Tuning the morphology and size of NiMoO4 nanoparticles anchored on reduced graphene oxide (rGO) nanosheets: The optimized hybrid electrodes for high energy density asymmetric supercapacitors

Abstract

• Porous NiMoO 4 NPs/rGO composite has been prepared through a facile hydrothermal approach followed by thermal treatment. • NiMoO 4 NPs/rGO composite electrode exhibits high specific capacitance of 2056 Fg -1 and long cyclic stability of 91.4 % after 10,000 cycles. • An asymmetric supercapacitor with high energy density and long cycle life is fabricated. In order to improve the capacitive performance of supercapacitors, NiMoO 4 electrode materials were successfully prepared by a simple and low cost hydrothermal route, and the morphology, microstructure and properties of the materials were successfully optimized by adding reduced graphene oxide (rGO). Electrochemical and sophisticated physical property tests are used to examine the qualities of items. As a supercapacitor electrode material, the NiMoO 4 /rGO composite performed admirably. The specific capacitance reached 2056 Fg -1 at a current density of 2 Ag -1 , which is greater than standard NiMoO 4 at the same current density (788 Fg -1 ). After 1000 charge/discharge cycles, NiMoO 4 /rGO retains 91.1 % of its initial capacitance. NiMoO 4 /rGO composites can be used in asymmetric supercapacitors, and the asymmetric supercapacitor device offers a high power density (60. 2 Whkg -1 ) and energy density (750.5 Whkg -1 ) when used as the positive electrode and activated carbon as the negative electrode. A combination of mesoporous-NiMoO 4 nanoparticles with a high specific surface area and good interaction with conductive rGO is responsible for the improved electrochemical performance of NiMoO 4 /rGO.