Nitrogen and Sulfur Co-doped Two-Dimensional Highly Porous Carbon Nanosheets for High-Performance Lithium-Sulfur Batteries

The multiple electron redox reactions of lithium (Li) and sulfur (S), concomitantly producing a series of lithium polysulfide intermediates, generally exhibit an insufficient cycle life and poor rate performance of lithium-sulfur (Li- S) batteries. This work reports a single-step and facile synthetic strategy for fabricating uniform, micro- and mesoporous, nitrogen-sulfur co-doped carbon nanosheets anchored on the surface of reduced graphene oxide (denoted as CNS@rGO). The composite was prepared by polymerizing m-aminobenzene sulfonic acid on the surface of graphene oxide (GO) and subsequent carbonization. The obtained CNS@rGO contains uniform micro- and mesopores for better sulfur loading and further accommodation of the discharged polysulfides. Such a free-standing electrode exhibits a stable specific capacity of 1355 mA h/g at 0.1 C (100 mA g(-1)) and good rate performance. CNS@rGO shows promising characteristics as a high-performance cathode material for Li-S batteries. Furthermore, even at a high current density of 1 C (1 A g(-1)), it exhibits high storage with a capacity of 476 mA h g(-1) over 300 cycles with a decay of 16.8%, which outperforms all previously reported carbon-based materials for Li-S batteries.

Automated summary

This study reports a low-cost and high-performance cathode material for lithium-sulfur batteries by preparing nitrogen-sulfur co-doped carbon nanosheets anchored on the surface of reduced graphene oxide.