Identification of Degradation Reasons for a CO₂ MEA Electrolyzer Using the Distribution of Relaxation Times Analysis

The application of membrane electrode assembly (MEA) in electrocatalytic CO₂ reduction (ECO₂R) technology is an essential step toward industrialization. Nevertheless, the issue of ECO₂R 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 ECO₂R 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 ECO₂R performance in MEA, which is crucial for advancing industrialization of ECO₂R technology.