Patent ID: 8142932

Claim:
A cathode active material for lithium secondary batteries, which has a core-shell multilayer structure, in which the core portion is made of Li 1+a Mn 2-a O 4-y A y (wherein A is at least one element selected from among F and S, 0.04≦a≦0.15, and 0.02≦y≦0.15), and the shell portion is made of Li[Li a (Mn 1−x M x ) 1−a ] 2 O 4-y A y (wherein M is at least one element selected from the group consisting of Fe, Co, Ni, Cu, Cr, V, Ti and Zn, A is at least one element selected from among F and S, 0.01≦a≦0.333, 0.01≦x≦0.6, and 0.02≦y≦0.15).