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

Qiu, Meijia; Sun, Peng; Liang, Yuxuan; Chen, Jian; Wang, Zhong Lin; Mai, Wenjie · Nat Commun · 2024

basic_science · Level V

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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<sub>g</sub> 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<sub>g</sub> 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<sub>g</sub> 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.