WO2014119776A1 - リチウムイオン二次電池負極活物質用黒鉛粉 - Google Patents
リチウムイオン二次電池負極活物質用黒鉛粉 Download PDFInfo
- Publication number
- WO2014119776A1 WO2014119776A1 PCT/JP2014/052401 JP2014052401W WO2014119776A1 WO 2014119776 A1 WO2014119776 A1 WO 2014119776A1 JP 2014052401 W JP2014052401 W JP 2014052401W WO 2014119776 A1 WO2014119776 A1 WO 2014119776A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- graphite powder
- electrode
- battery
- graphite
- lithium
- Prior art date
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/205—Preparation
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/21—After-treatment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/043—Processes of manufacture in general involving compressing or compaction
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present invention relates to graphite powder, graphite powder for battery electrodes, and batteries. More specifically, graphite powder suitable as an electrode material for a non-aqueous electrolyte secondary battery, its production method, graphite material for battery electrode containing the graphite powder, electrode for lithium ion battery, charge / discharge cycle characteristics, large current
- the present invention relates to a lithium ion secondary battery having excellent load characteristics.
- Lithium ion secondary batteries are mainly used as power sources for portable devices and the like. Mobile devices and the like have diversified functions and have increased power consumption. Therefore, the lithium ion secondary battery is required to increase its battery capacity and simultaneously improve the charge / discharge cycle characteristics. In addition, there is an increasing demand for high-power, large-capacity secondary batteries such as electric tools such as electric drills and hybrid vehicles. Conventionally, lead secondary batteries, nickel cadmium secondary batteries, and nickel metal hydride secondary batteries have been mainly used in this field. However, expectations for high-density lithium-ion secondary batteries that are small and light are high. A lithium ion secondary battery having excellent current load characteristics is demanded.
- the main required characteristics are long-term cycle characteristics over 10 years and large current load characteristics for driving high-power motors.
- a high volumetric energy density is required to extend the cruising range, which is harsh compared to mobile applications.
- This lithium ion secondary battery generally uses a lithium salt such as lithium cobaltate as a positive electrode active material and a carbonaceous material such as graphite as a negative electrode active material.
- a lithium salt such as lithium cobaltate
- a carbonaceous material such as graphite
- Graphite includes natural graphite and artificial graphite. Of these, natural graphite is available at low cost. However, since natural graphite has a scaly shape, when it is made into a paste together with a binder and applied to a current collector, the natural graphite is oriented in one direction. When charging with such an electrode, the electrode expands in only one direction, and the performance as an electrode is reduced. Although natural graphite granulated has been proposed, spherical natural graphite is crushed and oriented by pressing during electrode production. Moreover, since the reaction activity on the surface of natural graphite was high, the initial charge / discharge efficiency was low, and the cycle characteristics were not good. In order to solve these problems, Patent Document 1 proposes a method of coating carbon on the surface of natural graphite processed into a spherical shape. However, the cycle characteristics are not sufficient.
- Patent Document 4 discloses artificial graphite having excellent cycle characteristics.
- Patent Document 6 discloses an artificial graphite negative electrode manufactured from raw acicular coke.
- Patent Document 7 discloses an artificial graphite negative electrode manufactured from coke obtained by coating petroleum pitch with a liquid phase.
- Japanese Patent No. 3534391 (US Pat. No. 6,632,569) Japanese Patent Laid-Open No. 4-190555 Japanese Patent No. 3361510 JP-A-7-320740 (US Pat. No. 5,587,255) International Publication No. 2011/049199 Pamphlet Japanese Patent Laid-Open No. 2001-23638 International Publication No. 2003/064560 Pamphlet (Special Table No. 2005-515957)
- the material manufactured by the method described in Patent Document 1 can cope with the high capacity, low current, and medium cycle characteristics required for mobile applications and the like, but the large current and super long cycle of the large battery as described above. It is very difficult to meet requirements such as characteristics.
- the graphitized product described in Patent Document 2 is a very well-balanced negative electrode material, and can produce a battery with a high capacity and a large current. It is difficult to achieve a wide range of cycle characteristics.
- the method of Patent Document 3 can use fine powder such as natural graphite as well as fine powder of artificial graphite raw material, and exhibits extremely excellent performance as a negative electrode material for mobile use. However, the manufacturing method is complicated.
- Patent Document 4 has a volume energy density that is too low and is very expensive, so it is used only for some special large batteries.
- Patent Document 5 there is room for improvement in energy density per volume.
- patent document 6 although the improvement of initial charge / discharge efficiency is seen with respect to the conventional artificial graphite, the discharge capacity is inferior compared with natural graphite material.
- patent document 7 the subject remains in the capacity density of an electrode.
- the manufacturing method becomes complicated with the operation of using a large amount of organic solvent and volatilizing it.
- An object of the present invention is to provide a graphite powder for an electrode for a lithium secondary battery that is excellent in electrode capacity, initial charge / discharge efficiency and cycle capacity maintenance rate, and has a small electrode expansion during charge / discharge, and a battery electrode using the graphite powder It is providing the graphite material for lithium, the electrode for lithium batteries, and a lithium ion secondary battery.
- the present invention provides the following [1] to [6] graphite powder, [7] to [12] graphite powder production method, [13] graphite material for battery electrode, and [14] to [15] lithium battery.
- the present invention relates to an electrode for use, and a lithium ion secondary battery of [16].
- [1] Initial charge / discharge efficiency of a coin battery produced from an electrode (working electrode) obtained by compressing an electrode material containing graphite powder as an active material at a pressure of 0.5 t / cm 2, a lithium metal counter electrode, a separator, and an electrolyte.
- the graphite powder according to any one of 1 to 4 above, wherein an electrode expansion coefficient represented by the following formula is 100 to 130%; Electrode expansion rate (%) ⁇ (T500 / T10) ⁇ ⁇ 100 [6] A graphite powder obtained by compressing the graphite powder described in any one of 1 to 5 with a pressure of 1.5 to 5 t / cm 2 . [7] The method for producing graphite powder as described in any one of 1 to 6 above, comprising a step of graphitizing scaly coke at 2400 ° C. to 3600 ° C. and a step of contacting with scaly oxygen.
- the lithium ion battery negative electrode When the graphite powder in the present invention is used as a graphite material for battery electrodes, the lithium ion battery negative electrode has high electric capacity, high electrode density, excellent initial charge / discharge efficiency and capacity retention rate, and low electrode expansion coefficient in charge / discharge cycles. Can be obtained.
- the graphite powder in the present invention can be produced by a method excellent in economic efficiency, safety, and mass productivity including the oxidation treatment step in the same apparatus as the graphitization step.
- the negative electrode of a secondary battery is required to have a high capacity per unit volume.
- One method for increasing the capacity of the negative electrode is to increase the capacity per mass of the active material. This is because the capacity per mass of graphite tends to increase as the crystallinity of graphite increases.
- Another method for improving the capacity per volume of the negative electrode is to increase the amount of active material per electrode volume, that is, to improve the electrode density.
- an electrode of a battery is manufactured by applying an active material on a current collector plate and drying it, followed by pressing (compression). In addition to improving the filling capacity of the active material per volume, the press can extremely increase the electrode density if the active material is soft and deforms to some extent with the press.
- the electrode density tends to be improved.
- the electrode density at the time of manufacturing the battery is high, the electrode expands while charging and discharging are repeated, and as a result, the battery may not be downsized. Accordingly, the negative electrode active material is required to have a low electrode expansion coefficient.
- the graphite powder in a preferred embodiment of the present invention consists of scaly graphite particles.
- scaly graphite particles are graphite particles having a median aspect ratio of 1.4 or more measured with respect to 10,000 or more particles in LPF mode using FPIA-3000 manufactured by sysmex.
- graphite particles having a median aspect ratio of less than 1.4 are called massive particles.
- the graphite powder in a preferred embodiment of the present invention has an average interplanar spacing (d002) of (002) plane of 0.340 nm or less by X-ray diffraction method, and a thickness (Lc) in the C-axis direction of the crystal of 50 nm or more and 1000 nm or less. It is. By setting it as this range, the discharge capacity per mass of the electrode which uses graphite powder as an active material improves, and the electrode density by press improves. When d002 exceeds 0.337 nm or when Lc is less than 50 nm, the capacity per volume tends to decrease.
- (d002) is 0.338 nm or less, and (Lc) is 80 nm or more and 1000 nm or less. In the most preferred embodiment, (d002) is 0.336 nm or less, and (Lc) is 90 nm or more and 1000 nm or less.
- d002 and Lc can be measured by a known method using a powder X-ray diffraction (XRD) method (Inayoshi Noda, Michio Inagaki, Japan Society for the Promotion of Science, 117th Committee Material, 117-71-A-1) (1963), Michio Inagaki et al., Japan Society for the Promotion of Science, 117th Committee Sample, 117-121-C-5 (1972), Michio Inagaki, “Carbon”, 1963, No. 36, pages 25-34).
- XRD powder X-ray diffraction
- the median diameter (D50) of the graphite powder is 1 ⁇ m or more and 50 ⁇ m or less.
- D50 is 50 ⁇ m or less, lithium diffusion in the case of an electrode is performed quickly, and the charge / discharge rate is increased.
- More preferable D50 is 5 ⁇ m or more and 35 ⁇ m or less.
- D50 is 10 ⁇ m or more because unintended reactions are less likely to occur.
- D50 is more preferably 25 ⁇ m or less.
- the graphite powder in a preferred embodiment of the present invention is not pulverized after graphitization. Therefore, the rhombohedral peak ratio is 5% or less, more preferably 1% or less. By making such a range, the formation of intercalation compounds with lithium is smooth, and when this is used as a negative electrode material in a lithium ion secondary battery, the lithium occlusion / release reaction is not easily inhibited, and rapid charge / discharge characteristics Will improve.
- the graphite powder in a preferred embodiment of the present invention has a BET specific surface area of 0.4 m 2 / g or more and 5 m 2 / g or less, and more preferably 0.5 m 2 / g or more and 3.5 m 2 / g or less. More preferably not more than 1 m 2 / g or more 3.0 m 2 / g.
- the BET specific surface area is measured by a general method of measuring the amount of adsorption / desorption of gas per unit mass. As a measuring apparatus, for example, NOVA-1200 can be used, and measurement can be performed by nitrogen adsorption.
- the total pore volume by the nitrogen gas adsorption method under liquid nitrogen cooling is 8.0 ⁇ L / g. ⁇ 20.0 ⁇ L / g.
- the electrolytic solution easily penetrates and the rapid charge / discharge characteristics are improved.
- the total pore volume is 8.0 ⁇ L / g or more, the negative electrode obtained from the graphite powder becomes a negative electrode with few side reactions and high initial charge / discharge efficiency.
- the total pore volume is 8.5 ⁇ L / g to 17.0 ⁇ L / g. In a most preferred embodiment, the total pore volume is 8.7 ⁇ L / g to 15.0 ⁇ L / g.
- the electrode using graphite powder as an active material in a preferred embodiment of the present invention further stabilizes the contact between graphite particles by compressing at an appropriate pressure, and improves the initial charge / discharge efficiency.
- the initial charge / discharge efficiency of a coin battery made from an electrode (working electrode) formed by compressing the electrode material at a pressure of 3 t / cm 2, a lithium metal counter electrode, a separator, and an electrolyte solution is e ( 3)
- It has the feature of satisfying the conditions of Further preferred graphite powders are e (3) (%)-e (0.5) (%)> 2 and
- the most preferred graphite powder is e (3) (%)-e (0.5) (%)> 3 and e (3) (%)> 87.
- the discharge capacity per mass of the active material in the initial cycle of the coin battery when the pressure is 3 t / cm 2 is preferably 335 mAh / g or more, more preferably 340 mAh / g or more, and further preferably 345 mAh / g or more.
