A cell composed of a chlorine oxy-ion salt, acting as the battery positive, and anodes of magnesium or aluminum was found to be capable of producing potentials and currents comparable to those of conventional batteries. However, its use would have to be limited to that of a reserve type of battery with a short service-life because of the chemical interaction of the anodes with the electrolyte. This rate of reaction was considerably reduced by the presence of nitrate ion in the electrolyte. The rate of decomposition of hypochlorite solutions on aging was found not to be significant for their use in a reserve type of battery. The utilization of the reactants in the magnesium-chlorine oxy-ion cells was about 60% on a continuous discharge. Since these cells after being discharged would contain only a solution of common salt and a slurry of a metal hydroxide, they were innocuous with respect to the environment. Since this characteristic might make the battery of possible interest for a "green" motor vehicle, a battery was evaluated with respect to the adaptations that would be necessary for such an application.