| abstract |
A method of operating a fuel cell at an operating temperature below about 150 degrees Celsius, wherein the fuel cell has an anode and a cathode with an electrolyte interposed therebetween, the cathode having at least one surface in contact with a cathode chamber having a gas inlet and a gas outlet, and the anode in contact with an anode chamber having a gas inlet and a gas outlet, and the electrolyte containing less than about 500 ppm of a catalyst capable of enhancing the formation of radicals from hydrogen peroxide. The method includes the steps of applying a fuel to the anode chamber; applying an oxidant to the cathode chamber; and controlling the amount of water supplied to the anode chamber and the cathode chamber such that water vapor pressure is sub-saturated at the operating temperature at the gas outlet of the cathode chamber. Also disclosed is an apparatus comprising sensors to measure outlet relative humidity of the gas outlets of a fuel cell and a means to control the relative humidity on the gas inlets of a fuel cell, such that the apparatus can control the relative humidity of the gas inlets to maintain an average relative humidity in the fuel cell of less than 100%. |