Liu Qiuyan, Xu Shiwei, Li Xiaoyun, Chen Renjie, Wang Xuefeng, Gao Yurui, Wang Zhaoxiang, Chen Liquan
Key Laboratory for Renewable Energy, Chinese Academy of Sciences, Beijing Key Laboratory for New Energy Materials and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100190, China.
Nano Lett. 2023 Apr 12;23(7):2623-2629. doi: 10.1021/acs.nanolett.2c04898. Epub 2023 Mar 16.
Polymer electrolytes have been studied as an alternative to organic liquid electrolytes but suffer from low ionic conductivity. Propylene carbonate (PC) proves to be an interesting solvent but is incompatible with graphitic anodes due to its cointercalation effect. In this work, adding poly(ethylene oxide) (PEO) into a PC-based electrolyte can alter the solvation structure as well as transform the solution into a polymer electrolyte with high ionic conductivity. By spectroscopic techniques and calculations, we demonstrate that PEO can compete with PC in solvating the Li ions, reducing the Li-PC bond strength, and making it easier for PC to be desolvated. Due to the unique solvation structure, PC-cointercalation-induced graphite exfoliation is inhibited, and the reduction stability of the electrolyte is improved. This work will extend the applications of the PC-based electrolytes, deepen the understandings of the solvation structure, and spur designs of advanced electrolytes.
