Enhanced Fuel Cell Performance with Robust Pyridinium-Derivative-Functionalized SBS Triblock Copolymer Anion-Exchange Membranes

High Resolution Image Download MS PowerPoint Slide A series of polystyrene- block -polybutadiene- block -polystyrene (SBS) membranes functionalized with pyridinium derivatives (SBS-QA + py) were synthesized through free-radical chlorination of the polybutadiene segments using azobis(isobutyronitrile) (AIBN) as the free-radical initiator, promoting uniform chain growth. The resulting SBS-QA + py anion-exchange membranes (AEMs) were quaternized via a conventional solution-casting method. The membranes exhibited controlled ion-exchange capacities (IECs), water uptake (WU), and optimized interionic separation, achieving a balance between hydration, dimensional stability, and mechanical integrity. Noncovalent stacking interactions between the polystyrene and pyridinic segments significantly contributed to these properties. Notably, the SBS-Qdpy 2 AEM achieved a peak ionic conductivity of 101.23 mS cm –1 at 80 °C (IEC: 1.72 mequiv g –1 ) and a peak power density of 398.14 mW cm –2 in a H 2 /O 2 flow single cell at 80 °C, surpassing the performance of previously reported SBS-based AEMs. The membranes also demonstrated excellent chemical durability in 1 M NaOH solutions over 30 days, highlighting superior alkaline stability. These results underscore the critical role of optimized ion exchange and membrane morphology enhancing the fuel cell performance, positioning SBS-QA + py AEMs as promising candidates for next-generation fuel cells. Optimizing grafting, quaternization, and cross-linking will create stable AEMs with selective, well-defined nanoionic channels for efficient anion diffusion.