In general, the invention relates to electrode materials, e.g., novel cathode materials with high density, low cost, and high safety. A voltage design strategy based on the mixing of different transition metals in crystal structures known to be able to accommodate lithium in insertion and delithiation is presented herein. By mixing a metal active on the +2/+3 couple (e.g., Fe) with an element active on the +3/+5 or +3/+6 couples (e.g., V or Mo), high capacity multi-electron cathodes are designed in an adequate voltage window.
 This invention was made with government support under Contract No. DE-AC02-05CH11231 awarded by Office of Vehicle Technologies of the U.S. Department of Energy, under the Batteries for Advanced Transportation Technologies (BATT) Program Subcontract No. 6806960, and by the MRSEC Program of the National Science Foundation under award number DMR-0819762. The United States Government has certain rights in this invention.