Abstract: A method of charging a metal-air or metal-oxygen electrochemical cell which serves to extend the useful life of the cell. Charging of the cell takes place with the addition of hydrogen to the air or oxygen cell which prevents the formation of oxygen and reduces the deterioration of the electrodes caused by oxidation. The conventional metal-air or metal-oxygen cell which is capable of injecting air or oxygen to the gas electrode during cell discharge is slightly modified to give it the ability to also inject hydrogen to the gas electrode during charging.

Abstract: A sealed rechargeable nickel-zinc or silver-zinc electrochemical cell including two compartments, one having a zinc electrode and a first hydrogen electrode and the other having a nickel or silver electrode and a second hydrogen electrode electrically connected to the first hydrogen electrode. The two compartments share a common gas space. During discharge the cell acts as a conventional nickel-zinc or silver-zinc electrochemical cell. During charging the gases evolved are immediately internally consumed, allowing the entire cell to be sealed. Furthermore, when the cell is fully charged there is a noticeable voltage jump which serves as a clear indication that the cell is fully charged and helps prevent overcharging and its detrimental effects.