Nitrogen sulfur dual-doped porous biochar fibers for high performance lithium-sulfur battery

Porous carbons have gained great attention for applications in lithium-sulfur (Li-S) batteries. However, achieving high specific surface area, hierarchical porosity, and abundant heteroatom-doping with facile approaches is still challenging. Herein, nitrogen, sulfur dual-doped hierarchical porous carbons (PBF@N@S) are obtained via a simple and sustainable activation process of cotton fibers. The as-prepared PBF@N@S exhibits a hierarchically interconnected network porous structure and large specific surface area. Meanwhile, abundant nitrogen, sulfur atoms are simultaneously doped in the carbons. These characteristics make the carbon favorable for hosting sulfur. The PBF@N@S sample with 50 wt% sulfur content (PBF@N@S-S-50%) delivers a high initial capacity with excellent cycling performance. Such high performance suggests that the PBF@N@S-S could be a promising cathode material for Li-S batteries.