LiCuxIICuyIIIMn[2-(x+y)]III,IVO4 : 5 V cathode materials

A series of LiCu xII Cu y III Mn [2-(x+y)] III,IV O 4 spinels was prepared by solid-state methods. Powder x-ray diffraction analysis proved that the LiCu x II Cu y III Mn [2-(x+y)] III,IV O 4 family assumes cubic spinel structures with a unit cell parameter slightly smaller than that of LiMn 2 O 4 . Cyclic voltammetry and chronopotentiostatic techniques revealed that these materials exhibited two discharge regimes, at 4.1 and 4.9 V vs. the Li/Li + couple. The discharge capacity of LiCu x II Cu III (0.5-x) III Mn 1.5 III,IV O 4 was 71 mAh/g (97% of theoretical), with surprisingly good stability on cycling.