| Abstract Scope |
Potassium-sulfur (K-S) batteries are considered to a promising technology for large-scale energy storage due to their high theoretical energy density and the abundance of both potassium and sulfur. However, their practical application has been severely limited by the polysulfide shuttling effect at the sulfur cathode and the uncontrollable dendrite growth on the potassium metal anode, which together lead to rapid capacity fading and poor cycling stability. Herein, we developed a localized high-concentration electrolyte (LHCE) system consisting of potassium bis(fluorosulfonyl)imide (KFSI) dissolved in a mixed solvent of tetraethylene glycol dimethyl ether (G4), 1,3-dioxolane (DOL), and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TTE). The rational design of this multi-solvent system enables the modulation of solvent coordination to suppress the dissolution of potassium polysulfides. As a result, the cycling performance of the K-S battery is significantly improved, demonstrating the effectiveness of this electrolyte design strategy in addressing the intrinsic challenges of K-S battery chemistry. |