Organic-inorganic catalytic separator for robust Li-S batteries via ethanedithiol-functionalized VSe2 with ligand strategy

Overcoming polysulfide shuttling and sluggish sulfur electrochemistry remains pivotal for viable lithium-sulfur batteries. Herein, we develop an organic–inorganic catalytic interface engineered through molecular anchoring of ethanedithiol (EDT) on VSe 2 nanosheets (SH-VSe 2 ), which concurrently tailors the electronic structure and mediates dynamic redox processes. EDT coordination upshifts the d-band center of vanadium sites, strengthening polysulfide chemisorption while enhancing intrinsic catalytic activity. Critically, the surface-tethered EDT operates as a non-migratory redox mediator, drastically reducing Li 2 S nucleation/dissolution barriers through forming –SLi intermediate. When this catalyst is located at the cell separator, this synergistic design enables to transcend conventional adsorption-catalysis trade-offs in individual inorganic or organic catalyst systems by integrating polysulfide confinement with accelerated reaction kinetics. Consequently, Li–S batteries achieve exceptional rate capability (>760 mAh g −1 at 8C), extended cyclability (>80 % capacity retention over 500 cycles), and practical operation under high sulfur loading (5.2 mg cm −2 ). This work establishes a new strategy to boost Li–S cell performance based on the incorporation of organic redox mediator coupling inorganic catalysts by ligand functionalization. For the art of minimal effort for maximum effect, an ethanedithiol (EDT)-modified VSe 2 (SH-VSe 2 ) organic-inorganic catalyst was developed. The facile integration of VSe 2 with EDT simultaneously tailors the catalyst’s electronic structure and regulates polysulfide conversion, suppressing the shuttle effect and accelerating Li 2 S redox kinetics to synergistically boost Li–S battery performance.