Cathodic activation of gas diffusion electrodes

Claim 1

The method of claim 1 wherein the carbonaceous material is selected from the group consisting of carbon, graphite, boron carbide and mixtures thereof, the catalyst is selected from the group consisting of at least one of the metals of iridium, ruthenium, rhodium, palladium, platinum, gold, silver and titanium and characterized by reducing the gas rate for a period of time between 2 and 60 minutes.

Claim 3

A method of operating a metal-gas battery having an anode, an electrolyte, and a cathode; said anode comprising an oxidizable metal selected from the group consisting of iron, cadmium, and zinc, said cathode being a gas diffusion electrode comprising a coherent porous body containing an electrical conductor, particles of conducting material selected from the group consisting of carbon, graphite, boron carbide and mixtures thereof, a halogenated hydrocarbon binder inert to the electrolyte and a catalyst, and having a gas entrance side wherein a gas selected from the group consisting of air and O2 is fed into the gas diffusion electrode with electrolyte permeating the opposite side, said cell being used for causing current to flow externally through a load circuit connecting the anode and cathode; the method characterized by making the potential of the gas diffusion electrode more cathodic than at the normal operating range by reducing the rate of gas fed into the gas diffusion electrode to less than 5 cu. cm. per min. but greater than 0.01 cu. cm. per min. for each sq. cm. of exposed gas diffusion electrode area at least once for a period of time greater than about two minutes, said reduction of gas decreasing the cathodic potential to a value below +0.6 volts as measured against a reversible hydrogen reference electrode in the same electrolyte.