Evaluation of reduced graphene oxide/WO3/WS2 hybrids for high performance supercapacitor electrode

Abstract

Reduced graphene oxide (rGO) is added to WO3 and WS2 to develop several hybrid electrode materials, including rGO/WO3, rGO/WS2, and rGO/WO3/WS2 by a simple and cost-effective hydrothermal method to enhance the electrochemical performance. The structural/ morphological analysis of synthesized rGO/WO3, rGO/WS2, and rGO/WO3/WS2 hybrids were extensively characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Raman spectra, thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area. The extensive characterization shows that WO3/WS2 nanoparticles were homogeneously dispersed throughout the surface of rGO. The rGO/WO3/WS2 exhibits higher specific capacitance of 750 F/g at 10 mV/s as compared to rGO/WS2 (481 F/g), rGO/WO3 (382 F/g), and rGO (154 F/g). The rGO/WO3/WS2 electrode was found to have Rct and Rf values of 1.3 Ω cm2 and 1.5 Ω cm2, respectively. These values were found to be much lower than that of rGO electrode (47.2 Ω cm2 and 36.4 Ω cm2), indicating that the rGO/WO3/WS2 has much less resistances, which may be one of the primary causes of the outstanding electrochemical properties of the rGO/WO3/WS2. The retention capacity of 95.33 % upto 10,000 cycles at 1 A/g shows that this rGO/WO3/WS2 hybrid electrode also exhibits good cycling stability. The rGO/WO3/WS2 composites' respective energy and power densities are observed to be 702 Wh/kg and 5912 W/kg. The rGO/WO3/WS2 hybrid has been shown to be a superior anode material in supercapacitors because of the synergistic interaction of WS2, rGO, and WO3. These advantages include a bigger contact surface area, a shorter ion diffusion path, great charge transfer, and, most importantly, rGO's improved specific capacitance. It reveals that the rGO/WO3/WS2 hybrids can be a promising electroactive material for supercapacitor applications.