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

A series of (LiCuxCuyMn[2-(x+y)-Cu-II-Mn-II])O-III,IV(4) spinels was prepared by solid-state methods. Powder x-ray diffraction analysis proved that the (LiCuxCuyMn[2-(x+y)-Cu-II-Mn-II])O-III,IV(4) family assumes cubic spinel structures with a unit cell parameter slightly smaller than that of LiMn2O4. 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 (LiCuxCu(0.5-x)-Cu-II)(Mn1.5O4)-Mn-III-O-III,IV was 71 mAh/g (97% of theoretical), with surprisingly good stability on cycling.