Core–Shell-Structured S@rGO-void-CoSe₂Cathode Material for High-Performance Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs), despite their high theoretical energy density (∼2600 Wh/kg), are facing critical challenges, including the insulating nature of sulfur, polysulfide shuttling effect, and severe volume expansion. To address these issues, this work designs a core–shell-structured S@rGO-void-CoSe₂composite cathode through synergistic material-structure engineering. The three-dimensional reduced graphene oxide (rGO) network established as a conductive framework to enhance electron transport, while polar CoSe₂nanosheets chemically anchored polysulfides and catalytically accelerated their redox conversion. The SiO₂-templated hollow structure provided a buffer space to accommodate sulfur volume changes. Electrochemical properties were evaluated as follow, the electrode delivers an initial discharge capacity of 1124.2 mAh/g at 0.1C with 63.6% capacity retention after 100 cycles. Remarkably, under 1C cycling, it maintains 270 mAh/g after 1000 cycles with an ultralow decay rate of 0.065% per cycle, and outperforming behavior is better than that of conventional sulfur cathodes. This study demonstrates a multifunctional design strategy by integrating conductive networks, catalytic interfaces, and structural optimization. This study can offer a promising pathway toward high-energy and long-cycle-life LSBs.