Yao Nan, Sun Shu-Yu, Chen Xiang, Zhang Xue-Qiang, Shen Xin, Fu Zhong-Heng, Zhang Rui, Zhang Qiang
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
Advanced Research Institute for Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081, China.
Angew Chem Int Ed Engl. 2022 Dec 23;61(52):e202210859. doi: 10.1002/anie.202210859. Epub 2022 Nov 24.
Advanced electrolyte design is essential for building high-energy-density lithium (Li) batteries, and introducing anions into the Li solvation sheaths has been widely demonstrated as a promising strategy. However, a fundamental understanding of the critical role of anions in such electrolytes is very lacking. Herein, the anionic chemistry in regulating the electrolyte structure and stability is probed by combining computational and experimental approaches. Based on a comprehensive analysis of the lowest unoccupied molecular orbitals, the solvents and anions in Li solvation sheaths exhibit enhanced and decreased reductive stability compared with free counterparts, respectively, which agrees with both calculated and experimental results of reduction potentials. Accordingly, new strategies are proposed to build stable electrolytes based on the established anionic chemistry. This work unveils the mysterious anionic chemistry in regulating the structure-function relationship of electrolytes and contributes to a rational design of advanced electrolytes for practical Li metal batteries.
先进的电解质设计对于构建高能量密度的锂电池至关重要，并且将阴离子引入锂溶剂化鞘层已被广泛证明是一种很有前景的策略。然而，目前非常缺乏对阴离子在这类电解质中关键作用的基本认识。在此，通过结合计算和实验方法，探究了阴离子在调节电解质结构和稳定性方面的化学性质。基于对最低未占据分子轨道的综合分析，锂溶剂化鞘层中的溶剂和阴离子与游离态相比，其还原稳定性分别增强和降低，这与还原电位的计算结果和实验结果均相符。因此，基于已确立的阴离子化学性质，提出了构建稳定电解质的新策略。这项工作揭示了调节电解质结构 - 功能关系中神秘的阴离子化学性质，并有助于合理设计用于实际锂金属电池的先进电解质。
