Only one article has been published which uses a high energy density metal in conduction with a molten salt and an oxide ion solid electrolyte . This battery uses aluminum as the storage medium at 800°C, and mixes cryolite into the electrode to lower the melting point of the oxide, as is done with commercial aluminum smelters. However, the resulting open circuit voltage of the cell was only half the theoretical, and the power densities were only ~30 mW/cm2.