Enhanced Stability of Nitrogen Doped Porous Carbon Fiber on Cathode Materials for High Performance Lithium-Sulfur Batteries

Abstract

Lithium-sulfur (Li-S) batteries are considered to be one of the candidates for high-energy density storage systems due to their ultra-high theoretical specific capacity of 1675 mAh g^-1. However, problems of rapid capacity decay, volume of the active material expands sharply, and shuttle effect have severely restricted its subsequent development and utilization. Herein, we design a nitrogen-doped porous carbon nanofiber (NPCNF) network as sulfur-host by the template method. The NPCNF shows feather-like structure. After loading sulfur, NPCNF/S composite can keep a hierarchically porous structure. A high discharge capacity of 1301 mAh g^-1 is delivered for NPCNT/S composite at 0.1 C. The reversible charge/discharge capacity at 2 C is 576 mAh g^-1, and 700 mAh g^-1 is maintained after 500 cycles at 0.5 C. The high electrochemical performance of this NPCNT/S composite is attributed to the synergy effects of abundant N active sites and high electrical conductivity of the material.

Keywords: Lithium-sulfur battery, Porous carbon nanofiber, doped Nitrogen