Functionalized N-Doped Porous Carbon Nanofiber Webs for a Lithium-Sulfur Battery with High Capacity and Rate Performance

Functionalized N-doped porous carbon nanofiber webs/sulfur (N-PCNF/S) composites are first proposed as the cathode materials for an advanced lithium-sulfur battery. The functionalized N-doped porous carbon nanofiber webs (N-PCNF) with an appropriate N doping (4.32 wt %) are synthesized by a facile approach, which consists of pyrolyzation of polypyrrole nanofiber and a subsequent KOH activation. Instrumental analysis shows that N-PCNF possesses a large specific surface area (2642 m(2) g(-1)) and a high inner pore volume (1.31 cm(3) g(-1)). When evaluating its electrochemical properties in a lithium-sulfur battery, the N-PCNF/S composite with 77.01 wt % sulfur content displays an excellent electrochemical performance. The specific discharge capacity still reaches 749.8 mAh g(-1) after 180 cycles at 0.2 C. At a higher rate of 1 C, the capacity stabilizes at 666.0 mAh g(-1) after 200 cycles. This work demonstrates that combining the favorable aspects of N doping modification and one-dimensional nanostructure in the carbon matrix design is an effective way to improve the electrochemical performance of the carbon/sulfur cathodes.