Evaluation of Supercapacitor Properties of Radio Frequency Sputter Binder‐Free and Nanosandwich WO3/SiO2/WO3 Thin Film

Supercapacitors require efficient and environmentally friendly electrodes. This study investigates the promising potential of a tungsten oxide/silicon dioxide/tungsten oxide (WO 3 /SiO 2 /WO 3 ) thin film on a Cu substrate as an alternative to conventional metal oxide flexible electrodes. Motivated by the need for enhanced energy storage capabilities, the WO 3 /SiO 2 /WO 3 composite combines WO 3 high specific capacitance and electrochemical stability of WO 3 with improved mechanical durability and high surface area of SiO 2 , offering a synergistic solution to overcome electrode limitations. Utilizing the radio frequency magnetron sputtering technique, the WO 3 /SiO 2 /WO 3 thin film is precisely deposited on a Cu flexible substrate without organic additives, conductive agents, binder chemicals, or substrate pretreatment. Electrochemical characterization reveals the film's pseudocapacitive behavior, facilitated by the SiO 2 interlayer, enabling influential adjustment of electrolyte ions within the electrode structure. The obtained high specific capacitances at various scan rates and current densities demonstrate the potential of the thin film for supercapacitor applications. This research highlights the nanosandwich WO 3 /SiO 2 /WO 3 thin film as a promising material for flexible energy storage and intelligent nanodevices, making it a noteworthy candidate for various flexible applications. The findings contribute to the development of efficient and environmentally friendly energy storage solutions.