Screening Anion Exchange Membranes for CO2 Electrolysis

In membrane electrode assembly (MEA) electrolyzers for the electrochemical CO 2 reduction reaction (CO 2 RR) using alkaline or neutral electrolytes, anion exchange membranes (AEMs) play a critical role in determining mass transfer, energy efficiency, and stability within the reaction system. In this study, we compared commercial AEMs from three brands─Piperion, Sustainion, and Fumasep─to identify the membrane that offers the best CO 2 RR performance. The primary differences in the effects of AEMs on the CO 2 RR are reflected in energy efficiency, Faradaic efficiency of products, and device stability. Among all the AEMs, Fumasep 3–50 provides the highest energy efficiency, attributed to the excellent conductivity of the organic monomers composing it. Meanwhile, Piperion A20 and Sustainion X-37 grade RT demonstrate superior Faradaic efficiency and cation barrier properties, thereby enabling long-term CO 2 RR operation. This work screens available commercial AEMs for CO 2 electrolysis and identifies the essential parameters for the CO 2 RR, providing valuable insights for the electrochemical CO 2 reduction field.