Manipulation of Zn Deposition Behavior to Achieve High-Rate Aqueous Zinc Batteries via High Valence Zirconium Ions

Abstract

Aqueous zinc ion batteries are excellent energy storage devices with high safety and low cost. However, the corrosion reaction and zinc dendrite formation occurring on the surface of zinc anodes are hindering their further development. To solve the problems, zirconium acetate (ZA) was used as an electrolyte additive in the ZnSO₄ electrolyte. Attributing to the higher electro-positivity of Zr⁴⁺ than Zn²⁺, these high valence metal cations preferentially adsorb onto the surface of metallic zinc, shielding parasitic reactions between zinc and electrolyte, reshaping the electric field distribution, and directing preferential homogeneous deposition of Zn-ions on the Zn (002) crystal plane. Furthermore, the adsorption of Zr⁴⁺ on the Zn metal after electrochemical cycles can enhance the energy barrier of zinc atom diffusion, resulting in high resistance of corrosion and manipulation of the Zn²⁺ nucleation configuration. Attributing to these properties, the Zn//Zn symmetric cell with an electrolyte additive of ZA was able to cycle for 400 h under an extremely high current density of 40 mA cm^–2 with an area capacity of 2 mAh cm^–2. Meanwhile, the MnO₂//Zn coin cell still had 81.7 mAh g^–1 (85% retention of capacity) after 850 cycles under a current density of 1 A g^–1.