Role of Cerium Doping in Petal-Like NiO Grown Directly over Ni Foam for Enhancing the Super-Capacitive Behaviour

We have synthesized petal-like structure of cerium doped nickel oxide over the nickel foam using a hydrothermal method at 120 degrees C. The variation of the doping concentration of cerium from 1-7 mol% was studied to improve the capacitive behaviour. X-ray diffraction spectroscopy indicates the presence of the NiO phase without any impurities. Field emission scanning electron microscopy shows formation of 3D network by the interconnection of 2D petals morphology. Further, X-Ray data has been supported by the Raman scattering measurements. X-ray photoelectron spectroscopy data confirmed the presence of NiO along with traces of Ce3+ which categorically indicate successful doping of Ce3+ in NiO matrix. The electrochemical analysis shows the pseudo-capacitive behaviour with a specific capacitance of 794.58 F/g at 5 mV/s scan rate. It also shows the cyclic stability of 89.23 % after 800 cycles at a scan rate of 10 mV/s. Electrochemical impedance spectroscopy was carried out to investigate the involved charge transfer kinetics. The 5 mol% doping of cerium into the NiO crystal shows low resistance which provides a shortened path for the charge transfer. It helps to improve the electrochemical behaviour. Thus, the results have shown that cerium doping in NiO can improve the electrochemical performance of the system.