Cathode active material for lithium secondary battery, method of preparing the same, and lithium secondary battery containing the same

A method of preparing a cathode active material for a lithium secondary battery, the method comprising:

• preparing a core material containing a compound reversibly intercalating and deintercalating lithium, and doped with fluorine;
• preparing a lithium source, a phosphorus source, and/or a metal source;
• uniformly attaching the lithium source, the phosphorous source, and/or the metal source onto a surface of the core material by mixing the lithium source, the phosphorous source, and/or the metal source with the core material;
• and
• obtaining a core material of which a composite coating layer containing Li3PO4 and LiF and further containing a lithium metal compound, a metal oxide, a metal fluoride compound, and/or a combination thereof is formed on the surface by heat-treating the core material onto which the lithium source, the phosphorous source, and/or the metal source are attached.