Healable, Highly Conductive, Flexible, and Nonflammable Supramolecular Ionogel Electrolytes for Lithium-Ion Batteries

High-performance solid-state electrolytes with healability to repair mechanical damages are important for the fabrication of Li-ion batteries (LIBs) with enhanced safety and prolonged service life. In this study, we present the fabrication of healable, highly conductive, flexible, and nonflammable ionogel electrolytes for use in LIBs by loading ionic liquids and Li salts within a hydrogen-bonded supramolecular poly(ionic liquid) copolymer network. The ionogel electrolytes exhibit ionic conductivities as high as 10-3 S/cm, which is comparable to the conventional liquid electrolytes. The Li/LiFePO4 battery assembled with the ionogel membrane exhibits excellent cycling performance and delivers a steady high discharge capacity of 147.5 mA h g-1 and Coulombic efficiency of 99.7% after 120 cycles at the charge/discharge rate of 0.2 C. Importantly, the ionogel membranes can heal damages outside or inside a battery because of the reversible nature of the supramolecular interactions between the components. The damaged ionogel membranes after being healed can effectively restore the original performance of the LIBs.