An electrolytic system 10 is provided with a gas fed cathode 12 in contact with an electrolyte 15 to which an additive of trifluoremethane sulphonic acid (TFMSA) is added. The system can be employed in fuel cells, industrial electrolytic cells for production of gases such as chlorine, and in metal-air batteries. Preferably the cathode incorporates a catalyst such as gold, platinum, palladium, silver, or spinels of Ni and Co. The supply of fluid 18 to the anode of the fuel cell is a hydrocarbon or H 2 dissolved in NaOH. Oxygen or air is supplied 11, 12 to the cathode of the fuel cell. In the industrial electrolytic cell, the anodic source of fluid and electrolyte is brine solution, and the cathodic electrolyte is dilute caustic. In the metal-air battery, an anodic solution of NaOH is supplied to an anode of Al, Ga, Zn, etc. The cathodic solution and configuration are the same as with the fuel cell.