MoS2@N-doped graphene microtubes for fast sodium ion storage

Highlights: • A MoS₂@nitrogen-doped graphene microtubes electrode is synthesized by a pre-assembly and templating-carbonization process. • The composite material has ultras-high rate capability (327 mAh·g⁻¹ at 10 A·g⁻¹ and 262 mAh·g⁻¹ at 30 A·g⁻¹) • Our method can be extended to the preparation of other metallic sulfides three-dimensional microtubule structure materials. A composite electrode material consisting of MoS₂@nitrogen-doped graphene (NG) microtubes is synthesized by a pre-assembly and templating-carbonization process for fast sodium ion storage. This ingeniously designed microtubular structure is conducive to the flow of electrolyte and the rapid transfer of electrons. Moreover, the stable skeleton structure of NG microtubes can not only buffer the volume expansion but also provide more active sites for electrochemical reaction that is helpful in improving the stability and cyclability at high current densities. As a result, our composite materials with unique structural design demonstrate ultra-high rate capability (327 mAh·g⁻¹ at 10 A·g⁻¹ and 203 mAh·g⁻¹ at 50 A·g⁻¹) and better cycling stability (391 mAh·g⁻¹ after 100 cycles at 1 A·g⁻¹). Our method of creating microtubule structures may be used for many other related applications.