Abstract:

Supercapacitors are a new type of energy storage device that have great development prospects owing to their higher power density, rapid charging and discharging, long cycle life, and other advantages. Research on electrode materials can lead to the development of supercapacitors, in which the microstructure of materials largely determines their electrochemical performance. In this study, NiMoO₄/NiCo₂S₄ composite was prepared using hydrothermal method and heat treatment and then applied to supercapacitor electrodes. The composition and microstructure of nanocomposites were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N₂ adsorption and desorption. The prepared product shows excellent electrochemical performance: the specific capacitance was 847.2 F/g (higher than 576.1 F/g of NiMoO₄ electrode and 734.3 F/g of NiCo₂S₄ electrode) at a current density of 1 A/g, and 466.7 F/g at a high current density of 10 A/g. When NiMoO₄/NiCo₂S₄ composite material was used as the positive electrode and the active carbon as the negative electrode to form an asymmetric supercapacitor, the device retained 76% of the initial capacitance after 2000 cycles at a current density of 1 A/g, proving its excellent cycle stability. Thus, the present work can provide a reference for the development of NiMoO₄ as an electrode material for supercapacitors and serve as an experimental basis for the research of electrode materials with high specific capacitance and high cycle stability.

Key words: supercapacitor, NiMoO₄, NiCo₂S₄, composite