| 摘要 |
The positive electrode of a lithium ion secondary battery includes active material particles represented by LixNi1−yMyMezO2+δ, and the active material particles include a lithium composite oxide represented by LixNi1−yMyO2, (where 0.95≦̸x≦̸1.1, 0<y≦̸0.75, 0.001≦̸z≦̸0.05). The element M is selected from the group consisting of alkaline-earth elements, transition elements, rare-earth elements, IIIb group elements and IVb group elements. The element Me is selected from the group consisting of Mn, W. Nb, Ta, In, Mo, Zr and Sn, and the element Me is included in a surface portion of the active material particles. The lithium content x in the lithium composite oxide in an end-of-discharge state when a constant current discharge is performed at a temperature of 25° C. with a current value of 1C and an end-of-discharge voltage of 2.5 V satisfies 0.85≦̸x≦̸−0.013Ln(z)+0.871. |
