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Anion exchange membrane (AEM) electrolysis is a promising solution for large-scale hydrogen production from renewable energy resources. However, the performance of AEM electrolysis is still lower than what can be achieved with conventional technologies. The performance of AEM electrolysis is limited by integral components of the membrane electrode assembly and the reaction kinetics, which can be measured by ohmic and charge transfer resistances. We here investigate and then quantify the contributions of the ohmic and charge transfer resistances, and the rate-determining steps, involved in AEM electrolysis by using electrochemical impedance spectroscopy analysis. The factors that have an effect on the performance, such as voltage, flow rate, temperature and concentration, were studied at 1.5 and 1.9 V. Increased voltage, flow rate, temperature and concentration of the electrolyte strongly enhanced the anodic activity. We observed that here the anodic reaction offered a greater contribution to the overpotential than the cathode did.

A new ultrathin anion exchange membrane (AEM) is proposed for low cost AEM electrolysis. The advantages that thin membranes offer include reduced mass transport resistance and ohmic resistance. A membrane electrode assembly (MEA) with a thinner membrane will have improved hydroxide ion transfer due to the shorter ion transfer pathway. We fabricated a MEA with a commercially available ultrathin A-901 membrane (9 m thick) and non-noble metal catalysts. We determined the efficiency and stability of this ultrathin membrane using electrochemical impedance spectroscopy. The best performance recorded was 400 mA cm-2 at 1.94 V at 50 C. Over a period of 200 h, the voltage increase was only 200 V h-1 , which is <60% that of the more commonly used A-201 membrane. The ultrathin A-901 membrane exhibited slightly higher performance compared to the A-201 for a given catalyst, catalyst loading, and electrolyte concentration. Acta 3030 ® (CuCoO x) and Acta 4030 ® (Ni/(CeO 2-La 2 O 3)/C) were employed as the oxygen evolution reaction and hydrogen evolution reaction catalysts, respectively.

Anion exchange membrane (AEM) electrolysis eradicates platinum group metal electrocatalysts and diaphragms and is used in conventional proton exchange membrane (PEM) electrolysis and alkaline electrolysis.