JP3164458B2 - Manufacturing method of electrode material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an electrode material for a secondary battery. More specifically, the present invention provides
The present invention relates to a method for producing a negative electrode material for a secondary battery having high capacity and excellent charge / discharge characteristics.

[0002]

2. Description of the Related Art It has been proposed to use a conductive polymer such as polyacetylene as an electrode for a lithium secondary battery (JP-A-57-121168). However, the conductive polymer has a disadvantage that it lacks the doping amount of lithium ions, that is, the electrode capacity and the 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, Li is converted from the negative electrode body into Li ions and moves into the electrolytic solution.
And the electrodeposit is deposited again on the negative electrode body. However, when this charge / discharge cycle is repeated, the metal Li deposited along with the charge / discharge cycle becomes dendritic. Since the dendritic Li is an extremely active substance, it decomposes the electrolytic solution, resulting in a disadvantage that the charge / discharge cycle characteristics of the battery deteriorate. As this further grows, finally, the dendrite-like metal Li deposit penetrates through the separator and reaches the positive electrode body, causing a problem that a short circuit phenomenon occurs. In other words, there arises a problem that the charge / discharge cycle life is short.

In order to avoid such a problem, a carbonaceous material obtained by firing an organic compound is used as a negative electrode as a support,
Attempts have been made to support Li or an alkali metal mainly composed of Li on this. By using such a negative electrode body, the charge / discharge cycle characteristics of the negative electrode were remarkably improved, but on the other hand, the electrode capacity of the negative electrode was not sufficiently large. The present invention, under such circumstances, the electrode capacity is large,
It is an object of the present invention to provide an electrode material that enables a negative electrode having excellent charge / discharge cycle characteristics.

[0004]

That is, the present invention provides the following:
After mixing particles of the carbonaceous material (A) satisfying the condition (1) and particles of the organic compound (B) satisfying the following condition (2), the mixture was heated to carbonize the organic compound (B) . By crushing later, at least a part of the particles of the carbonaceous material (A),
An object of the present invention is to provide a method for producing an electrode material having a multiphase structure coated with a carbonaceous material (C) satisfying the condition (3). (1) Doo2 in X-ray wide-angle diffraction is 3.37 ° or less,
True density of 2.10 g / cm ³ or more and volume average particle size of 5μ
(2) The volume average particle diameter is smaller than the carbonaceous material (A); (3) Doo2 in X-ray wide angle diffraction is 3.38 ° or more;
In Raman spectrum analysis using an argon ion laser beam having a wavelength of 5145 °, 1580 to 1620 cm ⁻¹
Range peak P _A of a peak P _B in the range of 1350 ^-1, the ratio R = I _B / I _A of the intensity I _B of P _B with respect to the intensity I _A of the P _A of 0.2 or more That.

Hereinafter, the present invention will be described in more detail. (Multiphase structure) The electrode material of the present invention is obtained by mixing particles of the carbonaceous material (A) and particles of the organic compound (B) as described above, and then heating the mixture to carbonize the organic compound. An electrode material having a structure in which the carbonaceous material (A) is covered with the carbonaceous material (C),
The carbonaceous material (A) and the carbonaceous material (C) each have specific crystal characteristics. The carbonaceous material (A) is preferably entirely covered with the carbonaceous material (C) , but may have a partially covered structure in some cases.

[Raw Materials for Synthesis of Electrode Material] Carbonaceous Material (A) The particles of the carbonaceous material (A) have a dough
Is 3.37 ° or less, preferably 3.35 to 3.37 °, more preferably 3.35 to 3.36 °, and even more preferably 3.36 °. Furthermore, the crystallite size L in the C-axis direction
c is preferably at least 150 °, more preferably 200 °
Å or more, more preferably 220Å or more, particularly preferably 250Å or more, and most preferably 300Å or more. The true density is 2.10 g / cm ³ or more, preferably 2.10 g / cm ³ .
12 g / cm ³ or more, more preferably 2.14 g / cm ³ or more, more preferably 2.16 g / cm ³ or more, particularly preferably 2.18 g / cm ³ or more, and most preferably 2.20～2.26G /
cm ^3. Average particle size is 5 μm or more, preferably 7 μm
m to 60 μm, more preferably 8 to 50 μm, still more preferably 10 to 40 μm, and particularly preferably 12 to
-30 μm, most preferably 15-25 μm. The specific surface area is preferably 70 m ² / g or less, more preferably 0.1 to 50 m ² / g, even more preferably 0.5 to 30 m ² / g,
Particularly preferably 0.8 to ²⁰ m ² / g, most preferably 1.
0 to 15 m ² / g.

