Enhanced supercapacitor performance using a nitrogen doped graphene quantum dots/manganese dioxide/tin-organic framework (NGQDs/MnO₂/Sn-MOF) hybrid electrode

The composite material manganese dioxide and tin-based metal-organic framework doped with nitrogen-doped graphene quantum dots (NGQDs/MnO₂/Sn-MOF) was successfully synthesized via a hydrothermal method. The structure was thoroughly characterized using BET, XPS, SEM, and XRD analyses. This unique architecture not only enhances the electrode's conductivity but also facilitates efficient ion and electron transport during the electrochemical energy storage process. The NGQDs/MnO₂/Sn-MOF composite achieved an impressive capacity of 2130 C g⁻¹. When assembled into an asymmetric supercapacitor (ASC), with the NGQDs/MnO₂/Sn-MOF as the positive electrode and activated carbon (AC) as the negative electrode, the device demonstrated a specific capacitance of 272 C g⁻¹. It exhibited excellent electrochemical performance, achieving energy and power densities of 65.18 W h kg⁻¹ and 1200 W kg⁻¹, respectively. This study presents a novel approach for the rational design of well-oriented MOF arrays and an innovative material preparation technique, offering significant potential for advanced applications in the field of asymmetric supercapacitors.