Synergistic Fluoride and Polymer‑Regulated Interfacial Engineering of NiFe‑LDH Anodes for Ampere‑Scale Natural Seawater Electrolysis

ABSTRACT

Alkaline seawater electrolysis is a promising route for sustainable hydrogen production, yet its practical implementation is severely constrained by chloride‐induced corrosion and limited anode durability during the oxygen evolution reaction (OER). Here, we develop synergistic fluoride‐management, defect‐engineering, and polymer‐interfacial‐protection strategy for NiFe‐LDH anodes, enabling kilo‐hour‐scale operation at ampere‐level current densities in natural seawater. A custom‐designed microwave‐assisted method produces fluoride‐protected NiFe layered double hydroxide on nickel foam (F‑NiFe‑LDH ^MW /NF). The electrode is subsequently tailored through controlled Zn depletion to generate an evolving cation‐deficient environment, followed by electropolymerization of calmagite to construct a multifunctional poly(calmagite) (poly(CM)) interfacial layer. The optimized F‑NiFeZn ^vac ‑LDH ^MW @CM/NF anode delivered exceptional stable operation for 1000 h in simulated seawater and 1650 h in natural seawater at a commercial‐scale current density of 1000 mA cm ⁻² . Mechanistic analyses combining stage‐resolved characterization, electrolyte analysis, and DFT reveal complementary intrinsic and extrinsic stabilization mechanisms: F ⁻ regulation and the evolving cation‐defect environment modify the structural and electronic state of NiFe‐LDH, while poly(CM) suppresses Cl ⁻ access and adsorption and delays interfacial corrosion. During prolonged electrolysis, F ⁻ undergoes dynamic redistribution and gradual leaching, accompanied by controlled catalyst reconstruction rather than catastrophic structural degradation. This multilevel stabilization strategy can be a step forward toward practical seawater electrolysis.