High-temperature anion-exchange membrane fuel cells with balanced water management and enhanced stability

Over the last decade, anion-exchange membrane fuel cells (AEMFCs) have continued to show steady power output and durability improvements at low temperatures of 60°C–80°C. However, AEMFC durability still lags, largely due to the critical issue of water management. High-temperature operation (≥100°C) enables simplified water management, but additional material stability challenges remain, particularly concerning the chemical stability of the anion-exchange membranes (AEMs). Herein, we report the synthesis of lightly branched poly(arylene piperidinium) AEMs, leading to balanced water management and sufficient stability. The optimized membranes demonstrate high-temperature H2/O2 AEMFC operation at 100°C, with a peak power density of ∼2 W cm−2 and durability over a 195-h period under a constant current density of 600 mA cm−2 with only ∼4% voltage decay. This work illustrates an effective AEM design strategy through high-temperature operation to resolve water management issues, thereby improving AEMFC performance and durability.