Song Yun-Wei, Shen Liang, Yao Nan, Feng Shuai, Cheng Qian, Ma Jin, Chen Xiang, Li Bo-Quan, Zhang Qiang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, 100084, Beijing, China.
College of Chemistry and Chemical Engineering, Taishan University, 271021, Shandong, China.
Angew Chem Int Ed Engl. 2024 May 6;63(19):e202400343. doi: 10.1002/anie.202400343. Epub 2024 Feb 28.
Lithium polysulfides (LiPSs) are pivotal intermediates involved in all the cathodic reactions in lithium-sulfur (Li-S) batteries. Elucidating the solvation structure of LiPSs is the first step for rational design of electrolyte and improving Li-S battery performances. Herein, we investigate the solvation structure of LiPSs and find that Li salt anions tend to enter the first solvation sheath of LiPSs and form contact ion pairs in electrolyte. The anion-involved solvation structure of LiPSs significantly influences the intrinsic kinetics of the sulfur redox reactions. In particular, the LiPS solvation structure modified by lithium bis(fluorosulfonyl)imide endows Li-S batteries with reduced polarization and enhanced rate performances under high sulfur areal loading and lean electrolyte volume conditions. This work updates the fundamental understanding of the solvation chemistry of LiPSs and highlights electrolyte engineering for promoting the performances of Li-S batteries.
多硫化锂（LiPSs）是锂硫（Li-S）电池中所有阴极反应的关键中间体。阐明LiPSs的溶剂化结构是合理设计电解质和提高Li-S电池性能的第一步。在此，我们研究了LiPSs的溶剂化结构，发现锂盐阴离子倾向于进入LiPSs的第一溶剂化层，并在电解质中形成接触离子对。LiPSs的阴离子参与的溶剂化结构显著影响硫氧化还原反应的本征动力学。特别是，双（氟磺酰）亚胺锂修饰的LiPS溶剂化结构使Li-S电池在高硫面负载和贫电解质体积条件下具有降低的极化和增强的倍率性能。这项工作更新了对LiPSs溶剂化化学的基本认识，并突出了用于提升Li-S电池性能的电解质工程。
