In Situ Transformation of LDH into NiCo₂S₄-NiS₂ Nano-heterostructures on Hollow Carbon Boxes to Promote Sulfur Electrochemistry for High-Performance Lithium-Sulfur Batteries

The practical application of lithium-sulfur batteries is hindered by slow redox reaction kinetics and serious lithium polysulfide (LiPS) migration, especially in the scene of high sulfur loading and a lean electrolyte. A strategy has been proposed to catalyze the liquid-solid conversion of lithium polysulfides in “sealed” nanoboxes with the NiCo₂S₄-NiS₂ nano-heterostructures, in which both LiPS migration and retardation reaction kinetics can be handled simultaneously. The design of hollow carbon boxes can alleviate the volume expansion during the cyclic process. Meanwhile, the NiCo₂S₄-NiS₂ nano- heterostructures on hollow carbon boxes can effectively adsorb LiPS and catalyze their quick conversion, which have a synergistic enhancement effect on inhibiting the shuttle effect. Ultimately, this design achieves decent battery performance with a high specific capacity of 1207 mAh g^-1 at 0.2C and long-term cyclability with a capacity retention of 60.23% after 450 cycles at 1C as well as a high initial areal capacity of 6.09 mAh cm^-2 with a loading of 5 mg cm^-2 under an electrolyte/sulfur ratio of 8.0