Ultrastable Zinc Anode by Simultaneously Manipulating Solvation Sheath and Inducing Oriented Deposition with PEG Stability Promoter

Abstract

Aqueous zinc-ion batteries are a low-cost and safe energy storage system, but suffer from detrimental side reactions and Zn dendrites due to the strong interactions between Zn²⁺ and water molecules in the electrolytes, and random Zn²⁺ deposition on the anode surface. Here, an electrolyte involving a dual-functional additive of polyethylene glycol (PEG) to bypass these issues is reported. The electrolyte can not only tailor the solvation sheath of Zn²⁺ but also enable favorably oriented deposition of Zn²⁺ on the anode surface. The dendrite-free Zn anode in Zn//Zn cells is obtained with high Columbic efficiency (98.8%) and long cycling lifespan (1500 h), six times longer than that of electrolyte without PEG at 0.25 mA cm^-2 . What is more, the excellent cycling stability of the prepared batteries (Zn//V₂ O₅ ·1.6 H₂ O) suggests that the developed tailoring strategy may propel a promising pathway for stabilizing Zn metal anodes.

Keywords: dendrites; electrolyte additives; oriented deposition; solvation sheaths; zinc anodes.