Nippondenso Co., Ltd.

Norikazu Adachi

Hisanao Kojima

Yasushi Hayashi

An active material for a positive electrode of a secondary cell comprises particles of a metal oxide and a conductive layer formed on the surfaces of individual particles of the metal oxide and made of a carbon powder which has a specific surface area of at least 150 m.sup.2 /g when measured prior to the formation of the conductive layer. The conductive layer covers at least 15% of an apparent surface of the individual particles of the metal oxide and has a thickness ranging from 0.01 .mu.m to 0.3 .mu.m. The active material has a specific surface area of 3.5 m.sup.2 /g to 100 m.sup.2 /g. A method for making the active material is also described along with a positive electrode comprising the active material and a non-aqueous electrolytic secondary cell comprising the positive electrode.

Active materials for a secondary cell, a method for making the same,

A method for preparing an active substance for use in a positive electrode in chemical cells comprising a negative electrode is described. The method comprises preparing a mixed aqueous solution of a water-soluble lithium compound, a water-soluble transition metal compound, and an organic acid selected from the group consisting of organic acids having, in the molecule, at least one carboxyl group and at least one hydroxyl group and organic acids having at least two carboxyl groups, preparing an organic acid complex comprising lithium and a transition metal, and thermally decomposing the complex at temperatures sufficient for the decomposition to obtain the active substance. The complex may be prepared by dehydrating the solution. Alternatively, the complex may be formed by spraying the solution under heating conditions.

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Nagoya, Japan

Norikazu Adachi