Fabrication of 3D flower-like MoS2/graphene composite as high-performance electrode for capacitive deionization

3D flower-like MoS2/rGO composites were prepared with various volume ratios of water and ethanol as solvent by one-step hydrothermal method. The morphology and microstructure of the as-prepared composites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). In addition, the electrochemical and desalination performances of the composites were comparatively researched though cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge (GCD) and capacitive deionization (CDI). The results showed that the MoS2/rGO composite prepared from the solvent with the volume ratio of water and ethanol 2:1 exhibited a big BET surface area, superior capacitive performance, good cycling stability and excellent CDI performance with a maximum desalination capacity of 16.82 mg/g at 1.0 V in 200 mg/L NaCl solution. The results suggested that the MoS2/rGO composite could be a promising candidate for CDI device. The great desalination capacity and electrochemical performance of the composite may be attributed to its specific structure of 3D flower-like MoS2 disorderly entangled with rGO sheets and the synergies of rGO and 3D flower-like MoS2.