Beyond Catalysts and Membranes: Using Cell Assembly and Operating Strategies to Significantly Improve the Performance of AEM Electrolyzers

Green hydrogen, produced through water electrolysis, is a key enabler of a low-carbon energy future, and anion exchange membrane electrolyzers (AEMELs) have emerged as a promising technology due to their potential for ultra-low-cost operation. However, achieving low cell voltage at high current densities and maintaining long-term durability remain key AEMEL challenges. To address these issues, most research efforts to date have focused on developing advanced catalysts and membranes. In contrast, the influence of non-material factors, such as cell assembly parameters and operating conditions, remains underexplored, even though they can significantly impact performance. This study investigates how such variables affect AEMEL cell voltage and durability, using commercially available Aemion+® membranes and ionomers. Cell assembly parameters, including electrode pre-treatment, membrane thickness, cell hardware, and membrane–electrode assembly (MEA) compression, were evaluated alongside key operating conditions such as flow configuration and heating mode. These parameters are shown to have a significant influence on in-cell phenomena, including electrochemical reactions, water and gas transport, and thermal distribution, as well as critical in-cell properties such as electrode–membrane adhesion, interfacial resistance, electrical conductivity, porosity of the catalyst layer, and polymer swelling or shrinkage. A systematic investigation of these factors showed that their careful optimization can lead to substantial reductions in operating voltage, up to 360 mV at 1.0 A cm−2 , without any changes to the catalyst or membrane chemistry. These findings offer new insights into practical strategies for improving AEM electrolyzer performance and highlight the importance of considering engineering and operational design parameters alongside material innovations for commercial viability.