Patent ID: 7790318

Claim:
A method of preparing a positive active material for a lithium secondary battery, comprising: mixing a lithium source and a cobalt source at a mole ratio of 0.90 to 1.04 of lithium based on 1 mole of cobalt; and sintering the mixture at 950 to 980° C. for six to ten hours, producing the positive active material comprising a compound represented by formula 1: Li x CoO 2-y A y (1) wherein x is from 0.90 to 1.04, y is from 0 to 0.5, A is selected from the group consisting of F, S, and P, and the positive active material has a ratio of diffracted intensity of diffraction lines in 2θ=53° (104 plane) with respect to diffracted intensity of diffraction lines in the vicinity of 2θ=22° (003 plane) in X-ray diffraction patterns using a CoKα-ray from 10% to 70%.