JP2002198038A - Manufacturing method of metal doped carbonaceous thin- film negative electrode for nonaqueous electrolyte secondary cell, metal doped carbonaceous thin-film negative electrode for nonaqueous electrolyte secondary cell and nonaqueous electrolyte secondary cell using above - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a carbonaceous thin-film electrode doped with a metal element, which is excellent in charge and discharge cycle property, can realize high capacity, a negative electrode material for a nonaqueous electrolyte secondary cell and a nenaqueous electrolyte secondary cell, by a low temperature heat treatment process without relying on a binder forming method which causes lowering of operation reliability. SOLUTION: A secondary cell which has good charge and discharge cycle property and high capacity can be realized by using a metal-doped carbonaceous thin-film electrode, as a negative electrode of a nonaqueous electrolyte secondary cell, manufactured by coating it on a collector in heat treatment with coating solution which is made by dissolving or dispersing a compound including nonvolatile carbon and a metal compound into organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery having a negative electrode improved by metal doping, the negative electrode, and a method of manufacturing the negative electrode.

[0002]

2. Description of the Related Art In recent years, non-aqueous electrolyte secondary batteries with a high energy density using a carbon material negative electrode that occludes and releases lithium ions by a reversible electrochemical reaction have been put into practical use.
It is widely used as a power source for various portable electronic devices. As these carbon materials, in addition to natural graphite, petroleum pitch, coal tar pitch, needle coke, condensed polycyclic aromatic hydrocarbon compounds, mesophase carbon microbeads, mesophase carbon fibers, and other easily graphitic carbon materials are used at 2500 ° C or higher. , Preferably 3000 ° C
The artificial graphite-based carbon heat-treated at the above-mentioned high temperature is excellent in charge-discharge cycle characteristics, effective utilization rate of occluded lithium ions, flatness of discharge voltage, and the like, and is preferably used. Among them, the mesophase carbon material is known as an optimal carbon anode material because it exhibits excellent charge / discharge characteristics under a large current. However, these carbon materials having a developed graphite structure can only provide a discharge capacity of 300 to 370 mAh / g corresponding to the first-stage graphite intercalation compound C ₆ Li. Further, since a heat treatment near 3000 ° C. is required, it is an industrially disadvantageous material in terms of processing equipment cost, energy cost, and productivity.

On the other hand, among the above graphitizable carbon materials or non-graphitizable carbon materials which have been heat-treated at a relatively low temperature of 1000 to 2000 ° C., there are 37 amorphous carbon materials.
Materials exhibiting a large capacity of 0 mAh / g or more and up to about 700 mAh / g have been found. However, although the capacity is large, the electrochemical reversibility is poor and the utilization rate of the stored lithium ions is low. Low is an issue.

[0004] In order to solve this problem, a method has been proposed in which a different element having a larger capacity than carbon is added to carbon. Journal of Electrochemical Society, Vol. 141, p. 907 reports that the substitution of carbon for boron increases the discharge capacity and shifts the lithium insertion / extraction potential to the higher potential side. Also, Journal of Electrochemistry and Industrial Physical Chemistry, Vol. 64,
It is reported on pages 917 and 1181 that carbon doped with nitrogen by CVD exhibits excellent negative electrode properties. Further, Journal of Electrochemical Society, Vol. 142, p. 326 reports that the reversible capacity of carbon as a negative electrode in which silicon fine particles are added to an amorphous portion of carbon increases.
However, with these materials, a sufficient effect of improving the negative electrode material has not been obtained.

