Hollow Carbon Nanofibers Filled with MnO2 Nanosheets as Efficient Sulfur Hosts for Lithium-Sulfur Batteries

Lithium-sulfur batteries have been investigated as promising electrochemical-energy storage systems owing to their high theoretical energy density. Sulfur-based cathodes must not only be highly conductive to enhance the utilization of sulfur, but also effectively confine polysulfides to mitigate their dissolution. A new physical and chemical entrapment strategy is based on a highly efficient sulfur host, namely hollow carbon nanofibers (HCFs) filled with MnO2 nanosheets. Benefiting from both the HCFs and birnessite-type MnO2 nanosheets, the MnO2@HCF hybrid host not only facilitates electron and ion transfer during the redox reactions, but also efficiently prevents polysulfide dissolution. With a high sulfur content of 71wt% in the composite and an areal sulfur mass loading of 3.5mgcm(-2) in the electrode, the MnO2@HCF/S electrode delivered a specific capacity of 1161mAhg(-1) (4.1mAhcm(-2)) at 0.05C and maintained a stable cycling performance at 0.5C over 300cycles.