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

A hollow carbon nanofiber hybrid nanostructure anchored with titanium dioxide (HCNF@TiO2) 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@TiO2–S composite showed a clear core–shell structure with TiO2 nanoparticles coating the surface of the HCNF and sulfur homogeneously distributed in the coating layer. The HCNF@TiO2–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@TiO2 and good dispersion of sulfur in the HCNF@TiO2–S composite. Good conduct: A core–shell hybrid architecture hollow carbon nanofiber@titanium dioxide (HCNF@TiO2) 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).