Electrochemical performance of Ni₃V₂O₈/rGO composites for supercapacitor applications

Hydrothermally synthesized Ni₃V₂O₈ (NV) and Ni₃V₂O₈-reduced graphene oxide (NV-R) nanocomposites offer promising electrode materials for high-performance supercapacitors. The crystal structure and the phase purity of the composites were confirmed by X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectroscopy was confirmed the characteristic of M-O (M = Ni, V) vibrations. Field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) images confirmed that well-integrated Ni₃V₂O₈ nanoparticles were uniformly distributed on the rGO nanosheets. Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) were used to assess the electrochemical performance. The intimate contact between rGO and Ni₃V₂O₈ is consistent with rapid electron transport, good electrical conductivity, and a large electrochemically active surface area. Therefore, at a current density of 1 A g^-1, the NV-R electrode achieved a high specific capacitance of 494 F g^-1, which is larger than that of the NV electrode (264 F g^-1). In addition, the assembled asymmetric supercapacitor device exhibited a specific capacitance of 81 F g^-1, a specific energy density of 22.05 Wh kg^-1, and a power density of 4177 W kg^-1, maintaining 86.76% of the initial capacitance after 5000 charge-discharge cycles. The findings show that the NV-R/NF electrode, which is grown in situ, exhibits electrochemical performance and could be one of the ideal candidates for next-generation high-performance applications in supercapacitors.