Strategic Design of GDLs to Decouple Independent Gas and Water Transport in PEM Fuel Cells via Laser Ablation

This study presents a laser‐patterning strategy to optimize water management and enhance polymer electrolyte membrane fuel cell (PEMFC) performance by engineering the microporous layer (MPL) surface of gas diffusion layers (GDLs). By selectively introducing hydrophilic pathways onto inherently hydrophobic GDL surfaces, we achieved effective separation of water and gas transport paths without additional materials or complex multilayer processes. Our results demonstrate that hydrophilic paths aligned with the rib regions significantly outperform channel‐aligned patterns by facilitating efficient water discharge from reaction sites. This structural modification leads to substantial peak power density improvements of 23.8%, 43.2%, and 27.2% under relative humidity (RH) conditions of 40%, 60%, and 100%, respectively, compared to the conventional cell. These findings highlight laser ablation as an effective approach for overcoming mass transport limitations in high‐performance PEMFC systems.