活物質、およびそれを用いた電極、ならびにリチウムイオン二次電池

摘要

To provide an active material with high capacity, high initial charge-discharge efficiency, and high average discharge voltage. An active material according to the present invention includes a first active material and a second active material, wherein the ratio (δ) of the second active material (B) to the total amount by mole of the first active material (A) and the second active material (B) satisfies 0.4 mol %≦̸δ≦̸18 mol % [where δ=(B/(A+B))×100].