Electrochemical assessment of contact pressure effects on durability of high-temperature proton exchange membrane fuel cells under dynamic operation

This study examines the impact of nominal contact pressure on the electrochemical performance and degradation behaviour of high-temperature proton exchange membrane fuel cells (HT-PEMFCs) with pre-doped polybenzimidazole (p-PBI) membranes, focusing primarily on start-stop cycling durability. Three nominal contact pressures—0.30 MPa, 0.55 MPa, and 0.85 MPa—were applied during 70-cycle start-stop tests. Performance evolution was assessed using polarization curves, electrochemical impedance spectroscopy (EIS), distribution of relaxation times (DRT), and spatial current density mapping.