JP2886296B2 - Secondary battery electrode - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention relates to an alkali metal secondary battery having high capacity and excellent charge / discharge characteristics, and particularly to an electrode of a lithium secondary battery.

[Related Art] It has been proposed to use a conductive polymer such as polyacetylene as an electrode of a lithium secondary battery. However, the conductive polymer lacks the doping amount of Li ions, that is, the electrode capacity and stable charge / discharge characteristics.

Attempts have also been made to use lithium metal for the negative electrode of a lithium secondary battery, but in this case, the charge / discharge cycle characteristics are extremely poor.

That is, when discharging the battery, lithium is discharged from the negative electrode body to Li.
The lithium ions move into the electrolyte as ions, and at the time of charging, these Li ions become metallic lithium and are deposited again on the negative electrode body.
When this charge / discharge cycle is repeated, the metal lithium deposited in accordance with the cycle becomes dendritic. Since the dendritic metallic lithium is an extremely active substance, it decomposes the electrolytic solution, and as a result, there is a disadvantage that the charge / discharge cycle characteristics of the battery deteriorate. When this further grows, finally, a problem arises that the dendritic lithium metal deposit penetrates through the separator to reach the positive electrode body, causing a short circuit phenomenon. In other words, there is a problem that the charge / discharge cycle life is short.

In order to avoid such a problem, an attempt has been made to use a carbonaceous material obtained by calcining an organic compound as a support as a negative electrode, and to support an alkali metal, particularly lithium, as an active material. By using such a negative electrode body, the charge / discharge cycle characteristics of the negative electrode are remarkably improved, but on the other hand, the negative electrode molded body using the carbonaceous material as a carrier still has insufficient electrode capacity. There was a lack of flexibility, and no satisfactory electrode could be obtained as a sheet or spiral electrode.

[Problems to be Solved by the Invention] Under such technical background, the present invention provides an alkali metal having a large electrode capacity, excellent charge / discharge cycle characteristics, and improved self-discharge characteristics, particularly a negative electrode for a lithium secondary battery. It is intended to provide an electrode.

[Means for Solving the Problems] The inventors of the present invention have conducted intensive studies on the negative electrode in order to solve the above-described problems, and as a result, it has been found that particles of a carbonaceous material having physical properties described below and particles of a specific organic polymer are used. The present invention has been found to be extremely effective for achieving the above-mentioned object when an electrode is constituted by supporting an alkali metal, preferably a lithium active material, on a support made of a mixture with particles, and led to the present invention. Was.

That is, the present invention provides (1) a carbonaceous material particle satisfying the following characteristics and (a) an atomic ratio of hydrogen / carbon of less than 0.15, and (b) a plane spacing (d ₀₀₂ ) between (002) planes by X-ray wide-angle diffraction. ) Is 3.37 ° or more, and (c) volume average particle diameter is 2 to 150 μm; (2) diene compound polymer elastomer, alkenyl aromatic compound-diene compound copolymer, vinyl compound (excluding (meth) acrylate) ) -Diene compound copolymer, (meth) acrylate polymer or copolymer with other polymerizable monomer, and vinyl acetate polymer or copolymer with other polymerizable monomer One or more organic polymer particles having a volume average particle size of 5 μm or less and smaller than the volume average particle size of the carbonaceous material particles of (1); For the formed carrier molding (3) a secondary battery electrode, characterized in that carrying an alkali metal as an active material.

The secondary battery electrode of the present invention is characterized by the configuration of the above-described negative electrode, and the other elements can be configured in the same manner as the conventional secondary battery electrode.

In the negative electrode according to the present invention, the active material is an alkali metal, preferably lithium. The active material enters and exits the electrode body in response to charging and discharging of the battery.

In the present invention, the carbonaceous material used for the active material carrier constituting the electrode body has (a) an atomic ratio of hydrogen / carbon (H / C) of less than 0.15; (002) The surface spacing (d ₀₀₂ ) is 3.37 ° or more; and (c) the volume average particle diameter is 2 to 150 μm. In the carbonaceous material, other atoms, for example, atoms of nitrogen, oxygen, halogen and the like are preferably present in a proportion of 7 mol% or less, more preferably 4 mol% or less, particularly preferably 2 mol% or less. Good.

H / C is preferably less than 0.10, more preferably less than 0.07, particularly preferably less than 0.05.

