| abstract |
A positive electrode active material for a lithium ion battery having a high capacity and good rate characteristics is provided. The positive electrode active material for a lithium ion battery has a composition formula: Li x (Ni y M 1 -y ) O z Wherein M is at least one kind of Mn, Co, Al, Mg, Cr, Ti, Fe, Nb, Cu and Zr, x is 0.9 to 1.2, y is 0.70 to 0.79, z is 1.9 or more to be) As shown in Fig. the lattice constant a and the composition ratio (Li / M) satisfy the relationship of y = 1.108, y = -37.298x + 108.27, and y = y = 75.833x-217.1, and the lattice constant c is 14.2 to 14.25. |