Electro-oxidation of dimethyl ether in a polymer-electrolyte-membrane fuelcell

The possibility of using dimethyl ether (DME) as a fuel in direct oxidation polymer-electrolyte-membrane (PEM) fuel cells is investigated. A mechanism for DME electro-oxidation is proposed based on the results of half-cell ex periments using cyclic voltammetry combined with gas-chromatographic (GC) a nalyses of a single direct DME fuel cell. It is shown that, as a consequenc e of this mechanism, there is an additional overpotential at the anode of a direct DME fuel cell which is related to the initial adsorption step on th e catalyst surface. DME is typically not oxidized at the cathode of a PEM f uel cell. This minimizes unwanted effects of fuel crossover, leading to imp roved fuel-cell efficiencies compared to direct methanol fuel cells, especi ally at low-to-medium current densities. (C) 2000 The Electrochemical Socie ty. S0013-4651(00)121-9. All rights reserved.