The spacing (d ₀₀₂ ) of the (002) plane is preferably at least 3.38 °, more preferably 3.39 to 3.75 °, and even more preferably 3.
It is 41 to 3.70 °, particularly preferably 3.45 to 3.70 °.

If any of these parameters, that is, H / C or _d002 , deviates from the above range, the overvoltage at the time of charging / discharging at the electrode body becomes large, and as a result, gas is generated from the electrode body and the battery is discharged. Not only is safety significantly impaired, but also the charge / discharge cycle characteristics are degraded.

Further, the particles of the carbonaceous material have a volume average particle diameter of preferably 5 to 80 μm, more preferably 7 to 80 μm.
It is 50 μm, more preferably 8 to 30 μm, and particularly preferably 10 to 20 μm.

The specific surface area of the carbonaceous material particles measured by the BET method is preferably 1 to 100 m ² / g, more preferably ² to 80 m ² / g, and still more preferably 3 to 70 m ² / g.

Further, the carbonaceous material used for the support of the electrode body according to the present invention preferably has the following characteristics.

That is, the crystallite size Lc in the c-axis direction is preferably
220 ° or less, more preferably 180 ° or less, still more preferably 5 to 150 °, particularly preferably 10 to 80 °, and most preferably 12 to 70 °.

In Raman spectrum analysis using an argon ion laser beam having a wavelength of 5,145 °, the following formula: Is preferably less than 2.5, more preferably less than 2.0, particularly preferably 0.2 or more
It is less than 1.2, most preferably 0.3 or more and less than 1.0.

Here, the G value refers to a wavelength of 5,145
In the spectrum intensity curve recorded in the chart when the Raman spectrum analysis was performed using the argon ion laser light of Å, the integrated value (area intensity) of the spectrum intensity within the range of the wave number of 1,580 ± 100 cm ⁻¹ was calculated as the wave number 1,360 ± 100cm
^The value divided by the area intensity within the range of ^-1 corresponds to a measure of the degree of graphitization of the carbonaceous material.

That is, the carbonaceous material has a crystalline portion and an amorphous portion, and the G value is a parameter indicating the ratio of the crystalline portion in the carbonaceous structure.

Further, the carbonaceous material used for the support of the electrode body according to the present invention preferably satisfies the following conditions. That is, the distance a ₀ (2d ₁₁₀ ) twice as large as the plane distance d ₁₁₀ of the (110) plane in the X-ray wide-angle diffraction analysis is 2.38 to 2.47 °,
More preferably 2.39 ~ 2.46 °: the crystallite size La in the a-axis direction is preferably 10 ° or more, more preferably 15 ~ 150
Å, particularly preferably 19 to 70 °.

Further, the carbonaceous material used in the present invention has a pore volume measured by a mercury porosimeter of preferably 0.1 ml / g or more, more preferably 0.2 ml / g or more, still more preferably 0.4 ml / g or more, and particularly preferably 0.5 ml / g or more. g or more. This is because the larger the pore volume, the more likely it is that the pores of the carbonaceous material will be impregnated with a metal or an alloy of the active material that can form an alloy with the active material in the liquid phase described later.

Further, the carbonaceous material preferably has a total pore volume of 1.5 × 10 ⁻³ ml / g or more, as determined from the amount of nitrogen gas adsorbed. More preferably, the total pore volume is 2.0 × 10 ⁻³ ml / g or more,
More preferably, it is 3.0 × 10 ⁻² to 8 × 10 ⁻² ml / g, particularly preferably 4.0 × 10 ^{−3 to} 3 × 10 ⁻² ml / g.

The total pore volume and the average pore radius described below are determined by measuring the amount of adsorbed gas (or desorbed gas) on the sample under several equilibrium pressures using the constant volume method, It is determined by measuring the amount of gas present.

The total pore volume is determined from the total amount of gas adsorbed at a relative pressure P / P ₀ = 0.995, assuming that the pores are filled with liquid nitrogen.

P: Vapor pressure of the adsorbed gas (mmHg) P ₀ : Saturated vapor pressure of the adsorbed gas at the cooling temperature (mmHg) Further, from the amount of the adsorbed nitrogen gas (V _ads ), fill the pores using the following formula (1) The total pore volume is determined by converting to the amount of liquid nitrogen (V _liq ) used.

Here, a P _a and T, respectively atmospheric pressure (kgf / cm ²⁾ Temperature (° K), the V _m is the molecular volume of the gas adsorbed (34.7cm ³ / mol in nitrogen).

