3D heterojunction assembled via interlayer-expanded MoSe2 nanosheets anchored on N-doped branched TiO2@C nanofibers as superior anode material for sodium-ion batteries

High-performance sodium-ion batteries (SIBs) are highly expected in the field of large-scale static energy storage due to the low expenditure and abundant sodium resource. However, the sodium storage performance of anode materials for SIBs has suffered from the foot-dragging reaction kinetics arising from large-size Na + during intercalation/deintercalation, which imposes more stringent requirements on the morphology and structure of the potential anode electrodes. Herein, we successfully designed and synthesized a three-dimensional (3D) heterojunction as anode material for SIBs, which assembled by interlayer-expanded MoSe 2 nanosheets perpendicularly anchored on the nitrogen-doped branched TiO 2 @C nanofibers (MoSe 2 @NBT@CNFs). Not only does the branched TiO 2 @C nanofibers suppress the severe self-aggregation of MoSe 2 nanosheets but also buffer the volume expansion during the cycling process. Moreover, an expanded interlamellar distance of MoSe 2 nanosheets accelerate sodium ion diffusion, and strong chemical interactions between MoSe 2 nanosheets and carbon nanofibers are conducive to improve the charge-transfer kinetics and reinforce the structural durability. As might be expected, the MoSe 2 @NBT@CNFs anode can deliver excellent cycling performance with high reversibility (315.2 mAh g 1 after 800 cycles at 2 A g 1 ) and remarkable rate capability (194.2 mAh g 1 at 30 A g 1 ). The rational design strategy could offer guidance for developing high-performance metal chalcogenide-based electrode materials for SIBs.