In Situ Carbon-Doped Mo(Se0.85 S0.15 )2 Hierarchical Nanotubes as Stable Anodes for High-Performance Sodium-Ion Batteries.

ABSTRACT

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(Se0.85 S0.15 )2 (i.e., Mo(Se0.85 S0.15 )2C) 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(Se0.85 S0.15 )2C 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.