Nickel vanadate Ni3(VO4)2 nanoparticles were successfully synthesized by a sonochemical method. The characterization of this material was examined by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray diffraction (EDS), field emission scanning electron microscopy (FE-SEM), Raman spectroscopy X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The prepared sample was coated on nickel foam. The capacitive behavior of nanomaterials were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge test and electrochemical impedance spectroscopy (EIS) by a threeelectrode system in an aqueous solution of 6 M potassium hydroxide as the electrolyte. The electrochemical properties were studied at various scan rates in the potential range of 0.0 - 0.55 V. Electrochemical testing showed that Ni3(VO4)2 nanoparticles performance with high specific capacitance ~ 400 F g-1 at 2 A g-1 with enhanced rate capability and excellent capacity retention more than 85% after 1000 consecutive charge–discharge cycles.
