Flexible and freestanding heterostructures based on COF-derived N-doped porous carbon and two-dimensional MXene for all-solid-state lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered as one of the best future profession power sources owing to their ultrahigh energy density. Nevertheless, the commercialized Li-S batteries is challenging owing to the shuttle effect of lithium polysulfides (LiPSs), poor electronic activity of sulfur and safety issues. In this work, flexible and binder-free 3D porous 1,3,5-triformylbenzene-tris(4-aminophenyl) amine (Tf-TAPA) covalent-organic framework (COF) derived N-doped carbon (CTT)/ 2D transition metal carbides and nitrides (MXene) paper is designed as electronic conductive sulfur host to restrict the LiPSs. To boost the safety of Li-S batteries and further reduce the LiPSs diffusion, all-solid-state Li-S batteries are constructed by utilizing polyethylene oxide (PEO)-based solid electrolyte with low LiPSs solubility and high safety. With the synergistic advantages of porous and electronic conductive CTT, MXene and solid-state electrolyte, the all-solid-state Li-S batteries display excellent safety character and stable cycling stability about 584 mAh g−1 even after 100 cycles.