Topology-Controlled Dual Stacking Enables High Performance Anion Exchange Membranes.

Developing anion exchange membranes (AEMs) with high hydroxide conductivity and dimensional stability remains a key challenge for anion exchange membrane water electrolysis (AEMWE). While microporous architectures can facilitate ion transport, the accompanying structural disorder often compromises membrane stability. In this study, we introduce a topology-regulated packing strategy by incorporating triphenylene (TP) units into the polymer backbone to manipulate intermolecular organization. Molecular simulations and structural characterizations reveal that the TP topology induces dual stacking configurations, consisting of compact and tilted packing motifs. The coexistence of these two stacking modes enables the formation of ordered domains while preserving interconnected free volume, thereby promoting continuous ion-transport pathways without excessive swelling. As a result, the optimized membrane exhibits a hydroxide conductivity of 178.39 mS cm-1 with a low swelling ratio of approximately 10% at 80°C. Diffusion analyses further suggest that the topology-induced packing structure creates a favorable hydrated environment and facilitates efficient hydroxide transport. In AEMWE operation, the membrane delivers a current density of 3.163 A cm-2 at 1.8 V and 80°C and maintains stable operation for over 4000 h at 1 A cm-2. These findings establish molecular topology as an effective design parameter for simultaneously regulating ion transport and dimensional stability in AEMs.