Impacts of cathode catalyst layer defects on performance and durability in PEM fuel cells

Abstract

During the manufacturing of proton exchange membrane fuel cells (PEMFCs), the cathode catalyst layer (CCL) may contain regions of partially missing material due to deficient deposition or unintentional removal. The present research objective is to understand how larger (4.0, 5.9, and 8.5%) CCL missing areas may affect the performance and durability of PEMFCs. Three different CCL missing area samples are prepared and compared to defect-free CCL baselines in this work. The results show that such CCL missing areas reduce the performance of the defective fuel cell in all regions of the polarization curve, compared to defect-free cells. At low current densities, these performance voltage reductions are linear with the current density rise, followed by an exponential reduction at high current densities. The linear slope and onset of exponential voltage reduction are related to the investigated CCL missing area. However, no significant difference in the electrochemical surface area is observed. Additionally, chemical/mechanical and electrochemical cycling tests show no significant variance in the degradation between the baseline and CCL missing area samples, indicating that CCL missing areas do not significantly influence membrane or cathode durability.