Further, the average pore radius (γ _P ) of the carbonaceous material determined from the adsorption of nitrogen gas is preferably from 8 to 100 °. It is more preferably 10 to 80 °, further preferably 12 to 60 °, and particularly preferably 14 to 40 °.

The average pore radius (γ _P ) is obtained by calculating from V _liq obtained from the above equation (1) and the BET specific surface area S using the following equation (2).

Here, it is assumed that the pores are cylindrical.

Such a carbonaceous material can be obtained, for example, by heating and decomposing an organic compound at a temperature of 300 to 3,000 ° C. under a normal inert gas flow to carbonize it.

Examples of the starting organic compound include cellulose; phenolic resin; polyacrylonitrile, and poly (α).
Acrylic resins such as halogenated acrylonitrile); halogenated vinyl resins such as polyvinyl chloride, polyvinylidene chloride and chlorinated polyvinyl chloride; polyamide imide resins; polyamide resins; polyacetylene, poly (p
Any organic polymer compound such as a conjugated resin such as -phenylene); naphthalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene,
A condensed cyclic hydrocarbon compound obtained by condensing two or more monocyclic hydrocarbon compounds having three or more rings with each other, such as picene, perylene, pentaphene, and pentacene; or a carboxylic acid, carboxylic anhydride, or carboxylic acid of the above compound Derivatives such as imides; various pitches whose main component is a mixture of the above compounds; 3- or more-membered rings such as indole, isoindole, quinoline, isoquinoline, quinosaline, phthalazine, carbazole, acridine, phenazine, phenanthridine A condensed heterocyclic compound in which at least two heteromonocyclic compounds are bonded to each other or at least one monocyclic hydrocarbon compound having at least three membered rings; carboxylic acids and carboxylic anhydrides of the above compounds And derivatives such as carboxylic acid imides; furthermore, benzene or its carboxylic acids and carboxylic anhydrides Derivatives such as carboxylic acid imide, for example 1,2,4,5-tetracarboxylic acid, and derivatives such as its dianhydride or its diimide.

Further, a carbonaceous material such as carbon black or coke may be used as a starting source, and the carbonaceous material may be further heated to appropriately promote carbonization to form a carbonaceous material constituting a support for the electrode body according to the present invention.

The carrier constituting the electrode body of the present invention is formed of the above-mentioned carbonaceous material particles and a specific synthetic rubber, natural rubber, thermoplastic elastomer, or soft resin (hereinafter, these are collectively referred to as an elastic body or the like). It consists of a mixture with an adhesive.

The elastomer used in the present invention may be a diene compound polymer elastomer, a polymer of (meth) acrylate or a copolymer of another polymerizable monomer, a vinyl acetate polymer or polymerizable with the same. Copolymers with other monomers, alkenyl aromatic compound-diene compound copolymers, and vinyl compound (excluding (meth) acrylate) -diene compound copolymers.

Among these, a copolymer having an arbitrary molecular structure such as a random copolymer, a block copolymer or a graft copolymer is used. The alkenyl aromatic-diene compound copolymer and the vinyl compound-diene compound copolymer are 2
A block copolymer having the above segments is preferred.

These elastic bodies and the like have a volume average particle size of 5 μm or less, preferably 3 μm or less, more preferably 2 μm or less, further preferably 0.02 to 1.5 μm, and particularly preferably 0.05 to 1 μm.

In particular, the volume average particle diameter of the carbonaceous material particles described above,
A synthetic rubber, a natural rubber, a thermoplastic elastomer or a soft resin having a particle size of preferably 1/2 or less, more preferably 1/3 or less, and still more preferably 1/5 or less is used.

The mixing ratio of the particles of the carbonaceous material and the particles of the elastic body is preferably 30 parts by weight or less, more preferably 20 parts by weight or less, and still more preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the particles of the carbonaceous material. Parts, particularly preferably 0.5 to 10 parts by weight,
Most preferably, it is 1 to 7 parts by weight.

As a mixed form of the above-described carbonaceous material particles and an elastic body, for example, there is a form in which particles such as an elastic body are attached to the surface of the carbonaceous material particles.