Further, the above-mentioned carbon anode material is usually in the form of powder or fiber, and must be molded together with a suitable binder in order to be used as a battery electrode. In the case of a small coin-type battery, it is usually formed into a pellet shape, and in the case of a cylindrical battery for a large current, a metal current collector foil is formed as a coating film together with a binder. At this time, since the binder is usually an electrically insulating organic polymer such as a polyolefin, a fluorine-containing polymer, or a polyimide, the electric resistance in the electrode body after the molding increases, which hinders the output of the battery in a large current discharge. Had contributed. Also, in terms of long-term reliability, peeling, chipping, desorption, etc. of some carbon materials due to swelling or dissolving phenomena of the binder material in the electrolytic solution and deterioration due to electrochemical reaction have progressed over a long period of use. However, there is a problem that the performance of the battery is deteriorated. Therefore, a high-performance negative electrode and a method for producing the same, which sufficiently bring out the properties of a carbon material useful as a battery active material, have been eagerly desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a carbonaceous negative electrode doped with a metal element without using a binder resin which causes an increase in electric resistance. A second object of the present invention is to
A metal-doped carbonaceous negative electrode material for a non-aqueous electrolyte secondary battery that has excellent reversible capacity, high charge / discharge speed, high operation reliability, excellent charge / discharge cycle characteristics and can exhibit large capacity, and a non-aqueous material using the same An object of the present invention is to provide a water electrolyte secondary battery.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have studied with emphasis on a method of manufacturing a negative electrode to which a dopant of a carbon material is added. as a result,
(1) A non-aqueous electrolyte secondary characterized by being prepared by applying and heating a coating solution obtained by dissolving or dispersing a nonvolatile carbon-containing compound and a metal compound in an organic solvent on a current collector. Method for producing metal-doped carbon thin film negative electrode for battery,
(2) The metal-doped carbon thin film for a non-aqueous electrolyte secondary battery according to (1), wherein a coating liquid containing a nonvolatile carbon-containing compound and a metal compound but not containing a binder is used. (3) The non-aqueous method according to (1) or (2), wherein (3) a metal compound of a metal having a negative enthalpy of mixing a metal element of the metal compound and metal lithium has a negative value. A method for producing a metal-doped carbon thin film negative electrode for an electrolyte secondary battery, (4) the metal element of the metal compound is magnesium, aluminum, silicon, calcium, copper, zinc, gallium, germanium, arsenic, strontium,
Rhodium, palladium, silver, cadmium, indium,
The metal-doped carbon thin film negative electrode for a non-aqueous electrolyte secondary battery according to (3), which is selected from tin, antimony, barium, iridium, platinum, gold, mercury, thallium, lead, and bismuth. (5) The method for producing a metal-doped carbon thin film negative electrode for a non-aqueous electrolyte secondary battery according to (1) to (4), wherein the graphitizable carbon body is mesophase pitch carbon. And (6) the nonaqueous electrolyte secondary battery according to (1) to (5), wherein the organic solvent includes pyridine, quinoline, pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and cyclohexanone. Method for producing a metal-doped carbon thin film negative electrode for use, (7) a heat treatment temperature of 500 to
The method for producing a metal-doped carbon thin film negative electrode for a non-aqueous electrolyte secondary battery according to any one of (1) to (6), wherein the temperature is in the range of 2000 ° C .; The method for producing a metal-doped carbon thin film negative electrode for a non-aqueous electrolyte secondary battery according to any one of (1) to (7), (9) lithium containing no binder on the current collector A metal-doped carbonaceous negative electrode for a non-aqueous electrolyte secondary battery, comprising a metal-doped carbonaceous film capable of electrochemically storing and releasing ions, (10) electrochemically converting lithium ions A coating liquid comprising a non-volatile carbon-containing compound and a metal compound dissolved or dispersed in an organic solvent in a metal-doped carbonaceous film that does not contain a binder that can be occluded / released is coated on a current collector and heated. To (9), which is obtained by A metal-doped carbonaceous negative electrode for a non-aqueous electrolyte secondary battery as described in (11), characterized by using a metal compound of a metal element having a negative enthalpy of mixing the metal element and the metal lithium of the metal compound. (9) The metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to (10), (12) the metal element of the metal compound is magnesium, aluminum, silicon, calcium, copper, zinc, gallium, germanium, arsenic , Strontium, rhodium, palladium, silver, cadmium, indium, tin, antimony, barium, iridium, platinum, gold, mercury, thallium, lead, and bismuth. (13) The metal-doped carbonaceous negative electrode for an aqueous electrolyte secondary battery, wherein (13) the nonvolatile carbon-containing compound is a graphitizable carbon. To (1
The metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to 2), (14) the nonaqueous electrolyte secondary battery according to (13), wherein the graphitizable carbon is mesophase pitch carbon. (15) The metal-doped carbonaceous negative electrode for a battery, (15) wherein the organic solvent contains pyridine, quinoline, pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and cyclohexanone. Metal-doped carbonaceous negative electrode for non-aqueous electrolyte secondary battery, (16) heat treatment temperature of 500 to 2000 ° C
The metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to any one of (9) to (15), wherein
7) The metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to any one of (9) to (16), wherein the heat treatment atmosphere is an inert atmosphere, and (18) a nonvolatile carbon-containing compound. Is obtained by applying an organic solvent not containing a binder onto an electron-conductive foil-like current collector and then sintering the same. (9) to (17) A metal-doped carbonaceous negative electrode for a secondary battery, (19) an organic solvent containing a nonvolatile carbon-containing compound but not containing a binder is impregnated and applied to a current collector made of an electron-conductive porous body, and then fired. (9) to (18), wherein the metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to (9) to (18), and (20) the current collector is stainless steel. (19) a metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to (19), And a negative electrode provided with a metal-doped carbonaceous film capable of electrochemically occluding and releasing lithium ions without a binder on a current collector, and a non-aqueous electrolyte. Characteristic non-aqueous electrolyte secondary battery,
(22) A negative electrode provided with a metal-doped carbonaceous film containing no binder is coated on a current collector with a coating solution obtained by dissolving or dispersing a nonvolatile carbon-containing compound and a metal compound in an organic solvent. -The nonaqueous electrolyte secondary battery according to (21), which is obtained by heat treatment, (23)
The non-aqueous electrolyte secondary battery according to any one of (21) to (22), wherein a metal compound of a metal element having a negative enthalpy of mixing of the metal element and the metal lithium of the metal compound has a negative value. 24) The metal element of the metal compound is magnesium, aluminum, silicon, calcium, copper, zinc,
Gallium, germanium, arsenic, strontium, rhodium, palladium, silver, cadmium, indium, tin,
Antimony, barium, iridium, platinum, gold, mercury,
The nonaqueous electrolyte secondary battery according to (23), wherein the secondary battery is selected from thallium, lead, and bismuth.
5) The nonaqueous electrolyte secondary battery according to any one of (21) to (24), wherein the organic solvent includes pyridine, quinoline, pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and cyclohexanone. 26) The non-aqueous electrolyte secondary battery according to any one of (21) to (25), wherein the heat treatment temperature is in the range of 500 to 2000 ° C., (27) the heat treatment atmosphere is an inert atmosphere. The nonaqueous electrolyte secondary battery according to any one of (21) to (26), wherein (28) an organic solvent solution containing a nonvolatile carbon-containing compound is applied on an electron-conductive foil-like current collector. A nonaqueous electrolyte secondary battery according to any one of (21) to (27), wherein the negative electrode obtained by firing is used; porous After impregnation applied in the current collector made of a non-aqueous electrolyte secondary battery according to, characterized by using a negative electrode obtained by firing (21) through (28),
(30) The non-aqueous electrolyte secondary battery according to any one of (21) to (29), wherein the current collector is made of stainless steel. Reached.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The non-volatile carbon-containing compound of the present invention includes coal-based heavy oil such as coal tar pitch from soft pitch to hard pitch, dry distillation liquefied oil, etc .; Heavy oil such as ethylene tar and other heavy oils which are by-produced during thermal cracking of crude oil, naphtha and the like. Further, aromatic hydrocarbons such as acenaphthylene, decacyclene, and anthracene; N-ring compounds such as phenazine and acridine; S-ring compounds such as thiophene; alicyclic rings such as adamantane, biphenyl and terphenyl; Polymers such as polyphenylene, polyvinyl chloride and polyvinyl alcohol. Further, natural polymers such as cellulose and saccharides, thermoplastic resins such as polyphenylene sulfide, and polyphenylene oxide, and thermosetting resins such as furfuryl alcohol resin, phenol-formaldehyde resin, and imide resin can also be used. In particular, an easily graphitizable carbon body is suitably used as such a non-volatile carbon-containing compound. Mesophase pitch carbon is most preferably used as a non-volatile carbon-containing compound.

