Benzo-crown ether electrolyte additives in facilitating sulfur evolution and lithium anode stabilization for high-performance lithium–sulfur batteries†

Abstract

The application of lithium–sulfur (Li–S) batteries faces challenges such as sluggish redox kinetics of sulfur species and damage to the lithium anode. Herein we introduce crown ether-based electrolytes as additives to address these issues. Density functional theory (DFT) results verified the validity of dibenzo-24-crown-8 (D24C8), which was found to promote sulfur species conversion kinetics. Furthermore, the D24C8 additive enabled the reversion of lithium plating/stripping, suppressed dendrite growth and mitigated detrimental side reactions at the lithium anode caused by LiPSs. D24C8 exhibits outstanding performance in modulating the orbital energy levels of sulfur species and improving lithium anode stability, so it can be used as a bifunctional additive for regulating Li–S batteries. Li–S batteries with D24C8 demonstrated promising high-rate performance and long-term cycling stability, with over 1200 cycles at a 2 C rate and a capacity decay of only 0.034% per cycle. This work presents advanced electrolyte design for next-generation sustainable Li–S batteries and provides insights into optimizing analogous multiphase electrochemical energy-efficient reaction processes.