Organic Compound (B) As the organic compound (B), it is preferable to use the particles in the form of particles. To elaborate further on this pitch,
Examples include ethylene heavy-end pitch, crude oil pitch, coal pitch, asphalt cracked pitch, and pitch generated by thermally decomposing polyvinyl chloride and the like, which are generated when naphtha is decomposed. Further, these various pitches are further heated under an inert gas flow or the like, and the quinoline insoluble content is preferably 80% or more, more preferably 90% or more.
As described above, more preferably, the mesophase pitch can be used at 95% or more. Other organic compounds include naphthalene, phenanthrene, anthracene,
3 such as triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphene, pentacene
A condensed polycyclic hydrocarbon compound obtained by condensing two or more monocyclic hydrocarbon compounds having at least two membered rings with each other; or a derivative of the above compound such as carboxylic acid, carboxylic anhydride, or carboxylic acid imide; indole, isoindole , Quinoline, isoquinoline, quinoxaline, phthalazine, carbazole, acridine, phenazine, phenanthridine, and at least two heterocyclic monocyclic compounds having at least two
Fused or condensed heterocyclic compound which is bonded to one or more monocyclic hydrocarbon compounds having one or more 3-membered rings or more; derivatives of the above compounds such as carboxylic acids, carboxylic anhydrides, and carboxylic imides Can also be used. Further, as the organic compound, a halogenated vinyl resin such as polyvinyl chloride and polyvinylidene chloride, an acrylic resin, a phenol resin, and a cellulose resin can also be used. As the organic compound, one or more of the above-mentioned organic compounds can be used simultaneously.

The particles of the organic compound (B) have a volume average particle diameter D
(2) (μm) is the volume average particle diameter D (1) of the carbonaceous material (A) described above.
(Μm). Preferably, D (2) ≦ 2/3 · D
(1), more preferably D (2) ≦ １ ／ · D (1), and still more preferably D (2) ≦ ３ · D (1). As described above, by selecting and mixing particles of the organic compound having a volume average particle size smaller than the volume average particle size of the carbonaceous material (A), the particles of the organic compound are effective around the particles of the carbonaceous material (A). Can be coated.

Mixing ratio of raw materials The mixing ratio of the carbonaceous material (A) and the organic compound (B) is preferably as follows. W (A) = weight of carbonaceous material (A) / [weight of carbonaceous material (A) + weight of organic compound (B)] is preferably 0.40 to 0.95, more preferably 0.50 to 0.50. 93,
It is more preferably from 0.55 to 0.90, particularly preferably from 0.60 to 0.85, and most preferably from 0.65 to 0.80.

[Compression Adhesion and Carbonization] Further, a mixture of the particles of the carbonaceous material (A) and the particles of the organic compound (2) is pressed and adhered to the particles of the carbonaceous material (A) and the organic compound (B). It is preferred that the particles of (1) are adhered to each other. Next, the compressed adherent is heated and carbonized under an inert gas flow or a vacuum. Carbonization is performed in an atmosphere having an oxygen concentration of preferably 5 vol% or less, more preferably 3 vol% or less, further preferably 1 vol% or less, particularly preferably 0.5 vol% or less, and most preferably 0.3 vol% or less. The carbonization temperature is preferably 500 to 2800 ° C, more preferably 700 to 2
The temperature is 500 ° C, more preferably 800 to 2100 ° C. Thus, the carbonaceous material (C) obtained by carbonizing the organic compound (B) is obtained as a carbonaceous material having a multiphase structure in which the particles of the carbonaceous material (A) are coated. That is, carbonaceous matter (A)
Thus, an electrode material having a multiphase structure in which all or a part of the surface of the particles is coated with the carbonaceous material (C) is obtained. The electrode material thus carbonized is then pulverized, bound using a polymer material, and formed into an electrode shape.

[Characteristics of Carbonaceous Material (C)] The carbonaceous material (C) has a surface spacing doo2 of 002 plane in X-ray wide angle diffraction of 3.38.
Å or more. More preferably 3.39-3.80 °, even more preferably 3.40-3.75 °, particularly preferably 3.43-3.70 °, most preferably 3.45-3.65.
Å.

