ABSTRACT

Anion exchange membrane (AEM) electrolysis is one of the most promising water electrolysis technologies, combining the advantages of proton exchange membrane (PEM) electrolysis, such as high gas purity, high current densities and dynamic operation, while using cheap transition metal electrocatalysts known from alkaline water electrolysis (AWE). AEM water electrolysis (AEMWE), when operated liquid (electrolyte or water) free (dry) at the cathode side, offers simplified water management, reducing the balance-of-plant. Numerous factors, such as cell design, membrane properties, flow rate of electrolyte and operation parameters, directly or indirectly, impact the performance of AEMWE, which becomes even more vital when the cathode compartment is operated liquid free. Herein, this work presents a comprehensive overview of several factors involved in the performance of a dry cathode AEMWE. Advancements and challenges in membrane materials, asymmetric electrolyte feeds and operating parameters were analysed. Finally, to have a durable and efficient AEMWE, this article discusses current development on the dry cathode AEMWE technology and outlines prospective avenues for further improving the system.