A Highly Efficient Sulfur Host Enabled by Nitrogen/Oxygen Dual-Doped Honeycomb-Like Carbon for Advanced Lithium-Sulfur Batteries

High energy density and long cycle life of lithium-sulfur (Li-S) batteries suffer from the shuttle/expansion effect. Sufficient sulfur storage space, local fixation of polysulfides, and outstanding electrical conductivity are crucial for a robust cathode host. Herein, a modified template method is proposed to synthesize a highly regular and uniform nitrogen/oxygen dual-doped honeycomb-like carbon as sulfur host (N/O-HC-S). The unique structure not only offers physical entrapment for polysulfides (LiPSs) but also provides chemical adsorption and catalytic conversion sites of polysulfides. In addition, this structure offers enough space for loading sulfur, and a regular space of nanometer size can effectively prevent sulfur particles from accumulating. As expected, the as-prepared N/O-HC900-S with high areal sulfur loading (7.4 mg cm(-2)) shows a high areal specific capacity of 7.35 mAh cm(-2) at 0.2 C. Theoretical calculations also reveal that the strong chemical immobilization and catalytic conversion of LiPSs attributed to the spin density and charge distribution of carbon atoms will be influenced by the neighbor nitrogen/oxygen dopants. This structure that provides cooperative chemical adsorption, high lithium ions flux, and catalytic conversion for LiPSs can offer a new strategy for constructing a polysulfide confinement structure to achieve robust Li-S batteries.

Automated summary

A modified template method was proposed to synthesize nitrogen/oxygen dual-doped honeycomb-like carbon as a sulfur host, which offers physical entrapment and chemical adsorption/catalytic conversion sites for polysulfides, resulting in high sulfur loading and specific capacity. This structure provides a new strategy for constructing polysulfide confinement structures to achieve robust Li-S batteries.