Positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

A positive electrode active material for a non-aqueous electrolyte secondary battery, including a lithium-transition metal composite oxide represented by the general formula LiaNibCocAldXeOf, wherein 0.9≤a≤1.2, 0.88≤b≤0.96, 0≤c≤0.12, 0≤d≤0.12, 0≤e≤0.1, 1.9≤f≤2.1, b+c+d=1, and X represents at least one element selected from the group consisting of Mn, Mg, Ca, Sr, Ba, Ti, Zr, V, Nb, Ta, Mo, W, and B, wherein

• the lithium-transition metal composite oxide includes secondary particles formed by aggregation of primary particles, and has a volume of pores having a pore diameter of less than or equal to 0.3 μm, of greater than or equal to 6×10−4 and less than or equal to 50×10−4 mL/g, and a particle rupture strength at an average volume particle diameter, of greater than or equal to 120 MPa.