MoSe2/TiO2 heterostructure integrated in N-doped carbon nanosheets assembled porous core-shell microspheres for enhanced sodium storage

Engineering the structure and composition of electrode materials is one of the essential means for achieving excellent electrochemical performance. The rational design of Na+ host materials is still a massive challenge for sodium ion batteries (SIBs). Herein, MoSe2/TiO2 heterostructure is integrated with N-doped carbon nanosheets to assemble into hierarchical flowerlike porous core-shell microspheres (MoSe2/TiO2@N-C), which is firstly reported by room-temperature stirring coupled with vulcanization treatment. The cavity of the core-shell structure could provide enough storage space for Na+ and alleviate the volume expansion during charge/discharge processes. The apertures between nanosheets provide a guarantee for the rapid penetration of electrolyte to enhance the utilization rate of electrode materials. Furthermore, building heterostructures by combining different phase structures can facilitate electron transfer and accelerate reaction kinetics. Benefiting from the synergistic contributions of structure and composition, MoSe2/TiO2@N-C as SIBs anode material shows better reversible capacities of 302.5 mAh center dot g(-1) at 1 A center dot g(-1) for 400 cycles and 217.4 mAh center dot g(-1) at 4 A center dot g(-1) for 900 cycles. Strikingly, the reversible capacities can be restored entirely to the initial level after a high current density cycle.

Automated summary

In this study, a MoSe2/TiO2@N-C composite material was designed and prepared, which exhibited excellent electrochemical performance as an anode material for sodium ion batteries. The rational design of the composite structure and composition contributed to its high reversible capacities and the ability to restore to the initial level after high current density cycling.