Honeycomb-like Nitrogen and Sulfur Dual-Doped Hierarchical Porous Biomass-Derived Carbon for Lithium-Sulfur Batteries

Honeycomb-like nitrogen and sulfur dual-doped hierarchical porous biomass-derived carbon/sulfur composites (NSHPC/S) are successfully fabricated for high energy density lithium-sulfur batteries. The effects of nitrogen, sulfur dual-doping on the structures and properties of the NSHPC/S composites are investigated in detail by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and charge/discharge tests. The results show that N, S dual-doping not only introduces strong chemical adsorption and provides more active sites but also significantly enhances the electronic conductivity and hydrophilic properties of hierarchical porous biomass-derived carbon, thereby significantly enhancing the utilization of sulfur and immobilizing the notorious polysulfide shuttle effect. Especially, the as-synthesized NSHPC-7/S exhibits high initial discharge capacity of 1204mAhg(-1) at 1.0C and large reversible capacity of 952mAhg(-1) after 300cycles at 0.5C with an ultralow capacity fading rate of 0.08% per cycle even at high sulfur content (85wt%) and high active material areal mass loading (2.8mgcm(-2)) for the application of high energy density Li-S batteries.