Interfacial Electronic Coupling of Fe−N 4 Sites on CoNi-LDH Nanoneedle Arrays for High Efficient Rechargeable Zinc−Air Batteries

Developing high-performance, cost-effective bifunctional electrocatalysts is paramount for the advancement of rechargeable zinc−air batteries (ZABs). Herein, we report an innovative, low-temperature strategy to construct an interface-coupled Fe SAs (single atoms)/LDH/rGO heterostructure, featuring atomically dispersed Fe−N 4 sites anchored onto CoNi-LDH nanoneedle arrays grown in situ on reduced graphene oxide. Featuring a unique 'nanoneedle-on-sheet' architecture, the catalyst exhibits a high specific surface area (217.388 m 2 g −1 ) and optimized hierarchical porosity, which maximize the exposure of active sites and enhance mass transport. Spectroscopic analyses and density functional theory (DFT) calculations reveal that strong interfacial electronic coupling induces charge redistribution, effectively modulating the d -band center and lowering energy barriers for oxygen intermediates. Consequently, the Fe SAs/LDH/rGO-3 catalyst exhibits exceptional bifunctional activity with a narrow potential gap (Δ E ) of 0.558 V, significantly outperforming commercial Pt/C and RuO 2 . When integrated into ZABs, it delivers a remarkable peak power density of 176.5 mW cm −2 and an unprecedented cycling stability of 1400 h in aqueous systems, alongside superior flexibility and robustness in quasi-solid-state devices. This work offers a sophisticated interfacial engineering pathway for designing high-density single-atom catalysts for next-generation energy conversion.