We herein report the synthesis of electrolyte-filled activated carbon (AC) coated with an ion-conducting polymer (AC-N) to achieve a electrode material exhibiting enhanced capacitive properties. The successful formation of the polymer layer was confirmed by X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) analysis. In addition, electrochemical characterization was performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) at a range of concentrations (i.e., 0.25, 0.5, and 0.75M NaCl or Na2SO4). The specific capacitance obtained for the 0.75M Na2SO4-filled AC-N was 13.5% higher than the bare AC-N at a scan rate of 100mV/s, while the interfacial resistance was reduced by 94.6%. We therefore expect that the electrolyte-filled AC reported herein can improve the performance of the electrosorption based system by reducing cell resistance.