Microscale Tomography Investigations of Heterogeneous Porosity Distributions of PEMFC GDLs

A first comparison is made of the heterogeneous porosity distributions of various polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layer (GDL) materials. Microscale computed tomography imaging is performed for three main categories of commercially available GDL materials: carbon fiber paper, felt, and cloth. The methodology to analyze the through-plane and in-plane porosities of various materials is presented, and the relationship between heterogeneous porosity distributions and manufacturing techniques is discussed. This work also provides insight into the manufacturing process employed for GDLs.