Robust Piperidinium-Enriched Polystyrene Ionomers for Anion Exchange Membrane Fuel Cells and Water Electrolyzers

Durable and efficient anion exchange polyelectrolytes (AEPs) are crucial for the long-term operation of cost-effective anion exchange membrane fuel cells (AEMFCs) and water electrolyzers (AEMWEs). Here, we present a new class of γ-amine-piperidinium-functionalized polystyrene AEPs (P-AP-Ca), featuring a carbazole segment to tune ion exchange capacities (IECs). The P-AP-Ca AEPs possess high OH– conductivity and outstanding alkaline stability in 1 M NaOD/CD3OD/D2O at 80 °C for 6,000 h, making them among the most stable AEPs reported to date. P-AP-Ca-based AEMFCs with a Co–Mn cathode achieve a highest peak power density of 1.38 W cm–2 at 80 °C. Moreover, P-AP-Ca-based AEMWEs with a NiFeOOH anode deliver a high current density of 6.3 A cm–2 at 2 V, and the cell can be run stably at 2 or 3 A cm–2 over 1,100 h in 1 M KOH. These results demonstrate the remarkable robustness and effectiveness of these new AEPs for next-generation alkaline energy devices.