The carbonaceous material (C) has a peak P in the range of 1580 to 1620 cm ^-1 in Raman spectrum analysis using an argon ion laser beam having a wavelength of 5145 °.
_A, has a peak P _B in the range of 1350 ^-1,
The ratio of the intensity I _B of P _B with respect to the intensity I _A of the P _A: R = I _B
/ I _A is 0.2 or more. P _A is a peak observed corresponding to a crystal structure that grows and forms with the spread of the aromatic ring network plane, and P _B is a peak corresponding to a disordered amorphous structure. The carbonaceous material (C) preferably has R of 0.25 or more, more preferably 0.3 to 1.6, still more preferably 0.4 to 1.5, and particularly preferably 0.5 to 1.3. .

Further, the crystallite size in the C-axis direction (Lc)
Is preferably less than 220 °, more preferably 200 ° or less, further preferably 10 ° or more and less than 150 °, particularly preferably 15 to 100 °, and particularly preferably 16 to 70 °.

[Characteristics of Electrode Material] The electrode material of the present invention comprises:
It has a multiphase structure in which all or part of the surface of the particles of the carbonaceous material (A) is coated with the carbonaceous material (C), and has the following properties correspondingly. That is, in the Raman spectrum analysis described above, the peak P is in the range of 1580 to 1620 cm ^-1.
_A, has a peak P _B in the range of 1350 ^-1,
The ratio of the intensity I _B of P _B with respect to the intensity I _A of the P _A: R = I _B
/ I _A is 0.1 or more, preferably 0.2 or more, more preferably 0.3 to 1.6, more preferably 0.4 to 1.
5, particularly preferably 0.5 to 1.3. Further, the electrode material of the present invention preferably has at least two peaks in wide-angle X-ray diffraction corresponding to the above-mentioned multiphase structure. That is, it has two peaks corresponding to the carbonaceous matter (A) and the carbonaceous matter (C). Both peaks approximate the profile of each peak with an asymmetric Pearson VII function, and the least squares method can be separated by applying the Gauss-Jordan method. That is, a peak having a doo2 of 3.37 ° or less corresponding to the carbonaceous substance (A) and a doo corresponding to the carbonaceous substance (C).
It is preferred that o2 has a peak of 3.38 ° or more. The ratio of the peak intensities of both: I _R = I (doo2 3.3
It is preferable that peak (8 ° or more) / I (doo2 is 3.37 ° or less) is 0.001 or more, and 0.0
It is more preferably from 02 to 0.50, more preferably from 0.003 to 0.50.
More preferably, it is 0.30, and 0.005 to 0.5.
15 is particularly preferable, and 0.0007 to 0.10.
Is most preferred. The electrode material of the present invention preferably has a true density of not less than 2.05 g / cm ^{3 and} 2.08 g / cm ^3.
/ cm ³ or more, more preferably 2.10 to 2.25
g / cm ³ , more preferably 2.12 to 2.22 g.
/ cm ³ , particularly preferably 2.15 to 2.20 g /
Most preferably, it is cm ³ . Further, the electrode material of the present invention preferably has a volume average particle size of 5 to 80 μm, more preferably 7 to 70 μm, and 8 to 60 μm.
μm, more preferably 10 to 50 μm, and most preferably 12 to 40 μm.

[Polymer Binder] The electrode material of the present invention is usually mixed with a polymer binder and then formed into an electrode shape. Examples of the polymer binder include the following. Resin-like polymers such as polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, and cellulose. Rubbery polymers such as styrene / butadiene rubber, isoprene rubber, butadiene rubber, and ethylene / propylene rubber. Thermoplastic elastomeric polymers such as styrene / butadiene / styrene block copolymers, their hydrogenated products, styrene / isoprene / styrene block copolymers, and their hydrogenated products. Soft resinous polymers such as syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymer, and propylene / α-olefin (2 or 4 to 12 carbon atoms) copolymer. A polymer composition having ionic conductivity of alkali metal ions, particularly Li ions.