The metal compound used for doping the carbon material with a metal includes metal salts, organometallic compounds, metal complexes and the like. Examples of metal salts include:
Metal salt compounds such as calcium chloride, metal halide represented by tin iodide, silver nitrate represented by silver nitrate, strontium nitrate, and sulfate metal represented by copper sulfate and nickel sulfate are used. . As the organic metal compound, a metal compound having a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, or the like can be used. Examples of the metal complex include an organic metal complex such as a metal phthalocyanine and a metal porphyrin, and an inorganic metal complex represented by potassium ferrocyanide and Prussian blue. Such a metal compound forms the target metal-doped carbonaceous negative electrode by performing the following treatment together with the above-mentioned nonvolatile carbon-containing compound. At this time, it is not clear what form the metal is in the carbonaceous film, but it is considered that the metal can interact with the metal ion to be inserted and removed.

Good results can be obtained when the metal doped into the carbonaceous negative electrode has a negative enthalpy of mixing with lithium. The reason for this is not clear, but is presumed to form a solid solution with lithium ions inserted into the negative electrode. The enthalpy of mixing between metals can be considered, for example, based on numerical values described in Calfado Magazine, Vol. 31, p. Among such metal elements, magnesium, aluminum, silicon, calcium, copper, zinc, gallium, germanium, arsenic, strontium, rhodium, palladium, silver, cadmium, indium, tin, antimony, barium, iridium, platinum, gold , Mercury, thallium, lead and bismuth give good results.

The above materials may be formed on a current collector by a vacuum thin film forming method such as a vacuum vapor adsorption method, a sputtering method, a chemical vapor deposition (CVD) method, or may be dissolved or dispersed in an organic solvent. Then, a coating liquid may be prepared, and the resulting coating liquid may be coated on a current collector and subjected to a heat treatment to prepare a target metal-doped carbon thin film electrode. However, it is needless to mention that the latter method is suitable for mass production in industrial terms.

Although all known organic solvents can be used,
In particular, when an organic solvent containing at least pyridine, quinoline, pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and cyclohexanone is used, a coating liquid in which the above-mentioned nonvolatile carbon-containing compound is suitably dissolved or dispersed can be prepared. Organic solvents that may be used in combination with these organic solvents include alcohols represented by methanol, ethanol, ketones represented by acetone, 2-butanone, esters represented by ethyl acetate, butyl acetate, and diethyl. Ethers such as ether, tetrahydrofuran and dioxane, amines such as triethylamine and ethylenediamine, and the like are used.

The desired coating liquid can be obtained by mixing, stirring or dispersing the above-mentioned nonvolatile carbon-containing compound and metal compound with the above-mentioned organic solvent. When mixing both, heating and stirring may be performed, or mixing and dispersion may be performed using a dispersing device represented by a ball mill, an attritor, and a planetary mill.

The coating liquid is preferably a solution containing no dispersed particles, and is most suitable for obtaining a suitable film. However, even if the coating solution contains dispersed particles, if there is a dissolved component, the dissolution component is formed between the particles when the film is formed. A uniform film can be obtained by supplementing the carbonaceous material based on.
As a method for removing the dispersed particles from the dispersion, known means such as filtration and centrifugation can be used. Also,
Means for extracting a component soluble in a solvent from a material such as Soxhlet extraction is also useful and effective.

The coating liquid thus prepared is applied to the current collector using a known coating means such as blade coating, wire bar coating, spin coating, spray coating, dip coating, or bead coating. Can be applied. An electrostatic spray deposition (ESD) method in which an electric field is applied between a heated current collector and a nozzle containing a coating liquid to simultaneously perform film formation and heat treatment is preferably used.

The liquid applied on the current collector is heated to form a metal-doped carbonaceous film capable of electrochemically absorbing and releasing lithium ions. Good results are obtained when the heat treatment temperature at this time is in the range of 500 to 2000 ° C, and even better results are obtained when the temperature is in the range of 700 to 1200 ° C. The heat treatment may be performed in an air atmosphere, but better results can be obtained by performing the heat treatment in an inert gas atmosphere represented by nitrogen, argon, helium, or the like.

