Flow field architecture strongly influenced mass transport and water management in polymer electrolyte membrane fuel cells. Metal foam-based flow field improved reactant distribution and reduced flooding but were limited by localized weak-flow regions and pressure drop. In this study, a hybrid metal-foam/serpentine flow field was developed to enhance fuel cell performance. The performance of 25 cm² unit cell was evaluated using polarization curves and electrochemical impedance spectroscopy under pressurized conditions. Impedance-based resistance decomposition was employed to decouple ohmic, charge transfer, and mass transport contributions to cell performance for different flow fields. The hybrid metal foam flow field reduced mass transport resistance by 75% (from 981 to 246 mΩ cm² at 2.0 A cm⁻²) and achieved a peak power density of 0.971 W cm⁻², representing a 26% improvement compared with the metal foam flow field. These results indicated that combining directional convection through serpentine channels with multidirectional diffusion in metal foam improved reactant transport and mitigated concentration loss under high-load operation.
Kim et al. (Wed,) studied this question.