A Nonflammable Organic Electrolyte with a Weak Association State for Zinc Batteries Operated at −78.5 °C

Abstract

AbstractTraditional rechargeable Zn batteries fail to work in cold regions due to the high freezing point (Tf) and severe corrosivity of the aqueous electrolytes with excessive association (solvent‐solvent and solute‐solvent interactions). In this study, a nonflammable weak‐associated electrolyte (WASE) consisting of ZnCl2 salt and methanol/dichloromethane mixture as a solvent is developed to achieve high reversible Zn plating/stripping at low temperatures. The low self‐association interaction of the mixed solvent not only endures WASE with a low Tf of −119.2 °C but also facilitates the desolvation of interfacial Zn2+ and induces smooth Zn plating at low temperatures. Moreover, the water‐free WASE inhibits the hydrolysis of ZnCl2 and thus restrains the corrosion of Zn electrodes. Thanks to the above merits, the Zn||Zn, Zn||Cu, and Zn||polyaniline cells with WASE exhibit superb electrochemical performance at temperatures as low as −78.5 °C.