Nanocomposite cathod active material for lithium secondary batteries, method for preparing the same and lithium secondary batteries comprising the same

The present invention relates to a cathode active material nanocomposite for a lithium secondary battery, a method for preparing the same, and the lithium secondary battery comprising the same, and more specifically, to: a cathode active material nanocomposite for a lithium secondary battery which includes a core containing LiMn_2O_4, and LiMn(PO_3)_3 spread on a surface of the core; a method for preparing the same; and the lithium secondary battery comprising the same. According to the present invention, the production time and cost of the lithium secondary battery can be reduced, and the produced lithium secondary battery has excellent electrochemical properties.