High-Performance Poly(aryl piperidine- co -pyridine) Anion Exchange Membranes with Different Monomer Configurations for Fuel Cells and Water Electrolysis

To investigate the regulatory mechanisms of the main-chain configuration on the microscopic morphology, ion transport, mechanical, and chemical stability of anion exchange membranes (AEMs), a series of AEMs with different poly(aryl piperidine-co-pyridine) backbones were prepared, and their performance in anion exchange membrane fuel cells (AEMFCs) and anion exchange membrane water electrolyzers (AEMWEs) was evaluated. Both molecular dynamics simulations and experimental results demonstrated that rigid conjugated backbones could induce the formation of well-connected hydrophilic/hydrophobic microphase separation via strong π–π stacking interactions while suppressing excessive swelling. Among them, the p-PQPP-6-Pip exhibited a good OH– conductivity (111.45 mS/cm at 80 °C) and a peak power density of 697.76 mW/cm2 in AEMFCs and a current density of 1.96 A/cm2 at 2.2 V in AEMWEs. Furthermore, the hexyl-substituted piperidinium cations with low ring strain and ether-free polymer backbones endowed the AEMs with outstanding alkaline stability, with only 8.3–11.3% degradation in OH– conductivity in 2 M NaOH at 80 °C for 1800 h.