The application of a new series of layered first row transition metal oxides as cathodes in lithium ion cells is demonstrated. The cathodes were made from a quaternary oxide of lithium, chromium, and manganese belonging to the compositional series Li x Cr y Mn2−y O4+z with x>2.2, 0<y<2 and z≥0. The layered structure is stabilized by the partial substitution of the manganese by chromium and lithium atoms and by the partial or complete oxidation of the manganese to the +4 oxidation state.