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

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 CO2 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 LiFePO4 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.