Patent ID: 7179566

Claim:
A cathode active material for a secondary battery comprising a lithium-manganese composite oxide having a spinel structure and represented by the following general formula (I), Li a (M x Mn 2-x-y-z Y y A z )(O 4-w Z w ) (I) wherein 0.5≦x≦1.2, 0<y,0<z,x+y+z<2, 0<a≦1.2, and 0<w≦1, wherein M comprises at least one of Co, Ni, Fe, Cr and Cu, wherein Y comprises at least one element selected from the group consisting of Li, Be, B, Na, Mg, Al, K and Ca, wherein A comprises at least one of Ti and Si, wherein Z comprises at least one of F and Cl, and wherein an average discharge voltage with respect to a lithium standard potential is 4.5V or more.