The above-mentioned ion-conductive polymer composition includes a polymer compound such as polyethylene oxide, polypropylene oxide, polyepichlorohydrin, polyphosphazene, polyvinylidene fluoride, polyacrylonitrile, and a lithium salt or lithium. Or a system in which an organic compound having a high dielectric constant such as propylene carbonate, ethylene carbonate, or γ-butyrolactone is further added thereto. The polyphosphazene preferably has a polyether chain, particularly a polyoxyethylene chain in a side chain. The ionic conductivity of such an ionic conductive polymer composition at room temperature is preferably 10 ^−8.
S · cm ⁻¹ or more, more preferably 10 ⁻⁶ S · cm ⁻¹ or more, further preferably 10 ^-4 S · cm ⁻¹ or more, particularly preferably 10 ^-3.
S · cm ⁻¹ or more. Various forms can be adopted as a mixed form of the electrode material of the present invention and the above-mentioned polymer binder. That is, a form in which both particles are simply mixed, a form in which a fibrous binder is mixed in a form entangled with the particles of the electrode material, or the above rubber-like polymer, thermoplastic elastomer,
Examples include a form in which a layer of a binder such as a soft resin or an ion-conductive polymer composition is attached to the surfaces of particles of an electrode material. When a fibrous binder is used, the fiber diameter of the binder is preferably 10 μm or less, more preferably 5 μm.
The following fibrils (ultrafine fibers), particularly preferably fibrids (powder having tentacle-like ultrafine fibrils). The mixing ratio of the electrode material and the binder is
The binder is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, and still more preferably 1 to 10 parts by weight, based on 100 parts by weight of the electrode material.

Further, an alkali metal as an active material, in particular, a metal capable of forming an alloy with lithium, for example, aluminum can be mixed with the above mixture. Alternatively, an alloy composed of such a metal and an alkali metal, particularly lithium, for example, a lithium aluminum alloy can be used as a mixture. Such a metal or alloy may be in the form of particles, in the form of a thin layer coated on the surface of the electrode material, or in the form of being contained in the electrode material. The proportion of the metal or alloy is preferably 70 parts by weight or less, more preferably 5 to 60 parts by weight, and still more preferably 10 to 5 parts by weight, based on 100 parts by weight of the electrode material.
0 parts by weight, particularly preferably 15 to 40 parts by weight.

[Electrode molding] The electrode material of the present invention is a mixture of the above-mentioned binder or a metal capable of forming an alloy with the above-mentioned active material or an alloy of the above-mentioned metal and an active material. An electrode molding material can be obtained by forming an electrode molding material made of the mixture obtained as described above into a shape of an electrode by a method such as roll molding or compression molding. Alternatively, these components may be dispersed in a solvent and applied to a metal current collector or the like. The shape of the electrode molded body can be arbitrarily set, such as a sheet or a pellet.

An alkali metal, preferably a lithium metal, which is an active material, is added to the electrode molded body thus obtained.
It can be carried prior to or during assembly of the battery. As a method of supporting the active material on the carrier,
There are chemical methods, electrochemical methods, and physical methods.
For example, a method of immersing the electrode molded body in an electrolytic solution containing a predetermined concentration of alkali metal cation, preferably Li ion, and using lithium as a counter electrode, electrolytically impregnating the electrode molded body as an anode, A method of mixing an alkali metal powder, preferably a lithium powder, can be applied in the process of obtaining. Alternatively, a method of electrically contacting the lithium metal and the electrode molded body is also used. In this case, it is preferable that the lithium metal and the carbonaceous material in the electrode compact are brought into contact with each other via the lithium ion conductive polymer composition. The amount of lithium previously supported on the electrode compact in this manner is preferably 0.030 to 0.250 parts by weight, more preferably 0.060 to 0.200 parts by weight, and more preferably 1 part by weight per part by weight of the support. Preferably from 0.070 to 0.150 parts by weight, particularly preferably 0.00 to 0.150 parts by weight.
75 to 0.120 parts by weight, most preferably 0.080 to
0.100 parts by weight. The electrode of the present invention using such an electrode material is usually used as a negative electrode of a secondary battery, and is opposed to a positive electrode via a separator.

[Positive Electrode] The material of the positive electrode body is not particularly limited. For example, it is preferable to use a metal chalcogen compound which releases or acquires an alkali metal cation such as Li ion along with a charge / discharge reaction. Such metal chalcogen compounds include vanadium oxides, vanadium sulfides, molybdenum oxides, molybdenum sulfides, manganese oxides, chromium oxides, titanium oxides, titanium sulfides and the like. And complex sulfides. 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 , V
S ₂ , Cr _0.25 V _0.75 S ₂ , Cr _0.5 V _0.5 S ₂ and the like. Oxides such as LiCoO ₂ and WO ₃ ; CuS;
Sulfides such as Fe _0.25 V _0.75 S ₂ and Na _0.1 CrS ₂ ; N
phosphorus and sulfur compounds such as iPS ₃ and FePS ₃ ;
₂ , selenium compounds such as NbSe ₃ and the like can also be used. Further, a conductive polymer such as polyaniline or polypyrrole can be used. Furthermore, the specific surface area is 1
0 m ² / g or more, preferably 100 m ² / g or more, more preferably 500 m ² / g or more, particularly preferably 1000 m ² / g or more, and most preferably 2000 m ² / g or more of carbonaceous material can be used for the positive electrode. .

