Crosslinked Vinyl‐Capped Polyoxometalates to Construct a Three‐Dimensional Porous Inorganic–Organic Catalyst to Effectively Suppress Polysulfide Shuttle in Li–S Batteries

ABSTRACT Polyoxometalates (POMs) show promise for lithium–sulfur (Li–S) batteries but suffer from dissolution in the electrolyte during reaction. Therefore, fabricating stable 3D POM catalysts for high‐performance Li–S batteries presents a challenge. Herein, we address this by attaching acrylic isocyanate ligands to Anderson‐type POM clusters via amine‐isocyanate reactions, forming vinyl‐capped POMs, [( n ‐C 4 H 9 ) 4 N] 3 [MnMo 6 O 24 (C 20 H 30 N 4 O 6 )] (vinyl‐MnMo 6 ) and [( n ‐C 4 H 9 ) 4 N] 3 [CoMo 6 O 24 (C 20 H 30 N 4 O 6 )] (vinyl‐CoMo 6 ). Through further cross‐linking reactions of the capped vinyl groups, these POM monomers form insoluble, non‐crystalline 3D POM frameworks (poly‐MnMo 6 or poly‐CoMo 6 ). Theoretical calculations and in situ Raman spectroscopy demonstrate that organic ligand modification optimizes the electronic structure of POM skeletons, enhancing lithium polysulfide adsorption and catalytic conversion kinetics. As separator modification layers, these frameworks suppress polysulfide shuttling and facilitate uniform Li + diffusion for homogeneous Li deposition. Even under conditions of high sulfur loading (4.0 mg cm −2 ) and high rate (2.0 C), Li–S batteries equipped with poly‐MnMo 6 ‐modified separators are capable of stable operation over 150 cycles with a capacity of 514.7 mAh g −1 . Li//Li symmetric batteries with such separators exhibit stable operation over 1500 h. This study employs end‐group active moieties for cross‐linking to construct 3D porous POM frameworks, establishing a novel strategy for the design of highly active catalytic materials for Li–S batteries.