₁₀ , a fluorosulfonic acid represented by LiOSO ₂ C _n F _{2n + 1} (n is a positive integer of 6 or less), LiN (SO ₂ C _n F
_{2n + 1} ) (SO ₂ C _m F _{2m + 1} ) (m, n
Is a positive integer of 6 or less), LiC (SO ₂ C _p F
_{2p + 1) (SO 2 C} q F 2q + 1) (SO 2 C r F 2r + 1 methide salts (p represented by), q, r are each 6 or less positive integer), lower aliphatic carboxylic Lithium oxide, LiAlCl
₄ , Li salts such as LiCl, LiBr, LiI, lithium chloroborane and lithium tetraphenylborate can be used, and one or more of these can be used in combination. Among them, those in which LiBF ₄ and / or LiPF ₆ are dissolved are preferable. The concentration of the supporting salt is not particularly limited, but may be 0.1 to 1 liter of the electrolytic solution.
2-3 moles are preferred.

[0036] Solvents usable in the present invention include propylene.
Lencarbonate, ethylene carbonate, butyleneca
-Carbonate, chloroethylene carbonate, trifcarbonate
Fluoromethylethylene, difluoromethylethylene carbonate
, Monofluoromethyl ethylene carbonate, methyl hexafluoride
Acetate, methyl trifluoride acetate, dimethyl car
Carbonate, diethyl carbonate, methyl ethyl carbonate
, Gamma-butyrolactone, methyl formate, methyl acetate
1,2-dimethoxyethane, tetrahydrofuran,
2-methyltetrahydrofuran, dimethylsulfoxy
Do, 1,3-dioxolan, 2,2-bis (trifluoro
Romethyl) -1,3-dioxolan, formamide, di
Methylformamide, dioxolan, dioxane, ace
Tonitrile, nitromethane, ethyl monoglyme, phosphorus
Acid triester, boric acid triester, trimethoxymeth
Tan, dioxolane derivative, sulfolane, 3-methyl-
2-oxazolidinone, 3-alkylsydnone (alk
Propyl, isopropyl, butyl, etc.), propyl
Lencarbonate derivative, tetrahydrofuran derivative,
Non-prototypes such as ethyl ether and 1,3-propane sultone
And rotonic organic solvents.
Or a mixture of two or more. Among these,
Carbonate solvents are preferred, and cyclic carbonates and
It is particularly preferable to use a mixture of acyclic carbonates.
No. Ethylene carbonate as a cyclic carbonate,
Propylene carbonate is preferred. Also, non-annular cars
As carbonates, diethyl carbonate, dimethyl carbonate
Carbonate and methyl ethyl carbonate are preferred.
As the electrolytic solution that can be used in the present invention, ethylene carbonate
, Propylene carbonate, 1,2-dimethoxye
Tan, dimethyl carbonate or diethyl carbonate
LiCF is added to the electrolyte solution_ThreeSO_Three, LiCl
O_Four, LiBF_FourAnd / or LiPF₆Electrolyte containing
Is preferred. Especially propylene carbonate or ethyl
At least one of lencarbonate and dimethyl carbonate
And / or diethyl carbonate
LiCF in the mixed solvent_ThreeSO_Three, LiClO_FourOr
LiBF_FourLi and at least one salt selected from
PF ₆An electrolytic solution containing Put these electrolytes in the battery
The amount added to the material is not particularly limited.
It can be used depending on the amount and the size of the battery.

In addition to the electrolytic solution, the following solid electrolyte can be used in combination. Solid electrolytes are classified into inorganic solid electrolytes and organic solid electrolytes. Well-known inorganic solid electrolytes include nitrides, halides, and oxyacid salts of Li. Among them, Li ₃ N, LiI, Li ₅ N
_{I2, Li 3 N-LiI-} LiOH, Li 4 SiO 4, Li 4
_{SiO 4 -LiI-LiOH, xLi 3} PO 4 - (1-x) Li
₄ SiO ₄ , Li ₂ SiS ₃ , phosphorus sulfide compounds and the like are effective.

