TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Function: The membrane passes hydrogen gas preferentially over other gases (i.e., water, carbon dioxide and oxygen).Preferred Component: The membrane further comprises:(a) a catalytic layer and a dispersive layer, or a catalytic surface on both sides of the membrane that acts as a gas recombination mechanism of gases evolved from within the battery case;(b) electrolytes in contact with selective permeable films for electrochemical catalysis of hydrogen or oxygen or catalytic promotion of hydrogen oxygen recombination;(c) a diffusion layer for limiting recombination to a surface of catalysts or rate of recombination;(d) a non-selective gas permeable coating and hydrogen selectively permeable coating coated over a non-selective gas permeable coating (2);(e) diffusion gas mats placed on the membrane;(f) a seal for sealing the membrane of the battery case and for diffusing gas through the perforation in the battery case; and(g) a pressure relief valve or burst foil.The membrane is formed by:(a) coating and plugging pores of a porous substrate with selectively permeable materials;(b) coating a porous substrate with selectively hydrogen permeable materials; or(c) coating a porous substrate with vacuum deposited selectively permeable materials.Preferred Substrate: The substrate comprises porous semiconductors.    TECHNOLOGY FOCUS - CERAMICS AND GLASS - Preferred Substrate: The substrate can also comprise porous plastics, porous glasses or porous ceramics.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The catalytic surface comprises catalysts metals (a) from the transition metal elements comprising platinum, palladium, nickel, copper, silver, chromium, molybdenum, tungsten, cobalt, iron, ruthenium, titanium, zirconium, vanadium, niobium and/or tantalum; or (b) alloyed with elements i.e., carbon, silicon and tin for acting as a gas recombination mechanism of the gases hydrogen and oxygen evolved from within the battery case.Preferred Substrate: The substrate can also comprise porous metals.Preferred Material: The hydrogen permeable materials comprise transition metals or transition metal compounds or alloys. The vacuum deposited selectively permeable materials comprise platinum, palladium and its alloys, palladium/silver alloy, palladium/copper alloy, titanium/nickel alloy, AB2 (e.g., zirconium manganate) or AB5 (e.g., lanthanum nickelite) coatings, lanthanum, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, ruthenium or cobalt.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The membrane further comprises a gas permeable coating of silicone rubber, polyvinyl chloride, polyethylene, fluorosilicone, nitrile silicone, natural rubber, polytetrafluoroethylene, polymer electrolytes or perfluorosulfonic acid.Preferred Substrate: The substrate can also comprise etched nuclear particle track dielectric films of polycarbonate plastic, polyester, polyimide, polypropylene, porous polyethylene, or porous polyethersulfone.