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.