Kabushiki Kaisha Toyota Chuo Kenkyusho

Naoyoshi Watanabe

Kazumasa Takatori

Hideo Sobukawa

Haruo Doi

Toshihiko Tani

Tsuyoshi Sasaki

Masahiko Kato

Mikio Obayashi

Akihiko Murakami

Akio Takahashi

The present method is to produce an active material powder formed of a spinel oxide containing lithium or a layer-structured oxide containing lithium for a lithium secondary battery which is uniform in composition, fine in particle size and free of oxygen defects, and which is unlikely to cause capacity deterioration resulted from repetitive charge/discharge cycles at a high current density. A suspension 1 prepared by suspending an ingredient of the active material powder in a combustible liquid or an emulsion prepared by emulsifying a solution of the ingredient in the combustible liquid is sprayed in a droplet state 15 together with an oxygenic gas 2. The combustible liquid contained in the droplet 15 is burned to have the ingredient therein reacted and to evaporate the solvent. As a result, active material powder 4 formed of the spinel oxide containing lithium is obtained. An active material powder formed of the layer-structured oxide containing lithium is obtained by re-heating the oxide powder that has been generated by spraying and burning the droplet.

Method of producing active material powder for lithium secondary battery

Disclosed is a method for producing oxide powders and complex oxide powders having an oxygen amount smaller than the stoichiometric amount. The method comprises: spraying a combustible liquid that contains at least one raw material of metals capable of having a plural number of valences and compounds of such metals; and firing the raw material to give a powder of an oxide of at least one of said metals. The oxygen amount in the atmosphere in which the combustible liquid containing said raw material is sprayed and fired is smaller than the total of the oxygen amount necessary for the complete combustion of said combustible liquid and the oxygen amount necessary for the conversion of said raw material into an oxide that is the most stable in air at room temperature.

Method for producing oxide powder

A process for producing a powder of composite oxide which includes cerium and zirconium, or which includes cerium, zirconium and further a rare-earth element other cerium. The process includes: dissolving nitrate, sulfate and/or acetate of constituent elements of the composite oxide into water in a predetermined ratio; and spraying and heating a resulting aqueous solution to oxidize the constituent elements of the composite oxide for converting them into a powder of a composite oxide. The thus produced composite oxide powder is micro-fine, homogeneous, and heat resistant.

Process for producing composite oxide powder containing cerium and

Cast iron is pretreated in an aqueous solution of nitric acid and then immersed in molten sulfur until a sulfurized layer is formed on its surface. The sulfurized layer is very thick and stable and has excellent molten aluminum resistance. Its uniformity is further improved by a subsequent diffusion treatment at elevated temperatures.

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Aichi-ken, Japan

Naoyoshi Watanabe