In any case, the surface of the carbonaceous material particles is preferably 4/5 or less, more preferably 3/5 or less, of the surface of the carbonaceous material particles than the entire surface of the carbonaceous material particles coated with an elastic body or the like.
Hereinafter, particularly preferably 1/50 to 1/2, most preferably 1/2
A form coated with fine particles such as an elastic body over 0 to 2/5 is preferable from the viewpoint of improving electrode performance.

As the elastic body or the like used for the electrode carrier of the present invention, a latex-like material emulsified and dispersed in water is usually used.

The mixing of the above-described carbonaceous material particles and particles such as an elastic body,
The particles of the carbonaceous material are added to the latex in which the elastic body or the like is dispersed in water, and the particles are mechanically mixed, and then the water is evaporated to attach the particles of the elastic body or the like to the surface of the particle of the carbonaceous material. be able to.

Latexes such as elastic bodies used in the present invention include the following. As a latex of a diene compound polymer elastomer, isoprene rubber, butadiene rubber,
Latex such as chloroprene rubber and natural rubber.
As the latex of the alkenyl aromatic compound-diene compound copolymer, styrene-butadiene rubber (SBR),
Carboxy-modified styrene-butadiene rubber, styrene-
Latexes such as butadiene-vinylpyridine copolymers are available. Latexes of the vinyl compound-diene compound copolymer include latexes such as acrylonitrile-butadiene rubber, carboxyl-modified acrylonitrile-butadiene rubber, and butadiene-vinylpyridine copolymer.

Examples of the latex of a polymer of (meth) acrylic acid ester or a copolymer thereof with another polymerizable monomer include polyacrylic acid ester, acrylate-styrene copolymer, butadiene- (meth) acrylic acid. Latexes such as acid ester copolymers are available. Examples of latex for copolymerization of a vinyl acetate polymer or another polymerizable monomer with the same include polyvinyl acetate and vinyl acetate.
Latexes such as acrylate copolymers, vinyl acetate-maleate copolymers, and vinyl acetate-ethylene copolymers.

Further, hydrogenated products of the above-described diene compound polymer and alkenyl aromatic compound-diene compound copolymer, for example, hydrogenated products of styrene-butadiene-styrene block copolymer and hydrogenated styrene-isoprene-styrene block copolymer Additives and the like can also be used as the elastic body and the like in the present invention.

Of these, preferred are styrene-butadiene copolymer rubber latex, isoprene rubber latex, butadiene rubber latex, and natural rubber latex. Particularly preferred are styrene-butadiene copolymer rubber latex, isoprene rubber latex, and butadiene rubber latex.

Examples of the method for producing these latexes include (1) a method for producing by emulsion polymerization (butadiene rubber latex, styrene-butadiene rubber latex, carboxyl-modified styrene-butadiene rubber latex, butadiene-styrene-vinylpyridine latex, chloroprene latex, acrylic Latex, vinyl acetate). This is a method in which a monomer is emulsified in water with a suitable emulsifier (sodium fatty acid, sodium sulfonate, rosin acid soap, etc.) and polymerized.

There is also a method (2) in which a polymer solution obtained by solution polymerization is emulsified by adding an emulsifier (eg, rosin potassium oxide) and water and then the solvent is removed by drying (eg, isoprene rubber latex).

The support for the secondary battery electrode of the present invention can be formed as follows.

For example, a granular material in which an elastic material or the like is adhered to the surface of the carbonaceous material particles is compression-molded to form an electrode having an arbitrary shape such as a sheet or a film.

The compression molding temperature is preferably from room temperature to 150 ° C. The compression molding pressure is preferably 1 to 200,000 kg / c
m ² , more preferably 5 to 100,000 kg / cm ² . The compression molding time is preferably 0.1 seconds to 30 minutes, more preferably 0.3 seconds.
The time is from seconds to 10 minutes, more preferably from 0.5 seconds to 5 minutes.

The secondary battery electrode of the present invention is further formed by compression molding in such a manner that metal steel such as nickel or a thin film (foil) is used as a core material, and particles having an elastic body or the like attached to the surface of the above-mentioned carbonaceous material particles are pressed thereon. By doing so, a good balance between flexibility and strength can be maintained.

Alternatively, a thin sheet-shaped electrode carrier is formed by applying a mixed slurry of particles of a carbonaceous material and a dispersed liquid of an elastic body or the like to metal steel or foil, removing water by drying, and compression molding. Can be formed.

The thickness of the sheet-shaped support molding is preferably 1.5 mm or less, more preferably 1 mm or less, and still more preferably 5-500.
μm, particularly preferably 50 to 400 μm, most preferably 7 μm.
It is 0 to 300 μm.

