Composite Yolk-shell NiCo ₂ V ₂ O ₈ @TiO ₂ @NC Material as Anode for Lithium-ion Batteries

Transition metal vanadates, as an advantageous anode material for lithium-ion batteries, currently have bottlenecks such as unsatisfied conductivity and cycle stability caused by drastic volume changes during charging and discharging.In this study, NiCo2V2O8@TiO2@NC material with a multi-level composite core-shell structure was prepared using a step-by-step coating strategy to improve this defect.Initially, yolk-shell structured NiCo2V2O8 nanospheres were synthesized as the precursor through hydrothermal synthesis and ion exchange methods.Subsequently, a robust TiO2 layer and a nitrogen-doped carbon (NC) network structure were coated on the surface, resulting in the formation of a hierarchical mesoporous nanostructure.The specific yolk-shell nanosphere structure provides abundant channels for Li + transport in NiCo2V2O8, a promising electrochemical active material.Further coating with a TiO2 layer not only enhances the stability and durability of the material, but also offers additional electrochemical active sites.Moreover, the introduction of the nitrogen-doped carbon network structure not only improves the conductivity of the ordered multi-level core-shell NiCo2V2O8@TiO2@NC material but also facilitates rapid electron transport, further optimizing its electrochemical performance.Lithium-ion battery anode materials prepared under optimal conditions, NiCo2V2O8@TiO2@NC-0.2 exhibited an initial specific capacity of 1422.0 mAhg -1 , which remained 1011.9mAhg -1 after 500 cycles, corresponding to a specific capacity retention rate of 71.2%.This material is demonstrated high specific capacity, good rate performance, and excellent cycle stability, displaying promising prospective for a wide range of applications in energy storage devices.