Patent ID: 8748042

Claim:
A cathode active material comprising: complex oxide particle made of an oxide containing at least lithium (Li) and cobalt (Co); a coating layer which is provided on at least part of the complex oxide particle and is made of an oxide containing lithium and at least one of nickel and manganese wherein the average composition of the complex oxide particle being expressed by Li(1+x)Co(1−y)MyO(2−z), and wherein in diffraction peaks obtained by CuKα powder X-ray diffraction, there is a diffraction peak of the coating layer on the lower angle side in the range from 0.2° to 1.0° less than a diffraction peak belonging to face [101] of the complex oxide particle Li(1+x)Co(1−y)MyO(2−z) on the 2θ axis; where M represents at least one selected from the group consisting of magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), tungsten (W), zirconium (Zr), yttrium (Y), niobium (Nb), calcium (Ca), and strontium (Sr); and values of x, y, and z are respectively in the range of −0.10≦x≧0.10, 0≦y≧0.50, and −0.10≦z≧0.20.