Nickle-doped covalent organic frameworks/carbon nanotubes composite for high-performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are considered to be one of the most promising next-generation energy storage systems. In order to mitigate the shuttle effect of lithium polysulfides (LiPSs) in LSBs, the rational design of sulfur host with high physical confinement and catalytic activity is critical to enhance the performance of LSBs. Here, we successfully prepare a nickle-doped covalent organic frameworks/carbon nanotubes composite (Ni/COFs/CNTs) as the sulfur host in LSBs. COFs can confine and immobilize sulfur species. Moreover, CNTs and Ni nanoparticles can provide fast electron transfer pathways. Thus, Ni/COFs/CNTs composite can alleviate the shuttle effect during the cycling processes. The S/Ni/COFs/CNTs cathode displays a high initial reversible capacity of 1068.6 mAh g−1 and a high capacity retention (83.3 %) after 100 cycles at 0.1C. This work provides a useful strategy to the rational design of sulfur host for LSBs.