Tailoring eco-friendly siloxane-based electrolytes for high-performance lithium–sulfur batteries

Abstract

Lithium–sulfur batteries (LSBs), with their ultra-high theoretical energy density (2600 Wh kg⁻¹), are considered one of the most attractive high-energy batteries. However, the “shuttling effect” of polysulfides and the uncontrolled growth of lithium (Li) dendrites pose significant challenges to the practical implementation of LSBs. Herein, a lightweight and eco-friendly diethoxydimethylsilane (DEMS) is chosen as a multi-functional solvent for LSBs. The low polarity of DEMS promotes the “solid–solid” conversion of sulfurized polyacrylonitrile (SPAN) during charge–discharge processes, eliminating the shuttle effect of polysulfides. Moreover, the DEMS-based electrolyte enables highly reversible Li plating/stripping processes across a wide temperature range spanning from −20 to 60 °C. As a result, the Li/SPAN batteries using the DEMS electrolyte exhibit excellent cyclic stability at 0.2 C with retainable capacities of 524.4 mAh/g after 200 cycles, 598.8 mAh/g after 100 cycles, and 318.6 mAh/g after 50 cycles at 26, 60 and −20 °C, respectively. This study aims to identify low-cost and highly stable electrolytes through solvent screening to enhance the electrochemical performance of LSBs.