- the graphite powder has a graphite surface shape suitable for stabilizing the contact structure of the graphite particles in the electrode by compressing the graphite powder before electrode preparation in a powder state.
- the initial charge / discharge efficiency of the electrode using the graphite powder as an active material is improved.
- the graphite powder in a preferred embodiment of the present invention has an electrode density of 1.3-2. 2 when an electrode using the graphite powder as an active material is compressed at 3 t / cm 2 by the method described in the examples. 1 g / cm 3 .
- a more preferable electrode density is 1.5 to 2.1 g / cm 3
- a particularly preferable electrode density is 1.7 to 2.1 g / cm 3 .
- the graphite powder of the present invention can have a carbon coating layer on the particle surface of the graphite powder.
- a carbon coating layer By having the carbon coating layer, it is possible to improve cycle characteristics, charge state storage characteristics, and rapid charge / discharge characteristics as an electrode, and to suppress electrode expansion during charge / discharge.
- the electrode expansion coefficient represented by the following formula is 100 to 130%.
- Electrode expansion rate (%) ⁇ (T500 / T10) ⁇ ⁇ 100 In a more preferred embodiment, the electrode expansion rate is 100% to 125%, and in the most preferred case 100% to 122%.
- the manufacturing method of graphite powder is not limited, For example, the following methods are suitable. Calcination or raw coke can be used as a raw material for the graphite powder.
- a raw material for coke for example, petroleum pitch, coal pitch, coal pitch coke, petroleum coke, and a mixture thereof can be used. Among these, what heated the coke which performed the delayed coking on specific conditions in inert atmosphere is preferable.
- these liquids are heated to 450 ° C. or higher, more preferably 510 ° C. or higher, at least at the entrance to the drum, thereby increasing the residual carbon ratio during coke calcination.
- the pressure in the drum is preferably maintained at normal pressure or higher, more preferably 300 kPa or higher, and further preferably 400 kPa or higher. Thereby, the capacity
- coke is performed under conditions severer than usual, so that the liquid can be reacted more and coke having a higher degree of polymerization can be obtained.
- the obtained coke is cut out from the drum by a jet water flow, and the obtained lump is roughly pulverized to about 5 cm with a hammer.
- a biaxial roll crusher or a jaw crusher can be used, but pulverization is preferably performed so that the amount on a 1 mm sieve is 90% by mass or more. If excessive pulverization is performed to such an extent that a fine powder having a particle diameter of 1 mm or less is generated in large quantities, there is a possibility that inconveniences such as rising after drying or increased burnout may occur in the subsequent heating process.
- the coarsely ground coke can then be calcined. Calcination refers to heating to remove moisture and organic volatiles. When graphitization is performed on the calcined coke, the crystal grows more preferably.
- Calcination can be performed by heating with electricity or flame heating of LPG, LNG, kerosene, heavy oil or the like. Since a heat source of 2000 ° C. or less is sufficient for removing moisture and organic volatile components, flame heating, which is a cheaper heat source, is preferable when mass production is performed. Especially when processing on a large scale, the energy cost can be reduced by heating the coke with internal flame or internal heat while burning the organic volatiles of fuel and unheated coke in the rotary kiln. Is possible.
- the raw material coke in a preferred embodiment of the present invention preferably has an optical structure satisfying 2.0 ⁇ AR (60), more preferably 2.2 ⁇ AR (60), and more preferably 2.25 when observed with a polarizing microscope. Most preferably, ⁇ AR (60) is satisfied.
- ⁇ AR (60) is satisfied.
- a heat treatment is performed at 1100 ° C. and then observation with a polarizing microscope is performed.
- Lc is increased by graphitization, and the density of the electrode can be increased.
- AR (60) is a raw material coke or raw material calcined coke that has been heat-treated at 1100 ° C., and a cross section of the raw coke is extracted with a polarizing microscope to extract individual optical structures.
- the aspect ratio is when the integrated value is 60% of the total optical tissue area observed.
- a mass of several mm or more of calcined coke is embedded in a resin, and its cross section is observed by mirror finishing or the like. Further, it can be carried out by a method described in “Latest carbon material experimental technique (analysis / analysis bias) Carbon Society of Japan bias (2001), publication: Cypec Corporation, pp. 1-8”.
- [Resin buried] A double-sided tape is affixed to the bottom of a plastic sample container having an internal volume of 30 cm 3 , and coke particles having a size of several mm or more are placed thereon.
- Cold embedding resin (trade name: cold embedding resin # 105, manufacturer: Japan Composite Co., Ltd., sales company: Marumoto Struers Co., Ltd.) and curing agent (trade name: curing agent (M agent), Manufacturing company: Nippon Oil & Fats Co., Ltd., sales company: Marumoto Struers Co., Ltd.) and knead for 30 seconds.
- the obtained mixture (about 5 ml) is slowly poured into the sample container until it reaches a height of about 1 cm, and allowed to stand for 1 day to solidify. After coagulation, the coagulated resin is removed from the container and the double-sided tape is peeled off.
- the surface to be measured is polished using a polishing plate rotating type polishing machine. Polishing is performed such that the polishing surface is pressed against the rotating surface. The polishing plate is rotated at 1000 rpm. The counts of the polishing plates were # 500, # 1000, and # 2000 in order, and finally the alumina (trade name: Baikalox type 0.3CR, particle size 0.3 ⁇ m, manufacturer: Baikowski, sales company: Baikow Mirror polishing using Ski Japan). The polished resin is fixed with clay on a preparation, and observed using a polarizing microscope (OLYMPAS, BX51).
- optical tissue extraction The optical tissue is extracted using ImageJ (manufactured by the National Institutes of Health, USA) to determine the blue portion, yellow portion, red portion, and black portion.
- ImageJ manufactured by the National Institutes of Health, USA
- the parameters that define each color when using ImageJ for each color are as follows.
- the black portion that is, the portion corresponding to the resin portion instead of the optical structure is excluded from the statistical object, and the aspect ratio of each structure is calculated for each of the blue, yellow, and red optical structures.
- the pulverization of the calcined coke is not particularly limited, but can be performed, for example, as follows. There is no restriction
- the pulverization is preferably performed so that the volume-based median diameter (D50) by laser diffraction is 1 ⁇ m or more and 50 ⁇ m or less. In order to pulverize until D50 is less than 1 ⁇ m, a large amount of energy is required using special equipment. When D50 is 50 ⁇ m or less, lithium diffusion in the case of an electrode is performed quickly, and the charge / discharge rate is increased.
- D50 is 5 ⁇ m or more and 35 ⁇ m or less. Further, it is more preferable that D50 is 10 ⁇ m or more because unintended reactions are less likely to occur. In view of the necessity of generating a large current when used as a driving power source for automobiles or the like, D50 is more preferably 25 ⁇ m or less.
- graphitization is performed.
- pulverized calcined coke is mixed with one or more kinds selected from petroleum pitch, coal pitch and phenol resin. Mix the dressing.
- the petroleum-based pitch and coal-based pitch used for the coating material preferably contain 20% by mass or more of ⁇ -resin content and 10% by mass or less of quinoline insoluble content.
- the pitch spreads uniformly on the graphite surface during heating, and an effective carbon coating layer is formed, improving discharge capacity, initial charge / discharge efficiency, charge state storage characteristics, cycle characteristics, and electrode expansion. Contributes to suppression.
- the ⁇ resin content is 25% by mass or more and the quinoline insoluble content is 7% by mass or less.
- the ⁇ resin content is 30% by mass or more and the quinoline insoluble content is 4% by mass or less.
- the phenol resin used for the coating material is preferably thermoplastic. By using such a coating material, the resin spreads uniformly on the graphite surface during heating, and an effective carbon coating layer is formed. Discharge capacity, initial charge and discharge efficiency, charge state storage characteristics, cycle characteristics, rapid charge and discharge Contributes to improvement of characteristics and suppression of electrode expansion. It is more preferable to mix petroleum pitch and coal pitch in addition to the phenol resin because the phenol resin easily spreads uniformly on the graphite surface.
- Mixing of the particles obtained by pulverizing the calcined coke and the particles obtained by pulverizing the coating material can be carried out either wet or dry.
- the coating material is dissolved or dispersed in a solvent, calcined coke is further added, and then the solvent is removed by drying.
- the mixing is preferably performed by a dry method that does not use a solvent.
- the particles obtained by pulverizing the calcined coke and the particles obtained by pulverizing the coating material are generally not pulverized.
- a force such that the particles obtained by pulverizing the calcined coke are generally not pulverized.
- liner parts such as hammer mills, impeller mills, blades, and rotation speed are adjusted to reduce pulverization performance Can be preferably used.
- the hammer mill and the impeller mill have a strong mixing force and are suitable for continuously performing the dry coating process in a short time.
- a smooth film may not be formed by the coating material, but the coating material is softened by heating for graphitization and spreads on the surface of the particles obtained by pulverizing calcined coke to form a smooth film.
- Particles obtained by pulverizing petroleum pitch or coal pitch have a volume-based median diameter (D50) by laser diffraction method smaller than the median diameter (D50) of particles obtained by pulverizing calcined coke, and 0.01 ⁇ m or more and 25 ⁇ m.
- D50 volume-based median diameter
- D50 is 0.5 ⁇ m or more, and further preferably 1.0 ⁇ m or more.
- D50 is more preferably 10 ⁇ m or less, and further preferably 5 ⁇ m or less.
- Dc / Dp is 1.5 or more and 200. If it is less than the range, the formed film becomes more uniform, which is preferable.
- Dc / Dp is more preferably 50 or less, and further preferably 15 or less.
- Dc / Dp is more preferably 3 or more, and further preferably 8 or more.
- the amount of the particles obtained by pulverizing the coating material is 0.5% by mass or more and 15% by mass or less in the total mass of the particles obtained by pulverizing calcined coke and the particles obtained by pulverizing the coating material. It is preferable from the viewpoint of the per unit capacity. 1% by mass or more and 5% by mass or less is more preferable from the viewpoint of high-speed charge / discharge characteristics and power storage characteristics, and 1.2% by mass or more and 2.5% by mass or less is more preferable from the viewpoint of capacity per volume.
- the process can be simplified as compared with a process having a separate carbonization process after coating.
- firing can be performed at 500 ° C. to 1500 ° C. to carbonize the coating material. At this time, since the mass reduction at the time of the graphitization treatment is reduced, it is possible to increase the amount of treatment once in the graphitization treatment apparatus.
- the graphitization is preferably performed at a temperature of 2400 ° C. or higher, more preferably 2800 ° C. or higher, more preferably 3050 ° C. or higher, and most preferably 3150 ° C. or higher.
- a graphite crystal grows more, and an electrode capable of storing lithium ions at a higher capacity can be obtained.
- the graphitization temperature is preferably 3600 ° C. or lower. Electrical energy is preferably used to achieve these temperatures. Electrical energy is expensive compared to other heat sources, and consumes extremely large electric power to achieve 2000 ° C. or more.
- the carbon raw material Prior to graphitization, the carbon raw material is calcined and the organic volatiles are removed, that is, the fixed carbon content is 95% or more, more preferably 98% or more. More preferably, it is 99% or more.
- graphitization is performed in an oxygen-free atmosphere, for example, in a nitrogen-filled environment or an argon-filled environment.
- the graphitization is performed in an environment containing a certain concentration of oxygen or after the graphitization step. It is preferable that an oxidation treatment is performed.
- graphite has highly active sites such as dangling bonds on the surface, and these highly active sites cause side reactions inside the battery. Therefore, the initial charge / discharge efficiency, cycle characteristics, power storage characteristics decrease and It was the cause of electrode expansion.
