Electrostatic Self‐Adsorption Stabilized Ultra‐Thin Composite Membrane Enabling High‐Performance Alkaline Water Electrolysis

Abstract Developing high‐performance, ultra‐thin membranes for alkaline water electrolysis (AWE) remains challenging due to organic‐inorganic phase separation under harsh conditions. Here, an ultrathin (≈120 µm) polyether sulfone/zirconia (PES/ZrO 2 ) composite membrane is designed via interfacial engineering using a titanate coupling agent (CHOPT). The modified ZrO 2 exhibits opposite Zeta potential to PES, enabling electrostatic self‐adsorption that strengthens with alkalinity, ensuring durable nanoparticle anchoring. Incorporating a PPS mesh further enhances mechanical stability. The optimized membrane achieves exceptional performance: ultra‐low area resistance (0.09 Ω cm 2 ), high bubble point pressure (4.55 bar), and excellent hydrophilicity. In 30 wt% KOH at 80 °C, the membrane enables electrolyzer operation at 1.82–1.88 V (1.0 A cm −2 ) with 150‐hour stability. Additionally, theoretical calculations and molecular dynamics simulations provide insights into the mechanisms behind the membrane's outstanding performance. This work provides a scalable strategy for durable, high‐efficiency AWE membranes, addressing critical challenges in green hydrogen production.