Bio‐Based Solid Electrolytes Bearing Cyclic Carbonates for Solid‐State Lithium Metal Batteries

Abstract Green resources for lithium‐based batteries excite many researchers due to their eco‐friendly nature. In this work, a sustainable bio‐based solid‐state electrolyte was developed based on carbonated soybean oil (CSBO), obtained by organocatalyzed coupling of CO 2 to epoxidized soybean oil. CSBO coupled with lithium bis(trifluoromethanesulfonyl)imide salt on a bio‐based cellulose separator resulted in free‐standing membranes. Those membranes on electrochemical measurements exhibited ionic conductivity of around 10 −3 S cm −1 at 100 °C and around 10 −6 S cm −1 at room temperature with wide electrochemical stability window (up to 4.6 V vs. Li/Li + ) and transference number up to 0.39 at RT. Further investigations on the galvanostatic charge‐discharge of LiFePO 4 cathodes with CSBO‐based electrolyte membranes and lithium metal anodes delivered the gravimetric capacity of 112 and 157 mAh g −1 at RT and 60 °C, respectively, providing a promising direction to further develop bio‐based solid electrolytes for sustainable solid‐state lithium batteries.