Abstract: In a reactive metal-water electrochemical cell, an alkaline electrolyte containing soluble inorganic ions which are reduced preferentially to water at the cathode. More particularly, the additives substantially reduce or eliminate reduction of water and evolution of hydrogen at the cathode resulting in significant improvement in current efficiency, gravimetric energy density and cell potential at a given current. Additionally, suppression of hydrogen evolution makes possible a sealed system with venting of gases from the cell no longer necessary. The inorganic ions of the invention are nitrite, hypochlorite, chlorate, bromate, dinitrogen trioxide and sulfite ions which are formed when soluble salts of nitrite, sulfite, hypochlorate, bromate, chlorate, soluble gases such as dinitrogen trioxide and sulfur dioxide and other soluble inorganic compounds are dissolved in the alkaline electrolyte.