Simplified model for the direct methanol fuel cell anode

Abstract

A kinetic model for the anode of the direct methanol fuel cell (DMFC) is presented. The model is based on the generally accepted dual site mechanism of methanol oxidation, in aqueous solution, on well characterized Pt–Ru catalyst and it can predict the performance of the electrode as a function of cell temperature, anode potential and methanol concentration. In addition the model also generates data regarding the surface coverage of significant adsorbates involved in methanol oxidation on the dual site catalyst. The analysis of the initial complex model confirms that a simplification in anode modelling can be made and some of the kinetic parameter can be reliably neglected. Based on this approach a fast and simplified three parameter model is derived from the same complex kinetic mechanism. The kinetic parameters of both models are estimated from experimental anode polarisation data from a 9 cm 2 DMFC operating with various methanol feed concentrations and temperatures. The models were developed in Lab VIEW and this has greatly simplified the simulation process, giving a model with ca. 85–95% fit on the experimental data. Depending on the computational speed available, and the desired complexity of problem at hand, either of the models can be used to give accurate model simulations for methanol fuel cell polarisations.