Effects of Activation Process on Catkin Derived Carbon Materials and Its Electrochemical Performance as Matrix in Cathode of Li‐S Battery

Abstract

AbstractWillow catkin was selected as raw material to fabricated carbon matrix in cathode of lithium‐sulfur (Li−S) battery due to its unique tubular morphology. The effects of activation time on the microstructure and electrochemical properties were investigated. The direct pyrolysis product inherited the tube‐like morphology. After activated by KOH under high temperature once, the microtubes were shorten and pressed as ribbon‐like. Meanwhile abundant micropores were formed in the tube wall. Further activatated the product twice, the original tube‐like microstructure was collapsed. Thus the results demonstrated that extending the activation time greatly affected the microstructure of carbon product. Furthermore, the sample activated once exhibited the largest specific surface area of 2033.09 m2 g−1 and the largest sulfur loading ratio (71.1 %). Moreover, the suitable activated sample exhibited the highest specific discharge capacity (1365.8 mAh g−1) and the best cycling performance. Consequently, the activation process played an important role in the microstructure and electrochemical performance of catkin derived carbon matrix in Li−S battery.