In Situ Carbon-Doped Mo(Se_0.85S_0.15)₂Hierarchical Nanotubes as Stable Anodes for High-Performance Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are promising energy storage devices, but suffer from poor cycling stability and low rate capability. In this work, carbon doped Mo(Se0.85S0.15)2 (i.e., Mo(Se0.85S0.15)2:C) hierarchical nanotubes have been synthesized for the first time and serve as a robust and high-performance anode material. The hierarchical nanotubes with diameters of 300 nm and wall thicknesses of 50 nm consist of numerous 2D layered nanosheets, and can act as a robust host for sodiation/desodiation cycling. The Mo(Se0.85S0.15)2:C hierarchical nanotubes deliver a discharge capacity of 360 mAh g−1 at a high current density of 2000 mA g−1 and keep a 81.8% capacity retention compared to that at a current density of 50 mA g−1, showing superior rate capability. Comparing with the second cycle discharge capacities, the nanotube anode can maintain capacities of 102.2%, 101.9%, and 97.8% after 100 cycles at current densities of 200, 500, and 1000 mA g−1, respectively. This work demonstrates the best cycling performance and high-rate sodium storage capabilities of MoSe2 for SIBs to date. The hollow interior, hierarchical organization, layered structure, and carbon doping are beneficial for fast Na+-ion and electron kinetics and are responsible for the stable cycling performance and high rate capabilities.