Cathode active material, cathode including the cathode active material, and lithium battery including the cathode

A cathode active material comprising:

• a lithium composite oxide represented by Formula 1;
• and
• a lithium titanium oxide represented by Formula 2,
• wherein the lithium titanium oxide comprises titanium having an average oxidation number of 4-y, where 0<y<2:
• Li1+xMyM′1-yO2+z, [Formula 1]
• wherein M is Mn, Zr, Ti, Mo, Zn, or a combination thereof;
• M′ is Ni, Co, Mn, Cr, Fe, V, Al, Mg, Ti, Mo, Cu, Zr, B, or a combination thereof;
• −0.5<x<1;
• 0<y<1;
• and 0<z<1;
• and
• LiaTibMecOd, [Formula 2]
• wherein Me is Al, Zr, Mg, Sn, Si, Ce, Zn, Mo, or a combination thereof;
• 3<a<8;
• 4<b+c<7;b≧c;
• 0≦c<1;
• and 11<d<13.