Understanding the behaviour of low equivalent weight Aquivion® ionomers for enhanced proton exchange membrane water electrolysis

Given the importance of developing highly efficient and stable membranes for PEM electrolysis, this study aims to compare different Aquivion® short side chains membranes in terms of performance and durability. The membranes examined include bare cast polymers, cast polymers containing a radical scavenger and reinforced polymeric films. These membranes were used to prepare membrane-electrode assemblies (MEAs) for hydrogen production that were subjected to polarization tests, electrochemical impedance spectroscopy, and durability tests over 2000 h. In addition, diagnostic techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and optical microscopic imaging were performed to understand membranes and ionomer dispersion characteristics in MEAs and their role on performance and durability. By analysing the efficiency and stability of Aquivion® systems in different configurations, this study seeks to determine the most appropriate strategies for improving polymer electrolytes used in PEM water electrolysis for green hydrogen production. • Performance of 5 A cm −2 at 1.87 V achieved for reinforced Aquivion® membranes. • Scavenger-based Aquivion® membranes allow achieving improved stability. • Voltage efficiency of ∼79 % at 5 A cm −2 achieved with Aquivion® -based membranes. • No reinforced membrane thinning observed after 2000 h operation at 5 A cm −2 . • Series resistance has a major impact on performance at high current densities.