Positive electrode active material for nonaqueous electrolyte secondary battery, method for producing same, and nonaqueous electrolyte secondary battery using said positive electrode active material

A method of producing a positive electrode active material for nonaqueous electrolyte secondary batteries, comprising:

• a first step of mixing a lithium-metal composite oxide powder which is represented by a general formula:
• LizNi1-x-yCoxMyO2 (where 0≤x≤0.35, 0≤y≤0.35, and 0.95≤z≤1.30 are satisfied, and M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti and Al) and has a layered crystal structure constituted by primary particles and secondary particles formed by aggregation of the primary particles, to an alkaline solution with a tungsten compound dissolved therein at a tungsten concentration of 0.1 to 2 mol/L so that a solid-liquid ratio of the lithium-metal composite oxide powder to an amount of water in the alkaline solution falls within a range of 200 to 2500 g/L, and immersing a resulting mixture, followed by solid-liquid separation, to obtain a tungsten-containing mixture in which tungsten is uniformly dispersed on a surface of the primary particles of the lithium-metal composite oxide;
• and
• a second step of subjecting the tungsten-containing mixture to heat treatment to thereby form a compound containing tungsten and lithium on the surface of the primary particles of the lithium-metal composite oxide.