Study on carbon quantum dots synergistic with La1-xSrxCoO3 to improve supercapacitor performance

La0.7Sr0.3CoO3 with perovskite structure is a promising electrode material for supercapacitors, but its charge storage capacity is limited due to its inherent poor conductivity. Herein, our work used a simple sol–gel method to combine carbon quantum dots coupled with La0.7Sr0.3CoO3 to enhance the electrical conductivity of electrode materials and studied the synergistic effect of oxygen vacancy and carbon quantum dots to improve the electrochemical performance of electrode materials. The morphology, structure, and elemental valence of La0.7Sr0.3CoO3/CQDs were characterized by XRD, SEM, TEM, and XPS. Compared with La0.7Sr0.3CoO, La0.7Sr0.3CoO3-CQDs shows low resistivity, excellent electrical conductivity, and high specific capacitance; it showed high specific capacitance (878.1 F/g at 0.5 A/g), excellent rate performance (69.2% capacitance retention at 20A/g), and long cycle life. These results indicate that the synergistic effect of oxygen vacancies and carbon quantum dots in perovskite metal oxides improves the electrode performance of supercapacitors and provides a new idea for improving the electrode performance of electrode materials.