Ionic liquid assisted quasi-solid-state polymer electrolyte for rechargeable lithium metal batteries operating at room temperature

• Published in: Electrochimica acta Vol. 440; p. 141753
• Main Authors: Yuan, Yan, Xue, Kesi, Ma, Yitian, Peng, Xiuping, Wang, Bin, Liu, Xuyi, Liu, Manbo, Song, Yonghui, Lu, Hai
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2023
• Subjects: Ionic liquid; Lithium metal battery; PVDF; Solid electrolyte interphase; Solid polymer electrolyte; Solid electrolyte interphase; Lithium metal battery; PVDF; Solid polymer electrolyte; Ionic liquid
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2022.141753

•A IL-assisted quasi-solid-state polymer electrolyte was fabricated for lithium metal batteries.•The released IL under pressure serves as in-situ electrode surface wetter and solid/electrolyte interphase modifier.•The IL-assisted QSPE holds favorable overall properties and endows superior room-temperature performance for LMBs. Solid-state electrolytes are emerging as a promising approach to improve the safety and cycle life of lithium metal batteries (LMBs). However, low ionic conductivity, narrow potential window and deficient interfacial contact with the electrodes greatly hinder their practical applications. Herein, an ionic liquid (IL)-assisted quasi-solid-state polymer electrolyte (QSPE) by incorporating functional Pyr14TFSI into the PVDF matrix is developed. Profitted from the inherent interaction between the IL and polymer, the optimizedly-designed QSPE holds favorable overall properties including ionic conductivity, electrochemical window, Li ion transfer number and mechanical strength. Moreover, the SEM, XPS and EIS analyses reveal that the released IL under external pressure during cell assembly serves as a in-situ electrode surface wetting agent to promote ionic transport and charge transfer, as well as a solid/electrolyte interphase modifier to mitigate the electrolyte degradation and homogenize Li deposition. Consequently, the assembled quasi-solid-state LMBs demonstrate superior cycle and rate capability at room temperature. An ionic liquid (IL)-assisted quasi-solid-state polymer electrolyte by incorporating the functional Pyr14TFSI into the PVDF matrix was developed for advanced lithium metal batteries, in which the IL serves as both electrode surface wetter and solid/electrolyte interphase modifier. [Display omitted]