Phase Engineering of ZnSe by Small Molecules as a High-Performance Protective Layer for Zn Anode

Abstract

The practical application of aqueous zinc ion batteries is still hampered by the side reactions and dendrite growth on Zn anode. Herein, the phase engineering of ZnSe coating layer by incorporating small molecules is developed to enhance the performance of Zn anode. The unique electronic structure of ZnSe⋅0.5N₂H₄ promises strong adsorption for Zn atoms and enhanced ability to inhibit hydrogen evolution, thereby promoting uniform Zn deposition and preventing by-product and dendrite growth. Meanwhile, fast Zn²⁺ transfer and deposition kinetics are also demonstrated by ZnSe⋅0.5N₂H₄. As a result, the ZnSe⋅0.5N₂H₄@Zn symmetric cell achieves long-term cycling stability up to 1900 h and 300 h at high current densities of 5 mA cm⁻² and 20 mA cm⁻², respectively. The assembled ZnSe⋅0.5N₂H₄@Zn||NH₄V₄O₁₀ full cell presents outstanding cycling stability and rate capability. This work highlights the key role of crystal phase control of protective layer for high-performance zinc anode.