Fabrication of sputtered titanium vanadium nitride (TiVN) thin films for micro-supercapacitors

In the present work, we have demonstrated the micro-supercapacitor behavior of titanium vanadium nitride thin films fabricated on stainless steel substrates by a pulsed DC magnetron sputtering technique. The microstructural characterization from X-ray diffraction (XRD) reveals the FCC structure of TiVN thin films with a preferred (200) orientation. A faceted morphology with square-edge shaped dense grains of the thin films is observed from field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images. Ion scattering spectroscopy (ISS) and X-ray photoelectron spectroscopy (XPS) was used to determine the surface compositions and confirmed the absence of impurities. The specific capacitance (C_sp) of the electrode material was evaluated by cyclic voltammetry (CV). Galvanostatic charge–discharge (CD) test and the electrochemical impedance spectroscopy (EIS) measurements were also performed. The electrochemical result of fabricated TiVN displays a supercapacitive behavior. A maximum C_sp of 69 F/g (volumetric capacitance of 155.94 F/cm³) is obtained from both CV and CD studies. The experimental results reveal that the sputtered TiVN thin films area promising electrode material for electrochemical micro-supercapacitors.