Characterization of Transport Properties in Porous Media of a PEM Fuel Cell

Porous media is an essential part of polymer electrolyte membrane fuel cells (PEMFC). In order to optimize fuel cell performance and reduce catalyst consumption, mass transport in fuel cells needs to be improved. Understanding and modelling of mass transport in porous media of fuel cell (e.g. gas diffusion layer (GDL), micro porous layer (MPL) etc.) requires a knowledge of transport properties like diffusivity, permeability and Knudsen diffusivity. Current research is focused on experimental measurement of transport properties of porous media. A counter-diffusion bridge (Wicke-Kallenbach setup) has been used to estimate permeability, Knudsen diffusivity and effective diffusivity of GDLs and MPLs. The obtained transport properties are used with the recent theoretical models of multicomponent mass transport to estimate transport in fuel cells. The experimental studies show that conventional effective approximations like Bruggeman correlations are highly overpredicting and do not fully account for all the frictional forces in porous media.