# US 7,410,727 B2 · Graphite particles and lithium secondary battery using the same as negative electrode

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- Number: US 7,410,727 B2
- Document ID: US7410727B2
- Status: Granted
- Kind: B2
- Application number: 11/214,828
- Filed: 2005-08-31
- Published: 2006-01-05
- Granted: 2008-08-12
- Earliest claimed: 1996-08-08
- Assignees: Hitachi Chemical Company, Ltd.
- Inventors: Yoshito Ishii; Tatsuya Nishida; Atsushi Fujita; Kazuo Yamada
- Web page: https://patentgrep.com/patent/US7410727B2

## CPC

- H01M 4/0404: {by coating on electrode collectors}
- C01B 32/20: Graphite
- C01B 32/205: Preparation
- H01M 4/0433: {Molding}
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/1393: of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/587: for inserting or intercalating light metals
- H01M 10/052: Li-accumulators
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- C01P 2002/60: Compounds characterised by their crystallite size
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2004/54: Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/12: Surface area
- C01P 2006/14: Pore volume
- H01M 4/621: {Binders}
- H01M 10/058: Construction or manufacture
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y10T 29/49115: including coating or impregnating
- Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.]
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A graphite particle obtained by assembling or binding together a plurality of flat-shaped particles so that the planes of orientation are not parallel to one another, or a graphite particle in which aspect ratio is 5 or less or specific surface area is 8 m2/g or less or the size of crystallite in the direction of c-axis of the crystal is 500 Å or more and the size of crystallite in the direction of plane is 1,000 Å or less as measured by X ray broad angle diffraction, or a graphite particle in which pore volume of the pores having a size falling in a range of 102 to 106 Å is 0.4 to 2.0 cc/g per weight of graphite particle or pore volume of the pores having a size falling in a range of 1×102 to 2×104 Å is 0.08 to 0.4 cc/g per weight of graphite particle is suitable for production of negative electrode of lithium secondary battery, and a lithium secondary battery obtained therefrom is excellent in rapid charge-discharge characteristics, cycle characteristics, etc.

## Claims

### Claim 1

A graphite particle for a negative electrode of a lithium secondary battery, the graphite particle comprising a plurality of portions having planes of orientation not parallel to one another, and having a plurality of pores, wherein an aspect ratio of the graphite particle is 5 or less, wherein a pore volume of pores having a size falling in the range of 102 Å to 106 Å is 0.4 to 2.0 cc/g based on the weight of the graphite particle.

### Claim 2 (depends on 1)

The graphite particle according to claim 1, wherein the aspect ratio of the graphite particle is from 1.2 to 5.

### Claim 3 (depends on 1)

The graphite particle according to claim 1, wherein a specific surface area of the graphite particle is 8 m2/g or less.

### Claim 4 (depends on 1)

A graphite paste comprising the graphite particle of claim 1 and an organic binder.

### Claim 5 (depends on 4)

The graphite paste according to claim 4, further comprising a solvent.

### Claim 6 (depends on 4)

A negative electrode for a lithium secondary battery, obtained by coating the graphite paste of claim 4 on a current collector.

### Claim 7 (depends on 6)

A lithium secondary battery comprising a casing, a cover and at least one pair of negative and positive electrodes, said casing, cover and electrodes being disposed through intermediation of separators, and an electrolytic solution disposed in the surroundings thereof, wherein the negative electrode is the negative electrode of claim 6.

### Claim 8 (depends on 1)

The graphite particle according to claim 1, wherein the aspect ratio of the graphite particle is 1.3 or more.

### Claim 9 (depends on 1)

The graphite particle according to claim 1, wherein the aspect ratio of the graphite particle is from 1.3 to 3.

### Claim 10 (depends on 1)

The graphite particle according to claim 1, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is 1000 Å or more.

### Claim 11 (depends on 1)

The graphite particle according to claim 1, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is in a range from 1000 Å to 10000 Å.

### Claim 12

A graphite particle for a negative electrode of a lithium secondary battery, the graphite particle comprising a plurality of portions having panes of orientation not parallel to one another, and having a plurality of pores, wherein an aspect ratio of the graphite particle is 5 or less, wherein a pore volume of pores having a size falling in the range of 1×102 Å to 2×104 Å is 0.08 to 0.4 cc/g based on the weight of the graphite particle.

### Claim 13 (depends on 12)

The graphite particle according to claim 12, wherein the aspect ratio of the graphite particle is from 1.2 to 5.

