Fabrication of Functionalized Graphene-Based MnO2Nanoflower through Electrodeposition for High-Performance Supercapacitor Electrodes

Graphene is a potential energy storage material for supercapacitor electrodes because of its unique electronic and physical properties. In this study, graphene was functionalized chemically. The functionalized graphene (G) is an ideal substrate for anchoring MnO 2 nanoflower (NF) through controlled electrodeposition to improve the performance of supercapacitors. The controlled weight ratio of functionalized graphene and MnO 2 NF is 1:8. The G/MnO 2 NF electrodes exhibit excellent electrochemical performance with a high specific capacitance of 320.59 F g −1 at a current density of 0.5 A g −1 and excellent cycling stability with 95.5% capacitance retention over 3000 cycles. Symmetric supercapacitors with G/MnO 2 NF hybrid materials were also assembled as electrodes. The cells exert promising characteristics with a specific capacitance of 55.37 F g −1 at a scan rate of 5 mV s −1 , maximum energy density of 5.67 Wh kg −1 , and power density of 5.11 kW kg −1 . The facile and low-cost preparation technique of functionalized graphene and high-performance G/MnO 2 NF nanocomposites may provide a new paradigm for fabricating supercapacitors with superior performance.