Hierarchical micro-mesoporous carbon prepared from waste cotton textile for lithium-sulfur batteries

Abstract

As the next generation battery, the lithium-sulfur battery with high theoretical specific capacity and energy density needs to overcome the low practical discharge capacity and the poor cycle performance for the poor conductivity of sulfur and the shuttle effect of polysulfide. In this study, a hierarchical micro-mesoporous carbon (HPC) is designed and synthesized as a sulfur host from the cotton textile with KOH activation at 700 °C to combine the advantages of these two structures, where mesoporous structure can improve the infiltration of electrolyte to act as fast ionic channel and micropores have an excellent ability of binding sulfur. The HPC showed an excellent high specific surface area (2835.47 m2 g−1) and a high pore volume (2.82 cm3 g−1), and the ratio of the mesoporous reaches 57.85%. The sulfur in HPC/S was uniformly distributed in the host structure and no surface crystallization was observed by TEM characterization. Assembled in the lithium-sulfur battery, the cathode mixed with HPC/S and conductive agent delivers an initial discharge capacity of 1577 mAh g−1 at 0.1C, and a reversible capacity of 434.5 mAh g−1 after 300 cycles at the current rate of 1C.