A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

Abstract

Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300°C plays an important role in the sulfur encapsulation process. With 20h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40h at 300°C contained 51.3wt.% sulfur and delivered a high initial capacity of 1375mAhg−1 at 0.1C. Moreover, it showed good capacity retention of 704mAhg−1 at 0.1C and 578mAhg−1 at 2C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries.