Enhanced Dipolar Interaction Combined with Rigid-Flexible Side Chains for Promoting the Performance of Anion Exchange Membranes

Anion exchange membrane (AEM) performance is essential to fuel cell operation as it is the main component of anion exchange membrane fuel cells (AEMFCs). The development of advanced AEMs featuring efficient hydroxide conductivity and excellent alkali resistance holds substantial importance for the development of AEMFC. In this paper, a series of poly(carbazole-isatin)-based AEMs featuring different side chain structures are designed, aiming to explore the influence of different cation-dipole interaction strengths acting on flexible and "rigid-flexible" side chains on the overall membrane performance. Among them, membrane QCI-2O/8CF exhibits the best performance, as evidenced by a hydrophilic channel size of 4.49 nm from small-angle X-ray scattering testing, a hydroxide ionic conductivity of 166.25 mS cm-1 at 80 °C, and a conductivity retention of 90.71% after being immersed in 2 M NaOH solution at 80 °C for 1200 h. The fuel cell result shows that QCI-2O/8CF attains a peak power density of 695.24 mW cm-2 and its voltage decay rate is 0.47 mV h-1 after 60 h under a constant current density of 100 mA cm-2. This research will broaden the design directions of AEMs and promote the further development of AEMFC technology.