Disclosed herein is a layered core-shell
cathode active material for secondary
lithium batteries, in which the core layer has a
structural formula of Li1+a[MxMn1-x]2O4 (M is selected from a group consisting of Ni, Co, Mg, Zn, Ca, Sr, Cu, Zr, P, Fe, Al, Ga, In, Cr, Ge, Sn and combinations thereof, 0.01≦x≦0.25, 0≦a≦0.1) and the shell layer has a
structural formula of Li1+a[MyMn1−y]2O4 (M′ is selected from a group consisting of Ni, Mg, Cu, Zn and combinations thereof, 0.01≦y≦0.5, 0≦a≦0.1). In the layered
cathode active material, the core layer, corresponding to a 4V
spinel-type
manganese cathode, functions to increase the capacity of the active material while the shell layer, corresponding to a 5 V
spinel-type
transition metal mix-based cathode, is electrochemically stable enough to prevent the reaction of the components with electrolytes and the
dissolution of transition metals in electrolytes, thereby improving thermal and lifetime characteristics of the active material.