MoS₂ nanosheets decorated Ni₃S₂@MoS₂ coaxial nanofibers: Constructing an ideal heterostructure for enhanced Na-ion storage

Abstract: The performance of sodium ion batteries (SIBs) is mainly determined by the electrochemical activity and kinetic feature of electrode materials. High performance relies largely on the scrupulous design of nano-architectures and smart hybridization of bespoke active materials. It is fundamentally important for establishing a relationship between the structure/chemistry of these materials and their properties. Herein, we developed a novel synergistic Ni3S2-MoS2 core-shell nanofiber superstructure on 3D Ni/graphene foam by a one-step PVP-assisted hydrothermal reaction. Such hierarchical nanofibers can provide the homogeneous atomic heterointerface with porous hierarchical structure, resulting in the maximization of synergistic interaction. This unique structure results in very high specific capacity and rate capability as well as extremely long-term cycle stability. As anode electrode of SIBs, it exhibits a very high reversible specific capacity of 568 mAh g-1 at a current density of 200 mA g-1 with excellent rate capability (283 mAh g-1 at 5 A g-1), and the specific capacity can be well-maintained to 207 mAh g-1 at 5 A g-1 even after 400 cycles. The strategy developed in our study can open a new way to prepare other layered-material-based hybrid superstructure for next-generation energy storage devices.