Fabrication of core-shell NiMoO4@MoS2 nanorods for high-performance asymmetric hybrid supercapacitors

In this work, core-shell NiMoO4@MoS2 nanorods were successfully fabricated via a facile two-step hydrothermal method. By inheriting the merits of high electrical conductivity from MoS2 nanosheets and high pseudocapacitive activity from NiMoO4 nanorods, the hierarchical NiMoO4@MoS2 nanocomposite was endowed with improved electrical conductivity, enlarged specific surface area and enriched porosity, consequently enabling fast ion/electron transport and rapid Faradaic reactivity. Benefited from the synergism of NiMoO4 and MoS2, the NiMoO4@MoS2 electrode was superior to the NiMoO4 and MoS2 electrode, achieving specific capacitance of 2246.7 F g(-1), as well as showing good rate performance and improved cyclic stability (88.4% capacitance retention after 5000 cycles). The asymmetric supercapacitor device composed of the NiMoO4@MoS2 nanorods and hierarchical porous carbon exhibited a high energy density of 47.5 Wh kg(-1) at a power density of 0.44 kW kg(-1). The device also showed superior long-term cycling stability, retaining 80.2% of initial capacitance after 10 000 cycles. This work provides a simple strategy for scalable synthesis of integrated nanostructures, which holds great promise for the development of advanced supercapacitors. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.