A multi-functional protective material with atomically dispersed zincophilic sites enabling long-life zinc anodes

Abstract

Parasitic side reactions and the formation of zinc dendrites in aqueous solutions severely hinder the practical application of Zn metal anodes. Carbon materials with high electrical conductivity and mechanical robustness are promising protective materials for Zn anodes. However, the zincophobic nature of carbon materials impedes the cycling stability of zinc-ion batteries. Herein, a versatile design strategy is proposed utilizing carbon doped with single atoms with atomically dispersed zincophilic sites as a multi-functional protective material for high-performance zinc anodes. Taking bismuth-single-atom-doped carbon (Bi SAs) as an example, density functional calculations verify that the introduction of bismuth single atoms can enhance zincophilicity, promote robust adhesion to zinc foil, and effectively suppress hydrogen evolution. Guided by theoretical calculations, Bi single-atom-doped carbon nanobelts are synthesized and employed as a protective material to stabilize zinc anodes. As expected, due to the atomic-level zincophilic Bi sites, hydrophobicity, and enhanced ionic conductivity, the Bi SAs@Zn anode demonstrates over 4200 h and 600 h of reversible cycling at 5 mA cm⁻² and 20 mA cm⁻², respectively, in symmetric cells. Additionally, the Bi SAs@Zn//MnO₂ full cell achieves a stable lifespan of 1000 cycles at 1 A g⁻¹, retaining 95.58% of the initial capacity.