In the electrode carrier of the present invention, a conductive agent such as a metal powder such as expanded graphite and aluminum is added to the mixture of the above-mentioned carbonaceous material and the binder, usually in an amount of less than 50% by weight, preferably 30% by weight. Less than can be added.

An alkali metal, preferably lithium, is used as the active material supported on the support.

The method of supporting the active material on the carrier includes a chemical method, an electrochemical method, a physical method, and the like.
A method of immersing a carrier in an electrolytic solution containing a predetermined concentration of an alkali metal cation, preferably Li ion, and using lithium as a counter electrode to make the carrier an anode for electrolytic impregnation, and a process of obtaining a molded body of the carrier. And a method of mixing a powder of an alkali metal, preferably a powder of lithium or a lithium alloy.

Alternatively, a sheet of an alkali metal, preferably lithium, is bonded to a molded body of a carrier to form an electrode, which is incorporated in a battery and then charged and discharged to carry an alkali metal, preferably lithium.

The amount of the alkali metal, preferably lithium, previously supported on the negative electrode support in this manner is preferably 0.030 to 0.25 parts by weight, more preferably 0.060 to 0.20 parts by weight, and even more preferably 0.070 parts by weight, per part by weight of the support. ~ 0.15
Parts by weight, particularly preferably 0.075 to 0.12 parts by weight or less, most preferably 0.080 to 010 parts by weight.

The secondary battery electrode of the present invention is usually used as a negative electrode,
It faces the positive electrode via the separator.

For example, as shown in FIG. 1, the positive electrode body (1) and the negative electrode body (2) of the present invention are spirally rounded in a state where they face each other via a separator (3), and this is housed in a cylindrical can. It can be a cylindrical secondary battery.

The cathode body is not particularly limited, but is preferably made of, for example, a metal chalcogen compound that releases or acquires an alkali metal cation such as Li ion along with a charge / discharge reaction. Such metal chalcogen compounds include vanadium oxide, vanadium sulfide, molybdenum oxide, molybdenum sulfide, manganese oxide, chromium oxide, titanium oxide, titanium sulfide and the like. Complex oxides, complex sulfides, and the like can be given. Preferably Cr ₃ O ₈ , V ₂ O ₅ , V ₆ O ₁₃ , VO ₂ , Cr ₂ O ₅ , MnO ₂ , TiO ₂ , MoV ₂
O ₈ , TiS ₂ , V ₂ S ₅ , MoS ₂ , MoS ₃ , VS ₂ , Cr _0.25 V _0.75 S ₂ , C
r _0.5 V _0.5 S ₂ etc. Oxides such as LiCoO ₂ and WO ₃ ;
Sulfides such as CuS, Fe _0.25 V _0.75 S ₂ , Na _0.1 CrS ₂ , NiPS ₃ , F
phosphorus, such as EPS _3, sulfur compounds, can also be used such as selenium compounds VSe _2, NbSe _3.

Further, a conductive polymer such as polyaniline or polypyrrole can be used.

The separator holding the electrolytic solution is made of a material having excellent liquid retaining properties, for example, a nonwoven fabric of a polyolefin resin.
And, in this separator, aprotic organic solvents such as propylene carbonate, 1,3-dioxolan, and 1,2-dimethoxyethane are added to LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆
And a predetermined concentration of a non-aqueous electrolyte solution in which an electrolyte is dissolved.

Further, a solid electrolyte which is a conductor of an alkali metal cation such as Li ion can be interposed between the positive electrode body and the negative electrode body.

[Operation] In the secondary battery configured as described above, the active material ions are supported on the carrier at the time of charging, and the active material ions in the carrier are released at the time of discharging at the negative electrode. The electrode reaction proceeds.

On the other hand, when the metal chalcogen compound is used in the positive electrode, the active material ions are released to the positive electrode body during charging, and the active material ions are carried during discharging, so that the charging / discharging electrode reaction proceeds.

Alternatively, when a conductive polymer such as polyaniline is used for the positive electrode, a counter ion of the active material ion is supported on the positive electrode body during charging, and a counter ion of the active material is released from the positive electrode body during discharging. The electrode reaction proceeds.

In such a combination of the electrode reactions of the positive electrode body and the negative electrode body, the battery reaction accompanying the charge and discharge of the battery proceeds.

