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 LixCryMn2-yO4+z with x > 2.2, 0 < y < 2 and z greater than or equal to 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. Crown Copyright