POSITIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, METHOD OF PREPARING THE SAME, AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME

摘要

PURPOSE: A positive active material for lithium secondary battery and a method for preparing the same are provided to improve lifetime, high voltage characteristic, and heat stability. CONSTITUTION: A positive active material for lithium secondary battery comprises a core and a core-surface-treatment layer. The core includes a compound capable of reversible intercalation/deintercalation. The core-surface-treatment layer is formed on the surface of the core and includes ammonium-containing fluoride compounds. The ammonium-containing fluoride compounds have surface-treating atoms therein. A method for preparing the positive active material comprises the following steps of: drying the ammonium-containing fluoride compounds to remove moisture therefrom; dry-mixing the core and ammonium-containing fluoride compounds(S21); and coating the surface of the positive active material with the mixture(S23).