Self-assembled Mn-doped MoS2 hollow nanotubes with significantly enhanced sodium storage for high-performance sodium-ion batteries

In this work, Mn-doped MoS2 hierarchical nanotubes have been prepared by a solvothermal method. The diameter of Mn-MoS2 nanotubes is about 100-200 nm and the wall thickness is about 10-20 nm. Hierarchical ultrathin sheets are formed on the surface of MoS2 nanotubes. The formation mechanism of Mn-MoS2 nanotubes is discussed on the basis of contrast experiments. The hollow structure and hierarchical surface can provide more Na+ insertion/extraction sites and alleviate volume expansion. Besides these, the doping of Mn into MoS2 will enlarge the interplanar spacing, which consequently benefits the extraction/insertion processes of Na+ ions. A specific capacity of 441 mA h g(-1) was achieved at a current density of 0.1 A g(-1). A capacity of 160 mA h g(-1) is still maintained after 1000 cycles even at the current density of 1 A g(-1), indicating excellent cycling stability. The results suggest that Mn-MoS2 hierarchical nanotubes can be promising candidates for high performance SIBs.