| abstract |
(57) [Summary] [Constitution] Both the atomic ratio of lithium to the transition element on the particle surface and the atomic ratio of lithium to the transition element in the particle are 0.9. A composite oxide of lithium and a transition element having an atomic ratio of 1.2 to 1.2 and an atomic ratio of the former being larger than that of the latter is used as a positive electrode active material. [Effect] A lithium secondary battery having extremely excellent charge / discharge cycle characteristics is provided. |