[Effects of the Invention] The secondary battery electrode of the present invention is obtained by supporting an alkali metal, preferably lithium, on a support made of a mixture of the above-mentioned carbonaceous material particles and the above-mentioned particles such as elastic bodies. It can be shaped into a flexible sheet-like electrode system, and can be formed into a spiral shape to be applied to a cylindrical secondary battery. Further, it can be applied as an electrode of a thin sheet battery or a square battery.

In particular, according to the present invention, an electrode in which an elastic body or the like is attached to the surface of a carbonaceous material in the form of particles according to the present invention does not prevent lithium ions from being doped into and dedoped from the inside of the carbonaceous material due to charge and discharge. In particular, the electrode performance of the electrode can be enhanced as compared with the above-mentioned coating method. Therefore,
An object of the present invention is to provide an electrode capable of providing a secondary battery having high capacity and high output and excellent charge / discharge cycle characteristics.

EXAMPLES Hereinafter, the present invention will be described with reference to Examples and Comparative Examples.
Note that the present invention is not limited to this embodiment.

In the present invention, each measurement of elemental analysis and X-ray wide angle diffraction was carried out by the following methods.

“Elemental analysis” The sample was dried under reduced pressure at 120 ° C. for about 15 hours, and then dried at 100 ° C. for 1 hour on a hot plate in a dry box. Then, sampling was performed in an aluminum cup in an argon atmosphere, and the carbon content was determined from the weight of CO ₂ gas generated by combustion, and the hydrogen content was determined from the weight of H ₂ O generated. In the examples of the present invention described later, the measurement was performed using a Perkin Elmer 240C elemental analyzer.

"X-Ray Wide Angle Diffraction" (1) Spacing between ( ₀₀₂ ) planes (d ₀₀₂ ) and Spacing between (110) planes (d ₁₁₀ ) When the carbonaceous material is powder, as it is, Powdered in an agate mortar, about 15% by weight based on the sample
X-ray standard high-purity silicon powder as an internal standard substance is added and mixed, packed in a sample cell, and a monochromatic CuK α-ray with a granite monochromator is used as a radiation source. The diffraction curve was measured. For the correction of the curve, the following simple method was used without correcting so-called Lorentz, deflection factor, absorption factor, atomic scattering factor and the like. That is, the base line of the curve corresponding to the (002) and (110) diffractions is drawn, and the substantial intensity from the base line is re-plotted to obtain the (002) plane and the (110) plane.
A surface correction curve was obtained. Two-thirds of the peak height of this curve
Find the midpoint of the line where the line parallel to the angle axis drawn at the height of the line intersects the diffraction curve, correct the angle of the midpoint with an internal standard, make this twice the diffraction angle, and calculate the wavelength of the CuK α ray From λ, d ₀₀₂ and d ₁₁₀ are obtained by the following Bragg equation.

λ: 1.5418 ° θ, θ ′: diffraction angle corresponding to d ₀₀₂ , d ₁₁₀ (2) Crystallite size in c-axis and a-axis directions: Lc; La In the corrected diffraction curve obtained in the preceding section, the peak height The crystallite size in the c-axis and a-axis directions is obtained from the following equation using the so-called half-width β at half the position.

Although there are various arguments about the shape factor K, K = 0.90 was used. λ, θ and θ ′ have the same meaning as in the previous section.

Example 1 (1) Synthesis of carbonaceous material A crystalline cellulose granule (average radius: about 1 mm) was set in an electric heating furnace, heated to 1,000 ° C at a heating rate of 250 ° C / hour under a nitrogen gas flow, and further heated to 1,000 ° C. For one hour.

Thereafter, the mixture was allowed to cool, and the obtained carbonaceous material particles were set in another electric furnace, heated to 1,800 ° C. at a rate of 1,000 ° C./hour under a nitrogen gas flow, and further kept at 1,800 ° C. for 1 hour. .

The carbonaceous material thus obtained was placed in a 500 ml agate container, and two agate balls having a diameter of 30 mm, six agate balls having a diameter of 25 mm, and 16 agate balls having a diameter of 20 mm were charged and ground for 15 minutes.

The obtained carbonaceous material had the following characteristics as a result of analysis such as elemental analysis and X-ray wide-angle diffraction and measurement of particle size distribution and specific surface area.

