Single-atom decorated hollow mesoporous carbon spheres composited with free-standing carbon cloth supported cobalt sulfide nanowire arrays as high-performance sulfur host for lithium-sulfur batteries

Background: Lithium-sulfur batteries (LSBs) are a promising next generation electrochemical energy storage device. Its commercialization however is hindered by several technical challenges, particularly shuttling of polysulfides. Methods: A composite sulfur host, coupled with a porous current collector, was developed to mitigate the shuttling problem. Iron single atom (SAFe) decorated hollow mesoporous carbon spheres (HMCS), composited with cobalt sulfide nanowire arrays supported on free-standing carbon cloth (S-Co@CC), were fabricated as a high-performance sulfur host for LSBs. The sulfur host combines the high electrical conductivity and physical confinement capability of HMCS, the excellent polysulfides chemisorption capability of cobalt sulfide nanowire arrays, and the high catalytic efficiency of iron single atoms toward polysulfide conversion reactions, to achieve a high-performance LSB. Significant findings: The S-Co@CC/SAFe-HMCS based LSB exhibited a high initial specific capacity of 1430 mAh g- 1 at 0.1 C. For cycling stability, a specific capacity of 578 mAh g- 1 was maintained after a 600-cycle operation at 1 C, achieving an ultralow average capacity decay rate of 0.029 % per cycle. The design of composite sulfur hosts, combining all functional components in one, proves to be an effective strategy to advance the development of high-performance LSBs.