Cathode active material and secondary battery comprising the same

PURPOSE: A positive electrode active material, and a secondary battery including thereof are provided to decreasing the flow speed of electrons and lithium ions when an internal short circuit is generated inside the secondary battery. CONSTITUTION: A positive electrode active material contains a first lithium-containing metal composite oxide, and a second lithium-containing metal composite oxide coated on the first lithium-containing metal composite oxide. The second lithium-containing metal composite oxide has the higher resistance than the first lithium-containing metal composite oxide, and partially or entirely coated with a conductive carbon material.