Patent ID: 7326498

Claim:
A method of preparing a positive active material for a rechargeable lithium battery comprising: adding first and second compounds to a solvent to prepare an acidic coating solution with a pH of from 0.01 to 3, the first compound including an element that is capable of forming a double bond with an oxygen of a lithium metal oxide, and the second compound including at least one element selected from the group consisting of alkali metals, alkali earth metals, group 13 elements, group 14 elements, transition metals, and rare-earth elements; coating a lithium-containing compound with the acidic coating solution to produce a coated lithium-containing compound; and heat-treating the coated lithium-containing compound to form a surface-treatment layer comprising a compound represented by formula 1, MXO k (1) where, M is at least one element selected from the group consisting of alkali metals, alkali earth metals, group 13 elements, group 14 elements, transition metals, and rare-earth elements, X is an element that is capable of forming a double bond with oxygen, and k is a numerical value from 2 to 4.