Imidazolium‐Functionalized Fluorene‐Based Anion Exchange Membrane (AEM) for Fuel Cell Applications

Abstract After a fluorene‐based anion exchange membrane (AEM) containing 1‐isopropyl‐2‐methylimidazolium with alkyl side chains was prepared, the membrane properties, including OH – conductivities, ion exchange capacity (IEC), water uptake, swelling ratio, and chemical and thermal stabilities of the obtained membrane were assessed. The synthesized membrane exhibited low water uptake and good dimensional stability with adequate hydroxide conductivity. For example, the AEM showed a swelling ratio of 7% and hydroxide conductivity of 46 mS cm −1 at 80 °C in liquid water. The chemical stability was investigated in 1 M NaOH solution at room temperature and at 80 °C. At both temperatures, degradation of the imidazolium cationic groups was observed, although the main chain was chemically stable. All results obtained from this research are expected to provide important direction and insight for AEM synthesis for practical applications in anion exchange membrane fuel cells.