<p>The innovative disk-like electrodes hold great potential for large-scale industrial use due to their exceptional mechanical durability and advantageous capacitive properties. A novel, simple and scalable calcination method for preparing an oxidized disc-like electrode based on MWCNTs-Cobalt Oxide Alloy, followed by the photochemical deposition of cadmium sulfide (CdS) nanospheres under UV lamp irradiation was employed for highly efficient energy storage applications. Nitrogen adsorption/desorption isotherm (BET) and BJH pore size distribution curves show that the surface area, average pore size, and pore volume of CdS/MWCNTs-Cobalt Oxide Alloy are 7.9199 m² g^− 1, 18.689&#xa0;nm, and 0.0367 cm³ g^− 1, respectively. X-ray diffraction (XRD) analysis was conducted to determine the cobalt oxide phases produced through the calcination process in the CdS/MWCNTs-Cobalt Oxide Alloy. Field emission scanning electron microscopy (FESEM) analysis verified the structural characteristics of the CdS nanospheres formed through photochemical deposition. Electrochemical evaluation using a three-electrode setup demonstrated an impressive supercapacitance of about 12,000 mF cm^− 2 (24&#xa0;F g^− 1) at a current density of 5.0&#xa0;mA cm^− 2 in a 1.0&#xa0;M NaOH solution. Furthermore, the symmetric CdS/MWCNTs-Cobalt Oxide Alloy device showed excellent capacitive performance containing capacitance of 388 mF cm^− 2 (776 mF g^− 1), a power density of about 4,600 mW cm^− 2, and an energy density of about 121 mWh cm^− 2 at a current density of 0.6&#xa0;mA cm^− 2.</p>