Effect of Nickel doping on Cobalt Oxide nanoparticles for energy storage applications

We present a comprehensive study on the utilization of Ni-doped Co3O4 nanoparticles for energy storage applications, particularly in supercapacitors. X-ray diffraction analysis confirms the structural integrity and phase purity of the samples, exhibiting the characteristic peaks of the cubic spinel structure. X-ray photoelectron spectroscopy confirms the presence of Co, Ni, and O elements, with different valence states observed. Scanning electron microscope images reveal irregular nano-flakes with increased particle size and reduced porosity as the Ni doping concentration rises. The surface properties of nickel-doped cobalt oxide (Co3O4) nanoparticles are investigated through Brunauer–Emmett–Teller (BET) analysis. The research focuses on elucidating the specific surface area and adsorption characteristics, providing insights into the structural and textural features of the Ni-doped Co3O4 nanomaterials. Electrochemical analysis, including cyclic voltammetry and galvanostatic charge–discharge tests, demonstrates promising performance. Specifically, the 3 wt% Ni-doped Co3O4 sample exhibits a maximum specific capacitance of 299 F/g at a scan rate of 5 mV/s. The galvanostatic charge–discharge (GCD) profiles of all three Ni-doped Co3O4 nanoparticles were carried out, revealing quasi-triangular charge–discharge curves attributed to both pseudo capacitive and electric double-layer processes. Moreover, the 3% Ni-doped Co3O4 nanoparticles demonstrate a maximum specific capacitance of 347 F/g at a scan rate of 1.5 A/g. Additionally, the 5% Ni-doped Co3O4 nanoparticles exhibit an impressive capacity retention of 90% even after 5000 cycles. Our findings indicate that appropriate Ni doping on Co3O4 nanoparticles enhances their electrochemical performance, showing great potential for supercapacitor applications.