Bio-Based Solid Electrolytes Bearing Multi-Functional Cyclic Carbonates for Solid-State Lithium Batteries

Abstract

The solid-state battery has drawn a huge interest with its motive to overcome the issues and challenges faced by batteries using conventional liquid electrolytes. The novel idea of using green approaches or bio-based sources for lithium batteries excites many researchers due to their eco-friendly, less carbon footprint in its synthesis and recycling at the end. In this work, we report a full bio-based solid-state electrolyte based on functionalised carbonated soybean oil (CSBO) obtained from the naturally occurring epoxidised soybean oil (ESBO) using CO2 and biomass. CSBO shows remarkable adhesive properties as characterized by rheological measurements owing to its bigger chains bearing multifunctional cyclic carbonates. LiTFSI salt reinforced CSBO was characterized following standard electrochemical measurements exhibiting ionic conductivity to ≈ 10–3 S cm–1 at 100 ºC and 10–5 S cm–1 at room temperature. The electrochemical window for this electrolyte was obtained to be 4.8 V (vs. Li/Li+) and transference number up to 0.31, allowing it to be explored for high voltage cathodes. CBSO shows stable stripping and plating behaviour for longer cycles making it a good candidate for higher columbic efficiency electrolyte batteries. We also demonstrated the galvanostatic charge-discharge of LiFePO4 (Lithium Ferrrophosphate, LFP) with CSBO electrolytes delivering the gravimetric capacity of 110 mAhg-1 and 150 mAhg-1 appx. at ambient room and higher temperature respectively. Therefore, our study provides a promising direction of developing bio-based solid electrolytes to facilitate progress in sustainability, cost-effective and safe manner to create a solid-state lithium-ion battery for global utilization. Figure 1