METHOD FOR PRODUCING CATHODE ACTIVE MATERIAL FOR LITHIUM ION BATTERIES, CATHODE ACTIVE MATERIAL FOR LITHIUM ION BATTERIES OBTAINED BY THE PRODUCTION METHOD, LITHIUM ION BATTERY ELECTRODE, AND LITHIUM ION BATTERY

• US 20110037019A1
• Filed: 04/20/2009
• Published: 02/17/2011
• Est. Priority Date: 04/25/2008
• Status: Active Grant

• Current Assignee: Sumitomo Osaka Cement Company Limited
• Original Assignee: Sumitomo Osaka Cement Company Limited
• Inventors: Nakano, Masatsugu, Saitou, Mitsumasa
• Granted Patent: US 8,460,573 B2
• Time in Patent Office: Days
• US Class Current: 252/182.1
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 25/45 containing plural metal, or metal and ammonium
• CPC Class Codes: C01D 15/00 Lithium compounds
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• 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 4/366 as layered products
• CPC Class Codes: H01M 4/5825 Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10T 29/49107 Fuse making

Abstract

A method for producing a cathode active material for lithium ion batteries includes a step of synthesizing LiFePO₄ by carrying out a hydrothermal reaction using an Li salt, a Fe salt, and a phosphoric acid source as raw materials. Elements Li and Fe in the Li and Fe salts are added to the reaction system in amounts excessively larger than the theoretical amounts required for the hydrothermal reaction. The synthesized LiFePO₄ has an average primary particle size of equal to or larger than 30 nm and equal to or smaller than 100 nm.

Claims

1. A method for producing a cathode active material for lithium ion batteries, comprising:

at least a step of carrying out a hydrothermal reaction to produce LiFePO₄ by adding elements Li and Fe in Li and Fe salts, which are used as raw materials, in amounts excessively larger than the theoretical amounts required for the hydrothermal reaction, thus synthesizing LiFePO₄ which has an average primary particle size of equal to or larger than 30 nm and equal to or smaller than 100 nm.

2. The method for producing a cathode active material for lithium ion batteries according to claim 1, wherein

the Fe salt is added so that the molar ratio of Fe to P is equal to or larger than 1.01, and

the Li salt is added so that the molar ratio of Li to P is equal to or larger than 3.1.

3. The method for producing a cathode active material for lithium ion batteries according to claim 1, wherein

the Li salt is one, or two or more kinds of materials selected from the group consisting of chloride, sulfate, formate, acetate, citrate, and oxalate.

4. The method for producing a cathode active material for lithium ion batteries according to claim 1, wherein

the Fe salt is one, or two or more kinds of materials selected from the group consisting of chloride, sulfate, formate, acetate, citrate, and oxalate.

5. A cathode active material for lithium ion batteries which is obtained by the method for producing a cathode active material for lithium ion batteries according to claim 1.

6. A lithium ion battery electrode which is obtained by coating the cathode active material for lithium ion batteries according to claim 5 with carbon.

7. A lithium ion battery which has the lithium ion battery electrode according to claim 6 as a cathode.