In-situ deposition of amorphous Tungsten(VI) oxide thin-film for solid-state symmetric supercapacitor

Amorphous tungsten (VI) trioxide thin films were deposited on rigid Ni-foam and flexible PET substrates using RF magnetron sputtering technique. The impacts of sputtering RF power on microstructure, morphology, compositional and electrochemical properties of the deposited thin films were investigated by using Raman, FE-SEM, XPS and electrochemical techniques. The thicknesses of the deposited films were increased from 70 to 105 mu m as a function of RF power. The films contain uniform nanoparticles and the observed sizes are in the range of 25-70 nm. The films of WO3@Ni and WO3@PET deposited at an optimum RF power of 100 W exhibited the high areal capacitance of 22.01 mF/cm2 and 9.76 mF/cm2 with good cyclic retention of 81.03% and 69.53% after 5000 cycles respectively. Further, two solid-state symmetric supercapacitor (SSC) devices were assembled which shows pseudocapacitive behaviour. The devices delivered moderate energy densities of 0.48 mu Wh/cm2 and 0.20 mu Wh/cm2 and power densities of 312 mu W/cm2 and 150 mu W/cm2 for rigid Ni foam and flexible PET based devices respectively. This result demonstrated that the binder free in-situ deposition of WO3 films deposited at an optimum RF power of 100 W is more suitable to fabricate supercapacitor devices.

Automated summary

Amorphous tungsten (VI) trioxide thin films were successfully deposited on both rigid Ni-foam and flexible PET substrates using RF magnetron sputtering technique. The deposited films showed uniform nanoparticles and excellent electrochemical properties, leading to high areal capacitance and good cyclic retention. Two solid-state symmetric supercapacitor devices assembled with these films demonstrated moderate energy and power densities, indicating the potential for practical applications in supercapacitor devices.