Hierarchical nickel cobalt sulfide nanoparticles encapsulated in rose-shaped carbon spheres as high-performance anode materials for lithium-ion batteries

A rose-shaped binary Ni/Co metal-organic framework (Ni/Co-MOF) precursor assembled from numerous cross-linked 2D nanosheets was prepared via a facile hydrothermal reaction. The hierarchical structure was inherited by a one-step carbonization and sulfurization of the precursor and derived nickel cobalt bimetal sulfide nanoparticles encapsulated in rose-shaped carbon spheres (NiS2/CoS2@RCSs) composite. As an anode material for lithium-ion batteries (LIBs), the final composite material could improve conductivity, facilitate electrolyte penetration, and alleviate volume change. Beneficial from the unique nano-architecture plus the bimetallic synergistic effect, the obtained anode electrode achieves an exceptional cycling stability (747.7 mA h g−1 at 1.0 A g−1 after 400 cycles) with a superior rate capability (500.9 mAh g−1 at 4.0 A g−1). [Display omitted] •A rose flower-shaped Ni/Co-MOF was fabricated through a hydrothermal reaction.•The sulfides NPs embedded in carbon matrix were derived from carbonization and sulfurization of the precursors.•Hierarchical structure and the synergistic effect can improve the e-/Li+ conductivity of the composite.•NiS2/CoS2@RCSs electrode displays superior lithium storage performance when used as an anode.