Aquivion® membranes with low equivalent weight for improved PEM water electrolysis

To achieve sustainable growth and mitigate the effects of climate changes, the transition from fossil fuels to cleaner energy sources is becoming important. The development of new energy vectors and their integration with renewable energy sources and the energy grid infrastructure, however, present challenging barriers. It is often acknowledged that creating more scalable and effective storage solutions is essential to a sustainable future. Green hydrogen, generated via electrolysis, offers significant advantages: high energy density, improved transport efficiency and diverse applications spanning energy conversion and numerous industrial processes. PEM (proton exchange membrane) electrolysis is a particularly advantageous technology for water splitting, achieving high current densities, superior efficiency, high-purity hydrogen production and rapid response. This study investigates the performance and durability of different Aquivion® short side chain membranes for PEM electrolysis, a crucial area for developing highly efficient and stable electrolyzers. The research compares bare cast polymers, radical scavenger-containing polymers, and reinforced films, evaluating their performance in MEAs (membrane-electrode assemblies) by means of polarization tests, EIS (electrochemical impedance spectroscopy), and long-term (2000 hour) durability tests. Further analysis using XRD, XRF, TEM, SEM, and optical microscopy clarifies membrane and ionomer dispersion characteristics within the MEAs and their impact on overall performance and durability. Using both reinforced and radical scavenger-based membranes, an outstanding electrolysis performance was obtained at 90°C with 1.87 V at 5 A cm-2. The voltage efficiency at 5 A cm-2 is around 79%. To decrease the final cost of green hydrogen and the amount of renewable energy used, high voltage efficiencies are required. High operational current densities, on the other hand, are basically associated with lower capital costs because of the increased output rate. This is necessary for PEM to minimize utilization of CRMs. Post-operation analyses have shown minimal changes in the catalytic layers and essentially no membrane thinning. All these evidence indicate promising durability perspectives for the modified membranes.