Preparation and characterization of carbon quantum dots grafted Co₃O₄ nanocomposite for supercapacitors application

A pure Co₃O₄ nanoparticles and a carbon quantum dots (CQDs) anchored cobalt oxide (Co₃O₄/CQD) nanocomposite were synthesized by a simple hydrothermal method for supercapacitor application. The powder XRD measurement confirms the formation cubic phase of Co₃O₄. More HR-TEM measurements. The beneficial surface and electronic properties of CQDs were used for the refinement of the electrochemical accomplishments of Co₃O₄. The Co₃O₄/CQD and Co₃O₄ manifest half-cell specific capacitances of 193.8 F g⁻¹ and 123.6 F g⁻¹ @ current density of 4 A g⁻¹, respectively. The introduction of CQDs into the Co₃O₄ matrix increased the charge-transfer process, which is primarily responsible for the improved electrochemical capabilities of the nanocomposite. The hybrid asymmetric supercapacitor delivers an energy density of 2.49 W h kg⁻¹ @ a power density of 426 W kg⁻² with a capacitance retention of 81.8%.