Toward Stable Zinc-Ion Batteries: Use of a Chelate Electrolyte Additive for Uniform Zinc Deposition

Abstract

Zn-ion batteries are re-evaluated as a potential choice to address the safety issue and cost concerns of current energy storage systems. Unfortunately, further application is severely hindered by low coulombic efficiency and poor cycle life, which are caused by the undesirable dendrite growth and side reactions on metal Zn anode. Herein, ethylenediaminetetraacetic acid (EDTA) is employed as an electrolyte additive to solve the problem. The functional groups of EDTA adsorption layer on Zn foil results in refined grains by providing abundant nucleation sites for initial deposition and further induces uniform and flat Zn deposition without dendrites. Moreover, the chelation of EDTA with Zn2+ changes the coordination environment of hydrated Zn2+ and suppresses the side reactions. The smooth deposition of Zn endows the Zn anodes with super stability in both symmetric cells and Zn–V2O5 full cells. This work provides a simple and feasible approach for solving anode issues in high-performance and safe Zn-ion batteries.