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

Abstract

A pure Co3O4 nanoparticles and a carbon quantum dots (CQDs) anchored cobalt oxide (Co3O4/CQD) nano-composite 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 nano-composite. 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%.