- the highly active sites are removed by oxidation reaction in the graphite powder, the number of highly active sites on the surface of the graphite powder particles is small, and side reactions in the battery are suppressed. Thus, it is possible to obtain graphite powder with improved power storage characteristics and suppressed electrode expansion during charging and discharging.
- the method for producing graphite powder of the present invention includes a step of contacting with oxygen under heating.
- the step includes (a) contacting with oxygen during heating for graphitization, (b) graphite It can be performed by contacting with oxygen in the course of cooling after heating for conversion, or (c) by contacting with oxygen during independent heat treatment after the completion of the graphitization step.
- the graphitization treatment is not limited as long as it can be performed in an environment containing a certain concentration of oxygen.
- the graphite crucible is filled with a material to be graphitized and covered.
- a graphite crucible provided with a plurality of oxygen inlet holes with a diameter of 1 mm to 50 mm, or with a plurality of cylindrical oxygen inlets with a diameter of 1 mm to 50 mm connected to the outside of the graphite crucible This can be done by energizing and generating heat with the tube provided.
- Oxygen-containing gas may be lightly blocked by covering with felt or a porous plate. A small amount of argon or nitrogen may be introduced, but the oxygen concentration in the vicinity of the surface of the material to be graphitized (within 5 cm) is 1% or more, preferably 1 in the graphitization step without being completely replaced with argon or nitrogen. It is preferable to adjust to ⁇ 20%.
- oxygen-containing gas air is preferable, but a low oxygen concentration gas in which the oxygen concentration is adjusted within the above concentration can also be used.
- the surface oxidation occurs after the cooling process of the graphitization process or after the graphitization process.
- the furnace it is preferable to design the furnace so that air flows in when the graphitization furnace is cooled and the oxygen concentration in the furnace becomes 1 to 20%.
- the removal method include a method of removing the material in a range from a portion in contact with the oxygen-containing gas to a predetermined depth. That is, a portion deeper than the predetermined depth is obtained as a graphite material.
- the predetermined depth is 2 cm from the surface, more preferably 3 cm, and even more preferably 5 cm.
- the part which exists in a deep place has few opportunities to contact oxygen. It is preferable to obtain a material within 2 m from the portion in contact with the oxygen-containing gas as the graphite material. More preferably, it is within 1 m, and further preferably within 50 cm.
- the pulverization treatment is not performed after graphitization. However, it can be crushed to such an extent that the particles are not crushed after graphitization.
- the electrode is compressed. Contact between adjacent graphite particles inside becomes stable, and the electrode can be made suitable for repeated charge and discharge of the battery.
- the graphite material for battery electrodes in a preferred embodiment of the present invention comprises the above graphite powder.
- the graphite powder is used as a graphite material for battery electrodes, it is possible to obtain a battery electrode with a high energy density in which electrode expansion during charging and discharging is suppressed while maintaining high capacity, high coulomb efficiency, and high cycle characteristics.
- the graphite material for battery electrodes for example, it can be used as a negative electrode active material and a negative electrode conductivity-imparting material for lithium ion secondary batteries.
- graphite material for battery electrodes in a preferred embodiment of the present invention, only the above graphite powder can be used, but spherical natural graphite or artificial graphite having d002 of 0.3370 nm or less with respect to 100 parts by mass of graphite powder.
- a compounding of 0.01 to 120 parts by mass, preferably 0.01 to 100 parts by mass can also be used.
- the mixing can be performed by appropriately selecting a mixed material according to the required battery characteristics and determining the mixing amount.
- carbon fiber can be blended in the graphite material for battery electrodes.
- the blending amount is 0.01 to 20 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the graphite powder.
- carbon fibers examples include organic carbon fibers such as PAN-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers, and vapor grown carbon fibers.
- organic carbon fibers such as PAN-based carbon fibers, pitch-based carbon fibers, and rayon-based carbon fibers
- vapor grown carbon fibers having high crystallinity and high thermal conductivity is particularly preferable.
- carbon fibers are bonded to the surface of graphite powder, vapor grown carbon fibers are particularly preferable.
- Vapor grown carbon fiber is produced, for example, by using an organic compound as a raw material, introducing an organic transition metal compound as a catalyst into a high-temperature reactor together with a carrier gas, and subsequently heat-treating (Japanese Patent Laid-Open No. Sho 60- 54998, Japanese Patent No. 2778434, etc.).
- the fiber diameter is 2 to 1000 nm, preferably 10 to 500 ⁇ m, and the aspect ratio is preferably 10 to 15000.
- organic compound used as a raw material for carbon fiber examples include gases such as toluene, benzene, naphthalene, ethylene, acetylene, ethane, natural gas, carbon monoxide, and mixtures thereof. Of these, aromatic hydrocarbons such as toluene and benzene are preferred.
- the organic transition metal compound contains a transition metal serving as a catalyst.
- the transition metal include metals of groups IVa, Va, VIa, VIIa, and VIII of the periodic table.
- compounds such as ferrocene and nickelocene are preferable.
- the carbon fiber may be one obtained by pulverizing or pulverizing long fibers obtained by a vapor phase method or the like.
- the carbon fiber may be aggregated on the floc.
- the carbon fiber is preferably one having no thermal decomposition product derived from an organic compound or the like on its surface or one having a high carbon structure crystallinity.
- Carbon fibers to which no pyrolyzate is attached or carbon fibers having a high carbon structure crystallinity are obtained by, for example, firing (heat treatment) carbon fibers, preferably vapor grown carbon fibers, in an inert gas atmosphere. It is done. Specifically, carbon fibers to which no pyrolyzate is attached can be obtained by heat treatment at about 800 to 1500 ° C. in an inert gas such as argon.
- the carbon fiber having high carbon structure crystallinity is preferably obtained by heat treatment in an inert gas such as argon at 2000 ° C. or higher, more preferably 2000 to 3000 ° C.
- the carbon fiber preferably contains a branched fiber. Further, there may be a portion where the entire fiber has a hollow structure communicating with each other. Therefore, the carbon layer which comprises the cylindrical part of a fiber is continuing.
- a hollow structure is a structure in which a carbon layer is wound in a cylindrical shape, and includes a structure that is not a complete cylinder, a structure that has a partial cut portion, a structure in which two stacked carbon layers are bonded to one layer, etc. .
- the cross section of the cylinder is not limited to a perfect circle, but includes an ellipse or a polygon.
- the carbon fiber has an (002) plane average plane distance d002 of preferably 0.344 nm or less, more preferably 0.339 nm or less, and particularly preferably 0.338 nm or less, as determined by X-ray diffraction.
- a crystal having a thickness (Lc) in the C-axis direction of 40 nm or less is preferable.
- the electrode paste in a preferred embodiment of the present invention comprises the battery electrode graphite material and a binder.
- This electrode paste is obtained by kneading the battery electrode graphite material and a binder.
- known apparatuses such as a ribbon mixer, a screw kneader, a Spartan rewinder, a ladyge mixer, a planetary mixer, and a universal mixer can be used.
- the electrode paste can be formed into a sheet shape, a pellet shape, or the like.
- binder used for the electrode paste examples include fluorine-based polymers such as polyvinylidene fluoride and polytetrafluoroethylene, and rubber-based materials such as SBR (styrene butadiene rubber).
- the amount of the binder used is suitably 1 to 30 parts by weight, particularly preferably about 3 to 20 parts by weight, based on 100 parts by weight of the graphite material for battery electrodes.
- a solvent can be used when kneading.
- the solvent include known solvents suitable for each binder, such as toluene and N-methylpyrrolidone in the case of a fluoropolymer; water in the case of SBR; and dimethylformamide and isopropanol.
- a binder using water as a solvent it is preferable to use a thickener together. The amount of the solvent is adjusted so that the viscosity is easy to apply to the current collector.
- Electrode in a preferred embodiment of the present invention is composed of a molded body of the electrode paste.
- the electrode is obtained, for example, by applying the electrode paste onto a current collector, drying, and pressure-molding.
- the current collector include foils such as aluminum, nickel, copper, and stainless steel, and meshes.
- the coating thickness of the paste is usually 50 to 200 ⁇ m. If the coating thickness becomes too large, the negative electrode may not be accommodated in a standardized battery container.
- the method for applying the paste is not particularly limited, and examples thereof include a method in which the paste is applied with a doctor blade, a bar coater or the like and then molded with a roll press or the like.
- Examples of the pressure molding method include molding methods such as roll pressing and press pressing.
- the pressure during the pressure molding is generally about 2 to 3 t / cm 2 .
- the electrode density of the electrode increases and the battery capacity per volume also increases.
- the compression is too strong, the cycle characteristics are greatly deteriorated.
- the graphite powder is used to obtain an electrode by pressure molding using a paste, even if the compression is stronger than usual, the deterioration of cycle characteristics is small, and the initial charge / discharge efficiency is compressed. It produces a surprising effect that is different from the conventional technology recognition, which is improved by strengthening.
- the electrode density can also be improved by compression.
- Examples of the pressure molding method include molding methods such as roll pressing and press pressing.
- the pressure during pressure molding is preferably about 1.5 to 5 t / cm 2 , more preferably 2 to 5 t / cm 2 , and still more preferably 2.5 to 4 t / cm 2 .
- the electrode density of the electrode increases, the battery capacity per volume usually increases. However, if the electrode density is too high, the cycle characteristics usually deteriorate.
- the maximum value of the electrode density of the electrode obtained by using this electrode paste is usually 1.7 to 1.9 g / cm 3 .
- the electrode thus obtained is suitable for a negative electrode of a battery, particularly a negative electrode of a secondary battery.
- the characteristics of the electrode are improved in the same manner as described above, and in this case, the compression at the time of manufacturing the electrode may be within a normal range. That is, characteristics are improved by performing appropriate compression at any stage of compression in a powder state or compression after drying the paste.
- the graphite powder in the present invention is further mixed with a metal material that can form an alloy with an alkali metal and / or a metal material made of an alkali metal alloy (hereinafter sometimes referred to as a “metal material”). It is also possible to use it.
- a metal material that can form an alloy with an alkali metal preferably the metal capable of forming an alloy with lithium metal include, for example, aluminum (Al), lead (Pb), zinc (Zn), and tin (Sn).
- an alloy with an alkali metal preferably an alloy of lithium metal, when the composition (molar composition) of the alloy is expressed as Li x M (x is a molar ratio with respect to the metal M), the metal described above is used as M.
- the alloy may further contain other elements in the range of 50 mol% or less in addition to the metal described above.
- a mixing method of the graphite powder and the metal material is not particularly limited, and a known method can be used.
- a method as disclosed in Japanese Patent Laid-Open No. 5-286863 can be adopted, and specifically, the following three methods can be adopted.
- organic compound for example, two or more monocyclic hydrocarbon compounds having 3 or more members such as naphthalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene, pentaphen, and pentacene are condensed with each other.
- examples thereof include a condensed cyclic hydrocarbon compound and various pitches mainly composed of a mixture of the above compounds.
- the pitch include decomposition pitches such as crude oil pitch, naphtha pitch, asphalt pitch, coal tar pitch, polyvinyl chloride, and polyvinylidene chloride.
- heterocyclic monocyclic compounds such as indole, isoindole, quinoline, isoquinoline, quinoxaline, phthalazine, carbazole, acridine, phenazine, and phenatridine are bonded to each other, or one or more 3 Examples thereof include condensed heterocyclic compounds formed by bonding with a monocyclic hydrocarbon compound having at least a member ring.
- organic polymer compound examples include cellulose resin, phenol resin, furfuryl alcohol resin, polyacrylonitrile, acrylic resin such as poly ( ⁇ -halogenated acrylonitrile), polyamide resin, polyimide resin, polyacetylene, poly- (p-phenylene). And conjugated resins such as poly (p-phenylene vinylene).
