Improvement of Surface Stability of Zn Anode by a Cost-Effective Ercl3 Additive for Realizing High-Performance Aqueous Zinc-Ion Batteries

Abstract

Even rechargeable aqueous zinc-ion batteries (AZIBs) possess notable advantages in terms of enhanced safety and reduced cost. It is also facing the disadvantages of severe dendrite growth, zinc anode corrosion, and hydrogen evolution reaction, which pose obstacles to its actual implementation. Hence, this study presents the introduction of an economical and effective ErCl3 electrolyte additive to stabilize the Zn anode surface and address the aforementioned issues. The introduced Er3+ will cover the raised zinc dendrite surface and weaken the "tip effect" on the surface of the zinc anode via the "electrostatic shielding" effect. Simultaneously, the introduced Cl– can reduce the polarization of the zinc anode. Due to the collaborative effect of Er3+ and Cl–, the zinc anode corrosion, dendrite growth and hydrogen evolution have been efficiently inhibited. As a result, the utilization of an ErCl3 additive in the Zn||Zn-symmetric battery can exhibit the capability of achieving stable cycling for a duration of 1100 hours at 1 mA cm–2, 1 mAh cm–2, and exhibit a high average coulomb efficiency (99.2%). Meanwhile, Zn||MnO2 full battery based on ErCl3-added electrolyte also results in a reversible capacity of 157.1 mAh g–1 after 500 cycles. Remarkably, the battery has a little capacity decay of about 0.113% per cycle. This study offers a straightforward and economically efficient method for stabilizing the zinc anode and realizing high-performance AZIBs.

Keywords: Aqueous zinc batteries, Zinc anode, Surface stability, ErCl3 additive.