POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY

It is an object of the present invention to provide a positive electrode material having a large ratio of the discharge capacity around 4 V to the total discharge capacity including the discharge capacity at 4V or lower while making the discharge capacity around 4 V sufficient, for the purpose of providing a lithium secondary battery using a lithium transition metal phosphate compound excellent in thermal stability, utilizing the discharge potential around 4V (vs. Li/Li + ) that is higher than the discharge potential of LiFeP04, and being advantageous with respect to the detection of the end of discharge state, and a lithium secondary battery using the same. The present invention uses a positive active material for a lithium secondary battery containing a lithium transition metal phosphate compound represented by LiMn 1-x-y FexCoyPO 4 (0.1 ‰¤ x ‰¤ 0.2, 0 < y ‰¤ 0.2).