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, costeffectiveness, 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.

Automated summary

A new approach of incorporating trivalent yttrium ions in ZnSO4 electrolyte is proposed to control the deposition behavior of Zn ions on the electrode and prevent dendrite growth and side reactions. The study shows that the Zn//Zn cell with 0.1 M Y3+ ions can achieve dendrite-free Zn plating/stripping for up to 2080 h at 5 mA cm-2, and the Zn//NH4V4O10 cell delivers a high capacity retention of 89.6% after 2000 cycles at 5 A g-1.