T-Nb2O5@NbS2@C Composites Based on the Intercalation- Conversion Mechanism as an Anode Material for Li-Ion Batteries

Design of suitable composite materials and improvement of the corresponding electrochemical properties based on the intercalation-conversion mechanism are still challenging for Li storage devices. Nb2O5@NbS2 composites are prepared by a facile oil-phase synthetic process with carbon disulfide as the sulfur source and further synthesizing carbon by subsequent carbonization. As a result, the introduction of NbS2 with a conversion mechanism can effectively improve the low theoretical specific capacity of Nb2O5 with an intercalation mechanism in the field of lithium-ion anodes, and the in situ synthesized carbon overcomes poor conductivity of pure Nb2O5. Thus, the T-Nb2O5@NbS2@C electrode material delivered a higher reversible capacity of 636 mAh g-1 at 0.1 A g-1 than the T-Nb2O5 electrode with a capacity of 173 mAh g-1. Additionally, it also displayed a better cycle performance at a current density of 0.5 A g-1 after 400 cycles. Compared with the T-Nb2O5 electrode, its capacitance retention has increased by 21%. This work can be helpful to investigate a similar electrochemical mechanism of hybrid electrodes for energy storage systems.