Composite Membranes with Dual-Piperidinium Functionalization across Polymer Matrix and ZrO₂ surface for High-Performance Anion Exchange Membrane Water Electrolysis

Anion exchange membrane water electrolysis (AEMWE) has emerged as a promising candidate for cost-effective green hydrogen production because its alkaline operating environment enables the use of non-platinum-group-metal catalysts. However, the practical application of anion exchange membranes (AEMs) remains limited by the trade-off among hydroxide ion (OH-) conductivity, alkaline stability, and dimensional robustness. Herein, we report organic–inorganic composite membranes designed through ‘dual-piperidinium functionalization strategy’ across both the polymer matrix and ZrO₂ nanoparticle interfaces. An ether-free alternating copolymer bearing dual-piperidinium groups was employed to provide a high density of chemically stable ion-conducting sites, while dual-piperidinium-functionalized ZrO₂ nanoparticles were introduced as interfacial components rather than passive nanofillers. The matched cationic environment enhanced the compatibility between polymer and filler, promoted the formation of hydrated OH⁻-conducting interfacial regions, and reinforced the membrane against swelling-induced deformation. By coordinating ion transport in the bulk polymer phase with interfacial transport around the functionalized inorganic domains, the composite design simultaneously improved OH- conductivity, water-management behavior, and mechanical/dimensional stability. The optimized membrane exhibited enhanced electrochemical performance and operational stability under AEMWE conditions compared with the pristine polymer membrane and composites containing unmodified ZrO₂. These results demonstrate that extending an identical ion-conducting motif across polymer matrices and inorganic interfaces is an effective strategy for overcoming the conductivity–stability trade-off in composite AEMs.