Promoting polysulfide redox kinetics by Co9S8 nanoparticle-embedded in N-doped carbon nanotube hollow polyhedron for lithium sulfur batteries.

• The unique wounded CNTs were generated from the pyrolysis of the precursor without the addition of carbon sources. • The embedded Co 9 S 8 nanoparticle was obtained easily and required no further treatment or addition of metal sources. • This structure design strategy could be easily extended. • The Co 9 S 8 @NCNHP/S cathode exhibits the great electrochemical performance. [Display omitted] Lithium-sulfur (Li-S) battery is one of the most promising candidates for next-generation rechargeable batteries, while the volume expansion, severe shuttle effect, and sluggish reaction kinetics hinder its practical applications. Herein, a novel structure composed of Co 9 S 8 nanoparticles embedded in a N-doped carbon nanotube hollow polyhedron (Co 9 S 8 @NCNHP) is designed to address these issues. Co 9 S 8 nanoparticles can efficiently accelerate the kinetics of redox reaction and anchor the polysulfides, enhancing the electrochemical performance of cathodes. Furthermore, NCNHP can accommodate the huge volume expansion and block the diffusion of lithium polysulfides. Benefiting from this rational design, the Co 9 S 8 @NCNHP/S cathode exhibits a high initial discharge capacity of 1186 mAh·g−1 with a decay rate of 0.1% per cycle during 200 cycles at 0.2 C. An initial discharge capacity of 780 mAh·g−1 as well as a decay rate of 0.15% per cycle after 200 cycles can be obtained at a sulfur loading of 3.2 mg·cm−2. This strategy based on the combination of rational structure design and electrocatalysis could advance the cathode construction in Li-S batteries. [ABSTRACT FROM AUTHOR]