As the current collector, any known materials having electron conductivity can be used, but non-corrosive materials are particularly preferable. Examples of such a material include conductive carbon, gold, platinum, and stainless steel, and stainless steel is preferably used. The shape of the current collector is practically a foil or a porous body.

The thus prepared metal-doped negative electrode, the electrolyte solution described below, and the positive electrode plate are combined with other battery components such as a separator, a gasket, a current collector, a sealing plate,
A lithium ion secondary battery is configured in combination with a cell case and the like. The battery that can be manufactured is not particularly limited, such as a cylindrical type, a square type, a coin type, but basically, a current collector and a negative electrode material are placed on a cell floor plate, and an electrolyte and a separator are further placed thereon. A positive electrode is placed so as to face the negative electrode, and caulked together with a gasket and a sealing plate to form a secondary battery.

Non-aqueous solvents that can be used for the electrolyte include:
Propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, γ-butyrolactone, tetrahydrofuran, tetrahydrofuran, 2-methyltetrahydrofuran, sulfolane, 1,
A single organic solvent such as 3-dioxolane or a mixture of two or more organic solvents can be used.

In these solvents, L of about 0.5 to 2.0 M is added.
iCLO_Four , LiPF₆ , LiBF _Four , LiCF_ThreeSO_Three
 , LiAsF₆ Are dissolved to form an electrolyte.
In addition, the conductivity of alkali metal cations such as lithium ions
A solid polymer electrolyte which is a body can also be used. Correct
The material of the polar body is not particularly limited.
Which alkali metal cations can be stored and released during charge and discharge
It is preferable that the metal chalcogen compound be composed of a metal chalcogen compound. That
Oxidation of vanadium as a similar metal chalcogen compound
Material, vanadium sulfide, molybdenum oxide, molybdenum
Den sulfide, manganese oxide, chromium oxide, titanium
Oxide of tan, sulfide of titanium and their complex oxidation
And complex sulfides. Preferably, Cr
_ThreeO₈, V_TwoO_Five, V_FiveO₁₃, VO_Two, Cr_TwoO_Five, MnO_Two, T
iO_Two, MoV_TwoO₈, TiS_Two, V_Two S_Five, MoS_Two, Mo
S_Three, VS_Two, Cr_0.25V_0.75S_Two, Cr_0.5V_0.5 S_Two etc
It is. Also, LiMY_Two (M is the transition of Co, Ni, etc.
Metal Y is a chalcogen compound such as O or S), LiM_TwoY_Four 
(M is Mn, Y is O), WO_Three Oxides such as CuS, F
e_0.25V_0.75S_Two, Na_0.1CrS_Two Such as sulfide, NiP
S_Three, FePS_Three Such as phosphorus, sulfur compounds, VSe_Two, Nb
Se_Three And the like can also be used. this
These are mixed with the binder described below and applied on the current collector.
The positive electrode is used.

Examples of the binder that can be used for the above purpose include:
Solvent-stable, polyethylene, polypropylene,
Polyethylene terephthalate, aromatic polyamide, resin-based polymers such as cellulose, styrene-butadiene rubber,
Rubbery polymers such as isoprene rubber, butadiene rubber, and ethylene / propylene rubber, styrene / butadiene / styrene block copolymers, their hydrogenated products, styrene / isoprene / styrene block copolymers, and their thermoplasticity such as their hydrogenated products Elastomeric polymers, soft resinous polymers such as syndiotactic 12-polybutadiene, ethylene / vinyl acetate copolymer, propylene / α-olefin (2 to 12 carbon atoms) copolymer, polyvinylidene fluoride,
Fluoropolymers such as polytetrafluoroethylene and polytetrafluoroethylene / ethylene copolymers; and polymer compositions having ion conductivity of alkali metal ions, particularly lithium ions, may be mentioned.

Examples of the polymers having ion conductivity include polyether polymer compounds such as polyethylene oxide and polypropylene oxide, crosslinked polymers of polyether compounds, polyepichlorohydrin, polyphosphazene, polysiloxane, polyvinylpyrrolidone, and the like. Polyvinylidene carbonate, a system in which a lithium salt, or a lithium-based alkali metal salt is composited with a polymer compound such as polyacrylonitrile, or a high dielectric constant such as propylene carbonate, ethylene carbonate, and γ-butyrolactone A system containing an organic compound can be used. The ionic conductivity of such an ion-conductive polymer composition at room temperature is preferably 10 ^-5 S / cm or more, and more preferably 10 ^-3 S / cm or more.