- (Iii) A method in which a carbonaceous material is formed by thermally decomposing an organic compound in a gas phase on a mixture of graphite powder and a metallic material, and the graphite powder and the metallic material are bonded or coated with the carbonaceous material.
- organic compounds used at this time include aliphatic hydrocarbons such as propane, unsaturated hydrocarbon compounds, aromatic compounds such as benzene, toluene, and xylene, aromatic compounds such as benzene, naphthalene, and perylene, and condensed cyclic hydrocarbons.
- Derivatives such as carboxylic acids, carboxylic acid anhydrides, and carboxylic acid imides of compounds can be exemplified.
- a battery or a secondary battery can be used as a constituent element (preferably a negative electrode).
- a battery or a secondary battery in a preferred embodiment of the present invention will be described by taking a lithium ion secondary battery as a specific example.
- a lithium ion secondary battery has a structure in which a positive electrode and a negative electrode are immersed in an electrolytic solution or an electrolyte.
- the electrode in a preferred embodiment of the present invention is used for the negative electrode.
- a lithium-containing transition metal oxide is usually used as the positive electrode active material, preferably at least selected from Ti, V, Cr, Mn, Fe, Co, Ni, Mo and W.
- An oxide mainly containing at least one transition metal element selected from Fe, Co, and Ni and lithium and having a molar ratio of lithium to transition metal of 0.3 to 2.2 is used.
- Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, or the like may be contained within a range of less than 30 mol% with respect to the transition metal present mainly.
- lithium-containing transition metal oxides include Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , LixCo a Ni 1-a O 2 , Li x Mn 2 O 4 , Li x Co b V 1-b.
- the value of x is a value before the start of charging / discharging, and increases / decreases by charging / discharging.
- the average particle size of the positive electrode active material is not particularly limited, but is preferably 0.1 to 50 ⁇ m.
- the volume of particles of 0.5 to 30 ⁇ m is preferably 95% or more. More preferably, the volume occupied by a particle group having a particle size of 3 ⁇ m or less is 18% or less of the total volume, and the volume occupied by a particle group of 15 ⁇ m or more and 25 ⁇ m or less is 18% or less of the total volume.
- the specific surface area is not particularly limited, but is preferably 0.01 ⁇ 50m 2 / g by BET method, particularly preferably 0.2m 2 / g ⁇ 1m 2 / g.
- the pH of the supernatant when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.
- a separator may be provided between the positive electrode and the negative electrode.
- the separator include non-woven fabrics, cloths, microporous films, or combinations thereof, which are mainly composed of polyolefins such as polyethylene and polypropylene.
- organic electrolytes As the electrolyte and electrolyte constituting the lithium ion secondary battery in a preferred embodiment of the present invention, known organic electrolytes, inorganic solid electrolytes, and polymer solid electrolytes can be used. From the viewpoint of electrical conductivity, organic electrolytes are used. preferable.
- organic electrolyte examples include diethyl ether, dibutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethyl 5 glycol monobutyl ether, diethylene glycol dimethyl ether, ethylene glycol phenyl ether.
- Ethers such as formamide, N-methylformamide, N, N-dimethylformamide, N-ethylformamide, N, N-diethylformamide, N-methylacetamide, N, N-dimethylacetamide, N-ethylacetamide, N, N -Diethylacetamide, N, N-dimethylpropionamide, hexamethylphosphoryl
- Amides such as sulfoxides; sulfur-containing compounds such as dimethyl sulfoxide and sulfolane; dialkyl ketones such as methyl ethyl ketone and methyl isobutyl ketone; ethylene oxide, propylene oxide, tetrahydrofuran, 2-methoxytetrahydrofuran, 1,2-dimethoxyethane, 1,3-dioxolane, etc.
- Cyclic ethers of: carbonates such as ethylene carbonate and propylene carbonate; ⁇ -butyrolactone; N-methylpyrrolidone; solutions of organic solvents such as acetonitrile and nitromethane are preferred.
- esters such as ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, propylene carbonate, vinylene carbonate, ⁇ -butyrolactone, ethers such as dioxolane, diethyl ether, diethoxyethane, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, etc.
- Particularly preferred are carbonate-based non-aqueous solvents such as ethylene carbonate and propylene carbonate. These solvents can be used alone or in admixture of two or more.
- Lithium salts are used as solutes (electrolytes) for these solvents.
- Commonly known lithium salts include LiClO 4 , LiBF 4 , LiPF 6 , LiAlCl 4 , LiSbF 6 , LiSCN, LiCl, LiCF 3 SO 3 , LiCF 3 CO 2 , LiN (CF 3 SO 2 ) 2 and the like. is there.
- polymer solid electrolyte examples include a polyethylene oxide derivative and a polymer containing the derivative, a polypropylene oxide derivative and a polymer containing the derivative, a phosphate ester polymer, a polycarbonate derivative and a polymer containing the derivative. There are no restrictions on the selection of members other than those described above necessary for the battery configuration.
- the volume-based median diameter (D50) is determined using a Malvern master sizer as a laser diffraction particle size distribution measuring apparatus.
- Paste preparation 1.5 parts by mass of styrene butadiene rubber (SBR) and 2% by mass aqueous solution of carboxymethyl cellulose (CMC) are added to 97 parts by mass of graphite powder, and they are kneaded with a planetary mixer to obtain a main ingredient stock solution.
- SBR styrene butadiene rubber
- CMC carboxymethyl cellulose
- Electrode production NMP is added to the main agent stock solution to adjust the viscosity, and then applied onto a high purity copper foil and vacuum dried at 120 ° C. for 1 hour to obtain an electrode material.
- the amount of application is such that the amount of graphite powder is 5 mg / cm 2 .
- the obtained electrode material is punched into a circle and compressed at a pressure of about 0.5 to 3 t / cm 2 for 10 seconds to obtain an electrode.
- the density (g / cm 3 ) of the electrode layer excluding the current collector when compressed at a pressure P (t / cm 2 ) is defined as D (P).
- (C) Battery production In a dry argon atmosphere with a dew point of ⁇ 80 ° C. or lower, a coin battery comprising a polyethylene separator, an electrolytic solution, and a case is produced using the obtained electrode as a working electrode and lithium metal as a counter electrode.
- the electrolytic solution a solution obtained by dissolving 1 mol / L of LiPF6 as an electrolyte in a mixed solution of 8 parts by mass of EC (ethylene carbonate) and 12 parts by mass of DEC (diethyl carbonate) is used.
- (D) Charge / discharge test using coin battery The charge / discharge test of the working electrode is performed in a thermostat set at 25 ° C. with the produced coin battery. First, a current of 0.05 C is supplied until the open circuit voltage reaches 0.002 V, then maintained at 0.002 V, and stopped when the current value drops to 25.4 ⁇ A, thereby reducing the charging capacity of the working electrode. taking measurement. Next, current is passed at 0.05 C until the open circuit voltage reaches 1.5V. At this time, the ratio between the charge capacity and the discharge capacity measured in the first charge / discharge, that is, the value representing the discharge capacity / charge capacity in percentage is defined as the initial charge / discharge efficiency.
- the initial charge / discharge efficiency when compression at the time of electrode preparation is Pt / cm 2 is e (P)
- the discharge capacity in the initial charge / discharge is C (P)
- the electrode material is 0.5 t / cm 2 .
- the discharge efficiency e (3.0) and the discharge capacity C (3.0) in the first charge / discharge are measured.
- Cycle test A battery comprising a working electrode prepared in the same manner as the charge / discharge test using the coin battery of (2) above as a negative electrode, lithium cobaltate as a positive electrode, and an electrolyte and a polyethylene separator. Make it. Charging / discharging is repeated 1000 times in a 45 ° C. thermostat, and the ratio of the maximum value of the discharge capacity in each charge / discharge to the discharge capacity in the 1000th charge / discharge is called 1000 cycle capacity maintenance rate and expressed as a percentage.
- the thickness (T10) and (3) of the negative electrode active material layer measured by disassembling and measuring the battery prepared in (3) above after being charged and discharged for 2C and 10 cycles and then being discharged.
- the battery produced in (2) was charged / discharged for 2C for 500 cycles, then disassembled into a discharge state, disassembled and measured, and the electrode expansion coefficient: ⁇ (T500 / T10) ⁇ ⁇ 100 was determined from the thickness (T500) of the negative electrode active material layer. .
- a plurality of oxygen inflow holes are provided in the crucible so that air can enter and exit during and before and after the graphitization treatment, and the powder is oxidized for about one week in the cooling process, and the particles are scaly.
- a graphite powder was obtained. Coarse powder was removed from the obtained graphite powder using a sieve having an opening of 32 ⁇ m. The BET specific surface area, total pore volume, d002 and Lc of the obtained graphite powder were measured, and the results are shown in Table 1.
- Example 2 100 parts by mass of powder calcined coke 1 obtained in the same manner as in Example 1 and 2 parts by mass of petroleum-based pitch powder having a quinoline insoluble content of 1% by mass and a ⁇ resin content of 48% by mass are charged into a rotating and rotating mixer. Then, the mixture was dry mixed at 2000 rpm for 20 minutes, and the resulting mixture was graphitized by heating in an Atchison furnace using a sealed crucible for 1 week so that the maximum temperature reached about 3300 ° C. After the treatment, coarse powder was removed using a 32 ⁇ m sieve. The obtained graphite powder was oxidized in air at 1100 ° C. for 1 hour, and the coarse powder was removed using a sieve having an opening of 32 ⁇ m to obtain graphite powder having particles in the form of scales. The analysis results of the obtained graphite powder are shown in Table 1.
- raw coke 2 was calcined at 1100 ° C. and AR (60) was determined, it was 2.1.
- This powder raw coke 2 is subjected to graphitization treatment and oxidation treatment in the same manner as in Example 1, and the resulting graphite powder is removed using a 32 ⁇ m sieve and the coarse particles are scaly.
- Graphite powder was obtained. The analysis results of the obtained graphite powder are shown in Table 1.
- Example 4 A mixture of the powder calcined coke 1 and petroleum pitch powder described in Example 2 was graphitized at 3200 ° C. for 30 minutes in an argon atmosphere, then oxidized in the same manner as in Example 2, and a sieve having an opening of 32 ⁇ m. Was used to remove the coarse powder, and a graphite powder having particles in the form of scales was obtained. The analysis results of the obtained graphite powder are shown in Table 1.
- Example 5 The graphite powder obtained in Example 1 was compressed at 3.0 t / cm 2 . Table 1 shows the analysis results of the graphite powder after compression.
- Comparative Example 1 The coarse powder was removed using a sieve having an opening of 32 ⁇ m without oxidizing the graphite powder obtained by mixing and graphitizing treatment of Example 2 to obtain graphite powder having particles in the form of scales. The analysis results of the obtained graphite powder are shown in Table 1.
- Comparative Example 2 The graphite powder obtained by performing graphitization treatment in the same manner as in Example 4 was removed without oxidizing the coarse powder using a sieve having an opening of 32 ⁇ m to obtain graphite powder having particles in the form of scales. It was. The analysis results of the obtained graphite powder are shown in Table 1.
- Comparative Example 3 A natural graphite powder having a D50 of 18.0 ⁇ m was mechanically treated so that the particles were agglomerated to obtain a spherical natural graphite powder. After 90 parts by mass of this spherical natural graphite powder and 10 parts by mass of a petroleum pitch powder having a quinoline insoluble content of 1% by mass and a ⁇ resin content of 48% by mass were calcined at 2800 ° C. in a nitrogen atmosphere, Crushing to obtain graphite powder. The analysis results of the obtained graphite powder are shown in Table 1.
