A Model for the Porous Direct Methanol Fuel Cells Anode

The influence of the porous structure on the direct methanol fuel cells (DMFC) anode was studied with a model and experimentally. An agglomerate model of the electrode is used and kinetic equations based on the reaction mechanism for the electrochemical oxidation of methanol are derived. A fuel cell is used for experimental validation of the model. The model shows that mass transport limitations in the agglomerates are small and that the anode model can be simplified. However, the mass transport limitations in the liquid phase are of importance at lower methanol concentrations. Experiments studying methanol oxidation at very low current show that electrochemical oxidation of methanol starts at a certain onset-potential and does not follow a simple Butler-Volmer relationship. © 2002 The Electrochemical Society. All rights reserved.