Sulfur‐Induced Asymmetric Ni–Fe Dual Single‐Atom Sites for Decoupling Electrocatalytic Oxygen Activation From Chloride Poisoning in Seawater

ABSTRACT The practical deployment of seawater‐based zinc–air batteries (SZABs) is critically hindered by the dual challenges of sluggish oxygen reduction reaction (ORR) kinetics and severe chloride‐induced deactivation of conventional catalysts. Herein, we report an asymmetric Ni─Fe dual single‐atom catalyst, denoted as NiFe‐SNC, featuring atomically adjacent NiN ₄ and FeN ₃ S moieties. This unique architecture enables synergistic side‐on O ₂ adsorption across dual‐metal sites, facilitating direct O─O bond cleavage via a dissociative four‐electron ORR pathway. Crucially, first‐shell sulfur coordination on the Fe center modulates its electronic structure, effectively reducing its Lewis acidity and thereby suppressing competitive Cl ⁻ adsorption. In situ spectroscopic studies and theoretical calculations jointly validate this decoupled mechanism, where high ORR activity and exceptional chloride tolerance are achieved simultaneously. Consequently, NiFe‐SNC delivers a record‐high half‐wave potential (E _1/2 ) of 0.932 V versus RHE for alkaline seawater ORR. When integrated into SZABs, it achieves a peak power density of 187.74 mW cm ⁻² and demonstrates remarkable stability with over 300 h of continuous charge–discharge cycling. This work establishes a precise atomic‐level design paradigm, offering a generalizable strategy to engineer robust electrocatalysts that transcend the inherent limitations of seawater electrolytes for next‐generation marine energy systems.