Functionalized metal oxide electrode material plays an important role in the energy application of the supercapacitor. In this work, the comparative study of super-capacitance performance of hafnium oxide (HfO2) and sulfonated hafnium oxide (S-HfO2) nanomaterials is reported. The HfO2 nanoparticles were synthesized by the precipitation method. Subsequently, the prepared HfO2 nanoparticles were functionalized using sulfuric acid (H2SO4). Further, the synthesized nanoparticles were characterized and confirmed by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, High-resolution transmission electron microscope (HR-TEM), Field-Emission scanning electron microscope (FE-SEM) and Energy Dispersive X-Ray spectroscopy (EDS) techniques. The electrochemical properties and ion transfer characteristics of the supercapacitor were investigated by the cyclic voltammeter (CV) and galvanostatic charge-discharge (GCD) experiments. Moreover, the internal resistances of the material (HfO2 and S-HfO2) were analysed using Electrochemical Impedance Spectroscopy