Nickel cobalt complex hydroxide particles and method for producing the same, positive electrode active material for non-aqueous electrolyte secondary battery and method for producing the same, and non-aqueous electrolyte secondary battery

A positive electrode active material for non-aqueous electrolyte secondary battery comprising a lithium transition metal complex oxide represented by a formula:

• LiaNi1−x−yCoxMnyMzO2, wherein 0.95≤a≤1.2, 0.10≤x≤0.35, 0≤y≤0.35, 0<z≤0.05, M is at least one element selected from a group consisting of Al, Mg, Ca, Ti, Zr, Nb, Ta, Cr, Mo, W, Fe, Cu, Si, Sn, Bi, Ga, Y, Sm, Er, Ce, Nd, La, Cd and Lu,
• wherein the lithium transition metal complex oxide is in a form of secondary particles formed by agglomeration of primary particles,
• wherein the secondary particles comprise:
• a first layer having a radial depth ratio of less than 5% from a surface in the secondary particle;
• a second layer having a radial depth ratio in a range of 5% to less than 50% and located at an inner side than the first layer in the secondary particles;
• and
• a third layer having a radial depth ratio of 50% or greater and located at an inner side than the second layer in the secondary particles, and
• wherein a SEM-EDX spectrum of said element M with respect to the radial depth of the secondary particles have a peak in the second layer.