Local degradation in proton exchange membrane fuel cells with dead-ended anode

Abstract

The dead-ended anode (DEA) configuration can simplify proton exchange membrane fuel cell (PEMFC) systems and reduce system cost. However, the DEA configuration can also accelerate fuel cell degradation during long-term operations. Understanding the degradation mechanisms is crucial to improve fuel cell durability. In this study, experiments are performed to investigate the local degradation phenomena in PEMFCs during DEA operations. The detailed degradation mechanisms are revealed through various electrochemical analysis. The local polarization curves show that the local fuel cell performance decreases are very non-uniform and the inlet area suffers the most severe performance decrease. Electrochemical measurements indicate that the most serious carbon corrosion in catalyst layer occurs near the anode outlet. However, the most severe local membrane degradation is observed near the anode inlet. Furthermore, we observe that the pressure swing anode supply mode can significantly mitigate fuel cell degradation during DEA operation. The water and gas distributions in the anode are much more uniform with the periodical oscillatory flow under pressure swing mode, reducing local membrane dehydration and avoiding local hydrogen starvation. Thus, both the local membrane degradation and local carbon corrosion are significantly mitigated under the pressure swing mode.