The Study on the Capacitive Properties of Tungsten Oxide/Graphene Composites Prepared by Ultrasonic Spray Deposition

The fabrication of tungsten oxide/graphene thin films on fluorine-doped tin oxide (FTO) glass substrates using ultrasonic spray deposition technology is presented, and their potential application as supercapacitor electrode materials is explored. Ultrasonic spray deposition provides precise control over film thickness, low fabrication cost, scalability for large-area coating, and compatibility with green solvents, making it a sustainable thin-film deposition method. A template-assisted sol-gel chemistry was employed to synthesize mesoporous tungsten oxide films with high specific surface area, enabling enhanced charge adsorption/desorption and improved electrochemical performance. To further enhance the ionic conductivity, a graphene interlayer was introduced between the WO₃ film and the FTO substrate, forming a composite electrode structure. Electrochemical characterization using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) revealed superior performance of the WO₃/graphene electrode, achieving a specific capacitance of 161.68 F g^-1 at a 5 mV s^-1 scan rate from CV and 235.42 F g^-1 at 0.5 A g^-1 from GCD, significantly higher than those of pure mesoporous WO₃ (142.18 F g^-1 and 202.35 F g^-1, respectively). Furthermore, the electrode retained 71% of its capacitance after 1000 charge-discharge cycles, demonstrating excellent cycling stability.