Screening Anion Exchange Membranes for CO2 Electrolysis

In membrane electrode assembly (MEA) electrolyzers for the electrochemical CO₂ reduction reaction (CO₂RR) 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 CO₂RR performance. The primary differences in the effects of AEMs on the CO₂RR 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 CO₂RR operation. This work screens available commercial AEMs for CO₂ electrolysis and identifies the essential parameters for the CO₂RR, providing valuable insights for the electrochemical CO₂ reduction field.