Selective Anion‐Gating Interlayer Enables Chloride‐Resistant and Long‐Life Alkaline Seawater Electrolysis

ABSTRACT Hydrogen production through seawater electrolysis represents a promising route for sustainable energy conversion. Nevertheless, its practical implementation is impeded by severe chloride‐induced corrosion and the competing chlorine evolution reaction (CER), both of which predominantly affect the anodic oxygen evolution reaction (OER) and consequently deteriorate the overall efficiency and long‐term operational stability of the seawater electrolysis system for sustained hydrogen generation. To address these issues, this study introduces a Ni 3 N selective anion‐gating interlayer (SAGI) on a nickel foam substrate. This SAGI increases the electron density at the catalyst surface, effectively repelling Cl − ions from the nickel foam skeleton while allowing OH − ions to access the NiFeAl‐LDH catalytic surface. As a result, the electrolyzer requires only 1.92 and 2.12 V to achieve current densities of 400 and 1000 mA cm −2 , respectively. Moreover, the electrode demonstrates excellent durability, showing only a 5.8% and 13.6% increase in cell voltage after 500 h of continuous operation at 400 mA cm −2 in simulated and real alkaline seawater, respectively. This strategy is broadly applicable, extending the operational lifespan of various seawater electrolysis catalysts by 2–10 times, offering a promising approach to developing corrosion‐resistant, high‐performance electrocatalysts for direct seawater splitting.