Chiral carbon nanotubes decorated MoS2 nanosheets as stable anode materials for sodium-ion batteries

Abstract

Constructing carbon-based metal sulfides hybrids are efficient strategy for improving the sodium storage performance. And novel carbon materials are attractive in the development of electrodes. Herein, chiral amphiphiles are utilized to design chiral (C-CNTs) and straight (S-CNTs) nitrogen-doped CNTs through polycondensation and supramolecular assemble process, followed by pyrolysis. Besides, the CNTs can serve as skeleton, and MoS2 nanosheets are then anchored on the mesoporous CNTs matrix by hydrothermal reaction. Well-aligned architectures are obtained for MoS2/S-CNTs, while MoS2/C-CNTs are porous with short tubular morphology. As anode materials, MoS2/C-CNTs electrode outperforms the MoS2/S-CNTs counterparts and exhibits superior cycle stability and rate performances. It delivers a capacity of 368.8 mA h g−1 after 300 cycles at a high current density of 2 A g−1. Based on kinetics analysis, the percentage of capacitive charge storage is around 93.6% at the scan rate of 2 mV s−1. The phenomenon can be elucidated by the fast charge transfer resistance and small Warburg coefficient of MoS2/C-CNTs, which are superior to MoS2/S-CNTs. Therefore, the unique chiral structure combines the merits of expanded layer-spacing, nitrogen doping with high conductivity, and mesoporous channels, ensuring fast ion diffusion and pseudocapacitive behavior. This work provides an opportunity for fabricating other metal sulfides/C-CNTs SIBs anode materials with excellent cycling stability.