Patent ID: 7582383

Claim:
A complex oxide material with a layered structure containing at least Li and Ni, further comprising a quadrivalent element other than Mn and a trivalent element other than Co, said material being represented by a chemical formula Li x Ni a (Mn y M 1-y ) b (Co z M′ 1-z ) c O 2 (0<x<1.2, 0<y<1, 0<z<1, a+b+c=1, 9b≦5a+2.7, 0<a<1, 0<b<1, 0<c<1, M: quadrivalent element other than Mn, and M′: trivalent element other than Co) wherein the half-value width of any diffraction peak that appears at angles of 20° or greater and 80° or smaller in terms of 2θ value in an X-ray diffraction measurement using the Cu-kα line is 0.25 degrees or smaller.