The present research focuses on PVA: Gum Arabic: Ammonium Nitrate biopolymer blend electrolyte prepared using ultrasound-assisted solvent casting method and its applicability in Electric Double-Layer capacitor. AC impedance spectroscopic technique reveals the highest ionic conductivity of 10−5 Scm−1 at 303 K for 20 mol% ammonium nitrate doped sample which is higher than pure PVA. The transference number obtained for the prepared samples (0.94–0.96) confirms the dominant proton contribution to the conductivity. The constructed EDLC with the highest ionic conductivity electrolyte and carbon electrodes show a highest specific capacitance of 2909 mF/g. Intriguingly, the specific capacitance Cs values remain stable over 500 cycles which confirms its cycling stability.