In-situ characterization of Nafion®115 and Aquivion based MEAs behavior under High-Temperature PEM Electrolysis

Standard Proton Exchange Membrane Water Electrolyzers (PEMWE) typically contain a Perfluorosulfonic Acid (PFSA) membrane at the core of a Membrane Electrode Assembly (MEA). To ensure the durability and longevity of the materials, standard PEMWE typically operate between 60°C and 80°C. Operating PEMWE beyond 80°C is interesting because high temperatures improve the proton conductivity of the membrane and the reaction kinetics, thereby reducing ohmic and activation losses. Moreover, this simplifies notably the balance of plant because there is a true difficulty to cool high power low temperature electrolysers, particularly in hot areas. However, the literature reports that operating PEMWEs at temperatures higher than the membrane's glass transition temperature promotes membrane deformation and decomposition, resulting in the increase of the gas crossover across the membrane, the dissolution and detachment of the catalyst layer and the release of fluoride acid from the membrane [X]. In order for PEMWE to operate at high temperatures, new materials are needed and must be evaluated. In this work, we present a new temperature ramp method, ranging from 60 to 150 °C, capable of detecting short term materials degradations. For that, successive heating and cooling cycles were applied, and performance evolution was monitored using various electrochemical methods, including polarization curves, Electrochemical Impedance Spectroscopy (EIS), and chronoamperometry. As our method was developed and refined using the Nafion ® and Aquivion ® membranes, the results can be explained based on the literature and by cross-referencing all our experimental data.