Mesoporous Carbon Nanofiber-Sulfur Cathode for Lithium-Sulfur Batteries

Rechargeable lithium-sulfur batteries' commercial applications are still hindered by some major basic obstacles, such as the low electrical conductivity of sulfur and polysulfides, the dissolution of lithium polysulfides in organic electrolyte, and the volume expansion of sulfur during discharge. In this study, a mesoporous carbon nanofiber (MCNF) with graphitic pore wall prepared by an easy self-template strategy was designed to encapsulate sulfur and polysulfides in the carbon framework. The one-dimensional MCNF with graphitic pore wall can provide an effective conductive network for sulfur and polysulfides during cycling. The small mesopore of MCNF can also restrain the diffusion of long-chain polysulfides. Furthermore, MNCF with high volume can encapsulate a relatively high amount of sulfur and provide internal void space to accommodate volume expansion during discharge. The resulting MCNF-sulfur nanocomposite shows high and stable specific capacities of 820 mAh.g(-1) after 100 cycles at a rate of 0.8 A.g(-1).