Cathode Active Material for Lithium Ion Secondary Batteries, and Lithium Ion Secondary Battery

摘要

The objective of the present invention is to provide a lithium ion secondary battery, the charged state of which can be detected from the battery voltage with high accuracy, and which is able to achieve a high capacity in a high-potential range. This objective can be achieved by a cathode active material for lithium ion secondary batteries, which is composed of a lithium transition metal oxide containing Li and metal elements including at least Ni and Mn, and which is characterized in that: the atomic ratio of Li to the metal elements satisfies 1.15