polyaniline/sulfonated reduced graphene oxide (PANI/S-rGO) nanocomposite with different S-rGO contents (1:1, 1:2, and 1:3 wt%) were synthesized via hydrothermal approach. In the structure of this nanocomposite, the PANI nanoparticles were uniformly deposited into the sulfonated reduced graphene oxide layers. The surface functionalities and physical states of the samples were characterized with FT-IR, XRD, FE-SEM, EDX, and TEM measurements. Also, after preparing working electrodes, the chemical status of the models was investigated in a Sulfuric acid solution (0.5 M). The PANI/S-rGO-1 nanocomposite delivers the maximum specific capacitance of 1662.13 F/g, power density of 356 W/kg and energy density of 17.5 Wh/Kg, with electrochemical stability of 82% over 250 cycles as compared to other electrodes. Therefore, the superior electrochemical properties in the present work enable the nanocomposite to be utilized for energy storage-related devices (as electrode material) with optimum performance.