Investigation of cyclic voltammetry and impedance spectroscopy of thermally exfoliated biomass synthesized nickel decorated graphene

Abstract

The cyclic voltammetry and impedance spectroscopy of nickel decorated multilayered graphene (NiMGr) thin films were investigated by the thermal exfoliation of onion (Allium cepa) with different process temperature from 600 to 1000 °C. The AFM images reveal the size distribution of Ni particles varies from 50 to 100 nm on the surface of graphene sheets. The diffraction planes (002), (111) and (200) are observed at 24, 44.3 and 51.6° corresponding Ni particles embedded with NiMGr sheets. The Raman parameter, ID/IG and I2D/IG ratio varied from 0.94 to 0.8 and 2.52 to 1.38 respectively indicated the formation of NiMGr containing some defect states. The areal capacitance of NiMGr varied from 12.19 to 22.9 μF/cm2 respectively, with different process temperature from 600 to 1000 °C. The corrosion potential (Ecorr) and corrosion current density (Icorr)values are −0.18 V and −13.29 A/cm2 respectively, for the NiMGr processed at 1000 °C, showing the highest corrosion resistance against acidic solutions. These encouraging findings for NiMGr demonstrate its possibility in various fields like supercapacitors as well as anti corrosion coatings.