Honda Motor Co., Ltd.
POSITIVE ELECTRODE ACTIVE MATERIAL

Abstract:

To provide a positive electrode active material capable of improving cycle characteristics of a lithium ion secondary battery and achieving a desirable output. In a positive electrode active material that is an aggregate of lithium compounds each including a lithium-containing transition metal oxide, a recess is formed between primary particles constituting the positive electrode active material. A solid film containing lithium is formed in at least a part of the recess. The solid film has a thickness of 10 nm or more and 70 nm or less. The coverage rate, which is the proportion of the surface area of the recess covered by the solid film formed with respect to the entire surface area of the recess, is preferably 30% to 70%.