A Nonflammable Organic Electrolyte with a Weak Association State for Zinc Batteries Operated at ?78.5 ℃

摘要

Traditional rechargeable Zn batteries fail to work in cold regions dueto the high freezing point (T_f) and severe corrosivity of the aqueouselectrolytes with excessive association (solvent-solvent and solute-solventinteractions). In this study, a nonflammable weak-associated electrolyte(WASE) consisting of ZnCl_2 salt and methanol/dichloromethane mixtureas a solvent is developed to achieve high reversible Zn plating/strippingat low temperatures. The low self-association interaction of the mixedsolvent not only endures WASE with a low Tf of ?119.2 ℃ but also facilitatesthe desolvation of interfacial Zn~(2+) and induces smooth Zn plating at lowtemperatures. Moreover, the water-free WASE inhibits the hydrolysis ofZnCl_2 and thus restrains the corrosion of Zn electrodes. Thanks to theabove merits, the Zn‖Zn, Zn‖Cu, and Zn‖polyaniline cells with WASEexhibit superb electrochemical performance at temperatures as lowas ?78.5 ℃.