Preparation of 3D Reduced Graphene Oxide/MnO 2 Nanocomposites through a Vacuum‐Impregnation Method and Their Electrochemical Capacitive Behavior

In this work, three‐dimensional (3D) porous reduced graphene oxide (rGO) is prepared by means of a microwave‐hydrothermal method, and then MnO 2 is introduced in situ and anchored into the pores of the 3D‐rGO through a novel vacuum‐impregnation method to obtain the 3D‐rGO/MnO 2 nanocomposite. SEM images show the honeycomb structure of the 3D‐rGO/MnO 2 , and MnO 2 is tightly anchored on the surface and into the pores of 3D‐rGO. 3D‐rGO/MnO 2 nanocomposite electrodes display excellent electrochemical capacitive behavior, owing to the synergetic effect between the porous 3D‐rGO with high conductivity and MnO 2 with high theoretical capacitance . The 3D‐rGO/MnO 2 ‐5 sample, with an optimum MnO 2 content of (53.1%), gives the highest specific capacitance (278.5 F g −1 at 1 A g −1 ) and good rate capability. This sample also has remarkable cycling stability (93.5% capacitance retention after 10000 cycles). The 3D‐rGO/MnO 2 nanocomposite could be considered as a potential candidate for supercapacitor electrode materials.