Cobalt Sulfide Nanoparticles Embedded Carved Carbon Nanoboxes Dispersed in Iron Single-Atom decorated Multiwalled Carbon Nanotube Porous Structure as a Host Material for Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs) are promising electrochemical energy storage devices to answer ever-increasing energy storage demands. Its practical applications, however, are impeded by several technical obstacles, with shuttling of polysulfides as the main cause. A composite approach was developed for the design of effective sulfur host materials to tackle the issue. Here, cobalt sulfide nanoparticles embedded in carved N-doped carbon nanoboxes dispersed in iron single-atom decorated multiwalled carbon nanotube porous structure, S-Co@CCNB/SAFe-MWCNT, were developed as an effective sulfur host for LSBs. The sulfur host combines the high electrical conductivity and physical polysulfide confinement capability of MWCNTs, the excellent polysulfides chemisorption capability of CoS2, and the high catalytic efficiency of iron single-atoms toward polysulfide conversion reactions, to achieve a high performance LSB. The S-Co@CCNB/SAFe-MWCNT based LSB delivered a high initial specific capacity of 1432 mAh g–1 at 0.1 C, with a decent specific capacity of 538 mAh g–1 maintained at 2 C. For cycling stability, a specific capacity of 550 mAh g–1 was maintained after a 500-cycle operation at 1 C, giving a low average capacity decay rate per cycle of 0.043%.