Synthesis of hollow S/FeS2@carbon nanotubes microspheres and their long- term cycling performances as cathode material for lithium-sulfur batteries

The lithium-sulfur batteries as a promising next-generation rechargeable battery are practically limited by their poor long-term cycling performance originating from the dissolution of lithium polysulfides. Combining phys-ical and chemical interactions to trap lithium polysulfides is an effective way to improve the long-term cycling performance. Herein we have synthesized the hollow S/FeS2@Carbon nanotubes (S/FeS2@CNTs) microspheres by loading sulfur into FeS2@CNTs microspheres with carbon nanotubes entangling hollow FeS2 microspheres. The hollow S/FeS2@CNTs microspheres working as cathode for lithium-sulfur batteries have delivered initial discharge capacity of 1245 mA h g(-1) at 0.2 C. Particularly, the long-term cycling performance has been achieved that the capacity beyond 440.2 mA h g(-1) can maintain for 500 cycles at 1 C, with a low capacity decay rate of 0.024 % per cycle. The significantly improved cycling performance of S/FeS2@CNTs can be attributed to the synergistic effects that the dissolution of lithium polysulfides diminishes by combining the physical inter-action of CNTs with chemical absorption of FeS2, as well as the volume expansion of the cathode can be alle-viated by the internal void space.

Automated summary

In this study, hollow S/FeS2@CNTs microspheres were synthesized by loading sulfur into hollow FeS2 microspheres with carbon nanotubes. The resulting cathode material for lithium-sulfur batteries exhibited high initial discharge capacity and excellent long-term cycling performance.