Tailoring tetrahedral and pair-correlation entropies of glass-forming liquids for energy storage applications at ultralow temperatures

Abstract

Abstract Aqueous solution experiences either crystallization or vitrification as being cooled, yet the mechanism of this bifurcation is confused. Since the glass-transition temperature T g is much lower than the melting temperature, we herein propose an entropy-driven glass-forming liquid (EDGFL) as an attractive concept to develop anti-freezing electrolytes. The T g is delicately modulated via regulating local structural orders to avoid the energy-driven ice crystallization and enter an entropy-driven glass transition, which can be theoretically explained by the competitive effect between tetrahedral entropy of water and pair correlation entropy related to ions. The constructive EDGFL with a low T g of −128 °C and a high boiling point of +145 °C enables stable energy storage over an ultra-wide temperature range of −95~+120 °C, realizes superior AC linear filtering function at −95 °C, and helps improve the performance of aqueous Zn-ion batteries at ultralow temperatures. This special electrolyte will provide both theoretical and practical directions for developing anti-freezing energy storage systems adapting to frigid environment.