Inverse Design and Porous Metal Printing of GDL-integrated Flow Field Plates for High-temperature Hydrogen Fuel Cells

High-temperature (HT) proton exchange membrane (PEM) fuel cells (FC) offer key advantages for sustainable transportation, especially in heavy-duty applications, due to their improved thermal efficiency and water management. This study introduces an inverse design framework to develop flow field plates integrated with a gas diffusion layer (GDL), enabling scalable electrochemical performance from the unit cell to the plate level. A reduced-order, homogenization-based multiphysics model is developed to evaluate designs with approximately 1000× faster computation. Flow channel orientation is optimized using a tensor field method and dehomogenized into manufacturable geometries. Optimized designs, validated through high-fidelity 3D simulations, show up to 12% higher average current density and 88% lower pressure drop compared to conventional parallel and mesh configurations. To address fabrication challenges, solid-to-porous metal additive manufacturing is employed, producing monolithic structures that integrate flow channels with a porous metal GDL. Both numerical and physical tests confirm high permeability and improved power output compared to carbon-based GDLs. These findings highlight the effectiveness of combining advanced computational modeling with metal 3D printing to enhance the performance and manufacturability of high-temperature PEMFC, supporting their broader adoption in sustainable energy applications.