High-entropy electrolyte toward battery working under extreme conditions

With the rapid expansion of battery applications, the demand for operating batteries in extreme conditions (e.g., high/low temperatures, high voltages, fast charging, etc.) is ever rising. The electrolyte is a key component in batteries, with properties that have far-reaching effects on the battery performance. Yet, according to general design principles of the electrolyte, operation under such harsh environments seems infeasible. In response, battery communities are scrambling to develop new concepts and theories. From the thermodynamics point of view, the free energy of the mixed system seriously affects the formation of the solvation structure of the liquid electrolyte, and the stability of the solid electrolyte is largely governed by entropy. Tuning the entropy of the electrolyte, in principle, represents a viable strategy to promote electrolyte features. Here, the entropy-tuning effect of electrolytes for batteries working under extreme conditions is thoroughly discussed in respect of aqueous, non-aqueous, and solid-state electrolytes. We believe that such a perspective will spark new thinking on the rational design of electrolytes aimed for use under extreme conditions.