A dynamic electrostatic shielding layer toward highly reversible Zn metal anode

Aqueous Zn-ion batteries (AZIBs) have gained considerable attention due to their inherent safety, cost-effectiveness, and environmental friendliness. However, their application in large-scale energy storage system is hindered by uncontrollable dendrite growth and severe side reactions at the electrode-electrolyte interface. To address these challenges, we propose the incorporation of trivalent yttrium (Y³⁺) ions in ZnSO₄ electrolyte, which can form a cationic electrostatic shielding layer on the Zn anode to regulate the deposition behavior of Zn²⁺ ions. The inert Y³⁺ ions with a lower effective reduction potential will selectively adsorb on the active sites, facilitating uniform Zn deposition through a sustained dynamic electrostatic shielding effect. Moreover, the adsorbed Y³⁺ ions create a protective interface for the Zn anode, mitigating the corrosion reactions caused by water molecules. Consequently, the Zn//Zn cell with 0.1 M Y³⁺ ions demonstrates dendrite-free Zn plating/stripping over 2080 h at 5 mA cm⁻², and the assembled Zn//NH₄V₄O₁₀ cell delivers a high capacity retention of 89.6% after 2000 cycles at 5 A g⁻¹. This work develops a new rare earth ion additive and confirms its sustained dynamic electrostatic shielding effect for dendrite-free Zn deposition, providing theoretical support and an exploration direction for further investigation of unexplored rare earth elements. © 2023 Elsevier B.V.