PLATE-SHAPED PARTICLES FOR POSITIVE ELECTRODE ACTIVE MATERIAL OF LITHIUM SECONDARY BATTERIES, FILMS OF SAID MATERIAL AS WELL AS LITHIUM SECONDARY BATTERIES

An object of the present invention is to improve the characteristics such as cell capacity, by raising the exposure of a crystal plane (a plane other than the (003) plane: e.g., (101) plane and (104) plane), through which lithium ions are favorably intercalated and deintercalated, to an electrolyte. A plate-like particle or a film for a lithium secondary battery cathode active material has a layered rock salt structure. A plane other than the (003) plane is oriented in parallel with the plate surface (a surface orthogonal to a thickness direction) and step-like structures are two-dimensionally formed along the plate surface.