### Claim 14 (depends on 12)

The graphite particle according to claim 12, wherein a specific surface area of the graphite particle is 8 m2/g or less.

### Claim 15 (depends on 12)

A graphite paste comprising the graphite particle of claim 12 and an organic binder.

### Claim 16 (depends on 15)

The graphite paste according to claim 15, further comprising a solvent.

### Claim 17 (depends on 15)

A negative electrode for a lithium secondary battery, obtained by coating the graphite paste of claim 15 on a current collector.

### Claim 18 (depends on 17)

A lithium secondary battery comprising a casing, a cover and at least one pair of negative and positive electrodes, said casing, cover and electrodes being disposed through intermediation of separators, and an electrolytic solution disposed in the surroundings thereof, wherein the negative electrode is the negative electrode of claim 17.

### Claim 19 (depends on 12)

The graphite particle according to claim 12, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is 1000 Å or more.

### Claim 20 (depends on 12)

The graphite particle according to claim 12, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is in a range from 1000 Å to 10000 Å.

### Claim 21 (depends on 12)

The graphite particle according to claim 12, wherein the aspect ratio of the graphite particle is 1.3 or more.

### Claim 22 (depends on 12)

The graphite particle according to claim 12, wherein the aspect ratio of the graphite particle is from 1.3 to 3.

### Claim 23

A graphite particle for a negative electrode of a lithium secondary battery, the graphite particle comprising a plurality of portions having planes of orientation not parallel to one another, and having a plurality of pores, wherein an aspect ratio of the graphite particle is 5 or less, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is 1000 Å or more.

### Claim 24 (depends on 23)

The graphite particle according to claim 23, wherein the aspect ratio of the graphite particle is from 1.2 to 5.

### Claim 25 (depends on 23)

The graphite particle according to claim 23, wherein a specific surface area of the graphite particle is 8 m2/g or less.

### Claim 26 (depends on 23)

A graphite paste comprising the graphite particle of claim 23 and an organic binder.

### Claim 27 (depends on 26)

The graphite paste according to claim 26, further comprising a solvent.

### Claim 28 (depends on 26)

A negative electrode for a lithium secondary battery, obtained by coating the graphite paste of claim 26 on a current collector.

### Claim 29 (depends on 28)

A lithium secondary battery comprising a casing, a cover and at least one pair of negative and positive electrodes, said casing, cover and electrodes being disposed through intermediation of separators, and an electrolytic solution disposed in the surroundings thereof, wherein the negative electrode is the negative electrode of claim 28.

### Claim 30 (depends on 23)

The graphite particle according to claim 23, wherein the aspect ratio of the graphite particle is 1.3 or more.

### Claim 31 (depends on 23)

The graphite particle according to claim 23, wherein the aspect ratio of the graphite particle is from 1.3 to 3.

### Claim 32

A graphite particle for a negative electrode of a lithium secondary battery, the graphite particle comprising a plurality of portions having planes of orientation not parallel to one another, and having a plurality of pores, wherein an aspect ratio of the graphite particle is 5 or less, wherein a size Lc of crystallites in a c-axis direction of crystal (002) is in a range from 1000 Å to 10000 Å.

### Claim 33 (depends on 32)

The graphite particle according to claim 32, wherein the aspect ratio of the graphite particle is from 1.2 to 5.

### Claim 34 (depends on 32)

The graphite particle according to claim 32, wherein a specific surface area of the graphite particle is 8 m2/g or less.

### Claim 35 (depends on 32)

A graphite paste comprising the graphite particle of claim 32 and an organic binder.

### Claim 36 (depends on 35)

The graphite paste according to claim 35, further comprising a solvent.

### Claim 37 (depends on 35)

A negative electrode for a lithium secondary battery, obtained by coating the graphite paste of claim 35 on a current collector.

### Claim 38 (depends on 37)

A lithium secondary battery comprising a casing, a cover and at least one pair of negative and positive electrodes, said casing, cover and electrodes being disposed through intermediation of separators, and an electrolytic solution disposed in the surroundings thereof, wherein the negative electrode is the negative electrode of claim 37.

### Claim 39 (depends on 32)

The graphite particle according to claim 32, wherein the aspect ratio of the graphite particle is 1.3 or more.

### Claim 40 (depends on 32)

The graphite particle according to claim 32, wherein the aspect ratio of the graphite particle is from 1.3 to 3.