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Correlating Polysulfide Solvation Structure with Electrode Kinetics towards Long-Cycling Lithium–Sulfur Batteries |
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| Authors: | Zheng Li Li-Peng Hou Nan Yao Xi-Yao Li Zi-Xian Chen Dr Xiang Chen Dr Xue-Qiang Zhang Dr Bo-Quan Li Prof Qiang Zhang |
| Institution: | 1. Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084 P. R. China;2. Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081 P. R. China
School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, 100081 P. R. China;3. Advanced Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing, 100081 P. R. China |
| Abstract: | Lithium–sulfur (Li−S) batteries are promising due to ultrahigh theoretical energy density. However, their cycling lifespan is crucially affected by the electrode kinetics of lithium polysulfides. Herein, the polysulfide solvation structure is correlated with polysulfide electrode kinetics towards long-cycling Li−S batteries. The solvation structure derived from strong solvating power electrolyte induces fast anode kinetics and rapid anode failure, while that derived from weak solvating power electrolyte causes sluggish cathode kinetics and rapid capacity loss. By contrast, the solvation structure derived from medium solvating power electrolyte balances cathode and anode kinetics and improves the cycling performance of Li−S batteries. Li−S coin cells with ultra-thin Li anodes and high-S-loading cathodes deliver 146 cycles and a 338 Wh kg−1 pouch cell undergoes stable 30 cycles. This work clarifies the relationship between polysulfide solvation structure and electrode kinetics and inspires rational electrolyte design for long-cycling Li−S batteries. |
| Keywords: | Electrode Kinetics Lithium Polysulfides Lithium–Sulfur Batteries Pouch Cells Solvation Structure |