An In Situ Grown Anderson-Type Polyoxometalate-Based COFs Catalyst on Cobalt Hydroxide for Enhanced Polysulfide Conversion in Lithium–Sulfur Batteries

The shuttle effect has long been a major factor limiting the performance of lithium–sulfur batteries. In this paper, we prepared a POM-COF@Co(OH)2-NH2 composite material by in situ growth of an Anderson-type polyoxometalate-based covalent organic framework (POM-COF) on the surface of amino-functionalized layered cobalt hydroxide (Co(OH)2-NH2), and applied it to lithium–sulfur (Li–S) battery separators. This composite combines the strong polar chemical adsorption of Co(OH)2 with the high catalytic activity of POM-COF, effectively suppressing lithium polysulfide (LiPS) shuttling. Extensive characterizations confirmed the material’s structure, revealing its unique 3D nanoflower-like morphology and good crystallinity. Electrochemical tests showed that Li–S batteries with this composite separator achieved an initial capacity of 893 mAh g–1 at 1C, retaining 784 mAh g–1 after 300 cycles (87.7% capacity retention, a capacity fade rate of 0.04% per cycle). This work offers a new strategy for designing multifunctional composite separators and is highly significant for advancing Li–S battery technology.