As the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion dissociating group, a mixture of the polymer containing an ion dissociating group and the above aprotic electrolyte , A phosphate matrix polymer, and a polymer matrix material containing an aprotic polar solvent are effective. Furthermore, there is a method of adding polyacrylonitrile to the electrolytic solution. In addition, a method of using an inorganic and an organic solid electrolyte in combination is also known.

Further, another compound may be added to the electrolyte for the purpose of improving the discharge and charge / discharge characteristics. For example, pyridine, pyrroline, pyrrole, triphenylamine, phenylcarbazole, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine,
n-glyme, hexaphosphoric triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone and N, N'-substituted imidaridinone, ethylene glycol dialkyl ether, quaternary ammonium salt,
Polyethylene glycol, pyrrole, 2-methoxyethanol, AlCl3, conductive polymer electrode active material monomer, triethylenephosphoramide, trialkylphosphine, morpholine, aryl compound having a carbonyl group, 12-crown-4 Crown ethers,
Examples include hexamethylphosphoric triamide and 4-alkylmorpholine, bicyclic tertiary amines, oils, quaternary phosphonium salts, tertiary sulfonium salts, and the like. Particularly preferred is a case where triphenylamine and phenylcarbazole are used alone or in combination.

Further, in order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolyte. In addition, carbon dioxide gas can be included in the electrolytic solution in order to provide suitability for high-temperature storage.

It is desirable that the electrolyte contains as little water and free acid as possible. For this reason, it is preferable that the raw material of the electrolytic solution is sufficiently dehydrated and purified. The adjustment of the electrolytic solution is preferably performed in dry air or an inert gas having a dew point of −30 ° C. or less. The amount of water and free acid in the electrolytic solution is 0.1 to 500 ppm, more preferably 0.2 to 100 ppm.

The entire amount of the electrolytic solution may be injected once, but it is preferable to inject the electrolytic solution in two or more portions. In the case of injecting two or more times, each liquid may have the same composition but different compositions (for example, after injecting a non-aqueous solvent or a solution in which a lithium salt is dissolved in a non-aqueous solvent, a non-aqueous solution having a higher viscosity than the solvent may be used). A solution in which a lithium salt is dissolved in a solvent or a non-aqueous solvent is injected). Further, in order to shorten the injection time of the electrolyte solution, the pressure of the battery can may be reduced, or a centrifugal force or an ultrasonic wave may be applied to the battery can.

The battery can and the battery lid that can be used in the present invention are made of nickel-plated iron steel plate or stainless steel plate (SUS304, SUS304L, SUS304).
N, SUS316, SUS316L, SUS430, S
US444, etc.), nickel-plated stainless steel plate (same as above), aluminum or its alloy, nickel,
They are titanium and copper, and have a shape of a perfect circular cylinder, an elliptical cylinder, a square cylinder, or a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate or a nickel-plated iron steel plate is preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum or an alloy thereof is preferable. The shape of the battery can may be any of buttons, coins, sheets, cylinders, corners, and the like. A safety valve can be used for the sealing plate as a measure against the rise in the internal pressure of the battery can. In addition, a method of cutting a member such as a battery can or a gasket can also be used. In addition, various conventionally known safety elements (for example, a fuse, a bimetal, a PTC element, or the like as an overcurrent prevention element) may be provided.

For the lead plate used in the present invention, a metal having electrical conductivity (for example, iron, nickel, titanium, chromium, molybdenum, copper, aluminum, etc.) or an alloy thereof can be used. Battery lid, battery can, electrode sheet,
As a method for welding the lead plate, a known method (eg, DC or AC electric welding, laser welding, ultrasonic welding) can be used. A conventionally known compound or mixture such as asphalt can be used as the sealing agent for sealing.

The gaskets usable in the present invention are olefin polymers, fluorine polymers, cellulose polymers, polyimides and polyamides, and olefin polymers are preferred from the viewpoint of organic solvent resistance and low moisture permeability. Propylene-based polymers are preferred. Further, it is preferably a block copolymer of propylene and ethylene.

