Browsing by Author "Chakarayan, T."

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    Degradation studies over nickel foam current collector for supercapacitor application
    (Springer Science and Business Media B.V., 2025) Chakarayan, T.; Pallipad, A.; Shirasangi, R.; Purushothaman, P.; Prasad Dasari, H.P.
    The 3D porous structure of nickel foam makes it appealing as a current collector in supercapacitors. Cyclic voltammetry (CV) studies were conducted in a three-electrode cell with a 1.2 cm diameter Ni foam (working electrode), an Ag/AgCl (reference electrode), and a Pt (counter electrode) in KOH electrolyte solution. The effects of various scan rates, different concentrations of KOH, and degradation tests were evaluated. Characterization of Ni foam after cyclic study was carried out using X-Ray Diffraction (XRD), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and Field emission scanning electron microscopy (FESEM). The areal capacitance decreased from 341.71 to 196.83 mF cm? 2 with an increase in scan rate from 5 to 30 mV s? 1 for 1 M KOH. The increase in the redox peak currents is of order: 5 M > 3 M > 1 M > 7 M. From the XRD results, the Ni peak intensity decreased as the KOH concentration increased due to the formation of the oxide layer (NiOOH) following CV analysis. Bare Ni foam exhibited no peaks in the Raman spectra. However, the Ni foam after CV in 1, 3, 5, and 7 M KOH showed peaks around ~ 500–600 cm? 1 and ~ 1000 cm? 1, indicating the stretching vibrations of Ni-O and Ni-OH bonds, respectively. The peaks ~ 2800 cm? 1 indicate O-H stretching. From the FTIR spectra, the broad and weak peaks around ~ 3000–3750 cm? 1 for Ni foam after CV indicated O-H stretching, while peaks around ~ 1500–1650 cm? 1 and ~ 1100 cm? 1 represented hydroxyl and Ni-OH bending, respectively. Significant degradation was observed within the first 100 cycles. On the surface of the Ni foam, nanoflake structures were observed following the electrochemical measurements, indicating the presence of an oxide layer. This was confirmed by Energy Dispersive X-ray Spectroscopy (EDX) analysis, which revealed that the oxygen element’s weight%, along with potassium and carbon on the surface of Ni foam, increased with increasing KOH concentration. The maximum areal capacitance of 1628.44 mF cm? 2 at 5 mV s? 1 was obtained with 5 M KOH among the different electrolyte concentrations. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.