Crack-Engineered Microporous Layer for Mitigating Cathode Flooding in Polymer Electrolyte Fuel Cells

Abstract

Crack engineering within the microporous layer (MPL) of the gas diffusion layer (GDL) has emerged as a promising strategy to alleviate severe cathode flooding in polymer electrolyte fuel cells (PEFCs), especially under high current operation. Here, we report a connected-crack MPL architecture that forms continuous liquid water highways, extending from the catalyst layer (CL) to the GDL backing layer, effectively separating the liquid/gas transport. Three-dimensional reconstruction using X-ray computed tomography reveals that the microengineered cracks significantly reduce flooding at the CL-MPL interface by providing efficient drainage. Compared to the noncrack GDL, the connected-crack GDL (C-GDL) exhibits 20% higher peak power density of 1.23 W cm-2. Pore-scale simulations further validate the antiflooding capabilities of C-GDL, showing a 25-fold enhancement in water removal. This crack-engineered GDL thus offers an efficient and scalable route to water management challenges, enabling robust and high-performance PEFCs suitable for heavy-duty vehicle electrification.