Hydrogen / carbon (atomic ratio) = 0.04 d ₀₀₂ = 3.59Å, Lc = 14Å a ₀ (2d ₁₁₀ ) = 2.41, La = 25Å Volume average particle size = 35.8 μm Specific surface area (BET) = 8.2 m ² / g (2 ) Attachment of particles such as elastic material to the surface of carbonaceous material particles 93 parts by weight of the carbonaceous material particles described above were mixed with styrene-butadiene rubber (hereinafter referred to as SBR) latex (SBR content 40%).
%, Styrene content in SBR 23.5% by weight, average particle size 0.07
μm), dispersed in 7 parts by weight, and stirred and mixed at 25 ° C.

(3) Formation of Sheet Electrode Using a 100 mesh nickel wire mesh as a core material, the above-mentioned mixed solution was applied to both surfaces thereof and dried. Further pressure 10
It was compressed at 0 kg / cm ² to form a sheet-like electrode having a thickness of 0.3 mm.

This sheet electrode had flexibility and bending strength.

(4) Supporting of Lithium on the Support The above-described support is subjected to an electrolytic treatment in a 1 mol / LiClO ₄ propylene carbonate solution using lithium metal as one electrode and lithium metal as a counter electrode to form an active material. A negative electrode body was manufactured by supporting lithium. Electrolysis treatment conditions were as follows: bath temperature 20 ° C,
At a current density of 0.7 mA / cm ² , 650 mAh of substantial lithium was carried on the negative electrode body.

(5) Production of positive electrode body 10 g of MnO ₂ powder and 1 g of powdered polytetrafluoroethylene were kneaded, and the obtained kneaded product was roll-formed to a thickness.
It was a 0.2 mm sheet.

(6) Battery assembly A sheet-like electrode in which lithium is supported on a carrier made of particles having SBR adhered to the surface of the above-mentioned carbonaceous material is used as a negative electrode, a polypropylene nonwoven fabric is interposed as a separator, and the above-described positive electrode is used as a positive electrode. A sheet-like electrode made of MnO ₂ was laminated, spirally rounded as shown in FIG. 1, and housed in a stainless steel cylindrical can.

A separator, 1 mol of LiClO ₄ / - propylene carbonate solution impregnated, to seal the battery, and assembled into a battery, such as Figure 1.

(7) Battery characteristics For the battery manufactured in this way, at a constant current of 20 mA,
Discharged until the battery voltage reached 1.0V. Thereafter, the battery was charged at a constant current of 20 mA until the battery voltage reached 3.3 V. Thereafter, five cycles of preliminary charging and discharging were performed at a constant current of 20 mA under a potential regulation of an upper limit of 3.3 V and a lower limit of 1.8 V.

Thereafter, the battery was charged to 470 mAh at a constant voltage of 3.3 V and then discharged at a resistance of 200 Ω, and cycle evaluation was performed. Table 1 shows the performance at the 8th cycle and the 50th cycle.

Comparative Example 1 A battery was constructed in the same manner as in Example 1 except that a lithium metal sheet was used instead of the negative electrode battery of Example 1.

 Table 1 shows the characteristics of the battery.

The cloning efficiency at the 50th cycle was significantly reduced in Comparative Example 1, whereas the cloning efficiency in Example 1 was hardly changed as compared with the 8th cycle.

[Brief description of the drawings]

 FIG. 1 is an explanatory diagram showing the configuration of the battery of Example 1. 1 ... cathode body, 2 ... anode body 3 ... separator (including electrolyte)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01M 4/02 H01M 4/62 H01M 10/40

Claims (1)

(57) [Claims] (1) The carbonaceous material particles satisfying the following characteristics and (a) the atomic ratio of hydrogen / carbon is less than 0.15, (b) the plane spacing (d ₀₀₂ ) of the (002) plane by X-ray wide-angle diffraction ) Is 3.37 ° or more, and (c) the volume average particle diameter is 2 to 150 µm; (2) diene compound polymer elastomer, alkenyl aromatic compound-diene compound copolymer, vinyl compound (excluding (meth) acrylate) ) -Diene compound copolymer, (meth) acrylate polymer or copolymer with other polymerizable monomer, and vinyl acetate polymer or copolymer with other polymerizable monomer One or more organic polymer particles having a volume average particle size of 5 μm or less and smaller than the volume average particle size of the carbonaceous material particles of (1); (3) Secondary battery electrode, characterized in that carrying an alkali metal as an active material.