Ultra‐Fast and Scalable Saline Immersion Strategy Enabling Uniform Zn Nucleation and Deposition for High‐Performance Zn‐Ion Batteries

Abstract Although aqueous Zn‐ion batteries (ZIBs) with low cost and high safety show great potential in large‐scale energy storage system, metallic Zn anode still suffers from unsatisfactory cycle stability due to unregulated growth of Zn dendrites, corrosion, and formation of various side products during electrochemical reaction. Here, an ultrafast and simple method to achieve a stable Zn anode is developed. By simply immersing a Zn plate into an aqueous solution of CuSO 4 for only 10–60 s, a uniform and robust protective layer (Zn 4 SO 4 (OH) 6 ·5H 2 O/Cu 2 O) is formed on commercial Zn plate (Zn/ZCO), which enables uniform electric field distribution and controllable dendrite growth, leading to a long‐term cycle life of over 1400 h and high average Coulombic efficiency (CE) of 99.2% at 2.0 mA cm −2 and 2.0 mAh cm −2 . These excellent characteristics of the prepared Zn anode show great potential in practical applications for high‐performance aqueous Zn‐ion batteries.