Degradation in Anion Exchange Membrane Water Electrolysis: Insights from a Distribution of Relaxation Times Approach

Anion exchange membrane water electrolysis (AEMWE) is a promising method for hydrogen production, offering advantages over state-of-the-art technologies such as alkaline water electrolysis and proton exchange membrane water electrolysis. This study investigates degradation mechanisms in AEMWEs through extended electrochemical testing at varying temperatures. Using time-resolved electrochemical impedance spectroscopy and distribution of relaxation times (DRT) analysis, we observe both reversible and irreversible degradation processes. DRT analysis reveals distinct polarization losses, with a notable reversible degradation peak suggesting catalyst deactivation. Scanning electron microscopy shows significant damage to the anodic catalyst layer, including delamination and catalyst redeposition. Moreover, this study highlights the importance of incorporating leakage current testing to accurately assess membrane failure and emphasizes the need for standardized diagnostic methods and long-term testing protocols. The findings enhance understanding of the electrochemical processes in AEMWE, offering pathways to improve stability and efficiency.