Shin-kobe Electric Machinery Co., Ltd.

Koutaro Kobayashi

Kensuke Hironaka

Yoshimasa Koishikawa

A lithium secondary battery capable of improving high temperature cycle life characteristic effectively without decreasing discharge capacity. Amorphous carbon powder with a specific surface area of 10.0 m /g and a mean particle diameter of 7.0 &mgr;m is used as negative electrode active material and lithium manganate with a Li/Mn ratio of 0.58 is used as positive electrode active material. Since a surface area of the negative electrode active material layer is made large by setting the mean particle diameter of the amorphous carbon powder to 10 &mgr;m or less, the surface area of the negative electrode active material layer is sufficiently large that, even when inert coating is formed on the surface of the negative electrode due to manganese deposition caused by manganese elution from the positive electrode, high temperature cycle life characteristic can be improved without high temperature deterioration.

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Okayama, Japan

Koutaro Kobayashi