Fuel cells are electrochemical devices that convert the energy of a fuel (such as hydrogen, natural gas or other hydrocarbon-based fuels) directly into electricity. All fuel cells consist of an electrolyte layer in contact with an anode and a cathode on either side. The oxidation reaction occurs on the anode side of the fuel cell, while reduction takes place on the cathode. Single fuel cells are usually connected either in series, or in parallel, to form a stack, which is capable of producing s- eral watts to many kW of power, depending on the requirements. The fuel cell stack requires a...