The battery assembled as described above is
It is preferable to perform an aging treatment. The aging treatment includes a pretreatment, an activation treatment, and a post-treatment, whereby a battery having high charge / discharge capacity and excellent cycleability can be manufactured. The pre-treatment is a treatment for making the distribution of lithium in the electrode uniform, such as a control of dissolution of lithium, a temperature control for making the distribution of lithium uniform, a swing and / or rotation treatment, and an optional charge and discharge. Are performed. The activation process is a process for inserting lithium into the negative electrode of the battery body, and it is preferable to insert 50 to 120% of the amount of lithium inserted when the battery is actually used and charged.
The post-processing is a process for sufficiently activating the activation process,
There are a preservation process for making the battery reaction uniform and a charge / discharge process for determination, and these can be arbitrarily combined.

Preferred aging conditions (pretreatment conditions) before activation of the present invention are as follows. The temperature is preferably from 30 ° C. to 70 ° C., more preferably from 30 ° C. to 60 ° C., and even more preferably from 40 ° C. to 60 ° C. The open circuit voltage is preferably 2.5 V or more and 3.8 V or less,
2.5 V or more and 3.5 V or less are more preferable, and 2.8 V or more and 3.3 V or less are more preferable. Aging period is 1
It is preferably from 20 days to 20 days, particularly preferably from 1 day to 15 days. The charging voltage for activation is preferably 4.0 V or more, more preferably 4.05 V or more and 4.3 V or less, and 4.0 V or more.
The voltage is more preferably from 1 V to 4.2 V. As the aging condition after activation, the open circuit voltage is 3.9 V or more and 4.3 V.
The temperature is preferably from 4.0 V to 4.2 V, and the temperature is preferably from 30 ° C. to 70 ° C.
A temperature of at least 60 ° C is particularly preferred. The aging period is 0.
It is preferably from 2 days to 20 days, particularly preferably from 0.5 days to 5 days.

[0048] The battery of the present invention is covered with an exterior material if necessary. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, a plastic case, and the like. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be recognized.

The batteries of the present invention are assembled in series and / or in parallel as necessary and stored in a battery pack. In addition to safety elements such as positive temperature coefficient resistors, thermal fuses, fuses and / or current interrupting elements, battery packs have safety circuits (voltage, temperature, current, etc. of each battery and / or assembled battery as a whole, Then, a circuit having a function of interrupting the current may be provided. In addition to the positive and negative terminals of the whole battery pack, the positive and negative terminals of each battery, the temperature detection terminals of the whole battery pack and each battery, the current detection terminals of the whole battery pack, etc. shall be provided as external terminals on the battery pack. Can also. The battery pack may have a built-in voltage conversion circuit (such as a DC-DC converter). In addition, connection of each battery
The lead plate may be fixed by welding, or may be fixed with a socket or the like so as to be easily detachable. Further, the battery pack may be provided with a display function of the remaining battery capacity, the presence or absence of charging, the number of times of use, and the like.

The battery of the present invention is used for various devices.
In particular, video movies, portable VCRs with built-in monitors, movie cameras with built-in monitors, digital cameras, compact cameras, SLR cameras, film with lenses, notebook computers, notebook word processors, electronic organizers,
It is preferably used for mobile phones, cordless phones, razors, electric tools, electric mixers, automobiles and the like.

[0051]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the examples unless it exceeds the gist of the invention.

EXAMPLES AND COMPARATIVE EXAMPLES As a negative electrode material, a polycrystalline silicon simple substance (compound-1), a mixture of polycrystalline silicon and colloidal silica, heated at 1000 ° C., and a solid obtained by a vibration mill in argon gas. and the powder Te Si-SiO ₂ (compound-2 weight ratio 90-
10) was used. The average particle size of each of the negative electrode materials (compounds 1 to 4) used was in the range of 0.05 to 4 μm. These silicon compounds and the conductive agents (acetylene black, flaky artificial graphite,
A powder obtained by mixing the mixture with nickel ultrafine powder) is dispersed in an N-methyl-pyrrolidone solution of polyvinylidene fluoride to form a negative electrode paste, and after drying, the mixture is scraped and compression molded (1).
3 mmφ) to prepare a mixture pellet. The volume of each material was calculated from the density of the powder measured using a densitometer (Shimadzu Corporation, multi-volume pycnometer 1305).

