Organic-inorganic hybrid electrolytes from ionic liquid-functionalized octasilsesquioxane for lithium metal batteries

The use of highly conductive solid-state electrolytes to replace conventional liquid organic electrolytes enables radical improvements in the reliability, safety and performance of lithium batteries. Here, we report the synthesis and characterization of a new class of nonflammable solid electrolytes based on the grafting of ionic liquids onto octa-silsesquioxane. The electrolyte exhibits outstanding roomerature ionic conductivity (∼4.8 × 10^-4 S cm^-1), excellent electrochemical stability (up to 5 V relative to Li⁺/Li) and high thermal stability. All-solid-state Li metal batteries using the prepared electrolyte membrane are successfully cycled with high coulombic efficiencies at ambient temperature. The good cycling stability of the electrolyte against lithium has been demonstrated. This work provides a new platform for the development of solid polymer electrolytes for application in roomerature lithium batteries.