The invention provides a type of lithium-ion battery cathode materials applicable to a high charge cut-off voltage. The cathode materials comprises two active substances of LiCoO2 and Li (NixCoyMn1-x-y)O2, where 0.3≦x≦0.8, 0.1≦y≦0.4, and 0.6≦x+y≦0.9. Both LiCoO2 and Li(NixCoyMn1-x-y)O2 are doped with element M and then treated by surface coating with the oxide, sulfide, fluoride of element M′ or phosphate. The element M is at least one of the Mg, Ti, Al, Zr, B, La, Ce, Y, P, S, N or F while the element M′ is at least one of the Al, Ti, Mg, Zr, B, Si, Fe, La, Ce or Y. The cathode materials provided herein, having the advantages of excellent cycling performance and low cell swelling against high temperature, can help to remarkably increase the energy density of lithium-ion batteries. The invention also discloses a lithium-ion battery containing such cathode materials.