High-voltage spinel LiMn 1.5 Ni 0.5 O 4 (LMNO) is a promising cobalt-free cathode material which can deliver high energy density (650 W h kg -1 ) due to its high operating voltage ∼4.7 V (vs Li + /Li) arising from the Ni 2+ /Ni 4+ couple. As an important derivative of the extensively studied LiMn 2 O 4 mixed-valence spinel (LMO), LMNO has structural and chemical similarities with LMO. In both structures Li + occupy tetrahedral (T d ) sites, and the transition metals (TM) occupy octahedral (O h ) sites of the cubic close-packed oxygen arrays.