Oxidation in the Fuel Cell

Abstract

Although not a process of combustion in the accepted sense of oxidation accompanied by heat and light, stoichiometric oxidation forms the basis of direct conversion from chemical to electrical energy by means of the fuel cell. In contrast to primary and secondary cells, fuel and oxidant are supplied continuously during operation rather than being stored within the cell itself; consequently the electrodes are not consumed. Furthermore, the fuel and oxidant do not meet as such, as is the case in combustion, but are permitted to react only through the intermediary of some form of ionised molecule. Consequently the two electrodes are separated by an electrolyte, which must be a good conductor for ions, but an insulator for electrons which are required to be stripped from the reactants and to flow through an external circuit to do work (figure 20).