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

• 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.

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.

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