abstract |
Provide a positive electrode active material having a high energy density and capable of producing a non-aqueous electrolyte secondary battery having excellent charge / discharge cycle performance, and a positive electrode for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery using the same. I do. Compositional formula Li a Mn 0.5-x Ni 0.5 -y M x + y O 2 ( where 0.98 ≦ a <1.1, -0.1 ≦ x-y ≦ 0.1, M is Li, Mn , An element other than Ni). Further, the composition formula Li w Mn x 'Ni y' Co z 'O 2 ( where, x', y ', z ' , in the diagram ternary phase, (x ', y', z ') is the point A (0.51, 0.49, 0), point B (0.45, 0.55, 0), point C (0.25, 0.35, 0.4) and point D (0.31, 0 .29,0.4), which is a value in a range existing on or inside the line of the quadrangle ABCD having the apex as 0 ≦ w / (x ′ + y ′ + z ′) ≦ 1.30). A positive electrode active material containing a composite oxide. |