| abstract |
A nonaqueous electrolyte secondary battery is constituted of an anode made of lithium or lithium compound, a nonaqueous electrolyte containing lithium compound, and a cathode active material. The cathode active material is represented by expression Li X Co (1-Y) M Y O₂ (0.85 ≦ X ≦ 1.3, 0.05 ≦ Y ≦ 0.35, wherein M is a metal of at least one of W, Mn, Ta, Ti, Nb). The battery using the cathode active material of the present invention is improved in discharge capacity deterioration rate based on cycle and discharge capacity. |