Structural and chemical engineering of metal-organic framework-derived nickel disulfide nanosheets as the compacted cathode matrix for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are recognized as promising high-energy-density storage systems. It is crucial to develop the compacted sulfur cathodes with high sulfur content and high sulfur loading for practical application. The metal-containing nanosheets are promising cathode matrix to mediate the accompanying problems, such as low sulfur utilization, unavoidable polysulfides shuttling and poor rate performance. Herein, we develop Ni-MOF-based strategy to fabricate nickel disulfide nanosheets on the reduced graphene oxide surface (NSG). Benefiting from nanosheets structure, strong polysulfides affinity, high electronic conductivity and superior electrocatalytic effect of NSG heterostructure, the resultant electrode exhibits high electrochemical performance with 0.021% capacity decay per cycle in 1000 cycles. Remarkably, the electrode with 88 wt% sulfur content and 5.9 mg cm-2 sulfur loading delivers reversible capacity of 945 mA h g−1, areal capacity of 6.1 mA h cm−2 and volumetric capacity of 997 mA h cm−3 at 0.5 C, which is comparable with the state-of-the-art those in the reported energy storage systems. This work provides methodology guidance for the development of the cathode matrix to achieve high-energy-density and long-life Li-S batteries.