Self-Repairable and Flexible Polymer Network Electrolyte with Enhanced Lithium-Ion Conduction for Lithium Metal Batteries

Graphical Self-healing quasi-solid polymer electrolyte (SIPH-x-y%) with good flexibility was prepared by polyaddition method. SIPH-x-y% could show high room temperature ionic conductivity, high lithium ion transference number, and good interfacial stability with electrode. The Li/LFP battery assembled with SIPH-20-40% showed high specific capacity and excellent cycle performance. Developing high-performance functional polymer-based electrolytes is important for realizing next generation safe lithium metal batteries. In this study, a new type of quasi-solid polymer network electrolyte (SIPH-x-y%) was prepared by combining synthesized polymer network (SIPH) containing urethane bond linked ionic liquids (ILs), polyethylene glycol (PEG), and disulfide bond moieties, lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI), and glyme type additive. It was found that SIPH-20-40% was mechanically flexible, self-healable, and showed high ionic conductivity of 2.67×10 −4 S cm −1 . Also, SIPH-20-40% possesses a high lithium ion transference number of 0.43 and good electrochemical stability. These properties enabled the SIPH-20-40% electrolyte membrane to support Li/Li symmetrical cell to cycle stably during long term Li plating and stripping. The Li/SIPH-20-40%/LFP showed high delivered specific capacity and good stability (166.1 mAh g −1 after 106 cycles at 0.2 C). Such glyme doped polymer network electrolyte provides new experimental findings for developing polymer-based electrolyte with excellent mechanical integrity and battery related properties.