Polyoxometalate/cobalt selenide functional separator for synergistic polysulfide anchoring and catalysis in lithium-sulfur batteries

The polysulfides shuttle effect,sluggish sulfur redox kinetics and the corrosion of the Li anode have become important factors limiting the commercial application of lithium-sulfur batteries （LSBs）.Herein,the polyoxometalate （POM） nanoclusters with high catalytic activity and cobalt selenide with strong polarity are initially complemented to construct a PMo12/CoSe2@NC/CNTs multifunctional separator that can simultaneously solve the above problems.A series of experimental and theoretical results demonstrate that the Keggin-type POM,H3PMo12O40nH2O (PMo12) nanoclusters could function as catalytic centers for sulfur-involved transformations,with the CoSe2 nanoparticles serving as adsorption sites for soluble polysulfides.Accordingly,the assembled battery with the PMo12/CoSe2@NC/CNTs modified separator achieves an initial discharge capacity of 1263.79 mA h g-1,maintaining 635.77 mA h g-1,with a capacity decay rate of 0.06%per cycle after 500 cycles at 3C.This work provides a strategic approach for incorporating POM nanoclusters with polar periodic nanomaterials in LSB separators,contributing to the development of multifunctional separator materials,thus promoting the advancement of energy storage systems.