ALD TiO₂-Coated Flower-like MoS₂ Nanosheets on Carbon Cloth as Sodium Ion Battery Anode with Enhanced Cycling Stability and Rate Capability

We report the fabrication of 3D flower-like MoS 2 nanosheets arrays on carbon cloth as a binder-free anode for sodium ion battery. Ultrathin and conformal TiO 2 layers are used to modify the surface of MoS 2 by atomic layer deposition. The electrochemical performance measurements demonstrate that the ALD TiO 2 layer can improve the cycling stability and rate capability of MoS 2 . The MoS 2 nanosheets with 0.5-nm TiO 2 coating electrode show the highest initial discharge capacity of 1392 mA h g –1 at 200 mA g –1, which is increased by 53% compared with that of bare MoS 2 . After 150 cycles, the capacity retention rate of the TiO 2 -coated MoS 2 achieves 75.8% of its second cycle’s capacity at 200 mA h g –1 in contrast to that of 59% of pure MoS 2 . Furthermore, the mechanism behind the experimental results is revealed by ex situ scanning electron microscope (SEM), X-ray powder diffraction (XRD), and electrochemical impedance spectroscopy (EIS) characterizations, which confirms that the ultrathin TiO 2 modifications can prevent the structural degradation and the formation of SEI film of MoS 2 electrode.