A study of anode degradation under fuel starvation in polymer electrolyte membrane fuel cells using the EIS and distribution of relaxation time analysis

Abstract

In this study, we investigate the anode degradation under fuel starvation conditions in proton exchange membrane fuel cells (PEMFCs) via single-cell experiments using electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis. The cell voltage reversal is caused by insufficient hydrogen supply in PEMFCs under fuel starvation, accompanied by a high potential strike (over 1.5 V vs. RHE) resulting in significant anode degradation due to carbon corrosion. To simulate the anode degradation under fuel starvation, the cell voltage reversal tests (CRTs) were performed on a PEMFC single cell: the anode/cathode gas channel was purged with N2/Air, negative cell voltage (-1.0 V vs. RHE) was applied. In particular, during CRTs, H2 was purged in the cathode for in-situ analysis of the anode CL degradation, followed by electrochemical analysis and EIS. As a result, degradation and structural deformation of anode catalyst layer carbon support was confirmed by the change of anode ECSA, resistances, thickness, and D band intensity on Raman spectra after CRTs. In addition, the anode degradation appeared as a semicircle in the high-frequency region of the EIS data, and we used DRT to convert the semicircle of the EIS data to the anode resistance peak to identify the anode degradation.