Novel poly(biphenyl-alkylene) anion exchange membranes with excellent flexibility for fuel cells

As the core material of alkaline fuel cells, anion exchange membranes (AEMs) are one of the keys to determining the comprehensive performance of fuel cells. However, drawbacks, such as impoverished alkali stability, insufficient mechanical properties, and particularly low ionic conductivity, affect their application in fuel cells. Herein, a series of AEMs based on a new arylfluoroketone monomer [1-bromo-3- (trifluoroacetyl phenyl)-propane, TFAP-Br] was prepared using a backbone modification strategy. This study aims to investigate the effects of introducing TFAP-Br for copolymerization on the microphase separation, ionic conductivity, and mechanical properties of AEMs. Due to the presence of long side chains of alkylfluoroketone and arylfluoroketone, the AEMs exhibit a prominent microphase separation state, and the OH− conductivity can reach 156 mS cm−1 at 80 °C (IEC = 2.73 meq g−1). QBPNP-10 shows excellent mechanical properties with the elongation at break up to 91% in wet state and good alkali resistance with 95.2% OH− conductivity retention in a NaOH solution (2 mol L−1, 80 °C, 1560 h). Moreover, the peak power density (PPD) of a single cell assembled with QBPNP-10 can reach 852 mW cm−2 (80 °C), and the membrane has good in-situ durability.