Abstract
Benefiting from good ion accessibility and high electrical conductivity, graphene-based material as electrodes show promising electrochemical performance in energy storage systems. In this study, a novel strategy is devised to prepare binder-free Mn3O4-reduced graphene oxide (Mn3O4/rGO) electrodes. Well-dispersed and homogeneous Mn3O4 nanosheets are grown on graphene layers through a facile chemical co-precipitation process and subsequent flame procedure. This obtained Mn3O4/rGO nanostructures exhibit excellent gravimetric specific capacitance of 342.5 F g−1 at current density of 1 A g−1 and remarkable cycling stability of 85.47% capacitance retention under 10,000 extreme charge/discharge cycles at large current density. Furthermore, an asymmetric supercapacitor assembled using Mn3O4/rGO and activated graphene (AG) delivers a high energy density of 27.41 Wh kg−1 and a maximum power density of 8 kW kg−1. The material synthesis strategy presented in this study is facile, rapid and simple, which would give an insight into potential strategies for large-scale applications of metal oxide/graphene and hold tremendous promise for power storage applications.
Highlights
Supercapacitors have attracted much attention owing to their robust lifetimes, rapid charging capabilities and high power energy storage for mobile phone, hybrid electrical vehicles, back-up power systems, cranes, and lift [1,2,3,4,5]
The Transmission electron microscope (TEM) image (Figure 1d) shows an overview of the Mn3 O4 /rGO samples. This image demonstrates that the lightweight conductive rGO with abundant wrinkles serves as an excellent conductive bracket for Mn3 O4 nanosheet attachment
After a long time of high-power sonication before tested with TEM, the Mn3 O4 nanosheet was still stably anchored on the graphene layer surface with high density, suggesting a strong interaction between graphene layers and Mn3 O4 nanosheet
Summary
Supercapacitors have attracted much attention owing to their robust lifetimes, rapid charging capabilities and high power energy storage for mobile phone, hybrid electrical vehicles, back-up power systems, cranes, and lift [1,2,3,4,5]. An ASC is based on the Mn3 O4 NDs@NG and the assembled device exhibits high energy density of 90.7 W h kg−1 [24] The results of these studies demonstrated the beneficial role of rGO and the significance of synergistic effects. Various approaches have been proposed to synthesis MnOx /rGO hybrid materials, such as hydrothermal [27], chemical vapor deposition [10] and electrochemical deposition [28] These methods show limitation in large scale preparation for high quality materials. The results show it can achieve a high cell voltage of 1.6 V and deliver a maximum energy density 27.41 Wh kg−1 and a power density of 8 kW kg−1 Such fabrication technique demonstrates features of simplicity, rapidity and low-cost, a hopeful approach for producing metal oxide/graphene, holding tremendous promise for power storage systems
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