Dynamic Ion‐Pair Networks Enable Selective Li ⁺ Transport for Stable and Efficient Solid‐State Lithium‐Sulfur Batteries

Abstract

ABSTRACT Solid‐state lithium‐sulfur (Li‐S) batteries are intrinsically constrained by persistent Li + ‐anion coordination in polymer electrolytes, which couples Li + migration to anion motion and limits both interfacial stability and sulfur redox kinetics. Here, we show that incorporating an ionic liquid modified ZIF‐67 (IL@ZIF‐67) into a polymer solid electrolyte enables deliberate reorganization of ion coordination and reconfiguration of Li + transport pathways at the molecular level. ZIF‐67 sites preferentially anchor TFSI − , while confined ionic liquid domains reshape Li + coordination, establishing a dynamic ion‐pair network with weakened Li + ‐anion coupling and spatially restricted anions. This coordination reorganization decouples long‐range Li + transport from anion migration, lowers the Li + migration energy barrier, and homogenizes Li + flux across the electrolyte. Consequently, a stable LiF/Li 2 S‐rich solid electrolyte interphase forms at the lithium metal interface, while continuous Li + supply mitigates solid‐solid interfacial polarization and accelerates reversible S─C/S─S bond conversion and Li 2 S nucleation/decomposition kinetics in SPAN cathodes. As a result, the solid‐state Li‐S batteries deliver a high reversible capacity of 1004.97 mAh g −1 after 150 cycles at 0.2 C, prolonged cycling stability over 500 cycles at 1 C with a decay rate of ∼0.06% per cycle, highlighting ion‐pair regulation via ionic‐liquid‐engineered MOF fillers as an effective pathway toward high‐performance solid‐state Li‐S batteries.