Heterogeneous Through-Plane Distributions of Tortuosity, Effective Diffusivity, and Permeability for PEMFC GDLs

In this work, we applied the Tomadakis and Sotirchos transport model to heterogeneous porosity distributions measured from high resolution microscale computed tomography visualizations of polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layers (GDLs). We calculated the corresponding local distributions of tortuosity (tau), relative diffusivity [f(epsilon)], and single phase permeability (K). The heterogeneous distributions of relative diffusivity and permeability strongly correspond to the measured heterogeneous porosity distributions, exhibiting transitional surface and core regions. Reasonable agreement was found between the average properties of the GDL core region with bulk values from literature. This work provides insight into the heterogeneity of important properties, which should be considered when modeling transport phenomena in the PEMFC GDL. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3524284] All rights reserved.