Anion Exchange Membrane Seawater Electrolysis at 1.0 A cm −2 With an Anode Catalyst Stable for 9000 H

Abstract Hydrogen production through seawater electrolysis is promising but challenging due to severe anode corrosion by chlorine (Cl − ) ions. Herein, a corrosion‐resistant NiFe layered double hydroxide electrode (CAPist‐S1) is reported as a high‐performance electrocatalyst for seawater oxidation, achieving an industrial‐level current density of 1.0 A cm −2 at overpotentials of 200 and 220 mV in alkaline simulated (1 M KOH + 0.5 M NaCl) and natural (1 M KOH + seawater) seawater, respectively, along with extraordinary long‐term stability over 9000 h under 1.0 A cm −2 in alkaline natural seawater. A dense NiFe LDH interlayer generated between the NiFe LDH nanosheets and metal substrate is found to efficiently retard the penetration of Cl − ions to the substrate surface, improving the resistance to Cl − ions corrosion. Furthermore, this dense interlayer is an essential prerequisite for establishing a dynamic equilibrium between Fe leaching and redeposition over the in situ formed FeOOH, and this dynamic equilibrium can in turn stabilize the dense interlayer, maintaining the activity of CAPist‐S1 during prolonged electrolysis. Using CAPist‐S1 in an anion exchange membrane (AEM) seawater electrolyzer, the obtained electrolyzer stably functions over 700 h at 1.0 A cm −2 under room temperature, indicating promising prospects for industrial seawater electrolysis application.