Catalytic nanoreactors of interwoven MoSe2-CoSe@C heterostructure accelerating polysulfide redox in lithium-sulfur batteries

Single-component transition metal selenide (TMSe) hosts still struggle to balance the adsorption of lithium polysulfides (LPSs) and their catalytic conversion. Herein, a heterostructure host (MoSe 2 -CoSe@C) with an intra-spherical interwoven architecture was synthesized via impregnation-chemical vapor deposition. Benefiting from the synergy of adsorptive MoSe 2 and conductive CoSe, the heterointerface induces electron transfer from CoSe to MoSe 2 , upshifting the d-band center to enhance LPSs adsorption. Compared with their single-component hosts, the MoSe 2 -CoSe@C notably reduces the energy barriers of sulfur redox reactions, decreasing those for Li 2 S oxidation by 31.45 kJ mol −1 and for Li 2 S 4 reduction by 191.67 kJ mol −1 . Additionally, Co acts not only as a core component of the heterostructure but also induces the conversion of carbon-based materials into carbon nanotubes at high temperatures, thus forming a unique interwoven network. This network not only ensures efficient electron transport and inhibits the agglomeration of active components, but also increases the contact area between the host and active sulfur, thereby enhancing the number of effective catalytic sites. Consequently, the MoSe 2 -CoSe@C/S cathode achieves a discharge specific capacity of 582.1 mAh g −1 at a current density of 5C, with only 0.07% capacity decay per cycle over 200 cycles at 4C. This work provides a strategy to construct high-performance adsorption-catalytic hosts for lithium‑sulfur batteries (LSBs).