Synergistic Engineering of Membrane-Electrode Interfaces via Surface Patterning in Anion Exchange Membrane Water Electrolysis.

The membrane-electrode interface critically governs the performance and durability of anion exchange membrane (AEM) water electrolysis, yet engineering these interfaces in pre-formed hydrocarbon AEMs remains challenging due to their high glass-transition temperatures and thermally degradable quaternary-ammonium cations. Here, we report a dual-side patterning strategy enabled by localized solvent-induced surface softening combined with plasma-treated, gas-permeable polydimethylsiloxane molds, allowing capillary-driven pattern transfer without additional external pressure. Pillar (5 µm) and prism (10 and 20 µm pitch) features are uniformly replicated on both surfaces of a representative pre-formed hydrocarbon AEM while preserving bulk membrane properties. Decoupled cathode-, anode-, and dual-side patterning analysis reveals that both interfaces contribute, with the anode dominating and dual-side patterning yielding a 12.6% synergistic enhancement (4.65 vs. 4.13 A cm-2 at 2.0 V, 1.0 M KOH); under electrolyte-deficient conditions (1.0 mM KOH), this enhancement is amplified to 31%, supported by concentration-dependent double-layer capacitance analysis. The three-dimensional interlocked architecture also strengthens interfacial adhesion and, under dynamic load cycling (200 cycles, 400 h), suppresses catalyst-layer detachment relative to the flat reference. These findings establish dual-side membrane patterning as a structural route to enhance both performance and interfacial robustness in AEM water electrolysis.