Dew point: After sufficiently dehydrating and drying with a far-infrared heater in dry air of -50 ° C. or lower, a 15 mmφ L
1 mol / liter LiPF as electrolyte using i foil
₆ (a mixture of equal volumes of propylene carbonate and dimethoxyethane), and using a microporous polypropylene sheet and polypropylene nonwoven fabric as a separator,
A coin-type lithium battery was created.

The above-mentioned coin battery is charged at 2 mA.
In this case, charging was performed at a constant current up to 0.05 V, and the charging current was controlled so as to keep the voltage constant at 0.05 V until 2.5 hours had elapsed from the start of charging. Discharge is 0.2C, 1C
The test was performed at a constant current up to 0.7 V with a current amount corresponding to the current. Table 1 shows the discharge capacity (converted to the capacity per Si in the negative electrode material) of the first cycle at that time, the discharge capacity ratio of 1 C / 0.2 C, and the capacity retention rate at the 30th cycle of repeated charge and discharge. Indicated.

(Table 1) Battery Negative electrode material Conductive agent Conductive agent 0.2C Discharge capacity 1C / 0.2C Cycle life No. No. Type Addition amount (mAh / gSi) Capacity ratio (30 cycle%) (Volume ratio vsSi) 11 Acetylene 0 0.1 1940 0.85 65 Black 21 〃 0.5 1950 0.88 603 1 １．０ 1.0 2000 0.90 70 41 1 Artificial graphite 0.1 1900 0.82 605 1 (flaky) 0. 5 1950 0.83 63 61 1 1.0 1.060 0.85 6571 1 5.0 2010 0.88 67 8 1 Ni powder 0.1 1980 0.88 70 9 1 (INCO Type 210) 0.5 2010 0 .90 75 10 1 １．０ 1.0 2020 0.92 76 11 1 〃 5.0 2100 0.93 77 12 2 Acetylene 0.1 1920 0.85 75 Black 132 2 ０．５ 0.5 1940 0.88 76 14 2 １．０ 1.0 1970 0.90 80 15 2 Artificial graphite 0.1 1900 0.82 75 162 (scale) 0.5 1920 0.83 78 172 2 １．０ 1.0 1930 0. 85 78 18 2 〃 5.0 2000 0.88 81 19 2 Ni powder 0.1 1930 0.88 80 202 (INCO Type 210) 0.5 1880 0.90 85 21 2 １．０ 1.0 2000 0.92 84 22 2 〃 5.0 2050 0.93 85 Ratio 1 2 None 0.0 100--Ratio 22 None 0.0 50--

[0056]

As described above, in a non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material and a non-aqueous electrolyte, the positive electrode active material is a transition metal oxide containing lithium.
By using a compound containing a silicon atom and mixing and using a substance having a volume resistivity of 10 ² Ω · cm or less in the negative electrode mixture, a nonaqueous secondary battery with improved energy amount and cycle life could be obtained. .

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Claims (2)

[Claims] 1. A non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material, and a non-aqueous electrolyte, wherein the positive electrode active material is a lithium-containing transition metal oxide, and the negative electrode material is capable of inserting and releasing lithium. A non-aqueous secondary battery comprising a compound containing a silicon atom and containing, as a conductive agent, a substance having a volume resistivity of 100 Ω · cm or less in a negative electrode mixture. 2. The substance having a volume resistivity of 10 ² Ω · cm or less is at least one substance selected from metals such as metal powder, metal flakes and metal fibers, and carbon compounds such as carbon black, graphite and carbon fibers. The non-aqueous secondary battery according to claim 1, wherein: