An LDH-enhanced porous polyethersulfone membrane doped with alkali for anion exchange membrane fuel cells

Anion exchange membrane fuel cells (AEMFCs) have attracted significant attention for their ability to operate with non-precious metal catalysts for oxygen reduction, reducing the reliance on costly noble metals. However, the adoption of AEMFCs remains challenging due to the limited availability of anion exchange membranes that simultaneously offer high hydroxide conductivity and long-term stability. In this work, we present a high-performance alkali-doped porous polyethersulfone (PES) membrane with <i>in situ</i> grown oligo-layered layered double hydroxide (LDH) nanosheets (PES-LDH), fabricated through a simple process. The interconnected LDH nanosheets, along with the adsorbed alkali, create continuous fast hydroxide ion transport pathways. The resulting PES-LDH composite membrane exhibits superior structural and thermal stability, achieving an ultralow swelling ratio of 1.49% while maintaining its performance up to 110 °C. When integrated into an AEMFC, the membrane delivers high power densities of 680.7 mW cm^-2 at 80 °C and 455.6 mW cm^-2 at 110 °C. Moreover, the membrane demonstrates upgrading durability, with a voltage decay rate of approximately 16% over 100 hours at 0.1 A cm^-2. Notably, a secondary alkali doping process can fully restore its performance. These findings underscore the potential of the PES-LDH composite membrane for high-efficiency AEMFC applications.