Chloride‐Mediated Electron Buffering on Ni‐Fe Anodes for Ampere‐Level Alkaline Seawater Electrolysis

Abstract In water electrolysis, the long‐term stability of anodes is compromised by their degradation under oxidative conditions. This issue becomes more pronounced in seawater electrolysis, where the natural chloride ion (Cl − ) induces the chlorine evolution reaction (ClER) to produce corrosive byproducts. Herein, a series of small organic molecules (SOMs), featuring an aromatic carbon ring with para‐positioned carbonyl groups, are integrated with the conventional nickel‐iron (Ni‐Fe) based anode. This integration triggers a unique electron buffering effect to address anode degradation in natural seawater‐based electrolytes. It is found that preferential adsorption of Cl − onto SOMs prevents its direct interaction with metal active sites. Furthermore, SOM‐Cl serving as an electron buffering group significantly reduces the dissolution of Fe sites under the highly oxidative environment. As a result, the SOM‐Cl‐engineered anode enhances oxygen evolution activity by ≈1.7 times in seawater compared to pure water. In addition, the rationally designed anode works stably for over 200 h at a high current density of 1.3 A cm −2 in an alkaline seawater electrolyzer (ASE).