Patent ID: 7547491

Claim:
A composite cathode active material comprising a dry mixture prepared by a method comprising: providing at least one cathode active material selected from the group consisting of compounds represented by Formulae I and II; Li x Ni 1-y M y O 2-α X α I Li x Ni 1-y-z Co y M z O 2-α X α II wherein 0.90≦x≦1.1, 0≦y≦0.9, 0≦z≦0.5, 0≦α≦2, M is selected from the group consisting of Al, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and mixtures thereof, and X is an element selected from the group consisting of O, F, S and P, pretreating the cathode active material by mixing the cathode active material with an acid and an organic solvent to form a mixed solution, and drying the mixed solution to form a dry acid pretreated cathode active material.