Hierarchical Ni₃V₂O₈@N-Doped Carbon Hollow Double-Shell Microspheres for High-Performance Lithium-Ion Storage

Transition metal oxides (TMOs) are highly dense in energy and considered as promising anode materials for a new generation of alkaline ion batteries. However, their electrode structure is disrupted due to significant volume changes during charging and discharging, resulting in the short cycle life of batteries. In this paper, the hierarchical Ni₃V₂O₈@N-doped carbon (Ni₃V₂O₈@NC) hollow double-shell microspheres were prepared and used as electrode materials for lithium-ion batteries (LIBs). The utilization efficiency and ion transfer rate of Ni₃V₂O₈ were improved by the hollow microsphere structure formed through nanoparticle self-assembly. Furthermore, the uniform N-doped carbon layer not only enhanced the structural stability of Ni₃V₂O₈, but also improved the overall electrical conductivity of the composite. The Ni₃V₂O₈@NC electrode has an initial discharge capacity of up to 1167.3 mAh g^-1 at a current density of 0.3 A g^-1, a reversible capacity of up to 726.5 mAh g^-1 after 200 cycles, and still has a capacity of 567.6 mAh g^-1 after 500 cycles at a current density of 1 A g^-1, indicating that the material has good cycle stability and high-rate capability. This work presents new findings on the design and fabrication of complex porous double-shell nanostructures.