This paper reports on the preparation of graphene oxide (GO) modified with hafnium oxide (HO) nanoparticles composites by a simple mixing and their use as efficient electrode in electrochemical supercapacitors. The technique relies on simple mixing the aqueous solutions of hafnium oxide (HO) nanoparticles and graphene oxide (GO) at different ratios of GO content (20, 30 and 40 wt%). The morphological studies, chemical composition and electrochemical behavior of the resulting HO/GO nanocomposites were investigated by using UV/vis spectrometry, X-Ray Diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electrochemical respectively. The electrochemical performance, including the capacitive behavior of the HO/GO nanocomposites were investigated by cyclic voltammetry and galvanostatic charge-discharge curves. The HO/GO nanocomposites (40 wt%) ratio exhibited the best performance with a specific capacitance of 268 Fg^-1 at a scan rate 5 mVs^-1 in 1 M H₂SO₄ and it shows excellent long-term cycle stability.

Keywords: Hafnium Oxide (HfO₂); Graphene Oxide; Supercapacitor; Cyclic Voltammetry;