US Patent 8003250 High energy and power density electrochemical cells

The energy density of the entire cell may be improved while retaining high power density by use of an alkali metal transition metal polyanion compound as the cathode and a thin film metal or metalloid anode. The thin film anode may be initially unalloyed or partially unalloyed. During use, the thin film anode may be only partially unalloyed relative to the theoretical maximum. The high volumetric capacity of the metal anode makes it possible to use a dense or porous thin film anode in conjunction with a relatively thin particle-based cathode to thereby improve the energy density of the cell.