In Situ Templated Synthesis of Sponge-like Zn/Sb Dual-Atom Catalysts for Efficient Oxygen Reduction in Zn-Air...

Developing efficient electrocatalysts that can improve the oxygen reduction reaction (ORR) activity and optimize mass transfer efficiency is crucial for advancing rechargeable Zn-air batteries (ZABs). Herein, we report an in situ template strategy utilizing in situ formed Zn nanoclusters to construct a sponge-like framework with atomically dispersed dual-atom Zn/Sb sites (Zn/Sb-NC-g). The sponge-like structure with well-defined mesopores (2-5 nm) enhances both the mass transport of oxygen intermediates and the exposure of Zn/Sb-N_x active sites, thereby optimizing ORR kinetics. Systematic X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) analyses confirm the atomic-level dispersion of Zn/Sb atoms and their electronic interactions, which promote intrinsic ORR activity. The Zn/Sb-NC-g catalyst demonstrates superior ORR activity (with a half-wave potential reaching 0.905 V versus reversible hydrogen electrode), accelerated ORR kinetics, and excellent mass-transport property, which is significantly superior to its microporous and Zn single-atom counterparts. When assembled into ZABs, the catalyst delivers remarkable peak power densities up to 209 and 426 mW cm^-2 in aqueous and flexible batteries, respectively, with favorable cycling stability for over 1000 h at 10 mA cm^-2. Such a synthetic strategy for constructing sponge-like porous structure with dual-atom Zn/Sb sites offers an effective approach to develop highly efficient electrocatalysts for Zn-air batteries.