Multi-Scale Structure Engineering of ZnSnO₃ for Ultra-Long-Life Aqueous Zinc-Metal Batteries

Suppressing the severe water-induced side reactions and uncontrolled dendrite growth of zinc (Zn) metal anodes is crucial for aqueous Zn-metal batteries to achieve ultra-long cyclic lifespans and promote their practical applications. Herein, a concept of multi-scale (electronic-crystal-geometric) structure design is proposed to precisely construct the hollow amorphous ZnSnO₃ cubes (HZTO) for optimizing Zn metal anodes. In situ gas chromatography demonstrates that Zn anodes modified by HZTO (HZTO@Zn) can effectively inhibit the undesired hydrogen evolution. The pH stabilization and corrosion suppression mechanisms are revealed via operando pH detection and in situ Raman analysis. Moreover, comprehensive experimental and theoretical results prove that the amorphous structure and hollow architecture endow the protective HZTO layer with strong Zn affinity and rapid Zn²⁺ diffusion, which are beneficial for achieving the ideal dendrite-free Zn anode. Accordingly, excellent electrochemical performances for the HZTO@Zn symmetric battery (6900 h at 2 mA cm^-2 , 100 times longer than that of bare Zn), HZTO@Zn||V₂ O₅ full battery (99.3% capacity retention after 1100 cycles), and HZTO@Zn||V₂ O₅ pouch cell (120.6 Wh kg^-1 at 1 A g^-1 ) are achieved. This work with multi-scale structure design provides significant guidance to rationally develop advanced protective layers for other ultra-long-life metal batteries.