Ionic liquid enhanced composite solid electrolyte for high-temperature/long-life/dendrite-free lithium metal batteries

The composite solid electrolytes (CSEs) inherits the high safety of the inorganic solid electrolyte and the easy processing of the organic polymer electrolyte , thereby exhibiting a broad application prospect. However, the performance of the CSE was hard to realizing its practical application in lithium metal batteries . Herein, the significant impact of CSE performance brought about by the addition of ionic liquids was studied and summarized: significantly increase ionic conductivity ; constructing a viscoelastic interface between electrode and electrolyte to reduce the interface impedance; forming a stable and LiF-rich SEI at the negative electrode to inhibit the growth of lithium dendrites ; wetting the LiFePO 4 porous cathode. The LiFePO 4 /CSE-60/Li battery displays high initial discharge specific capacity of 158.2 mAh g −1 and a capacity retention of 86.3% after 400 cycles at 1 C at 55 °C, and with coulombic efficiency of 99.7%. The surface of the lithium metal anode after long-term cycling exhibits to dendrite-free morphology. This research highlights the critical role that ionic liquids play in improving the performance of CSEs and will shed light on designing CSEs for LMB practical applications.