Fe-Nx Sites enriched microporous carbon nanoflower planted with tangled bamboo-like carbon nanotube as a strong polysulfides anchor for lithium–sulfur batteries

Serious shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPSs) have a massive impact on obstructing the practical application of lithium-sulfur (Li–S) batteries. To address such issues, Fe-Nx sites enriched microporous nanoflowers planted with tangled bamboo-like carbon nanotubes (Fe-Nx-C/Fe₃C-CNTs NFs) are found to be effective catalytic mediators with strong anchoring capabilities for LiPSs. The bamboo-like carbon nanotubes catalyzed by Fe₃C/Fe entangled each other to form a conductive network, which encloses a flower-like microporous carbon core with embedded well-dispersed Fe-Nx active sites. As expected, electrons smoothly transfer along the dense conductive bamboo-like carbon network while the flower-like carbon core consisting of micropores induces the homogeneous distribution of tiny sulfur and favors the lithium ions migration with all directions. Meanwhile, Fe-Nx sites strongly trap long-chain LiPSs with chemical anchoring, and catalyze the redox conversion of LiPSs. Due to the aforementioned synergistic effects, the S@Fe-Nx-C/Fe₃C-CNTs NFs cathode exhibited a remarkable specific capacity (635 mAh ${\rm{g}}_{\rm{s}}^{{\rm{ - 1}}}$) at 3 C and a favorable capacity decay with 0.04% per cycle even after 400 cycles at 1 C.