Hitachi Chemical Company, Ltd.

Hitachi, Ltd.

Yoshito Ishii

Atsushi Fujita

Kazuo Yamada

Tatsuya Nishida

Tatsuo Horiba

Hidetoshi Honbo

Yasushi Muranaka

Seiji Takeuchi

Hideto Momose

Hiroki Mikuni

Keiji Okabe

Yuriko Ida

Nobushige Nakamura

Souichirou Suda

Hidetoshi Honbou

Katsunori Kodato

Teppei Takahashi

An anode material for a lithium ion secondary battery that includes a carbon material having an average interlayer spacing das determined by X-ray diffraction of from 0.335 nm to 0.340 nm, a volume average particle diameter (50% D) of from 1 &#x3bc;m to 40 &#x3bc;m, a maximum particle diameter Dof 74 &#x3bc;m or less, and at least two exothermic peaks within a temperature range of from 300&#xb0; C. to 1000&#xb0; C. in a differential thermal analysis in an air stream.

Anode material for lithium ion secondary battery, anode for lithium ion secondary battery, and lithium ion secondary battery

A negative electrode for a lithium secondary battery includes a layer of a mixture containing graphite powder and an organic binder on a current collector, wherein a diffraction intensity ratio (002)/(110) measured by X-ray diffractometry of the layer of a mixture is 500 or less. A lithium secondary battery includes the negative electrode for a lithium secondary battery, and a positive electrode that includes a lithium compound. This results in less deterioration in the rapid charge and discharge characteristics and the cycle characteristics when the density of the negative electrode is made higher, thereby providing a high capacity lithium secondary battery having the improved energy density per unit volume of the secondary battery.

Negative electrode for lithium secondary battery and lithium secondary battery

A method for forming a negative electrode for a lithium secondary battery, includes providing a paste comprising graphite particulates comprise assembled or bound graphite particles in each of which a plurality of flat-shaped particles are assembled or bound together so that the planes of orientation are not parallel to one another, and the mixture including 3 to 10 parts by weight of the organic binder per 100 parts by weight of the graphite particulates, a binder and a solvent, coating the paste on a current collector, drying the paste coated on the current collector to form a mixture of the graphite particulates and the binder, and integrating the mixture with the current collector by pressing to provide a density of the mixture of graphite particulates and organic binder of 1.5 to 1.9 g/cm.

Graphite particles and lithium secondary battery using the same as negative

Disclosed are carbon particles for a negative electrode of a lithium ion secondary battery, the carbon particles having a pore volume of pores having a size of 2&#xd7;10 to 2&#xd7;10&#x212b;, of 0.1 ml/g or less with respect to the mass of the carbon particles; having an interlayer distance d(002) of a graphite crystal as determined by an X-ray diffraction analysis, of 3.38 &#x212b; or less; having a crystallite size Lc in the C-axis direction of 500 &#x212b; or more; and having a degree of circularity of the particle cross-section in the range of 0.6 to 0.9. Therefore, the carbon particles for the negative electrode of the lithium ion secondary battery enables to have high capacity and have superior rapid charge characteristics, a negative electrode for a lithium ion secondary battery using the carbon particles, and a lithium ion secondary battery can be provided.

Carbon particles for negative electrode of lithium ion secondary battery, negative electrode for lithium ion secondary battery, and lithium ion secondary battery

Graphite particles and lithium secondary battery using the same as negative electrode

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 m/g or less or the size of crystallite in the direction of c-axis of the crystal is 500 &#x212b; or more and the size of crystallite in the direction of plane is 1,000 &#x212b; 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 10to 10&#x212b; 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&#xd7;10to 2&#xd7;10&#x212b; 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.

A negative electrode for a lithium secondary battery, comprising a layer of a mixture containing graphite powder and an organic binder on a current collector, wherein a diffraction intensity ratio (002)/(110) measured by X-ray diffractometry of the layer of a mixture is 500 or less,

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 m/g or less or the size of crystallite in the direction of c-axis of the crystal is 500 &#x212b; or more and the size of crystallite in the direction of plane is 1,000 &#x212b; 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 10to 10&#x212b; is 0.4 to 2.0 cc/q per weight of graphite particle or pore volume of the pores having a size falling in a range of 1&#xd7;10to 2&#xd7;10&#x212b; 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.

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 m/g or less or the size of crystallite in the direction of c-axis of the crystal is 500 &#x212b; or more and the size of crystallite in the direction of plane is 1,000 &#x212b; 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 10to 10&#x212b; 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&#xd7;10to 2&#xd7;10&#x212b; is 0.08 to 0.4 cc/a 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.

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Hitachi, Japan

Yoshito Ishii