| abstract |
To provide a lithium secondary battery that achieves high energy density and improved cycle life. A Li a (Co 1-xyz Ni x Mn y M z) O 2 [M is Li, Mg, Al, Si, Fe, at least one of Ti and Cu] is represented by, a, x, Let it be a lithium secondary battery which contains two types of compounds with which y and z satisfy | fill specific conditions as a positive electrode active material. [Selection] Figure 1 |