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

Abstract Traditional rechargeable Zn batteries fail to work in cold regions due to the high freezing point (T_f) 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 T_f 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.