A ternary anhydrous eutectic electrolyte for stable zinc-ion batteries


 


Abstract

Aqueous zinc-ion batteries show promising prospects for large-scale energy storage due to their low cost and high safety. Nevertheless, their practical application is constrained by issues such as water-induced side reactions and the growth of zinc dendrites. In this study, we design a water-free deep eutectic electrolyte (FAU) which consists of zinc trifluoromethanesulfonate, acetamide, and urea. By eliminating the aqueous environment to suppress parasitic reactions and regulating the Zn2+ solvation structure, the reversibility and stability of the zinc anode are significantly enhanced. Moreover, this electrolyte promotes uniform and dense zinc deposition while forming a unique and stable organic-inorganic hybrid solid electrolyte interphase layer on the zinc anode surface, thereby effectively inhibiting dendrite growth and zinc corrosion. 

The Zn||Zn symmetric cell employing the FAU-4 electrolyte demonstrates stable cycling for over 5100 h and exhibits excellent adaptability across a broad temperature range from 25 to 80  °C. Meanwhile, the Zn||PANI full cell delivers a high capacity of 123 mA h g‒1 and maintains a high Coulombic efficiency during cycling, significantly outperforming conventional aqueous electrolyte systems. This work provides a reference for the development of high-performance and high-stability zinc-based energy storage systems.

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