| abstract |
A positive electrode active material comprises a Li-transition metal-layered oxide represented by the formula: Lia(NibCocAldMee)O2 (in which Me=Mn, Mg, Ti, Ru, Zr, Nb, Mo, W; 1.00≤a≤1.15; 0.25<b<1; 0<c≤0.30; 0≤d≤0.05; 0≤e≤0.40), and is constituted of secondary particles formed by aggregation of primary particles. As to a compositional ratio of Li which is derived from unreacted substances or decomposed products in the secondary particles, a variation coefficient (Standard deviation value/Average value) of a Li-compositional ratio: Li/M (M=Ni+Co+Al+Me) is 30% or less. The positive electrode active material hardly deteriorates even if repeatedly charged/discharged, and enables stable charge/discharge, and then a non-aqueous electrolyte secondary battery is enabled to have an excellent output property and a long lifetime. |