<![CDATA[The development of sustainable materials for solid polymer electrolytes has encouraged the utilization of industrial waste as a source of functional materials. This study aims to synthesize and characterize silica derived from fly ash using the sol-gel method for potential application in solid polymer electrolyte materials. Silica extraction involved HCl acid treatment, NaOH alkaline dissolution, precipitation, filtration, and drying. Structural and electrochemical properties were characterized using Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). FTIR analysis confirmed the formation of amorphous silica through silanol (Si–OH) and siloxane (Si–O–Si) functional groups, with the strongest absorption peak at 1001.55 cm⁻¹ corresponding to Si–O–Si stretching and a broad band at 3374.41 cm⁻¹ associated with hydroxyl groups and adsorbed water. EIS analysis showed frequency-dependent impedance and dielectric behavior over 10¹–10⁶ Hz. The real and imaginary impedance decreased with increasing frequency, indicating reduced polarization and enhanced ion transport. The Nyquist plot exhibited a depressed semicircle and diffusion tail, indicating combined bulk conduction and ion-diffusion behavior. The ionic conductivity reached 1.30 × 10⁻⁶ S/cm. The dielectric constant was highest at low frequencies and decreased with increasing frequency, while dielectric loss approached zero at high frequencies. These results indicate that fly ash-derived silica has structural and electrochemical characteristics suitable for further investigation as a filler in solid polymer electrolyte materials.]]>
