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:
Jan. 08, 2002
Filed:
May. 27, 1998
Akihiko Shirakawa, Chiba, JP;
Takao Noda, Chiba, JP;
Showa Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A cathode electroactive material is disclosed, comprising a compound oxide having a spinel structure. The compound oxide comprises lithium, manganese and oxygen and has an atomic ratio of lithium to manganese of Li/Mn=0.48 to 0.55, a true density of 4.05 g/cm or more and a lattice constant of 8.240 Å or less. The compound oxide is obtained by mixing a lithium compound with manganese carbonate having a specific surface area of 10 m /g or more, then reacting the mixture at a temperature of from 350 to 680° C. for at least one hour, and heat-treating the resulting spinel structure compound oxide at a temperature of from 730 to 900° C. Also disclosed is a nonaqueous secondary battery comprising the cathode electroactive material.