This chapter provides a broad overview of fuel cells (FC) technology and an entry into the literature. United Technologies FC operations carried out much research in phosphoric acid technologies, which later found use in proton exchange membrane (PEM)-based FCs. The function of fuel cell is to take in a stream of fuel (e.g., hydrogen) and oxidant (e.g., oxygen in air) and harvest the current resulting from the electro- chemical “burning“ of the fuel, the direct conversion of chemical to electrical energy. The molten carbonate fuel cell and solid oxide fuel cell operates at high temperature, thus enabling the use of less active catalysts. Alkaline Fuel Cell (AFC) use an alkaline electrolyte to conduct current by hydroxide between anode and cathode. The AFC is the first practically developed FC and was initially utilized as a power plant for vehicles and spacecraft, decentralized power supply, and energy storage.
