Investigating the Effect of Non-Uniform Microporous Layer Intrusion on Oxygen Transport in Dry and Partially Saturated Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

Pore network modelling was utilized to simulate the oxygen transport behavior and water saturation within stochastically generated gas diffusion layers (GDLs) at various liquid water inlet conditions. The oxygen diffusion coefficient in dry conditions was found to linearly decrease as a function of the MPL intrusion depth into the GDL. In partially saturated conditions, increasing MPL intrusion minimized the fluctuations in both oxygen diffusion coefficient and breakthrough saturation over the range of sparse inlet conditions (7% inlet face coverage) to flooded inlet conditions (80% inlet face coverage). Breakthrough saturation was highly dependent on MPL intrusion depth with flooded liquid water inlet conditions compared to sparse liquid water inlet conditions. This study suggests that when the GDL is invaded by liquid water through cracks in the MPL, preferential MPL configurations exist for improving oxygen transport and minimizing substrate saturation given particular inlet conditions.