POSITIVE ELECTRODE ACTIVE MATERIAL OF LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a lithium secondary battery improved in battery characteristics, especially in discharge voltage and discharge capacity at a high rate.SOLUTION: A positive electrode active material 222 of a lithium secondary battery has a lamellar rock-salt structure. The positive electrode active material comprises: secondary particles made up of a large number of primary particles 222a having an average particle diameter of 0.01-5 μm. The secondary particles are characterized in that: a (003)-plane orientation rate is 60% or larger; an average particle diameter is 1-100 μm; an aspect ratio is 1.0 to 2 (exclusive of 2); a porosity is 3-30%; a ratio of open pores V is 70% or larger; an average pore diameter of the open pores is 0.1-5 μm; and the average particle diameter of the primary particles divided by the average pore diameter of the open pores is a value of 0.1-5.