Hydrothermally Synthesized Cobalt‐Doped NiO Nanoflakes: Enhanced Electrochemical Performance for High‐Performance Supercapacitors

Abstract This study examines cobalt‐doped nickel oxide (Co‐NiO) nanomaterials synthesized through a hydrothermal method, focusing on their potential as high‐performance electrodes for supercapacitors. By varying cobalt dopant concentrations (X=0, 0.01, 0.05, 0.1), we aimed to enhance the electrochemical properties through strategic Co‐doping. The Co_xNi_1‐xO nanomaterials were characterized using several techniques, including X‐ray diffraction (XRD), UV‐visible spectroscopy, field emission scanning electron microscopy (FESEM), X‐ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS). The analysis showed that Co‐doping preserved the NiO phase structure while significantly altering the morphology and electrochemical characteristics. The sample with (X=0.1) achieved a specific capacitance of 880 F/g at a current density of 1 A/g, significantly outperforming the undoped NiO, which had a capacitance of 335 F/g. Additionally, the Co‐NiO demonstrated 83.3 % capacitance retention after 1000 cycles at a current density of 10 A/g. These findings highlight the potential of Co‐NiO as an effective electrode material for supercapacitors.