Inhibition of polysulfide shuttling in high-polarity electrolytes via liquid/quasi-solid interface in lithium-sulfur batteries

The shuttle effect is one of the most notable challenges in the fundamental research and practical use of lithium-sulfur (Li-S) batteries, especially within high-polarity electrolytes containing enriched polysulfides. Herein, we demonstrate a proof-of-concept study showing that the issue can be resolved by constructing a liquid-state/quasi-solid-state (LS/QSS) two-phase interface that is composed of a high-polarity QSS electrolyte and a weak-polarity LS one. The weak-polarity electrolyte shows negligible solubility to polysulfides and good compatibility to Li metal, resulting in the substantially improved cyclic stability of the Li anode for more than 1400 h in Li∣Li symmetrical cells. Moreover, over 300 cycles were achieved in the Li-S battery with the polysulfide-enriched LS/QSS electrolyte. This finding indicates that the LS/QSS electrolyte can effectively suppress the chemical reaction between electrolyte components and lithium metal. The concept of LS/QSS two-phase electrolyte provides a new strategy for the application of high-polarity solvents in energy conversion/storage devices.