Abstract: A fuel cell is operated at a temperature which is not greater than substantially 250.degree. C., has an electrolyte which can be a solid polymer electrolyte, a liquid phosphoric acid electrolyte, or a liquid alkaline electrolyte, and a cathode and an anode each comprising a platinum catalyst. Hydrogen fuel gas is supplied to the anode and a gaseous oxidant, for example oxygen is supplied to the cathode. The cathode and anode are both connected to first and second circuits in parallel. The first circuit includes a load to be powered by the fuel cell and a first switch. The second circuit includes a battery and a second switch. The switches are operated by a control. When the first swtich is closed the cell powers the load and the second switch is open. When the first switch is open the second switch is closed so the battery applies a reverse D.C. potential the anode and cathode.