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

摘要

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/Fe_(3)C-CNTs NFs)are found to be effective catalytic mediators with strong anchoring capabilities for LiPSs.The bamboo-like carbon nanotubes catalyzed by Fe_(3)C/Fe entangled each other to form a conductive network,which encloses a flowerlike 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/Fe_(3)C-CNTs NFs cathode exhibited a remarkable specific capacity(635 mAh g_(s)^(-1))at 3 C and a favorable capacity decay with 0.04%per cycle even after 400 cycles at 1 C.