Dual‐Scale‐Patterned Anion Exchange Membrane With Coupled Interface for Durable Water Electrolysis

ABSTRACT The widespread adoption of anion exchange membrane (AEM) water electrolysis is impeded by rapid performance decay, largely caused by catalyst layer detachment under low catalyst loading conditions. To overcome this, we present a structurally graded AEM design that establishes efficient transport pathways from the molecular level to the membrane/catalyst layer interface. At the bulk transport level, molecular dynamics simulations and experimental validation confirm that the designed polymer matrix, based on the C‐F backbone and flexible cationic side chains, promotes favorable microphase separation. This leads to well‐connected ionic nanochannels that facilitate superior bulk hydroxide conduction. At the membrane/catalyst interface, a biomimetic micro‐nano pattern, inspired by aquatic plants, is engineered onto the membrane surface via an industrially scalable embossing calendaring process. The resulting patterned interface optimizes interfacial contact, enhancing catalyst adhesion and mass transfer. By integrating these two scales of transport, a highly efficient membrane electrode assembly is realized, enabling synergistic management of ions, water, and gas bubbles. The resulting AEM achieves a record‐high hydroxide ion conductivity of 338.2 mS cm −1 at 80°C and exceptional ductility, with elongation of 162.0%, surpassing all previously reported AEMs. More importantly, the water electrolysis demonstrates markedly enhanced operational stability under various conditions.