The effect of cation doping on spinel LiMn2O4: a first-principles investigation

The effect of the cation doping on the electronic structure of spinel LiMyMn2−yO4 (M=Cr, Mn, Fe, Co and Ni) has been calculated by first-principles. Our calculation shows that new M-3d bands emerge in the density of states compared with that in LiMn2O4. Simultaneously, the new O-2p bands appear accordingly in almost the same energy range around the Fermi energy owing to the M-3d/O-2p interaction. It is found that the appearance of new O-2p bands in the lower energy position results in a higher intercalation voltage. Consequently, the origin of higher intercalation voltage in LiMyMn2−yO4 can be ascribed to the lower O-2p level introduced by the doping cation M.