- Comparative Example 5 The graphite powder obtained in Example 3 was compressed at 3.0 t / cm 2 . Table 1 shows the analysis results of the graphite powder after compression.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
Description
また、電動ドリル等の電動工具や、ハイブリッド自動車用等、高出力で大容量の二次電池への要求が高まっている。この分野は従来より、鉛二次電池、ニッケルカドミウム二次電池、ニッケル水素二次電池が主に使用されているが、小型軽量で高エネルギー密度のリチウムイオン二次電池への期待は高く、大電流負荷特性に優れたリチウムイオン二次電池が求められている。
これらのうち天然黒鉛は安価に入手できる。しかし、天然黒鉛は鱗片状を成しているので、バインダーとともにペーストにし、それを集電体に塗布すると、天然黒鉛が一方向に配向してしまう。そのような電極で充電すると電極が一方向にのみ膨張し、電極としての性能を低下させる。天然黒鉛を造粒して球状にしたものが提案されているが、電極作製時のプレスによって球状化天然黒鉛が潰れて配向してしまう。また、天然黒鉛の表面の反応活性が高いために、初回充放電効率が低く、さらに、サイクル特性も良くなかった。これらを解決するため、特許文献1等では、球状に加工した天然黒鉛の表面に、炭素をコーティングする方法が提案されている。しかし、サイクル特性が十分でない。
特許文献5にはサイクル特性に優れた、人造黒鉛が開示されている。
特許文献6には生の針状コークスから製造された人造黒鉛負極が開示されている。
特許文献7には石油ピッチを液相でコーティングしたコークスから製造された人造黒鉛負極が開示されている。
特許文献2に記載の黒鉛化品は、非常にバランスの良い負極材であり、高容量、大電流の電池を作製可能であるが、大型電池に要求される、モバイル用途をはるかに超えた長期にわたるサイクル特性を達成することは困難である。
特許文献3の方法は、人造黒鉛原料の微粉の他、天然黒鉛等の微粉も使用可能であり、モバイル用負極材としては、非常に優れた性能を発揮する。しかし、製造方法が煩雑である。
特許文献4に記載の負極材料は、体積エネルギー密度があまりにも低く、また、価格も非常に高価なため、一部の特殊な大型電池にしか使用されていない。
特許文献5では、体積当たりエネルギー密度に向上の余地があった。
特許文献6では、従来の人造黒鉛に対して、初回充放電効率の改善は見られるものの放電容量が天然黒鉛材料に比して劣る。
特許文献7では、電極の容量密度に課題が残っている。また、大量の有機溶剤を使用し、これを揮発させるという操作を伴い、製造方法が煩雑となる。
本発明の課題は、電極容量、初回充放電効率及びサイクル容量維持率に優れ、充放電時の電極膨張が小さいリチウム二次電池用電極のための黒鉛粉、及びその黒鉛粉を使用した電池電極用黒鉛材料、リチウム電池用電極、及びリチウムイオン二次電池を提供することにある。
[1]黒鉛粉を活物質とする電極材料を0.5t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(0.5)、前記電極材料を3t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(3)したとき、以下の条件を満足する黒鉛粉。
e(3)(%)-e(0.5)(%)≧1 (1)
e(3)(%)>85 (2)
[2]窒素ガス吸着法による全細孔容積が8.0μL/g~20.0μL/gである前記1に記載の黒鉛粉。
[3]前記黒鉛粉が、表面に炭素被覆層を有するものである前記1または2に記載の黒鉛粉。
[4]窒素ガス吸着法による全細孔容積が8.0μL/g~20.0μL/gであり、粒子が鱗片状粒子である黒鉛粉。
[5]負極活物質として黒鉛粉を用いてリチウムイオン電池を作製し充放電サイクルを行い、10サイクル後の負極活物質層の厚みをT10、500サイクル後の負極活物質層の厚みをT500としたとき、次式で示される電極膨張率が100~130%である前記1~4のいずれかに記載の黒鉛粉;
電極膨張率(%)={(T500/T10)}×100
[6]前記1~5のいずれかに記載の黒鉛粉を1.5~5t/cm2の圧力により圧縮してなる黒鉛粉。
[7]鱗片状コークスを2400℃~3600℃で黒鉛化する工程及び加熱下において酸素と接触させる工程を含む前記1~6のいずれかに記載の黒鉛粉の製造方法。
[8]加熱下において酸素と接触させる工程が、黒鉛化のための加熱時に酸素と接触させるものである前記7に記載の黒鉛粉の製造方法。
[9]加熱下において酸素と接触させる工程が、黒鉛化のための加熱後に冷却する過程で酸素と接触させるものである前記7に記載の黒鉛粉の製造方法。
[10]加熱下において酸素と接触させる工程が、黒鉛化の工程が完了した後、独立した加熱処理時に酸素と接触させるものである前記7に記載の黒鉛粉の製造方法。
[11]黒鉛化前に石油系ピッチ、石炭系ピッチ及びフェノール樹脂の中から選ばれる1種類以上の炭素材料との乾式混合を行う前記7~10のいずれかに記載の黒鉛粉の製造方法。
[12]前記石油系ピッチ及び石炭系ピッチが、キノリン不溶分が10質量%以下、βレジン分が20質量%以上である前記11に記載の黒鉛粉の製造方法。
[13]前記1~6のいずれかに記載の黒鉛粉を含む電池電極用黒鉛材料。
[14]前記13に記載の電池電極用黒鉛材料とバインダーを含むペーストを集電体上に塗布して乾燥した後、圧縮してなるリチウム電池用電極。
[15]電池電極用黒鉛材料とバインダーを含むペーストを集電体上に塗布して乾燥した後、1.5~5t/cm2の圧力により圧縮してなる前記14に記載のリチウム電池用電極。
[16]前記14または15に記載の電極を含むリチウムイオン二次電池。
本発明における黒鉛粉は、黒鉛化工程と同じ装置で酸化処理工程を含む、経済性、安全性、量産性に優れた方法で製造することが可能である。
二次電池の負極は、単位体積あたりの容量が高いことが要求されている。負極の容量向上のための1つの方法は、活物質の質量あたりの容量を向上させることがある。これは、黒鉛の質量あたりの容量は黒鉛の結晶性が高いほど増加する傾向にある。
負極の体積当たりの容量の向上のためのもう一つの方法は、電極体積あたりの活物質量を増加させること、すなわち電極密度の向上がある。通常、電池の電極は活物質を集電板上に塗工乾燥した後、プレス(圧縮)を行なうことにより製造される。プレスは体積あたりの活物質の充填性を向上させる上に、活物質が柔らかくプレスに伴ってある程度変形すると、電極密度を極めて大きくすることが可能である。黒鉛の結晶性が高く、結晶のC軸方向の厚み(Lc)が大きいほど電極密度が向上する傾向にある。しかし、電池作製時の電極密度が高くても、充放電を繰り返すうちに電極が膨張してしまうために結果的に電池が小型化出来ない場合がある。したがって、負極の活物質には電極膨張率が低いことが求められる。
本発明において鱗片状の黒鉛粒子とは、sysmex社製FPIA-3000を用いてLPFモードで10000個以上の粒子に対して測定された粒子のアスペクト比の中央値が1.4以上である黒鉛粒子のことを言う。ここで言う粒子のアスペクト比は、粒子投影像の内部に最長の線分をとったものを長軸とし、粒子投影像内部にあり長軸と垂直な線分のうち最長のものを最大長垂直軸としたときに、アスペクト比=長軸長/最大長垂直軸長である。一方、アスペクト比の中央値が1.4未満である黒鉛粒子を塊状の粒子と呼ぶ。
d002およびLcは、既知の方法により粉末X線回折(XRD)法を用いて測定することができる(野田稲吉、稲垣道夫、日本学術振興会、第117委員会資料、117-71-A-1(1963)、稲垣道夫他、日本学術振興会、第117委員会試料、117-121-C-5(1972)、稲垣道夫、「炭素」、1963、No.36、25-34頁参照)。
このような範囲とすることで、リチウムとの層間化合物の形成がスムーズになり、これを負極材料としてリチウムイオン二次電池に用いた場合、リチウム吸蔵・放出反応が阻害されづらく、急速充放電特性が向上する。
なお、黒鉛粉中の菱面体晶構造のピーク割合(x)は、六方晶構造(100)面の実測ピーク強度(P1)、菱面体晶構造の(101)面の実測ピーク強度(P2)から、下記式によって求める。
x=P2/(P1+P2)
例えば、前記黒鉛粉を活物質とする電極材料を0.5t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(0.5)、前記電極材料を3t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(3)したとき、以下の式(1)及び(2):
e(3)(%)-e(0.5)(%)≧1 (1)
e(3)(%)>85 (2)
の条件を満足するという特徴を有する。
さらに好ましい黒鉛粉は、e(3)(%)-e(0.5)(%)>2、かつe(3)(%)>86である。
最も好ましい黒鉛粉は、e(3)(%)-e(0.5)(%)>3、かつe(3)(%)>87である。
また、前記圧力が3t/cm2のときの前記コイン電池の初回サイクルの前記活物質の質量あたりの放電容量は、好ましくは335mAh/g以上、より好ましくは340mAh/g以上、さらに好ましくは345mAh/g以上である。
電極膨張率(%)={(T500/T10)}×100
さらに好ましい実施様態においては電極膨張率は100%~125%であり、最も好ましい場合においては100%~122%である。
黒鉛粉の製造方法は限定されないが、例えば下記のような方法が好適である。
黒鉛粉の原料にはか焼または生コークスを用いることが出来る。コークスの原料としては、例えば、石油ピッチ、石炭ピッチ、石炭ピッチコークス、石油コークスおよびこれらの混合物を用いることができる。これらの中でも、特定の条件下でディレイドコーキングを行ったコークスを、不活性雰囲気で加熱したものが好ましい。
ディレイドコーカーに通す原料としては、原油精製時の重質溜分に対して、流動床接触分解を行った後に触媒を除去したデカントオイルや、瀝青炭等から抽出されたコールタールを200℃以上の温度で蒸留し、得られたタールを100℃以上に昇温することによって十分に流動性を持たせたものが挙げられる。ディレイドコーキングプロセス中、少なくともドラム内入り口においては、これらの液体が450℃以上、さらには510℃以上に昇温されていることが好ましく、それによりコークスのか焼時に残炭率が高くなる。また、ドラム内での圧力は好ましくは常圧以上、より好ましくは300kPa以上、さらに好ましくは400kPa以上に維持する。これにより負極としての容量がより高まる。以上の通り、通常よりも過酷な条件においてコーキングを行うことにより、液体をより反応させ、より重合度の高いコークスを得ることができる。
か焼を行ったコークスに対して黒鉛化を行うと、結晶がより成長するために好ましい。
内容積30cm3のプラスチック製サンプル容器の底に両面テープを貼り、その上に数mm大以上のコークス粒子を乗せる。冷間埋込樹脂(商品名:冷間埋込樹脂#105、製造会社:ジャパンコンポジット(株)、販売会社:丸本ストルアス(株))に硬化剤(商品名:硬化剤(M剤)、製造会社:日本油脂(株)、販売会社:丸本ストルアス(株))を加え、30秒練る。得られた混合物(5ml程度)を前記サンプル容器に高さ約1cmになるまでゆっくりと流し入れ、1日静置して凝固させる。凝固の後、凝固した樹脂を容器から取り出し、両面テープを剥がす。
研磨板回転式の研磨機を用いて、測定する面を研磨する。研磨は、回転面に研磨面を押し付けるように行う。研磨板の回転は1000rpmで行う。研磨板の番手は、#500、#1000、#2000の順に行い、最後はアルミナ(商品名:バイカロックス タイプ0.3CR、粒子径0.3μm、製造会社:バイコウスキー、販売会社:バイコウスキージャパン)を用いて鏡面研磨する。研磨した樹脂をプレパラート上に粘土で固定し、偏光顕微鏡(OLYMPAS社製、BX51)を用いて観察を行う。
観察は200倍で行う。偏光顕微鏡で観察した画像は、OLYMPUS製CAMEDIA C-5050 ZOOMデジタルカメラをアタッチメントで偏光顕微鏡に接続し、撮影する。シャッタータイムは1.6秒で行う。撮影データのうち、1200ピクセル×1600ピクセルの画像を解析対象とする。これは480μm×540μmの視野を検討していることに相当する。
光学組織の抽出はImageJ(アメリカ国立衛生研究所製)を用いて、青色部、黄色部、赤色部、黒色部を判定する。各色のImageJ使用時に各色を定義したパラメーターは以下の通りである。
粉砕する手法に特に制限はなく、公知のジェットミル、ハンマーミル、ローラーミル、ピンミル、振動ミル等を用いて行なうことができる。
粉砕は、レーザー回析法による体積基準のメジアン径(D50)が1μm以上50μm以下となるように行なうことが好ましい。D50が1μm未満になるまで粉砕するには特殊な機器を用いて大きなエネルギーが必要となる。D50を50μm以下とすることにより、電極とした場合のリチウム拡散が素早く行われ、充放電速度が高くなる。より好ましいD50は5μm以上35μm以下である。また、D50を10μm以上とすることにより、目的外反応が起きにくくなるためさらに好ましい。自動車等駆動電源として使う際には大電流発生が必要であるとの観点からは、D50は25μm以下であることがさらに好ましい。
黒鉛粉の粒子表面上に炭素被覆層を形成する場合は、黒鉛化の前に、例えば、粉砕したか焼コークスに、石油系ピッチ、石炭系ピッチ及びフェノール樹脂の中から選ばれる1種類以上の被覆材を混合する。
このような被覆材を用いることで、加熱時に黒鉛表面に樹脂が均一に広がり、効果的な炭素被覆層が形成され、放電容量や初回充放電効率、充電状態保存特性、サイクル特性、急速充放電特性の改善と電極膨張の抑制に寄与する。フェノール樹脂に加えて石油系ピッチ及び石炭系ピッチを混合することは、フェノール樹脂が黒鉛表面に均一に広がりやすくなるためさらに好ましい。
