An Ultrathin Inorganic Molecular Crystal Interfacial Layer for Stable Zn Anode

Zn metal anode suffers from dendrite growth and side reactions during cycling, significantly deteriorating the lifespan of aqueous Zn metal batteries. Herein, we introduced an ultrathin and ultra-flat Sb₂O₃ molecular crystal layer to stabilize Zn anode. The in situ optical and atomic force microscopes observations show that such a 10 nm Sb₂O₃ thin layer could ensure uniform under-layer Zn deposition with suppressed tip growth effect, while the traditional WO₃ layer undergoes an uncontrolled up-layer Zn deposition. The superior regulation capability is attributed to the good electronic-blocking ability and low Zn affinity of the molecular crystal layer, free of dangling bonds. Electrochemical tests exhibit Sb₂O₃ layer can significantly improve the cycle life of Zn anode from 72 h to 2800 h, in contrast to the 900 h of much thicker WO₃ even in 100 nm. This research opens up the application of inorganic molecular crystals as the interfacial layer of Zn anode.