Positive electrode active material containing solid solution active material, positive electrode containing the positive electrode active material, and non-aqueous electrolyte secondary battery using the positive electrode

A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, comprising:

• coating a surface of a solid solution active material represented by the composition formula (1):
• Li1.5[Ni0.40Mn0.60Co0.40[Li]0.1]Oz (1)
• wherein X represents at least one selected from Ti, Zr and Nb, 0≤e≤0.5, a+b++c+d+e=1.5, 0.1≤d≤0.4, and 1.1≤[a+b+c+e]≤1.4, and z represents the number of oxygen atoms satisfying an atomic valence, with alumina;
• and
• preparing the solid solution active material, wherein the preparing comprises:
• a first step of mixing an organic acid salt of a transition metal having a melting point of 100° C. to 350° C.;
• a second step of melting the mixture obtained in the first step at 100° C. to 350° C.;
• a third step of subjecting the molten substance obtained in the second step to pyrolysis at a temperature equal to higher than the melting point;
• and
• a fourth step of calcining the pyrolysate obtained in the third step.