High-Performance Anion Exchange Membranes with π-π Stacking and Hydrogen Bonding Bifunctional Units

Strong intermolecular interactions facilitate the formation of efficient ion transport channels, which, in turn, significantly boost the performance of anion exchange membranes (AEMs). Herein, 9-anthracene methanol with both π-π stacking and hydrogen bonding intermolecular forces is used as a bifunctional unit to synthesize high-performance AEMs through the Friedel-Crafts superacid catalytic reaction for the first time. The π-π stacking in the bifunctional units can induce hydrophilic pyridine cations to aggregate, and the hydrogen bonding can provide transport sites for OH- and water molecules in the hydrophobic component. They collaborate to build long-range ordered ion channels. Therefore, the prepared membrane QPHANPD-20 exhibits an extremely high conductivity of 173.18 mS/cm at 80 °C. In addition, the QPHANPD-20 AEM exhibits excellent alkali resistance: after soaking in 3 mol/L KOH solution at 80 °C for 1440 h, the OH- conductivity retention rate remains as high as 90.8%. Furthermore, the fuel cell based on QPHANPD-20 exhibits superior power density (1.771 W/cm2 at 80 °C) and durability: at a current density of 0.4 A/cm2, it only shows a voltage drop of 0.082 V after 180 h of operation. This study proposes a strategy for synthesizing high-performance AEMs based on dual functional units of π-π stacking and hydrogen bonding, which further enhances the application value of AEMs in fuel cells.