Patent ID: 8968933
Filing Date: 2015-03-03
Classification: H01M,Y02E,Y02P

Abstract:
1. A method for preparing an anode active material comprising a core comprising a crystalline carbon-based material, and present on a surface of said core, a composite coating layer comprising one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon, and silicon oxide enabling intercalation and deintercalation of ions, the method comprising: (a) mixing a precursor for a raw material of the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon with silicon oxide enabling intercalation and deintercalation of ions, followed by purification, to prepare a mixture for coating, wherein the precursor for the raw material of the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon is a pitch solution and the pitch solution is mixed with the silicon oxide enabling intercalation and deintercalation of ions prior to purification of the pitch solution, wherein after mixing of the pitch solution with silicon oxide enabling intercalation and deintercalation of ions, the mixture is subjected to purification, wherein purification comprises removing impurities by thermal treatment, followed by cooling and grinding, wherein the impurities comprise hydrocarbons and sulfur having a relatively low boiling point, wherein said thermal treatment is conducted under an inert atmosphere at a temperature of 350° C. to 700° C.; (b) mixing the mixture for coating with a crystalline carbon-based material to prepare a core-shell precursor comprising the raw material mixture for coating applied to the core comprising the crystalline carbon-based material; and (c) baking the core-shell precursor to carbonize the raw material of the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon into the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon.