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Construction of Hierarchical CNT/rGO-Supported MnMoO4 Nanosheets on Ni Foam for High-Performance Aqueous Hybrid Supercapacitors

Mu, Xuemei, Du, Jingwei, Zhang, Yaxiong, Liang, Zhilin, Wang, Huan, Huang, Baoyu, Zhou, Jinyuan, Pan, Xiaojun, Zhang, Zhenxing, Xie, Erqing
ACS applied materials & interfaces 2017 v.9 no.41 pp. 35775-35784
activated carbon, anodes, capacitance, carbon nanotubes, cathodes, energy, energy density, foams, graphene, graphene oxide, manganese, molybdates, nanosheets, nickel, synergism
Rationally designed conductive hierarchical nanostructures are highly desirable for supporting pseudocapacitive materials to achieve high-performance electrodes for supercapacitors. Herein, manganese molybdate nanosheets were hydrothermally grown with graphene oxide (GO) on three-dimensional nickel foam-supported carbon nanotube structures. Under the optimal graphene oxide concentration, the obtained carbon nanotubes/reduced graphene oxide/MnMoO₄ composites (CNT/rGO/MnMoO₄) as binder-free supercapacitor cathodes perform with a high specific capacitance of 2374.9 F g–¹ at the scan rate of 2 mV s–¹ and good long-term stability (97.1% of the initial specific capacitance can be maintained after 3000 charge/discharge cycles). The asymmetric device with CNT/rGO/MnMoO₄ as the cathode electrode and the carbon nanotubes/activated carbon on nickel foam (CNT-AC) as the anode electrode can deliver an energy density of 59.4 Wh kg–¹ at the power density of 1367.9 W kg–¹. These superior performances can be attributed to the synergistic effects from each component of the composite electrodes: highly pseudocapacitive MnMoO₄ nanosheets and three-dimensional conductive Ni foam/CNTs/rGO networks. These results suggest that the fabricated asymmetric supercapacitor can be a promising candidate for energy storage devices.