Positive electrode active material for lithium ion secondary battery, lithium ion secondary battery positive electrode using the same, and lithium ion secondary battery

Abstract

A positive electrode active material for a lithium ion secondary battery includes: a first active material selected from active materials represented by composition formula (1); and a second active material represented by composition formula (2). A ratio a/b of an average particle diameter a of the first active material to an average particle diameter b of the second active material is in a range of 1≦a/b≦60. LiwNix(M1)y(M2)zO2   (1) where M1 is at least one element selected from Co and Mn, M2 is at least one element selected from Al, Fe, Cr, Ba, Mn, and Mg, 0.9<w<1.1, 2.0<(x+y+z+w)≦2.1, 0.3<x<0.95, 0.01<y<0.4, and 0.001<z<0.2. LiaVOPO4   (2) where 0<α≦1.2.

Dependencies are inferred from the claim text.