A computational study of the high voltage LixCoyMn4−yO8 cathode material

Abstract

We present a theoretical investigation of a family of promising cathode materials, the spinel phases Li_xCo_yMn_4−yO₈ where 0⩽x⩽2 and 0⩽y⩽4. A combination of atomistic static lattice simulations and high quality electronic structure calculations has been used to investigate the effects of cation ordering, the structural changes during lithium insertion and the unusually high cell voltages that have been measured in these materials. An analysis of the calculated electronic structures indicates that the generation of discharge voltages over 5 V is linked to the reduction of cobalt atoms in the structure. The involvement of oxygen p states is also a possibility.