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Optimizing the performance of electrode materials to improve the energy density of supercapacitors is the focus of current research. Construction and design with complex yolk-shell structure, as a supercapacitor electrode material, are of great significance and challenging. Herein, a self-sacrificing template strategy was used to construct uniform carbon-modified NiS/NiS2 yolk-shell spheres using a Ni-based metal–organic framework (Ni-soc-MOF) as the precursors. Especially, the carbon shells produced by the pyrolysis of the organic ligand can improve mechanical stability and electron conductivity. Therefore, the as-obtained NiS/NiS2@C nanocomposites display a high specific capacity (1082 C g−1at 1 A g−1) and outstanding cycling stability (85% capacity retention after 5000 cycles). In addition, a hybrid supercapacitor device based on the yolk-shell NiS/NiS2@C nanocomposite and porous carbon can deliver a high energy density of 56.2 Wh kg−1 at 800 W kg−1, while exhibiting an excellent capacity retention of 86% after 10,000 charge/discharge cycles, demonstrating the promising potential of yolk-shell NiS/NiS2@C nanocomposites via Ni-soc-MOF-derived route in practical application.
Wang et al. (Thu,) studied this question.