POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS SECONDARY BATTERIES, METHOD FOR MANUFACTURING POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS SECONDARY BATTERIES, POSITIVE ELECTRODE FOR NONAQUEOUS SECONDARY BATTERIES, AND NONAQUEOUS SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a positive electrode active material for nonaqueous secondary batteries high in capacity and rate characteristic.SOLUTION: A positive electrode active material for nonaqueous secondary batteries comprises: a transition metal compound expressed by the chemical formula, AMDO(where "A" represents an alkali metal or alkali-earth metal, "M" represents a metal element including at least one transition metal element, "D" represents a typical element which makes a covalent bond with oxygen O to form an anion, and x, y and z satisfy: 0x2; 1y2; and 3z7) with carbon coating formed thereon. In the positive electrode active material, the average primary particle diameter is in a range of 10-200 nm. The ratio of an actual measurement of the specific surface area measured with the carbon coating removed therefrom to a specific surface area calculated based on the assumption that particles having the average primary particle diameter are perfect spheres in shape is in a range of 1.0-2.0. The porosity of secondary particles is in a range of 33-48 vol.%. Preferably, the transition metal compound is expressed by the chemical formula LiMPO4 (where M represents a metal element including at least one of Fe, Mn, Co and Ni).