Wide-Temperature and High-Rate Operation of Lithium Metal Batteries Enabled by an Ionic Liquid Functionalized Quasi-Solid-State Electrolyte

The development of high-energy-density solid-state lithium metal battery has been hindered by the unstable cycling of Ni-rich cathodes at high rate and limited wide-temperatures adoptability. In this study, an ionic liquid functionalized quasi-solid-state electrolyte (FQSE) is prepared to address these challenges. The FQSE features a semi-immobilized ionic liquid capable of anchoring solvent molecules through electrostatic interactions, which facilitates Li+ desolvation and reduces deleterious solvent-cathode reactions. The FQSE exhibits impressive electrochemical characteristics, including high ionic conductivity (1.9 mS cm-1 at 30 degrees C and 0.2 mS cm-1 at -30 degrees C) and a Li+ transfer number of 0.7. Consequently, Li/NCM811 cells incorporating FQSE demonstrate exceptional stability during high-rate cycling, enduring 700 cycles at 1 C. Notably, the Li/LFP cells with FQSE maintain high capacity across a wide temperature range, from -30 to 60 degrees C. This research provides a new way to promote the practical application of high-energy lithium metal batteries. An ionic liquid functionalized quasi-solid-state electrolyte (FQSE) is fabricated. The FQSE demonstrates outstanding electrochemical properties and can effectively inhibits side reactions between the electrolyte and Ni-rich cathodes. It enables Li/NCM811 cells to achieve stable cycling, enduring up to 700 cycles at 1 C. image