Preparation of nitrogen doped CNTs porous carbon materials based on MOF in situ growth and its application in lithium sulfur cathode

Abstract

Porous carbon structure is widely used as sulfur carrier to improve the cycle stability and rate performance of lithium sulfur batteries. However, due to the amorphous carbon structure of porous carbon nanostructures, it is still a big challenge for porous carbon nanostructures to obtain high sulfur content and high sulfur surface density. In order to improve the electronic conductivity of porous carbon, maintain its long cycle life and good rate performance, we prepared N-doped graphitized CNTs by high temperature sintering. CNTs encapsulated bulk porous carbon was prepared using ZIF-67 and melamine as precursors(Co-NC@CNTs/S). The CNTs are "slubby" structure and the tube wall is graphite. Due to the unique structure of Co-NC@CNTs, the positive cathode of Co-NC@CNTs/S has better electrochemical performance than Co-NC/S positive cathode. Under the condition of high sulfur (82wt%), the cathode can not only obtain high discharge capacity (1293mAhg⁻¹ at 0.1C) and excellent rate performance (727.8 mAhg⁻¹), but also achieve long cycle stability of more than 100 cycles (capacity decay rate of each cycle is 0.17%).