Sulfur Encapsulated in a TiO2-Anchored Hollow Carbon Nanofiber Hybrid Nanostructure for Lithium–Sulfur Batteries

Graphical Good conduct : A core–shell hybrid architecture hollow carbon nanofiber@titanium dioxide (HCNF@TiO 2 ) composite has been successfully prepared as an improved conductive matrix for encapsulating sulfur as a cathode material for lithium–sulfur batteries. This hybrid composite exhibited improved electrochemical performance over the original HCNF–S composite (see figure). A hollow carbon nanofiber hybrid nanostructure anchored with titanium dioxide (HCNF@TiO 2 ) was prepared as a matrix for effective trapping of sulfur and polysulfides as a cathode material for Li–S batteries. The synthesized composites were characterized and examined by X-ray diffraction, nitrogen adsorption–desorption measurements, field-emission scanning electron microscopy, scanning transmission electron microscopy, and electrochemical methods such as galvanostatic charge/discharge, rate performance, and electrochemical impedance spectroscopy tests. The obtained HCNF@TiO 2 –S composite showed a clear core–shell structure with TiO 2 nanoparticles coating the surface of the HCNF and sulfur homogeneously distributed in the coating layer. The HCNF@TiO 2 –S composite exhibited much better electrochemical performance than the HCNF–S composite, which delivered an initial discharge capacity of 1040 mA h g −1 and maintained 650 mAh g −1 after 200 cycles at a 0.5 C rate. The improvements of electrochemical performances might be attributed to the unique hybrid nanostructure of HCNF@TiO 2 and good dispersion of sulfur in the HCNF@TiO 2 –S composite.