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 MoSe2 nanosheets perpendicularly anchored on the nitrogen-doped branched TiO2 @C nanofibers (MoSe2 @[email protected]). Not only does the branched TiO2 @C nanofibers suppress the severe self-aggregation of MoSe2 nanosheets but also buffer the volume expansion during the cycling process. Moreover, an expanded interlamellar distance of MoSe2 nanosheets accelerate sodium ion diffusion, and strong chemical interactions between MoSe2 nanosheets and carbon nanofibers are conducive to improve the charge-transfer kinetics and reinforce the structural durability. As might be expected, the MoSe2 @[email protected] anode can deliver excellent cycling performance with high reversibility (315.2 mAh g1 after 800 cycles at 2 A g1) and remarkable rate capability (194.2 mAh g1 at 30 A g1). The rational design strategy could offer guidance for developing high-performance metal chalcogenide-based electrode materials for SIBs.