Herein, Polyaniline (PANI) and polyaniline/silver oxide/silver (PANI/Ag2O-Ag) nanocomposite were synthesized using a photopolymerization method. The functional group, structural, surface morphology, and optical properties of the samples were revealed using Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and Ultraviolet-Visible spectroscopy techniques, respectively. XRD confirm the structure of the PANI with Ag2O-Ag. These nanoparticles appeared in porous shapes over PANI as indicated by SEM images that gave the composites the mushroom shapes. The composite is a promising electrode for the symmetric supercapacitor with high efficiency capacitance. This capacitance is calculated under different electrolyte that is, NaOH, NaCl, Na2S2O3, and HCl, where the charge/discharge and cyclic voltammetry curve were studied under these electrolytes. The electrochemical properties of the PANI/Ag2O-Ag nanocomposite as supercapacitor electrode materials were investigated using different electrolytes. The results confirm that the specific capacitance values are dependent on the types of the electrolytes, in which Na2S2O3 and HCl have the optimum values of 160 and 145.2 F/g, respectively at 0.4 A.g−1. Moreover, the values of energy density were 122.2 and 20.08 W h kg−1, respectively. The results also reveal that the capacitor has high stability with a very small loss in capacitance retention. This study proposes that PANI/Ag2O-Ag are a promising material as an electrode for high-performance supercapacitors that can be applicable in the industrial field soon.