The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 12, 2013
Filed:
Jul. 28, 2009
Tooru Fujiwara, Nishinomiya, JP;
Hiroshi Yamamoto, Ikeda, JP;
Tooru Fujiwara, Nishinomiya, JP;
Hiroshi Yamamoto, Ikeda, JP;
Chuo Denki Kogyo Co., Ltd., Niigata, JP;
Abstract
A carbon material suitable as a negative electrode material for a lithium ion battery which can suppress decomposition of a nonaqueous electrolytic solution, which has excellent compressibility capable of highly dense packing, and which can form an electrode of high capacity without worsening charge and discharge efficiency or cycling performance. Graphite powder A having an average particle diameter of 10-30 μm and a specific surface area S1 of at most 12.5 m/g and pitch powder B having a softening point of 80-180° C. and an average particle diameter of 15-150 μm are mixed in proportions such that the mass ratio A/B is 98/2-95.5/4.5, and the resulting mixed powder is subjected to heat treatment in a stationary condition in an inert atmosphere at 900-1100° C. to carbonize the pitch and thereby manufacture a carbon material having carbon adhered to the surface of the above-described graphite powder. Carbon preferentially adheres to the edge planes of the graphite particles. The carbon material has a specific surface area S2 of 1.0-5.0 m/g, and it satisfies 0.4≦S2/S1≦0.8.