Intrinsic Solubilization of Lithium Nitrate in Ester Electrolyte by Multivalent Low-Entropy-Penalty Design for Stable Lithium-Metal Batteries

Abstract

LiNO₃ is a remarkable additive that can dramatically enhance the stability of ether-based electrolytes at lithium metal anodes. However, it has long been constrained by its incompatibility with commercially used ester electrolytes. Herein, we correlated the fundamental role of entropy with the limited LiNO₃ solubility and proposed a new low-entropy-penalty design that achieves high intrinsic LiNO₃ solubility in ester solvents by employing multivalent linear esters. This strategy is conceptually different from the conventional enthalpic methods that relies on extrinsic high-polarity carriers. In this way, LiNO₃ can directly interact with the primary ester solvents and fundamentally alters the electrolyte properties, resulting in substantial improvements in lithium-metal batteries with high Coulombic efficiency and cycling stability. This work illustrates the significance of regulating the solvation entropy for high-performance electrolyte design.

Keywords: Entropy; Lithium Nitrate; Lithium-Metal Batteries; Solubility; Solvation Structures.