Preparation of polyaniline-coated cobalt nitride nanoflowers as sulfur host for advanced lithium–sulfur battery

Lithium–sulfur (Li–S) batteries are promising candidates for large-scale high-energy-density devices owing to their potential high energy density, low cost, and more pronounced ecological compatibility. Nevertheless, their commercial applications of Li–S batteries are limited by the low electrical conductivity of sulfur, huge volume swell, shuttle effect, and slow redox reactions. In order to solve the above issues, various sulfur hosts have been developed and combined with active sulfur to form a composite. Polyaniline-coated cobalt nitride nanoflowers loaded with sulfur (CoN/S@PANI nanoflowers) were prepared by simple liquid phase precipitation followed by nitridation, sulfurization, and coating with polypyrrole. The CoN nanoflowers possessed a hierarchical nanostructure with a large specific surface area, which could reduce the volume swelling of sulfur and the shuttle effect of polysulfides. The polyaniline coating with high electrical conductivity can adsorb the polysulfides and promote the electrochemical reaction kinetics. Therefore, the CoN/S@PANI nanoflowers exhibit a high initial capacity of 895 mAh g−1 at 0.5 A g−1, which was kept at 736 mAh g−1 over 100 cycles. This paper reports a new route to prepare a sulfur host for advanced lithium–sulfur batteries.