Enhancing Sodium-Ion Transport by Hollow Nanotube Structure Design of a V 5 S 8 @C Anode for Sodium-Ion Batteries.

V 5 S 8 has received extensive attention in the field of sodium-ion batteries (SIBs) due to its two-dimensional (2D) layered structure, and weak van der Waals forces between V-S accelerate the transport of sodium ions. However, the long-term cycling of V 5 S 8 still suffers from volume expansion and low conductivity. Herein, a hollow nanotube V 5 S 8 @C (H-V 5 S 8 @C) with improved conductivity was synthesized by a solvothermal method to alleviate cracking caused by volume expansion. Benefiting from the large specific surface area of the hollow nanotube structure and uniform carbon coating, H-V 5 S 8 @C exhibits a more active site and enhanced conductivity. Meanwhile, the heterojunction formed by a few residual MoS 2 and the outer layer of V 5 S 8 stabilizes the structure and reduces the ion migration barrier with fast Na + transport. Specifically, the H-V 5 S 8 @C anode provides an enhanced rate performance of 270.1 mAh g -1 at 15 A g -1 and high cycling stability of 291.7 mAh g -1 with a retention rate of 90.98% after 300 cycles at 5 A g -1 . This work provides a feasible approach for the structural design of 2D layered materials, which can promote the practical application of fast-charging sodium-ion batteries.