Facile Synthesis of NiMoO₄ Nanorod Electrode for Aqueous Hybrid Supercapacitor with High Energy Density

Abstract

NiMoO₄ nanorods (NRs) were successfully fabricated on Ni foam with robust adhesion via a simple and cost-effective hydrothermal treatment, followed by a calcined process. In a three-electrode configuration with 3 mol L⁻¹ KOH aqueous solution. The NiMoO₄ NRs supported on Ni foam as working electrodes achieve a high specific capacity of 1320 C g⁻¹ at a charge and discharge current density of 2 mA cm⁻², and a desirable rate capability (884 C g⁻¹ even at 10 mA cm⁻²) and a superior cycling ability with 88% capacity retention after 4000 cycles at 10 mA cm⁻². To enhance the energy density and enlarge the voltage window, the aqueous hybrid supercapacitor has subsequently been constructed by employing the NiMoO₄ and activated carbon electrodes as positive and negative electrodes, respectively, which delivered a high energy density of 52 Wh kg⁻¹ at a power density of 725 W kg⁻¹. Impressively, the device indicates a long-term cycling stability with capacitance retention of 123% even after 9000 cycles in aa safe voltage range from 0 V to 1.45 V. These results definitely imply the promising prospect of NiMoO₄ NR electrodes for application in supercapacitors.