Tube‐in‐tube Structure Design and In‐situ Growth of Fe3C for Efficient Reaction Kinetics in Lithium‐sulfur Batteries

To improve the sulfur reaction kinetics and inhibit the notorious shuttle effects, a tube‐in‐tube structure decorated by carbon nanotubes (CNT) and Fe 3 C nanoparticles (TIT/Fe 3 C‐CNT) is designed as sulfur host for lithium‐sulfur batteries (LSBs) in this work. The construction of tube‐in‐tube structure increases the active sites and the specific surface area of the material. Additionally, Fe 3 C nanoparticles can effectively adsorb the soluble lithium polysulfides and promote their catalytic conversion, thus greatly alleviating the shuttle effects. As a result of these advantages, the TIT/Fe 3 C‐CNT‐based cathode exhibits a high reversible capacity of 841 mAh g −1 after 200 cycles with a low decay of 0.056 % per cycle at 0.5 C. This work provides a promising and reasonable approach to the rational design of sulfur host for LSBs.