湿式により行なう場合は、例えば、前記被覆材を溶媒に溶解または分散させ、か焼コークスをさらに添加した後、溶剤を乾燥除去する。ただし、湿式では有機溶剤を用いるが、有機溶剤は取扱いに注意が必要であり、またその蒸気発生を防ぐことや回収することが必要となる。そのため前記混合は溶剤を使用しない乾式で行なうことが好ましい。
これらの温度を達成するためには電気エネルギーを用いることが好ましい。電気エネルギーは他の熱源と比べると高価であり、特に2000℃以上を達成するためには、極めて大きな電力を消費する。そのため、黒鉛化以外に電気エネルギーは消費されないほうが好ましく、黒鉛化に先んじて炭素原料はか焼され、有機揮発分が除去された状態、すなわち固定炭素分が95%以上、より好ましくは98%以上、さらに好ましくは99%以上となっていることが好ましい。
特に、黒鉛化炉の空気を窒素やアルゴンで置換しないことによって、黒鉛化処理と酸化処理を同一設備で行うことが好ましい。このような方法で黒鉛化処理および酸化処理を行うことで、黒鉛粉の表面が酸化されることにより表面のダングリングボンド等の高活性部位が除去される等して電池特性が改善する。また、工程および設備を簡略化することが出来るため経済性・安全性・量産性が向上する。
上記(c)のように、黒鉛化を行った後に別途酸化処理を行う場合は、酸素存在下で500℃以上の温度で温度に応じて適切な酸素濃度、加熱時間で処理を行う。
深い場所に存在する部分は酸素と接触する機会が少なくなる。酸素含有気体と接する部分から2m以内の材料を黒鉛材料として取得することが好ましい。より好ましくは1m以内であり、さらに好ましくは50cm以内である。
本発明の好ましい実施態様における適度な酸化処理を経て、粒子の表面形状および表面活性を改質することによって製造された黒鉛粉を活物質として電極を作製した際、該電極を圧縮すると、該電極内部で隣接する黒鉛粒子間の接触が安定なものとなり、該電極を電池の繰り返しの充放電に適したものとすることが可能である。
本発明の好ましい実施態様における電池電極用黒鉛材料は、上記黒鉛粉を含んでなる。上記黒鉛粉を電池電極用黒鉛材料として用いると、高容量、高クーロン効率、高サイクル特性を維持したまま、充放電における電極膨張が抑制された高エネルギー密度の電池電極を得ることができる。
本発明の好ましい実施態様における電極用ペーストは、前記電池電極用黒鉛材料とバインダーとを含んでなる。この電極用ペーストは、前記電池電極用黒鉛材料とバインダーとを混練することによって得られる。混錬には、リボンミキサー、スクリュー型ニーダー、スパルタンリューザー、レディゲミキサー、プラネタリーミキサー、万能ミキサー等公知の装置が使用できる。電極用ペーストは、シート状、ペレット状等の形状に成形することができる。
バインダーの使用量は、電池電極用黒鉛材料100質量部に対して1~30質量部が適当であるが、特に3~20質量部程度が好ましい。
混練する際に溶媒を用いることができる。溶媒としては、各々のバインダーに適した公知のもの、例えばフッ素系ポリマーの場合はトルエン、N-メチルピロリドン等;SBRの場合は水等;その他にジメチルホルムアミド、イソプロパノール等が挙げられる。溶媒として水を使用するバインダーの場合は、増粘剤を併用することが好ましい。溶媒の量は集電体に塗布しやすい粘度となるように調整される。
本発明の好ましい実施態様における電極は前記電極用ペーストの成形体からなるものである。電極は例えば前記電極用ペーストを集電体上に塗布し、乾燥し、加圧成形することによって得られる。
集電体としては、例えばアルミニウム、ニッケル、銅、ステンレス等の箔、メッシュ等が挙げられる。ペーストの塗布厚は、通常50~200μmである。塗布厚が大きくなりすぎると、規格化された電池容器に負極を収容できなくなることがある。ペーストの塗布方法は特に制限されず、例えばドクターブレードやバーコーター等で塗布後、ロールプレス等で成形する方法等が挙げられる。
本発明の好ましい実施態様における黒鉛粉は、ペーストを用いた加圧成形により電極を得る場合、その圧縮を通常よりも強くしてもサイクル特性の低下が小さく、初回充放電効率に至っては圧縮を強くすることにより向上するといった従来の技術認識とは異なる驚くべき効果を発揮する。もちろん圧縮により電極密度を向上することもできる。
(i)黒鉛粉と金属質物との混合物に、有機化合物を添加し、加熱して、有機化合物を液相状態を経由して炭素化させて炭素質物を形成しつつ黒鉛粉と金属質物とを結合または被覆する方法。有機化合物としては、例えば、ナフタレン、フェナンスレン、アントラセン、トリフェニレン、ピレン、クリセン、ナフタセン、ピセン、ペリレン、ペンタフェン、ペンタセンのような3員環以上の単環炭化水素化合物が互いに2個以上縮合してなる縮合環式炭化水素化合物、上記化合物の混合物を主成分とする各種ピッチがあげられる。ピッチとしては、例えば、原油ピッチ、ナフサピッチ、アスファルトピッチ、コールタールピッチ、ポリ塩化ビニル、ポリ塩化ビニリデン等の分解ピッチがあげられる。また、インドール、イソインドール、キノリン、イソキノリン、キノキサリン、フタラジン、カルバゾール、アクリジン、フェナジン、フェナトリジンのような3員環以上の複素単環化合物が互いに少なくとも2個以上結合するか、または1個以上の3員環以上の単環炭化水素化合物と結合してなる縮合複素環化合物があげられる。
(iii)黒鉛粉と、金属質物の混合物上に、有機化合物を気相で熱分解させて炭素質物を形成して、黒鉛粉と金属質物とを炭素質物で結合または被覆する方法。このとき用いる有機化合物は、例えば、プロパン等の脂肪族炭化水素、不飽和炭化水素化合物、ベンゼン、トルエン、キシレン等の芳香族化合物、ベンゼン、ナフタレン、ペリレン等の芳香族化合物、縮合環式炭化水素化合物のカルボン酸、カルボン酸無水物、カルボン酸イミドのような誘導体をあげることができる。
前記電極を構成要素(好ましくは負極)として、電池または二次電池とすることができる。
リチウムイオン二次電池を具体例に挙げて本発明の好ましい実施態様における電池または二次電池を説明する。リチウムイオン二次電池は、正極と負極とが電解液または電解質の中に浸漬された構造をしたものである。負極には本発明の好ましい実施態様における電極が用いられる。
なお、上記以外の電池構成上必要な部材の選択についてはなんら制約を受けるものではない。
なお、実施例及び比較例の黒鉛粉についての、X線回折法による平均面間隔(d002)と結晶のC軸方向の厚み(Lc)、BET比表面積、AR(60)は、本明細書の発明を実施するための形態の欄に詳述した方法により測定する。また、その他の物性の測定方法は以下の通り。
レーザー回折式粒度分布測定装置として、マルバーン製マスターサイザーを用いて、体積基準のメジアン径(D50)を求める。
(2)細孔容積の測定
黒鉛粉約5gをガラス製セルに秤量し、1kPa以下の減圧下300℃で約3時間乾燥して、水分等の吸着成分を除去した後、黒鉛粉の質量を測定する。液体窒素冷却下における、乾燥後の黒鉛粉の窒素ガスの吸着等温線をQuantachrome社製Autosorb-1で測定する。P/P0=0.992~0.995での測定点での窒素吸着量と乾燥後の黒鉛粉の質量から全細孔容積を求める。
(a)ペースト作製:
黒鉛粉97質量部にスチレンブタジエンゴム(SBR)とカルボキシメチルセルロース(CMC)2質量%水溶液とを各1.5質量部加え、プラネタリーミキサーにて混練し、主剤原液とする。
主剤原液にNMPを加え、粘度を調整した後、高純度銅箔上に塗布して120℃で1時間真空乾燥し、電極材料を得る。塗布の量は、黒鉛粉の量が5mg/cm2となる量とする。得られた電極材料を円形に打ち抜き、約0.5~3t/cm2の圧力で10秒間圧縮し、電極を得る。圧力P(t/cm2)で圧縮した時の集電体を除く電極層の密度(g/cm3)をD(P)とする。
露点-80℃以下の乾燥アルゴン雰囲気下で、得られた電極を作用極、リチウム金属を対極として、さらにポリエチレンセパレータと電解液とケースから成るコイン電池を作製する。電解液にはEC(エチレンカーボネート)8質量部及びDEC(ジエチルカーボネート)12質量部の混合液に、電解質としてLiPF6を1mol/L溶解したものを用いる。
作製したコイン電池で前記作用極の充放電試験を25℃に設定した恒温槽内で行う。
はじめに、開回路電圧が0.002Vとなるまで0.05Cの電流を流した後、0.002Vで維持し、電流値が25.4μAに低下した時点で停止させることで作用極の充電容量を測定する。次に、開回路電圧が1.5Vとなるまで0.05Cで電流を流す。この際、第一回目の充放電で測定された充電容量と放電容量の比,すなわち放電容量/充電容量を百分率で表した値を、初回充放電効率とする。前記電極作製時における圧縮がPt/cm2であったときの初回充放電効率をe(P)、初回充放電における放電容量をC(P)とし、前記電極材料を0.5t/cm2の圧力で圧縮したときの初回充放電効率e(0.5)、初回充放電における放電容量C(0.5)、及び前記電極材料を3.0t/cm2の圧力で圧縮したときの初回充放電効率e(3.0)、初回充放電における放電容量C(3.0)を測定する。
上記(2)のコイン電池による充放電試験と同様の方法で用意した作用極と同様のものを負極とし、コバルト酸リチウムを正極として、さらに電解液とポリエチレンセパレータからなる電池を作製する。45℃の恒温槽内で充放電を1000回繰り返し、各充放電における放電容量のうちの最大値と1000回目の充放電における放電容量の比を、1000サイクル容量維持率と呼び百分率で表す。
上記(3)で作製した電池を2C、10サイクルの充放電を行った後に放電状態にして解体し測定した負極活物質層の厚さ(T10)と(3)で作製した電池を2C、500サイクルの充放電を行った後に放電状態にして解体し測定した負極活物質層の厚さ(T500)から電極膨張率:{(T500/T10)}×100を求める。
AR(60)=2.2であるか焼コークスをホソカワミクロン製バンタムミルで粉砕し、その後32μmの目開きの篩を用いて粗粉をカットした。次に、日清エンジニアリング製ターボクラシファイアーTC-15Nで気流分級し、粒径が1.0μm以下の粒子を実質的に含まないD50=22.3μmの粉末か焼コークス1を得た。
この粉末か焼コークス1をアチソン炉にて最高到達温度が約3300℃となるように1週間かけて加熱することで黒鉛化処理を行った。この時、るつぼに複数の酸素流入孔を設け、黒鉛化処理の最中及び前後で空気が出入りできるようにし、冷却過程において約1週間をかけて粉体の酸化を行い、粒子が鱗片状である黒鉛粉を得た。
得られた黒鉛粉を32μmの目開きの篩を用いて粗粉を除去した。得られた黒鉛粉のBET比表面積、全細孔容積、d002及びLcを測定して、結果を表1に示した。また、圧力を0.5t/cm2として作製した電池の初回充放電効率e(0.5)及び容量C(0.5)、並びに、圧力を3.0t/cm2として作製した電池の初回充放電効率e(3.0)、容量C(3.0)、密度D(3.0)及び1000サイクル容量維持率を測定し、表1に併せて示した。
さらに得られた黒鉛粉のSEMを図1に示す。
実施例1と同様にして得た粉末か焼コークス1を100質量部と、キノリン不溶分1質量%、βレジン分48質量%の石油系ピッチ粉末2質量部とを自転公転式混合機に投入し、2000rpmで20分間乾式混合を行い、得られた混合物を、密閉されたるつぼを使用してアチソン炉にて最高到達温度が約3300℃となるように1週間かけて加熱することで黒鉛化処理を行った後、32μmの目開きの篩を用いて粗粉を除去した。得られた黒鉛粉を空気中で1100℃で1時間酸化処理を施し、32μmの目開きの篩を用いて粗粉を除去し、粒子が鱗片状である黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
中国産生コークスを実施例1と同様の方法で粉砕及び分級し、粒径が1.0μm以下の粒子を実質的に含まないD50=24.5μmの粉末生コークス2を得た。生コークス2は1100℃でか焼してAR(60)を求めると2.1であった。
この粉末生コークス2を実施例1と同様の方法で黒鉛化処理及び酸化処理を行い、得られた黒鉛粉を32μmの目開きの篩を用いて粗粉を除去し、粒子が鱗片状である黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
実施例2に記載の粉末か焼コークス1と石油系ピッチ粉末の混合物をアルゴン雰囲気中で3200℃で30分間黒鉛化した後、実施例2と同様の方法で酸化し、32μmの目開きの篩を用いて粗粉を除去し、粒子が鱗片状である黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
実施例1で得られた黒鉛粉を、3.0t/cm2で圧縮した。圧縮後の黒鉛粉の分析結果を表1に示す。
実施例2の混合及び黒鉛化処理で得られた黒鉛粉を酸化することなく32μmの目開きの篩を用いて粗粉を除去して、粒子が鱗片状である黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
実施例4と同様の方法で黒鉛化処理を行って得られた黒鉛粉を酸化することなく32μmの目開きの篩を用いて粗粉を除去して、粒子が鱗片状である黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
D50が18.0μmである天然黒鉛粉末を、粒子が塊状となるように力学的処理を行い、球状天然黒鉛粉末を得た。この球状天然黒鉛粉末90質量部と、キノリン不溶分1質量%、βレジン分48質量%の石油系ピッチ粉末10質量部とを均一に混合した後、窒素雰囲気下2800℃で焼成し、ピンミルで解砕して黒鉛粉を得た。得られた黒鉛粉の分析結果を表1に示す。
AR(60)=2.0であるか焼コークスを用いた以外は実施例1と同様の操作を行なったところ、粒子が塊状である黒鉛粉が得られた。得られた黒鉛粉の分析結果を表1に示す。
また得られた黒鉛粉のSEMを図2に示す。
