NiS2/rGO/S capable of lithium polysulfide trapping as an enhanced cathode material for lithium sulfur batteries

To realize the practical application of lithium sulfur batteries, it is critical to build up a rational cathode structure which is highly conductive and also has the ability to adsorb the soluble lithium polysulfides generated during operation. In this work, we demonstrate a NiS2/rGO/S electrode material in which rGO serves as the conductive agent and NiS2 as the soluble lithium polysulfides adsorbent. The NiS2/rGO/S was synthesized via a microwave-assisted method with a subsequent sulfur deposition process. The catalytic properties and adsorption capacity of NiS2 have been confirmed by electrochemical characterization and adsorption experiments. Benefiting from the strong chemical bonding between the NiS2 and lithium polysulfide species, catalytic activity of NiS2, and good electrical conductivity of rGO, the nanostructured sulfur cathode maintains a higher specific capacity of 400 mAh g−1 after 800 cycles at a rate of 1.0 C with a Coulombic efficiency of about 98%.