Identification of Degradation Reasons for a CO 2 MEA Electrolyzer Using the Distribution of Relaxation Times Analysis.

The application of membrane electrode assembly (MEA) in electrocatalytic CO 2 reduction (ECO 2 R) technology is an essential step toward industrialization. Nevertheless, the issue of ECO 2 R failure in MEA during extended operation hinders its industrial application. In this work, we employed in situ, nondestructive electrochemical impedance spectroscopy (EIS) techniques combined with distribution of relaxation times (DRT) methodology to diagnose the causes of the failure. By systematically investigating the variations in polarization resistance throughout the degradation process and utilizing a controlled variable approach to identify the origin of polarization, we diagnosed the degeneration of ionomers as the primary cause of the performance degradation of ECO 2 R in this instance. We further confirmed the reliability of our findings through material characterization and respraying ionomers onto the catalyst surface. This research provides an effective diagnostic method for the failure analysis of ECO 2 R performance in MEA, which is crucial for advancing industrialization of ECO 2 R technology.