US Patent 7598002 Enhanced electrochemical cells with solid-electrolyte interphase promoters

An electrochemical cell with an alkali metal containing anode having high discharge capacity, charge efficiency and low self-discharge. The addition of at least one nitramide or dinitramide salt of a metal cation to the electrochemical cell electrolyte unexpectedly lowers first cycle irreversible capacity, adds higher cycle life, lowers self-discharge and beneficially addresses several additional degrees of freedom with respect to electrolyte solvent selection while providing higher charge capacity. Additives include the lithium metal salts of nitramide or dinitramide, and the electrolyte consists essentially of a lithium metal salt dissolved in a at least one of an aqueous solvent, molten salt solvent system and a non-aqueous solvent mixture of at least one of organic ethers, esters, carbonates, acetals.