Polymer-Based Wettability Engineering for Gas Management in Water Electrolyzers

Water electrolysis powered by renewable electricity is a key technology for green hydrogen production, but its actual efficiency, stability, and safety are often limited by gas-management issues at dynamic gas–liquid–solid interfaces. Gas bubbles generated during electrolysis can block catalytic active sites, increase ohmic and mass-transport overpotentials, induce mechanical degradation of catalysts, and promote gas crossover through porous separators. In this talk, I will present our recent efforts to address these challenges through polymer-based wettability engineering. Porous hydrophilic hydrogel overlayers are introduced as a universal strategy to impart superaerophobicity to diverse electrodes by physically separating catalytic active sites from bubble-adhesion sites. Bio-derived and synthetic polymer hydrogels promote rapid bubble detachment and enhance hydrogen evolution under both acidic and alkaline conditions, and this concept is further expanded into gel-like aerophobic surface systems for scalable fabrication of bubble-repellent electrodes for various gas-evolving reactions. I will also discuss the extension of wettability engineering from electrode surfaces to electrolyzer components. Anisotropically wettable porous transport layers, prepared by partial hydrophobic modification of metal foams, provide directional pathways for electrolyte supply and gas removal, thereby reducing mass-transport losses in anion-exchange membrane water electrolyzers. In addition, superaerophobic hydrogel-modified diaphragms suppress gas crossover in alkaline water electrolyzers by accelerating bubble release and preventing gas penetration. These studies demonstrate that polymer-based control of interfacial wettability can serve as an effective materials-design strategy for improving the efficiency, stability, and safety of water electrolyzers for green hydrogen production.