Unveiling the Entropic Effect of Electrolytes on Kinetics and Cyclability for Practical Lithium-Sulfur Batteries.

Son, Donghyeok; Kim, Jinuk; Zhao, Wenhui; Cho, Hannah; Lee, Dong Gyu; Son, Junsu; Xu, Liangliang; Park, Cheol-Young et al. · ACS Nano · 2025

basic_science · Level V

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Abstract

Lithium-sulfur (Li-S) batteries under low-temperature and lean electrolyte conditions for practical application are hindered by a sluggish conversion reaction, low sulfur utilization, and cycling stability. Herein, we designed a high-entropy (HE) electrolyte by mixing three Li salts. The HE electrolyte simultaneously improves lithium sulfide (Li<sub>2</sub>S) conversion reaction kinetics, sulfur utilization, and cyclability due to the anticlustering effect on lithium polysulfides, three-dimensional Li<sub>2</sub>S growth, and robust anion-derived solid electrolyte interphase layer formation, respectively. Consequently, the HE electrolyte exhibits a high initial reversible capacity (1159.9 mAh g<sup>-1</sup>) and cycling stability for 40 cycles under a low electrolyte-to-sulfur ratio (3.5 μL mg<sup>-1</sup>) at the pouch cell level. In addition, the Li-S cell with HE electrolyte exhibits high cycling stability with a capacity decay of 0.01% per cycle during 200 cycles at -15 °C.