Alkaline direct alcohol fuel cells

Direct alcohol fuel cells can offer very high energy densities and therefore are most suitable to replace or compliment batteries for portable power supply or back-up power solutions. Products available today use methanol as fuel and proton exchange membrane based fuel cell technology. This hampers the introduction of larger systems as the use of larger amounts of platinum based catalysts renders them expensive. Changing to an alkaline electrochemistry may help to avoid this problem by allowing for the use of less expensive catalyst metals. Also other fuels might become useable. In this paper development of materials for alkaline direct alcohol fuel cells using methanol or ethylene glycol as possible fuels are reported. With respect to the anode reaction different PdM/C catalysts with M = Ag,Ni were synthesized and characterised for the methanol and ethylene glycol oxidation. It was found that all catalysts achieve high performance with both alcohols. For the cathode side MnO2was investigated as platinum group metal free catalysts. It was found that in presence of crossed-over alcohol the performance becomes comparable to that of platinum. Finally concepts for ionomeric binders will be introduced which will allow for later operation of the cell without added bases.