LITHIUM TRANSITION METAL COMPOSITE OXIDE FOR POSITIVE ELECTRODE ACTIVE MATERIAL OF LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY USING IT

摘要

PROBLEM TO BE SOLVED: To provide lithium transition metal composite oxide with low deterioration in cycles when used as a positive electrode active material, and to provide a lithium secondary battery with good cycle characteristics especially in use under high temperature environment. SOLUTION: This lithium transition metal oxide has secondary particles formed by aggregation of primary particles, and the ratio of the average volume of the primary particles to that of the secondary particles is specified to 0.01 or more. By reducing the number of primary particles constituting the secondary particles, electric conductivity is kept even if the secondary particles are collapsed, and deterioration in cycles can be suppressed.