Integrated flow field–porous transport layers for mass and thermal management in high-current-density PEM water electrolysis

Under high-current-density operation, the anode of a proton exchange membrane water electrolyzer (PEMWE) faces interfacial contact resistance, constrained gas–liquid transport, and inadequate thermal management. Two integrated flow field–porous transport layer (FFPTL) architectures are proposed: an axially modulated hexagonal prism architecture (AMHP-FFPTL) and a fine three-dimensional mesh architecture (F3DM-FFPTL). Designs are fabricated via metal additive manufacturing. A three-dimensional, non-isothermal, two-phase multiphysics model and single-cell polarization, impedance, and surface-temperature measurements are used to compare their performance with a conventional parallel-flow-field and separate-PTL baseline. The integrated FFPTL architectures eliminate the FF/PTL contact interface, reducing interface-related ohmic losses and modifying liquid-water supply and oxygen transport. At 4.0 A cm −2 , the pressure drops decrease by 46.95% and 39.91% for AMHP-FFPTL and F3DM-FFPTL, respectively, relative to the baseline. AMHP-FFPTL exhibits the lowest pressure drop and the most uniform liquid-water saturation, temperature, and current density distributions, whereas F3DM-FFPTL provides the most uniform in-plane oxygen distribution. Measurements support cell-level performance trends, while internal transport fields remain model predictions. Multi-objective and weight-sensitivity analyses identify trade-offs within the sampled designs. Under the single-cell conditions, the power-saving benefit is dominated by reduced cell voltage, with lower pumping demand providing a contribution.