Solvation Structure and Interfacial Regulation for Extremely Stable Zinc Metal Anodes Operating in a Wide Range of Temperatures

Abstract

Aqueous zinc-metal batteries are promising for large-scale energy storage owing to their reasonable energy density, safety and low cost. However, their practical applications are limited by hydrogen evolution, corrosion, and dendrite formation of Zn anode and there is trade-off between efficiency and stability at high and low temperatures. Herein, we propose a solvation chemistry regulation strategy that can adjust the Zn2+-solvation structure and in situ form a robust and Zn2+-conducting Zn5(CO3)2(OH)6 SEI on the Zn surface, using hybrid electrolytes of water and a polar aprotic N, N-dimethylformamide. As verified by experimental characterizations and computational analyses, the unique solvation structure and the newly formed solid electrolyte interface are created by hybrid electrolytes, resulting in highly reversible and dendrite-free Zn plating/stripping process as well as thermal stability and high ionic conductivity from −30 to 70 °C. The Zn||Zn symmetric cells in hybrid electrolytes are very stable over 2500 h at 25 ℃ and 2000 h even at –20 ℃. Thus, the stability and reversibility of the hybrid zinc-ion capacitors with Zn metal anode in hybrid electrolytes are firstly achieved in a wide and extreme temperature range, demonstrating high capacity retentions and Coulombic efficiencies over 14000, 10000, and 600 cycles at 25, −20, and 70 ℃, respectively.