Experimental and theoretical investigation of mass transport in porous media of a PEM fuel cell

Abstract

Porous media is an integral part of polymer electrolyte fuel cell (PEMFC) electrodes. In this study, an experimental setup is presented to investigate convective and diffusive mass transport in porous media of fuel cell electrodes. A new theoretical model was developed in order to correct for inconsistencies in current models. Based on the new model, a new data extraction technique was used to obtain permeability and Knudsen diffusivity of a porous media from steady state pure convection measurements. The model was also used to obtain effective diffusivity of porous media from mass transport experiments. Using the obtained transport properties, the models were used to predict mass transport in the electrodes under different operating conditions. Preliminary comparisons of experimental and theoretical predictions show that the new mass transport model is capable of predicting mass transport in the electrode accurately. The results concluded that the traditionally used Bruggeman correlation overpredicts the electrode effective diffusivity by as much as 3-4 times.