The separator for holding the electrolyte is generally a material having excellent liquid retention properties. For example, the separator is impregnated with the above electrolyte using a nonwoven fabric or a porous film of a polyolefin resin. Is expressed.

[0024]

Next, the present invention will be described in detail with reference to examples. However, the examples are for describing the present invention in detail, and it is refused that the present invention is not limited by these examples. Not even. All parts mentioned here are parts by weight.

(Example-1) 5 parts of mesophase pitch carbon (manufactured by Petka Co., Ltd.) were pulverized well in a mortar and then placed in a soxhlet extraction thimble filter paper. Extraction was performed by an extraction device. The extract was taken out, 1 part of tin iodide was added, and the mixture was stirred well. This liquid was filtered using a fluoropore filter, and then placed in a syringe, followed by ESD (electrostatic spray deposition).
Sprayed on stainless steel foil heated to 000 ° C. The DC voltage applied between the syringe and stainless steel at this time was 12 k.
V. A film was formed in a nitrogen gas. The thickness of the tin-doped carbon thin film thus obtained was 35 μm.

The thus obtained electrode (negative electrode) was sandwiched with a polypropylene separator impregnated with an electrolytic solution to prepare a cell facing the lithium metal electrode, and a charge / discharge test was performed. As the electrolytic solution, a solution in which lithium perchlorate was dissolved at a ratio of 1 mol / L in a solvent in which ethylene carbonate and propylene carbonate were mixed at a weight ratio of 1: 1 was used.

The charge / discharge test was performed by a constant current charge / discharge method. Current density of 0.1 mA / cm ² and potential difference between electrodes is 0 V
, And then undoped until the potential difference between the electrodes reached 1.5 V. The charge and discharge were repeated 5 cycles, and the doping capacity and the undoping capacity were measured. Table 1 shows the measurement results.

(Comparative Example 1) One part of mesophase pitch carbon (manufactured by Petka Corporation) ground in a mortar was mixed with 10 parts of a solvent obtained by mixing dimethylformamide and 2-butanone at a weight ratio of 1: 1. 3 using a mill
Time-dispersed. Thus, a dispersion of mesophase pitch carbon was obtained. The size of the fine particles contained in the coating liquid was found to be an average particle size of 0.25 μm by particle size distribution measurement. Polyvinylidene fluoride (P
VdF) 1 part of this dispersion was added to and dissolved, and the resulting mixture was stirred to obtain a slurry-like coating liquid. This slurry was spin-coated on a nickel foil and pre-dried at 80 ° C. After further pressurizing and pressing, vacuum drying was performed at 110 ° C. to form an electrode (negative electrode). The thickness of the carbon thin film thus obtained was 31 μm. After producing a cell in the same manner as in Example 1 using this negative electrode, a test was performed in exactly the same manner as in Example 1. Table 1 shows the results.

Example 2 A planetary mill was used together with 1 part of mesophase pitch carbon (made by Petka Corporation) ground in a mortar and 10 parts of a solvent in which quinoline and cyclohexanone were mixed at a weight ratio of 1: 1. For 3 hours. In this way, a dispersion in which the mesophase pitch carbon was partially dissolved was obtained. Particle size distribution measurement revealed that the size of the fine particles contained in the dispersion was 0.2 μm or less. To this dispersion was added 0.2 parts of trichloroisopropylsilane, and the mixture was thoroughly stirred. This dispersion coating solution was spin-coated on a nickel foil and preliminarily dried at 100 ° C. Further, under a nitrogen gas atmosphere, 1000
Heating and sintering at ℃ resulted in an electrode (negative electrode). The thickness of the carbon thin film thus obtained was 30 μm. After producing a cell in the same manner as in Example 1 using this negative electrode,
The test was performed in the same manner as in Example-1. Table 1 shows the results.
Shown in

Comparative Example 2 A test was performed in the same manner as in Example 1 except that high-temperature calcined carbon (Mitsubishi Gas Chemical: 2800 ° C.) was used instead of mesophase pitch carbon. Table 1 shows the results.

