IntroductionAssembly pressure and porous flow-field architecture influence proton exchange membrane fuel cell (PEMFC) performance through interfacial contact, reactant transport, water management and membrane integrity. This study evaluates membrane-electrode assembly (MEA)/catalyst-coated membrane (CCM) compression and nickel-foam interface effects using complementary experimental and computational evidence.MethodsA 4 cm2 single-cell PEMFC was tested at a nominal temperature of 80 °C using relative-humidity-dependent polarisation measurements, electrochemical impedance spectroscopy (EIS), compression-ratio measurements, direct foam-contact damage observations and scanning electron microscopy pore characterisation. ANSYS Fluent simulations screened metal-foam porosity from ε = 0.5 to 0.9, with the principal comparison between ε = 0.6 and ε = 0.9, together with convergence and mesh screening.ResultsControlled compression produced an approximately 19.5% performance improvement under the tested condition, whereas direct unprotected foam contact caused membrane-damage and crossover risk. At 0.5 V, the CFD model predicted that reducing porosity from ε = 0.9 to ε = 0.6 increased current density from 1.4660 to 1.7420 A cm−2, an approximately 18.8% increase, and increased power density from 0.733 to 0.871 W cm−2. EIS measurements supported humidity- and compression-dependent changes in ohmic and transport behaviour.DiscussionCompression and foam porosity should be treated as coupled electrochemical, transport and mechanical design variables. Nickel-foam flow fields require controlled gasket height, compression strain, surface protection and direct CFD-to-experiment validation before performance claims are extended to stack-level operation.