Facile fabrication of binder-free reduced graphene oxide/MnO2/Ni foam hybrid electrode for high-performance supercapacitors

A novel three-dimensional reduced graphene oxide aerogel and MnO2 (rGO/MnO2) hybrid is prepared via a mild method and freeze-drying treatment, followed by an electrodeposition process. The characterization results reveal that the deposited MnO2 is homogeneously anchored on the graphene sheets, which is served as binder-free electrode material to fabricate high-performance supercapacitor. The specific capacitance of rGO/MnO2 on Ni foam reaches 288 F g(-1) at 0.5 A g(-1). The assembled symmetrical rGO/MnO2/Ni supercapacitor exhibits a maximum energy density of 26.82 Wh kg(-1) and a maximum power density of 8.61 kW kg(-1), whose capacitance retention maintains 94.7% over 1000 cycles. Moreover, it can successfully activate different LEDs after being charged. These appreciable performances are primarily put down to the cooperative effect of porous structure of rGO/MnO2 and pseudocapacitive property of MnO2, which provides adequate electroactive sites and facilitates the electron/ion transfer during the electrochemical processes. (C) 2019 Elsevier B.V. All rights reserved.