Sputter deposited chromium nitride thin electrodes for supercapacitor applications

Transition metal nitrides have attracted significant attention for energy storage applications due to their unique structural, electronic and catalytic properties. In this study, chromium nitride thin films have been deposited on 304L steel substrate by reactive magnetron DC sputtering and then it used as a supercapacitor electrode without additional processing. These films were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-ray analysis (EDAX, Oxford Instruments), and X-ray photoelectron spectroscopy (XPS) techniques. XRD spectra shows the (1 1 1), (2 0 0), and (2 2 0) planes of the cubic phase of CrN film. The Raman spectra of CrN thin film shows the acoustic vibrational mode at 238 cm−1, and optical mode at 619 cm−1. The FE-SEM images show the columnar structure of CrN thin films. The electrochemical properties were evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The working electrode showed remarkably high specific capacitance of 41.6 F/g at the scan rate of 5 mV/s. The working electrode depicted high capacitance retention of 87% up to 2000 cycles. The electrochemical performance of the CrN showed that they can be used as potential electrode material for electrochemical supercapacitors.