Fe-Nx Sites Enriched Microporous Carbon Nanoflower Planted with Tangled Bamboo-like Carbon Nanotube as a Strong Polysulfides Anchor for Lithium-Sulfur Batteries

Abstract 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 this issue, Fe-Nx sites enriched microporous nanoflowers planted with tangled bamboo-like carbon nanotubes (Fe-Nx-C/Fe3C-CNTs NFs) are reported as effective catalytic mediators with strong anchoring capabilities for LiPSs. Huge-diameter hollow bamboo-like carbon nanotubes, generated with the catalysis of Fe3C/Fe, entwine with each other to form an inartificial conductive network subsequently, and thus package the flower-like microporous carbon core embedded with 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 gs-1) at 3 C and a favorable capacity decay with 0.04% per cycle even after 400 cycles at 1 C.