実施例3で得られた黒鉛粉を3.0t/cm2で圧縮した。圧縮後の黒鉛粉の分析結果を表1に示す。
Claims (16)
- 黒鉛粉を活物質とする電極材料を0.5t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(0.5)、前記電極材料を3t/cm2の圧力で圧縮してなる電極(作用極)とリチウム金属対極とセパレータと電解液から作製したコイン電池の初回充放電効率をe(3)したとき、以下の条件を満足する黒鉛粉。
e(3)(%)-e(0.5)(%)≧1 (1)
e(3)(%)>85 (2) - 窒素ガス吸着法による全細孔容積が8.0μL/g~20.0μL/gである請求項1に記載の黒鉛粉。
- 前記黒鉛粉が、表面に炭素被覆層を有するものである請求項1に記載の黒鉛粉。
- 窒素ガス吸着法による全細孔容積が8.0μL/g~20.0μL/gであり、粒子が鱗片状粒子である黒鉛粉。
- 負極活物質として黒鉛粉を用いてリチウムイオン電池を作製し充放電サイクルを行い、10サイクル後の負極活物質層の厚みをT10、500サイクル後の負極活物質層の厚みをT500としたとき、次式で示される電極膨張率が100~130%である請求項1または4に記載の黒鉛粉;
電極膨張率(%)={(T500/T10)}×100 - 請求項1または4に記載の黒鉛粉を1.5~5t/cm2の圧力により圧縮してなる黒鉛粉。
- 鱗片状コークスを2400℃~3600℃で黒鉛化する工程及び加熱下において酸素と接触させる工程を含む請求項1~6のいずれかに記載の黒鉛粉の製造方法。
- 加熱下において酸素と接触させる工程が、黒鉛化のための加熱時に酸素と接触させるものである請求項7に記載の黒鉛粉の製造方法。
- 加熱下において酸素と接触させる工程が、黒鉛化のための加熱後に冷却する過程で酸素と接触させるものである請求項7に記載の黒鉛粉の製造方法。
- 加熱下において酸素と接触させる工程が、黒鉛化の工程が完了した後、独立した加熱処理時に酸素と接触させるものである請求項7に記載の黒鉛粉の製造方法。
- 黒鉛化前に石油系ピッチ、石炭系ピッチ及びフェノール樹脂の中から選ばれる1種類以上の炭素材料との乾式混合を行う請求項7に記載の黒鉛粉の製造方法。
- 前記石油系ピッチ及び石炭系ピッチが、キノリン不溶分が10質量%以下、βレジン分が20質量%以上である請求項11に記載の黒鉛粉の製造方法。
- 請求項1~6のいずれかに記載の黒鉛粉を含む電池電極用黒鉛材料。
- 請求項13に記載の電池電極用黒鉛材料とバインダーを含むペーストを集電体上に塗布して乾燥した後、圧縮してなるリチウム電池用電極。
- 電池電極用黒鉛材料とバインダーを含むペーストを集電体上に塗布して乾燥した後、1.5~5t/cm2の圧力により圧縮してなる請求項14に記載のリチウム電池用電極。
- 請求項14または15に記載の電極を含むリチウムイオン二次電池。
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112014000661.0T DE112014000661T5 (de) | 2013-02-04 | 2014-02-03 | Graphitpulver für ein aktives Material einer negativen Elektrode einer Lithiumionensekundärbatterie |
US14/765,510 US9997769B2 (en) | 2013-02-04 | 2014-02-03 | Graphite power for negative electrode active material of lithium-ion secondary battery |
KR1020157020770A KR20150103219A (ko) | 2013-02-04 | 2014-02-03 | 리튬 이온 2차 전지 부극 활물질용 흑연 분말 |
JP2014559796A JP6535467B2 (ja) | 2013-02-04 | 2014-02-03 | リチウムイオン二次電池負極活物質用黒鉛粉 |
CN201480007273.7A CN104969389B (zh) | 2013-02-04 | 2014-02-03 | 锂离子二次电池负极活性物质用石墨粉 |
US15/973,810 US20180261828A1 (en) | 2013-02-04 | 2018-05-08 | Graphite power for negative electrode active material of lithium-ion secondary battery |
US15/983,462 US10522821B2 (en) | 2013-02-04 | 2018-05-18 | Graphite power for negative electrode active material of lithium-ion secondary battery |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2013019980 | 2013-02-04 | ||
JP2013-019980 | 2013-02-04 | ||
JP2013-053788 | 2013-03-15 | ||
JP2013053788 | 2013-03-15 |
Related Child Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/765,510 A-371-Of-International US9997769B2 (en) | 2013-02-04 | 2014-02-03 | Graphite power for negative electrode active material of lithium-ion secondary battery |
US15/973,810 Division US20180261828A1 (en) | 2013-02-04 | 2018-05-08 | Graphite power for negative electrode active material of lithium-ion secondary battery |
US15/983,462 Division US10522821B2 (en) | 2013-02-04 | 2018-05-18 | Graphite power for negative electrode active material of lithium-ion secondary battery |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014119776A1 true WO2014119776A1 (ja) | 2014-08-07 |
Family
ID=51262474
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2014/052401 WO2014119776A1 (ja) | 2013-02-04 | 2014-02-03 | リチウムイオン二次電池負極活物質用黒鉛粉 |
Country Status (6)
Country | Link |
---|---|
US (3) | US9997769B2 (ja) |
JP (1) | JP6535467B2 (ja) |
KR (1) | KR20150103219A (ja) |
CN (2) | CN108502877A (ja) |
DE (1) | DE112014000661T5 (ja) |
WO (1) | WO2014119776A1 (ja) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021181973A1 (ja) * | 2020-03-13 | 2021-09-16 | 三洋電機株式会社 | 非水電解質二次電池 |
WO2022162949A1 (ja) * | 2021-02-01 | 2022-08-04 | 昭和電工マテリアルズ株式会社 | リチウムイオン二次電池用負極材の製造方法及びリチウムイオン二次電池の製造方法 |
CN116813349A (zh) * | 2023-07-26 | 2023-09-29 | 安康太伦新材料有限公司 | 一种负极材料石墨化箱式炉用石墨箱板材料及其制备方法 |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6681014B2 (ja) * | 2015-05-29 | 2020-04-15 | 株式会社Gsユアサ | 蓄電素子 |
KR20170011163A (ko) | 2015-07-21 | 2017-02-02 | 현대자동차주식회사 | 연료분사 인젝터의 제어방법, 및 이의 제어시스템 |
KR101967456B1 (ko) | 2017-12-01 | 2019-04-09 | 현대오트론 주식회사 | 닫힘 시간 감지 값을 이용한 인젝터 고장 진단방법 |
KR102276630B1 (ko) * | 2018-09-10 | 2021-07-13 | 도레이 카부시키가이샤 | 이차 전지용 전극 및 이차 전지 |
CN109319774B (zh) * | 2018-10-10 | 2021-03-05 | 中钢集团鞍山热能研究院有限公司 | 一种用中低温干馏煤焦油制备负极材料的方法 |
KR102492760B1 (ko) * | 2019-01-14 | 2023-01-27 | 주식회사 엘지에너지솔루션 | 음극 활물질의 제조 방법 |
KR102163787B1 (ko) | 2020-05-12 | 2020-10-08 | 에스아이에스 주식회사 | 인조흑연 생산용 원료의 자동 충진 및 처리장치 |
WO2022013070A1 (en) * | 2020-07-16 | 2022-01-20 | Solvay Specialty Polymers Italy S.P.A. | Binder for silicon-based anode material |
CN115472829A (zh) * | 2021-06-10 | 2022-12-13 | 国家能源投资集团有限责任公司 | 负极材料及其制备方法与应用、负极片与应用 |
CN114291814B (zh) * | 2021-12-24 | 2024-04-16 | 东北师范大学 | 一种石墨负极材料及其制备方法和应用 |
CN115448308A (zh) * | 2022-09-19 | 2022-12-09 | 南昌航空大学 | 一种废旧锂电池负极粉料深度除杂和靶向修复再生石墨负极材料的方法 |
KR20240073851A (ko) * | 2022-11-16 | 2024-05-27 | 카이펭 루이펭 뉴 머티리얼 컴퍼니 리미티드 | 음극 소재 및 배터리 |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05307977A (ja) * | 1992-04-28 | 1993-11-19 | Mitsubishi Petrochem Co Ltd | 非水溶媒二次電池およびその電極材料 |
JPH09129232A (ja) * | 1995-10-31 | 1997-05-16 | Matsushita Electric Ind Co Ltd | 非水電解液二次電池 |
JP2000348726A (ja) * | 1999-03-31 | 2000-12-15 | Hitachi Powdered Metals Co Ltd | 非水系二次電池の負極用黒鉛粒子 |
JP2003272625A (ja) * | 2002-03-15 | 2003-09-26 | Sanyo Electric Co Ltd | 非水電解質二次電池 |
JP2011082054A (ja) * | 2009-10-08 | 2011-04-21 | Osaka Gas Chem Kk | 負極炭素材用コークス、負極炭素材及びリチウムイオン電池 |
JP5081335B1 (ja) * | 2011-04-21 | 2012-11-28 | 昭和電工株式会社 | 黒鉛材料、電池電極用炭素材料、及び電池 |
JP5266428B1 (ja) * | 2011-10-21 | 2013-08-21 | 昭和電工株式会社 | 黒鉛材料、電池電極用炭素材料、及び電池 |
Family Cites Families (25)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3035308A (en) * | 1957-01-24 | 1962-05-22 | Siemens Planiawerke A G Fur Ko | Production of graphitizable pitch coke and graphite products |
DE1102030B (de) * | 1959-12-03 | 1961-03-09 | Hoechst Ag | Rueckstellmittel des Bindepechs fuer die Herstellung von Kohleformkoerpern |
US3369871A (en) * | 1965-07-15 | 1968-02-20 | Cabot Corp | Preparation of metallurgical carbon |
US4604184A (en) * | 1983-11-16 | 1986-08-05 | Domtar Inc. | Modified coal-tar pitch |
JP3126030B2 (ja) | 1990-11-22 | 2001-01-22 | 大阪瓦斯株式会社 | リチウム二次電池 |
