Hierarchical porous MnO2/3D graphene oxide/carbon cloth used as practical mass-loading supercapacitor electrodes

Abstract

Supercapacitor electrodes with high mass loading of active materials often exhibit low areal capacitances due to stacking problem of heavy loading. In this study, we present a 3D hierarchical porous graphene oxide (GO) nanosheets grown on carbon cloth (CC), termed as 3DGO/CC. With its high specific surface area, ample space to accommodate the volume expansion, and ideal ion transfer pathways, 3DGO/CC emerges as a promising candidate for high-loading active materials. Utilized as an efficient support matrix for MnO2 loading, an ultrahigh mass loading of MnO2 (17.32 mg cm−2) is deposited onto the surface of 3DGO, forming a MnO2/3DGO/CC electrode without stacking. The conductive porous 3DGO/CC composite scaffold optimizes the utilization of MnO2 active material, resulting in a high areal capacitance. An optimal electrode achieves an impressive areal capacitance of 3.18 F cm−2 at 1 mA cm−2 which was 4.1 times higher than that of the pristine MnO2/CC electrode and maintains a retention of 74.5 % at 32-fold current density. Ultimately, the assembled asymmetric supercapacitor demonstrates a superior electrochemical performance with a maximum energy density of 495.36 μWh cm−2 at the power density of 1.02 mW cm−2. This study supplies an efficient method for preparing MnO2-based electrodes with excellent areal capacitance.