Positive electrode active material for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery using the positive electrode active material

A positive electrode active material for a nonaqueous electrolyte secondary battery, comprising primary particles of a lithium-nickel composite oxide represented by the following general formula (1) and secondary particles composed by aggregation of the primary particles, wherein

• a membranous covering having a thickness of 1 nm to 200 nm and containing W and Li is present at least on the surface of the primary particles exposed on the outer face of the secondary particles and the surface of the primary particles exposed to internal voids of the secondary particles, and
• a c-axis length in the crystal of the lithium-nickel composite oxide is 14.183 angstroms or more and 14.205 angstroms or less, as determined by Rietveld analysis on X-ray diffraction.
• (Chemical formula 1)
• General formula:
• LibNi1-x-yCoxMyO2 (1)
• (In the formula, M is at least one type of element selected from Mg, Al, Ca, Ti, V, Cr, Mn, Nb, Zr and Mo, b is a numerical value satisfying 0.95≤b≤1.03, x is a numerical value satisfying 0<x≤0.15, y is a numerical value satisfying 0<y≤0.07, and x+y is a numerical value satisfying x+y≤0.16.)