[Electrolyte] As the electrolyte, an organic solvent may be used.
As the electrolyte, an electrolytic solution obtained by dissolving an alkali metal salt or a quaternary ammonium salt is used. As the electrolyte, L
iClO ₄ , LiPF ₆ , LiAsF ₆ , LiBF ₄ , Li
Alkali metal salts such as SO ₃ CF ₃ and LiN (SO ₂ CF ₃ ) ₂ , and tetraalkylammonium salts can be used. Alkali metal salts are preferred. The concentration is 0.2
Mol / l or less is preferable, and 0.3 to 1.9 mol / l is more preferable. As a solvent for dissolving the electrolyte, a cyclic ester compound such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, and γ-butyrolactone can be used. Further, a chain ether, a cyclic ether, a chain ester compound, or the like can be used. Examples of the chain ether compound include 1,2-dimethoxyethane, and examples of the cyclic ether compound include crown ether (e.g., 12-crown-4), 1,2-dimethyltetrahydrofuran, dioxolan, and tetrahydrofuran. . Examples of the chain ester compound include diethyl carbonate. As a solvent for dissolving the electrolyte, it is preferable to use a mixed solvent composed of at least two kinds of solvents. For example, ethylene carbonate in the mixed solvent is mixed with 5 vol% or more and less than 60 vol%, more preferably 7 vol%.
vol% or more and less than 50 vol%, more preferably 10 to 45%
vol%, particularly preferably 12 to 40 vol%, most preferably 15 to 40 vol%. Also, L
A solid electrolyte which is a derivative of an alkali metal cation such as i-ion may be interposed between the positive electrode body and the negative electrode body. As the separator for holding the electrolytic solution, a material excellent in liquid retention properties, for example, a nonwoven fabric of polyolefin such as polyethylene and polypropylene can be generally used.

[0022]

In the battery thus constructed, the active material ions are carried on the carrier at the time of charging at the negative electrode,
At the time of discharge, the active material ions in the carrier are released, so that a charge / discharge 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 carried on the positive electrode body during charging, and a counter ion of the active material ion is released from the positive electrode body during discharging. The reaction proceeds. As described above, the battery reaction accompanying the charge and discharge of the battery proceeds by the combination of the electrode reactions of the positive electrode body and the negative electrode body.

[Measurement Method] In the present invention, the properties of the carbonaceous material such as (a) wide-angle X-ray diffraction, (b) true density, (c) volume average particle diameter, and (d) Raman spectrum are as follows. Was measured by (A) Wide-angle X-ray diffraction: (1) Spacing between ( ₀₀₂ ) planes (d ₀₀₂ ) If the carbonaceous material is powder, it is powdered in an agate mortar if the carbonaceous material is in the form of powder; Wt% X
High-purity silicon powder for a line standard is mixed as an internal standard substance, packed in a sample cell, and a wide angle X-ray diffraction curve is measured by a reflection type diffractometer method using a CuKα ray monochromatized by a graphite monochromator as a source. For the correction of the curve, the following simple method is used without correcting so-called Lorentz, polarization factor, absorption factor, atomic scattering factor and the like. That is, a baseline of a curve corresponding to the (002) diffraction is drawn, and the substantial intensity from the baseline is re-plotted to obtain a correction curve for the (002) plane. The midpoint of the line where the line parallel to the angle axis drawn to two-thirds of the peak height of this curve intersects the diffraction curve is determined, the angle of the midpoint is corrected by the internal standard, and this is repeated. The doubled angle is obtained, and d ₀₀₂ is obtained from the wavelength λ of the CuKα ray by the following Bragg equation.

[0024]

(Equation 1) λ: 1.5418 ° θ: diffraction angle corresponding to d ₀₀₂

(2) Crystallite size in the c-axis direction: Lc In the corrected diffraction curve obtained in the preceding section, the crystallite size in the c-axis direction is calculated by using the so-called half width β at half the peak height. Is calculated by the following equation.

[0026]

(Equation 2)

The shape factor K was 0.90. λ, θ
Has the same meaning as in the previous section. (B) True density: Measured using a multi-pycnometer (manufactured by Yuasa Ionics) using a gas replacement method with helium gas. (C) Volume average particle size: Measured using a laser diffraction type particle size distribution analyzer (manufactured by Horiba, Ltd.). (D) Raman spectrum: measured using an argon laser beam as a light source and JASCO NR1000 as a spectroscope.

