Anchoring function for polysulfide ions of ultrasmall SnS₂ in hollow carbon nanospheres for high performance lithium–sulfur batteries

Graphical abstract: - Highlights: • S/AHCNS-SnS₂ were synthesized by APCVD and wet-impregnation method. • Ultrasmall SnS₂ particles are homogeneous particles with a diameter of about 6 nm. • The cell retains a high capacity of 924 mAh g⁻¹ after 200 cycles at 0.2 C. • The improved cycling performance is ascribed to the anchoring function of SnS₂. - Abstract: Tin sulfide-anchored sulfur-hollow carbon nanospheres (S/AHCNS-SnS₂) composites are synthesized by uniformly dispersing conductive SnS₂ particles into hollow carbon nanospheres activated with potassium hydroxide, followed by impregnating sulfur. Surface morphology and structure of this composite are characterized using a field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), Brunauer–Emmett–Teller (BET) method, X-ray power diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The first discharge capacity of the sample containing 10 wt.% SnS₂ exhibits a high special capacity value of about 1237.5 mAh g⁻¹ at 0.2 C, and after 200 cycles retains 924 mAh g⁻¹. Tin sulfide particles play a favorable role on adsorption towards polysulfides which would influence electrochemical process. This strategy of immobilization of sulfur with small amount of metal sulfide particles anchored in AHCNS provides a considerable approach to elevate the sulfur loading, coulombic efficiency, and cycling stability for Li–S batteries.