Confine Sulfur in Polyaniline-Decorated Hollow Carbon Nanofiber Hybrid Nanostructure for Lithium–Sulfur Batteries

A polyaniline-decorated hollow carbon nanofiber (HCNF@PANI) hybrid nanostructure was prepared as a conductive 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, Fourier transformation infrared spectroscopy, nitrogen adsorption–desorption measurements, field emission scanning electron microscopy, scanning transmission electron microscopy, and electrochemical methods, such as cyclic voltammetry, galvanostatic charge–discharge tests, and rate performance tests. The obtained HCNF@PANI-S composite showed an obvious core–shell structure with a PANI layer coating on the surface of the HCNF, and sulfur homogeneously distributes in the coating layer. The HCNF@PANI-S composite exhibited much better electrochemical performance than the HCNF-S composite, which delivered initial discharge capacity of 960 mAh g–1 and maintained 535 mAh g–1 after 200 cycles at 0.5 C rate. The improvements of electrochemical performances may be attributed to the unique hybrid nanostructure of HCNF@PANI and good dispersion of sulfur in the HCNF@PANI-S composite.