Monolayer standing MnO2-Nanosheet covered Mn3O4 octahedrons anchored in 3D N-Doped graphene networks as supercapacitor electrodes with remarkable cycling stability

Abstract

Transition-metal oxides holds great promise for high-performance supercapacitors, but even state-of-the-art ones show practical capacitances far below their theoretical values and deliver much lower power densities than carbon-based materials. Herein, we report the rational design and preparation of novel Mn3O4/MnO2 hierarchical nanoarchitectures/N-doped graphene (NG) composites as an advanced supercapacitors electrode material. The Mn3O4/MnO2 particles consist of monolayer standing MnO2-nanosheet covered Mn3O4 octahedrons; they are closely anchored, well dispersed in the NG networks by the modulation of Zeta potential, which is an effective technique for developing suchlike hybrid structures. The 3D conductive network of NG providing an open pathway for electron/ion transport together with close touching Mn3O4/MnO2 assure both enhanced conductivity and strong component synergy, thus promotes the electrode reaction kinetics. The Mn3O4/MnO2-NG exhibits a high specific capacitance of 739 F g−1 at 0.5 A g−1, excellent rate capability, and superior stability of 93.4% capacitance retention after 10000 cycles. The novel Mn3O4/MnO2-NG composite is very promising as an advanced electrode material for high energy- and power-density electrochemical storage devices.