Exploring the potential of Ni-doped CuO nanoparticles as a promising electrode material for asymmetric supercapacitors

Abstract

In the current study, monoclinic Cu_1-xNi_xO (x = 0.00, 0.03, 0.05, 0.07 M) nanoparticles (NPs) were prepared using the chemical precipitation method. NPs resulting from this process are named NC0 (pure), NC3 (3 %), NC5 (5 %), and NC7 (7 %). The X-ray diffraction confirmed the Ni ions were successfully substituted into the CuO lattice and the crystallite size of the nanoparticles showed a decreasing trend. Scanning electron microscopy confirmed the surface morphology of samples NC0 and NC7 are rod-like and flower-like. The cyclic voltammetry (CV) and galvanostatic charge-discharge tests in 2 M KOH, the pseudocapacitive behaviour of the Cu_1-xNi_xO (x = 0.00, 0.07 M) electrodes was examined. The computed values of specific capacitance (Cs) for the Cu_1-xNi_xO (x = 0.00) electrode are 433.33 F/g, while the corresponding value for the Cu_1-xNi_xO (x = 0.07) electrode is 578.97 F/g at scan rates of 5 mV/s. GCD curves demonstrate that Cu_1-xNi_xO (x = 0.00, 0.07 M) electrodes have specific capacitance (Cp) of 238.98, and 396.67 F/g at a current density of 1 A/g. After 2000 cycles, the retention was 88.36 % and the increased coulombic efficiency was 85.74 % at Cu_1-xNi_xO (x = 0.07 M) electrode. Vibrating sample magnetometer are characteristics at room temperature and found that Cu_1-xNi_xO (x = 0.00, 0.03, 0.05, 0.07 M) becomes ferromagnetic behaviour.