Preparation of NiCo₂S₄/carbon hollow sphere for long cycle lithium sulfur batteries

Uniformly distributed NiCo₂S₄ nanoparticles on hollow carbon spheres were prepared by carbonisation and in-situ vulcanisation methods as a positive electrode host for lithium–sulphur batteries. Among them, carbon hollow spheres can provide a huge internal cavity, which prevents volume expansion during the charge and discharge process. At the same time, the physically limit the dissolution of polysulfides in the electrolyte and can also provide high conductivity. The NiCo₂S₄ nanoparticles on the surface can establish a specific polar environment for charge and discharge and can interact with polysulfides to mitigate the loss of active materials through chemical adsorption. Under the synergistic effect of NiCo₂S₄ and carbon hollow spheres, the electrode with a special structure of NiCo₂S₄/carbon hollow spheres as sulfur host exhibits excellent long cycle performance. At a current density of 335 mA g⁻¹, it still has a high discharge specific capacity of 526 mAh g⁻¹ after 500 cycles.