Supercapacitive activities of potentiodynamically deposited nanoflakes of cobalt oxide (Co3O4) thin film electrode

• The potentiodynamic electrodeposition mode is employed to deposit Co3O4 thin films.
• Obtained thin film of Co3O4 exhibited nanoflake-like morphology.
• The Co3O4 thin film electrode showed maximum specific capacitance of 365 Fg−1.

In the present work, the Co3O4 thin films are successfully prepared via potentiodynamic electrodeposition method onto inexpensive stainless steel substrate. As-deposited films were heat treated at 623 K for their conversion into Co3O4. These films were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) techniques. The X-ray diffraction (XRD) study revealed the formation of cobalt oxide (Co3O4) with cubic crystal structure. The FT-IR study supports the formation of Co3O4 material. The SEM image of Co3O4 film showed nanoflake-like morphology with an average thickness of 100 nm. Supercapacitive properties of Co3O4 thin film electrode were examined using cyclic voltammetry and charge–discharge techniques. The Co3O4 thin film electrode showed maximum specific capacitance of 365 Fg−1 in 1 M KOH electrolyte at the scan rate of 5 mV s−1. The charge–discharge technique was employed to estimate the values of specific energy, power and coulombic efficiency as 64 W h kg−1, 21.53 kW kg−1 and 99%, respectively.

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