JP3653105B2 (ja) | 1993-02-25 | 2005-05-25 | 呉羽化学工業株式会社 | 二次電池電極用炭素質材料 |
JP3285520B2 (ja) * | 1996-08-08 | 2002-05-27 | 日立化成工業株式会社 | 黒鉛粒子、黒鉛粒子の製造法、黒鉛粒子を用いた黒鉛ペースト、リチウム二次電池用負極及びリチウム二次電池 |
CA2262613C (en) | 1996-08-08 | 2006-11-28 | Hitachi Chemical Company, Ltd. | Graphite particles and lithium secondary cell using them as negative electrode |
JP3361510B2 (ja) | 1996-10-30 | 2003-01-07 | 日立化成工業株式会社 | リチウム二次電池用負極及びその製造法並びにリチウム二次電池 |
TW399029B (en) * | 1996-12-25 | 2000-07-21 | Sony Corp | Graphite powder suitable for negative electrode material of lithium ion secondary batteries |
JP3054379B2 (ja) * | 1997-04-18 | 2000-06-19 | 日本カーボン株式会社 | リチウム二次電池負極材用黒鉛を被覆した黒鉛質粉末とその製法 |
JP3651225B2 (ja) * | 1998-01-30 | 2005-05-25 | 日立化成工業株式会社 | リチウム二次電池、その負極及びその製造法 |
US6989137B1 (en) * | 1998-10-09 | 2006-01-24 | Showa Denko K.K. | Carbonaceous material for cell and cell containing the carbonaceous material |
JP3534391B2 (ja) | 1998-11-27 | 2004-06-07 | 三菱化学株式会社 | 電極用炭素材料及びそれを使用した非水系二次電池 |
US6632569B1 (en) | 1998-11-27 | 2003-10-14 | Mitsubishi Chemical Corporation | Carbonaceous material for electrode and non-aqueous solvent secondary battery using this material |
JP2001023638A (ja) | 1999-07-05 | 2001-01-26 | Sumitomo Metal Ind Ltd | リチウムイオン二次電池負極用黒鉛粉末の製造方法 |
TW574764B (en) * | 2002-01-25 | 2004-02-01 | Toyo Tanso Co | Negative electrode material for lithium ion secondary battery |
US20030160215A1 (en) | 2002-01-31 | 2003-08-28 | Zhenhua Mao | Coated carbonaceous particles particularly useful as electrode materials in electrical storage cells, and methods of making the same |
JP2006164570A (ja) * | 2004-12-02 | 2006-06-22 | Nippon Steel Chem Co Ltd | リチウム二次電池負極用黒鉛材料の製造方法およびリチウム二次電池 |
WO2008084675A1 (ja) | 2006-12-26 | 2008-07-17 | Mitsubishi Chemical Corporation | 非水系二次電池用複合黒鉛粒子、それを含有する負極材料、負極及び非水系二次電池 |
CN100557741C (zh) * | 2007-01-10 | 2009-11-04 | 复旦大学 | 高比表面鳞片状石墨作为电极材料的电化学电容器 |
US8038977B2 (en) * | 2008-02-06 | 2011-10-18 | Chuo Denki Kogyo Co., Ltd. | Carbon powder suitable as a negative electrode material for nonaqueous secondary batteries |
KR101071176B1 (ko) | 2009-10-22 | 2011-10-10 | 쇼와 덴코 가부시키가이샤 | 흑연재료, 전지전극용 탄소재료 및 전지 |
GB201020616D0 (en) | 2010-12-06 | 2011-01-19 | Univ Ariel Res & Dev Co Ltd | Device for imparting distance information |
JP5623262B2 (ja) * | 2010-12-13 | 2014-11-12 | Jx日鉱日石エネルギー株式会社 | リチウムイオン二次電池負極用黒鉛材料およびその製造方法、リチウムイオン二次電池 |
-
2014
- 2014-02-03 CN CN201810256775.3A patent/CN108502877A/zh not_active Withdrawn
- 2014-02-03 JP JP2014559796A patent/JP6535467B2/ja active Active
- 2014-02-03 US US14/765,510 patent/US9997769B2/en active Active
- 2014-02-03 KR KR1020157020770A patent/KR20150103219A/ko active Search and Examination
- 2014-02-03 WO PCT/JP2014/052401 patent/WO2014119776A1/ja active Application Filing
- 2014-02-03 DE DE112014000661.0T patent/DE112014000661T5/de not_active Withdrawn
- 2014-02-03 CN CN201480007273.7A patent/CN104969389B/zh active Active
-
2018
- 2018-05-08 US US15/973,810 patent/US20180261828A1/en not_active Abandoned
- 2018-05-18 US US15/983,462 patent/US10522821B2/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH05307977A (ja) * | 1992-04-28 | 1993-11-19 | Mitsubishi Petrochem Co Ltd | 非水溶媒二次電池およびその電極材料 |
JPH09129232A (ja) * | 1995-10-31 | 1997-05-16 | Matsushita Electric Ind Co Ltd | 非水電解液二次電池 |
JP2000348726A (ja) * | 1999-03-31 | 2000-12-15 | Hitachi Powdered Metals Co Ltd | 非水系二次電池の負極用黒鉛粒子 |
JP2003272625A (ja) * | 2002-03-15 | 2003-09-26 | Sanyo Electric Co Ltd | 非水電解質二次電池 |
JP2011082054A (ja) * | 2009-10-08 | 2011-04-21 | Osaka Gas Chem Kk | 負極炭素材用コークス、負極炭素材及びリチウムイオン電池 |
JP5081335B1 (ja) * | 2011-04-21 | 2012-11-28 | 昭和電工株式会社 | 黒鉛材料、電池電極用炭素材料、及び電池 |
JP5266428B1 (ja) * | 2011-10-21 | 2013-08-21 | 昭和電工株式会社 | 黒鉛材料、電池電極用炭素材料、及び電池 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021181973A1 (ja) * | 2020-03-13 | 2021-09-16 | 三洋電機株式会社 | 非水電解質二次電池 |
WO2022162949A1 (ja) * | 2021-02-01 | 2022-08-04 | 昭和電工マテリアルズ株式会社 | リチウムイオン二次電池用負極材の製造方法及びリチウムイオン二次電池の製造方法 |
WO2022163014A1 (ja) * | 2021-02-01 | 2022-08-04 | 昭和電工マテリアルズ株式会社 | リチウムイオン二次電池用負極材の製造方法及びリチウムイオン二次電池の製造方法 |
CN116813349A (zh) * | 2023-07-26 | 2023-09-29 | 安康太伦新材料有限公司 | 一种负极材料石墨化箱式炉用石墨箱板材料及其制备方法 |
Also Published As
Publication number | Publication date |
---|---|
DE112014000661T5 (de) | 2015-11-26 |
KR20150103219A (ko) | 2015-09-09 |
CN104969389A (zh) | 2015-10-07 |
CN104969389B (zh) | 2018-08-24 |
JPWO2014119776A1 (ja) | 2017-01-26 |
US20150364751A1 (en) | 2015-12-17 |
JP6535467B2 (ja) | 2019-06-26 |
US10522821B2 (en) | 2019-12-31 |
US9997769B2 (en) | 2018-06-12 |
US20180269469A1 (en) | 2018-09-20 |
CN108502877A (zh) | 2018-09-07 |
US20180261828A1 (en) | 2018-09-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10522821B2 (en) | Graphite power for negative electrode active material of lithium-ion secondary battery | |
US11031587B2 (en) | Negative electrode material for lithium-ion batteries including non-flaky artificial graphite including silicon-containing particles, artificial graphite particles and carbonaceous material | |
US10377634B2 (en) | Carbon material, material for a battery electrode, and battery | |
JP5461746B1 (ja) | 炭素材料、電池電極用炭素材料、及び電池 | |
US20190363348A1 (en) | Negative electrode material for lithium ion secondary cell | |
JP6472933B2 (ja) | 黒鉛材およびそれを用いた二次電池用電極 | |
JP5571270B1 (ja) | 炭素材料、電池電極用炭素材料、及び電池 | |
JP5877284B1 (ja) | 炭素材料、その製造方法及びその用途 | |
US10377633B2 (en) | Carbon material, method for producing same, and use for same | |
TW201940424A (zh) | 石墨材料、其製造方法及其用途 | |
JP2011060467A (ja) | リチウムイオン二次電池用負極材料およびその製造方法 | |
JP4933092B2 (ja) | リチウムイオン二次電池用負極材料、リチウムイオン二次電池用負極およびリチウムイオン二次電池 | |
JP2005019096A (ja) | 非水系2次電池 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 14745521 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2014559796 Country of ref document: JP Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 20157020770 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14765510 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 1120140006610 Country of ref document: DE Ref document number: 112014000661 Country of ref document: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 14745521 Country of ref document: EP Kind code of ref document: A1 |