Hereinafter, the present invention will be further described with reference to examples.

EXAMPLE 1 Carbonaceous material (A) having a doo2 of 3.36 °, a true density of 2.25 g / cm ³ , a volume average particle size of 20 μm, and a specific surface area of 8.7 m ² / g in X-ray wide angle diffraction. Was added and mixed with 70 parts by weight of the particles having a volume average particle diameter of 2 μm. After the mixture was pressed and adhered, the mixture was set in an electric heating furnace, heated at a rate of 200 ° C./hour under N ₂ flow, and then heated to 1300 ° C. The temperature was further maintained at 1300 ° C. for 1 hour to carbonize the pitch. Doo2 of carbonaceous material (C)
Was 3.50 °, and the peak intensity ratio R in the Raman spectrum was 0.50. This was pulverized to obtain an electrode material of particles having a volume average particle diameter of 25 μm. This particle has two peaks with a doo2 of 3.36 ° and 3.50 ° in X-ray diffraction, and a peak intensity ratio R in the Raman spectrum.
Was 0.49. The true density is 2.16 g / cm ³ , BE
The T specific surface area was 1.2 m ² / g. 7 parts by weight of polyethylene was mixed with 93 parts by weight of the electrode material, and the mixture was pressed on a nickel wire net. This was dried by heating to 130 ° C. in a vacuum to obtain an electrode compact. A solution of LiClO ₄ / ethylene carbonate (50 vol%) and diethyl carbonate (50 vol%) having a concentration of 1 mol / liter was put in a glass cell, and the above-mentioned electrode compact was opposed to an electrode in which lithium metal was pressed on a nickel metal mesh. To form a battery cell. 0V at 1.5mA between both electrodes
The operation of charging to 1.5V and discharging to 1.5V was repeated. Table 1 shows the results.

Comparative Example 1 Only the pitch particles were set in an electric heating furnace, and were flowed under N _{2 for} 20 minutes.
The temperature was raised at 0 ° C./hour and raised to 1300 ° C. One more
It was kept at 300 ° C. for 1 hour to carbonize. The electrode performance was evaluated in the same manner as in Example 1 except that this carbonaceous material was used instead of the carbonaceous material of Example 1. Table 1 shows the results.

[0030]

[Table 1]

[0031]

The electrode material of the present invention, when used as an electrode for a secondary battery by being formed into an electrode molded article by using the above-described carbonaceous material as a main component, has an electrode capacity. It is large and exhibits excellent charge / discharge cycle characteristics.

────────────────────────────────────────────────── (5) Continuation of the front page (51) Int.Cl. ⁷ Identification code FI H01M 10/40 C04B 35/52 (56) References JP-A-4-368778 (JP, A) JP-A-5-94838 (JP JP-A-5-121066 (JP, A) JP-A-5-286763 (JP, A) JP-A-5-307959 (JP, A) JP-A-5-29973 (JP, A) 4-171677 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 4/04 C04B 35/52 C04B 41/87 H01M 4/02 H01M 4/58 H01M 10/40

Claims (3)

(57) [Claims] A mixture of particles of a carbonaceous material (A) satisfying the following condition (1) and particles of an organic compound (B) satisfying the following condition (2) is mixed, and then heated to form an organic compound (A). B) was carbonized
A method for producing an electrode material having a multiphase structure in which at least a part of the particles of the carbonaceous material (A) is coated with the carbonaceous material (C) satisfying the following condition (3) by pulverization later : (1) X Doo2 in line wide angle diffraction is 3.37 ° or less,
True density of 2.10 g / cm ³ or more and volume average particle size of 5μ
(2) The volume average particle diameter is smaller than the carbonaceous material (A); (3) Doo2 in X-ray wide angle diffraction is 3.38 ° or more;
In Raman spectrum analysis using an argon ion laser beam having a wavelength of 5145 °, 1580 to 1620 cm ⁻¹
Range peak P _A of a peak P _B in the range of 1350 ^-1, the ratio R = I _B / I _A of the intensity I _B of P _B to the intensity IA of the P _A of 0.2 or more There is. 2. The organic compound (B) is pitch.
2. The production method according to 1. 3. Particles of carbonaceous material (A) and particles of organic compound
After mixing, the mixture is pressed and adhered.
Is the production method according to 2.