Uniform and oriented zinc deposition induced by artificial Nb2O5 Layer for highly reversible Zn anode in aqueous zinc ion batteries

• Nb 2 O 5 artificial film is coated on Zn metal via a facile spin-coating process. • High dielectric constant of Nb 2 O 5 promotes homogeneous Zn-ion flux. • Various in-situ analyses confirm uniform Zn electrodeposition behavior with Nb 2 O 5 . • Nb 2 O 5 @Zn anode shows good full cell performance with VO 2 cathode. Zn metal has recently emerged as a promising candidate for stable and reversible anode in aqueous rechargeable batteries. However, despite the high reversibility of Zn metal in aqueous media, Zn metal anode utilization is limited owing to unavoidable dilemmas, such as dendrite growth, hydrogen gas evolution, and “dead Zn”, eventually leading to battery breakdown. Herein, we propose a Nb 2 O 5 film as an effective coating layer to guarantee uniform ion flux and a rapid transportation pathway for Zn ions through Maxwell–Wagner polarization, resulting in homogeneous Zn electrodeposition under the Nb 2 O 5 layer. The artificial Nb 2 O 5 layer coated on the Zn surface (Nb 2 O 5 @Zn) acted as a guide for Zn deposition, enabling a dense and uniform morphology of electrodeposited Zn oriented in a specific direction. The symmetric Nb 2 O 5 @Zn anode system exhibited stable plating/stripping for up to 1000 h. Outstanding durability and resilience (220 h at 5 mA cm −2 /5 mAh cm −2 ) and rapid plating/stripping with excellent recovery (returning to 1 from 10 mA cm −2 ) were verified under harsh cycling conditions. The excellent characteristics of Nb 2 O 5 layer resulted in high electrochemical stability and performance for a full cell with a VO 2 cathode for practical applications. A highly reversible Zn ion aqueous battery was demonstrated by thin Nb 2 O 5 layer coating on Zn metal anode. An artificial Nb 2 O 5 layer effectively suppressed preferential Zn dendrite growth and hydrogen evolution reaction and facilitated Zn ion transport for homogenous Zn electrodeposition. As such, the Zn ion battery with proposed method exhibited an outstanding electrochemical performance over a wide range of cycling conditions.