Cross-linked anion exchange membranes containing conjugated polycyclic rings with high ionic conductivity

Cross-linked anion exchange membranes (AEMs) have attracted significant attention as an effective strategy for limiting swelling. We synthesized a novel monomer, MOS, which contains seven-membered ring and conjugated structure. In this study, a novel series of AEMs was developed by copolymerizing MOS with 1-methyl-4-piperidone and p-terphenyl. The crosslinked architecture was then created by linking two polymer backbones using 1,4-diazabicyclo [2.2.2] octane (DABCO) as a crosslinker. Incorporating DABCO introduces multiple cationic centers, which not only raises the density of ion-conducting sites but also promotes the formation of more continuous pathways for ion transport. Furthermore, the conjugated structure within the polymer backbone further promotes ion transport. Based on the above design, the cross-linked AEMs prepared effectively improved the trade-off between swelling ratio and ionic conductivity. The QPTP-MDA-9 AEM synthesized via this strategy exhibited ideal conductivity of 183.41 mS cm -1 at 80 °C, with a swelling ratio of only 16.73%. Anion exchange membrane fuel cells (AEMFCs) utilizing this membrane achieved peak power density of 1.02 W cm -2 . After soaking in 2 M NaOH solution at 80 °C for 1056 h, the membrane retained 93.26% of its initial conductivity. The comprehensive performance of the prepared AEMs surpasses that of most advanced AEMs, demonstrating broad application prospects.