Spatial Confinement of Sn/TiO2 Nanoparticles in Hollow Mesoporous Carbon Spheres Opal for Stable Zn Metal Anodes

Abstract

AbstractThe sluggish Zn2+ diffusion and high nucleation energy barrier induce uncontrolled growth of Zn dendrites and detrimental parasitic reactions, severely hampering the commercialization of Zn metal anodes (ZMAs). Herein, hollow mesoporous carbon sphere opal with confined Sn/TiO2 clusters (HMCSST) is designed as the host to spatially regulate the Zn deposition. Owing to the capillary effect of the ordered hierarchical porous structure, the mass diffusion can be dramatically accelerated to promote a fast deposition kinetics at the interface between ZMA and electrolyte. Besides, the encapsulated ultrafine Sn/TiO2 clusters serve as zincophilic sites to achieve both the uniform Zn deposition on the hierarchical porous opal host and the high thermodynamic stability of ZMAs. Benefiting from the structural and componential merits, the HMCSST host effectively reduces the activation energy to enable a temporal‐spatial ordering of Zn nucleation and growth. As expected, the stable HMCSST‐Zn electrode guarantees steady Zn platting/stripping with long‐term stability over 1300 h in a symmetrical cell at a depth of discharge of 37.5%. As a proof‐of‐concept demonstration, an HMCSST‐Zn||ammonium vanadate full cell shows a long lifespan over 5000 cycles at 10.0 A g−1 with low polarization.