Example 3 A test was performed in the same manner as in Example 1 except that aluminum iodide was used instead of tin iodide used as a metal compound. Table 1 shows the results.

Example 4 A test was conducted in the same manner as in Example 1 except that nickel nitrate was used in place of tin iodide used as a metal compound. Table 1 shows the results.

Example 5 A test was performed in the same manner as in Example 2 except that zinc iodide was used in place of trichloroisopropylsilane used as the metal compound. Table 1 shows the results.

Example 6 A test was performed in the same manner as in Example 2 except that cobalt nitrate was used in place of trichloroisopropylsilane used as the metal compound. Table 1 shows the results.

[0035]

[Table 1] (*): No metal element was doped.

[0036]

According to the present invention, a carbonaceous negative electrode doped with a metal element can be formed from a nonvolatile carbon-containing compound and a metal compound without using a binder resin. In addition, by using the carbonaceous negative electrode doped with a metal element prepared according to the present invention, the reversible capacity is excellent, the charge / discharge speed is fast, the operation reliability is high, the charge / discharge cycle characteristics are excellent, and the large capacity is developed. A non-aqueous electrolyte secondary battery using a metal-doped carbonaceous negative electrode material for a non-aqueous electrolyte secondary battery is provided.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H029 AJ02 AJ03 AJ05 AJ14 AK02 AK03 AK05 AM03 AM04 CJ02 CJ22 DJ11 5H050 AA02 AA07 AA08 AA19 BA17 CA02 CA03 CA04 CA07 CA09 CA11 CB07 DA03 DA04 FA18 GA02 GA10 GA22

Claims (9)

[Claims] 1. A non-aqueous electrolyte solution prepared by applying and heating a coating solution obtained by dissolving or dispersing a nonvolatile carbon-containing compound and a metal compound in an organic solvent on a current collector. A method for producing a metal-doped carbon thin film negative electrode for a secondary battery. 2. The metal-doped carbon for a non-aqueous electrolyte secondary battery according to claim 1, wherein a coating liquid containing a nonvolatile carbon-containing compound and a metal compound but not containing a binder is used. Method for producing a porous thin film negative electrode. 3. The non-aqueous electrolyte secondary according to claim 1, wherein a metal enthalpy of mixing the metal element of the metal compound and the metal lithium has a negative value. A method for producing a metal-doped carbon thin film negative electrode for a battery. 4. A non-aqueous electrolyte secondary comprising a current collector and a metal-doped carbonaceous film capable of electrochemically occluding and releasing lithium ions without a binder. Metal-doped carbonaceous negative electrode for batteries. 5. A coating comprising a binder-free metal-doped carbonaceous film capable of electrochemically occluding and releasing lithium ions by dissolving or dispersing a nonvolatile carbon-containing compound and a metal compound in an organic solvent. 5. A liquid obtained by applying and heating a liquid on a current collector.
5. The metal-doped carbonaceous negative electrode for a nonaqueous electrolyte secondary battery according to 4. 6. The non-aqueous electrolyte secondary battery according to claim 4, wherein a metal compound of a metal element having a negative enthalpy of mixing the metal element of the metal compound and the metal lithium has a negative value. Metal-doped carbonaceous negative electrode for batteries. 7. A non-aqueous electrolyte comprising a positive electrode, a negative electrode having a metal-doped carbonaceous film capable of electrochemically occluding and releasing lithium ions on a current collector without a binder, and a non-aqueous electrolyte. A non-aqueous electrolyte secondary battery, comprising: 8. A coating solution obtained by dissolving or dispersing a nonvolatile carbon-containing compound and a metal compound in an organic solvent, wherein the negative electrode provided with a metal-doped carbonaceous film containing no binder is provided.
The non-aqueous electrolyte secondary battery according to claim 7, which is obtained by applying and heating on a current collector. 9. The non-aqueous electrolyte secondary according to claim 7, wherein a metal compound of a metal element having a negative enthalpy of mixing the metal element and the metal lithium of the metal compound is used. battery.