POSITIVE ELECTRODE, PRODUCTION METHOD THEREOF, AND LITHIUM SECONDARY BATTERY USING THE SAME

• US 20090280411A1
• Filed: 04/10/2007
• Published: 11/12/2009
• Est. Priority Date: 06/16/2006
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Nishimura, Naoto, Ohira, Koji, Nishimura, Kasuhito
• Application Number:
  US12/305,065
• Publication Number:
  US 20090280411A1
• Time in Patent Office: Days
• US Class Current: 429/221
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/136 Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/1395 of electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1397 of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A positive electrode for a lithium secondary battery obtained by bonding a positive electrode-active material, a conductive material, and a current collector with a carbon which has a graphitization degree expressed by a peak intensity ratio, i.e. the ratio of peak intensity at 1360 cm⁻¹ to peak intensity at 1580 cm⁻¹ in the argon laser Raman Spectrum, of 1.0 or lower.

Claims

1. A positive electrode for a lithium secondary battery obtained by bonding a positive electrode-active material, a conductive material, and a current collector with a carbon which has a graphitization degree expressed by a peak intensity ratio, i.e. the ratio of peak intensity at 1360 cm⁻

1 to peak intensity at 1580 cm<sup>−

1</sup> in the argon laser Raman Spectrum, of 1.0 or lower.

2. The positive electrode for the lithium secondary battery according to claim 1, wherein the peak intensity ratio ranges from 0.4 to 1.0.

3. The positive electrode for the lithium secondary battery according to claim 1, wherein the carbon is a carbon formed by heat treating a carbon precursor under an inert atmosphere.

4. The positive electrode for the lithium secondary battery according to claim 3, wherein the carbon precursor is polyvinylpyrrolidone, carboxymethyl cellulose, poly(vinyl acetate) or saccharides.

5. The positive electrode for the lithium secondary battery according to claim 1, wherein the carbon is used in the range of 1 to 30 parts by weight to 100 parts by weight of the positive electrode-active material.

6. The positive electrode for the lithium secondary battery according to claim 1, wherein the conductive material is a vapor grown carbon fiber, and the positive electrode-active material is LiFePO₄.

7. A method of producing a positive electrode according to claim 1 comprising thermally treating, in an inert atmosphere, a current collector on which a mixture of a positive electrode-active material a conductive material, and a carbon precursor is supported.

8. The method of producing the positive electrode according to claim 7, wherein the mixture contains water as a solvent.

9. The method of producing the positive electrode according to claim 7, wherein the thermal treatment is carried out in the temperature from 250°

C. to 800°

C.

10. The method of producing the positive electrode according to claim 7, wherein a heating speed until the temperature at the thermal treatment from a temperature before the thermal treatment is 200°

C./h or lower.

11. A lithium secondary battery using the positive electrode according to claim 1.