In recent years, there has been a growing interest in environmentally friendly synthesis methods for functional materials, particularly those employing natural chelating agents. In this study, cobalt ferrite (CoFe2O4) ceramics were synthesized via a green sol–gel route assisted by cassava starch, and their structural, morphological, and dielectric properties were investigated. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase cubic spinel structure (space group Fd \(\overline{3 }m\) ), with crystallite sizes of 56.7 nm (CFO#M5) and 45.7 nm (CFO#M15). Scanning electron microscopy (SEM) revealed irregular grain morphologies ranging from 124 nm to the micrometer scale. Fourier transform infrared (FTIR) showed absorption bands between 927 and 3706 cm−1, mainly associated with hydroxyl (O–H), adsorbed carbon dioxide (CO2), and carbonates (CO₃2⁻) groups from precursor residues. Energy-dispersive X-ray fluorescence (ED-XRF) analysis confirmed the presence of cobalt, iron, and oxygen with approximate atomic contents of 21.2%, 33.2%, and 45.6%, respectively, consistent with the stoichiometry of cobalt ferrite. Impedance spectroscopy revealed non-Debye relaxation behavior and interfacial polarization of the Maxwell–Wagner type. The sample CFO#M5 exhibited the highest grain boundary resistance (0.1004 MΩ) and higher dielectric permittivity at low frequencies, while the sample CFO#M15 showed greater dielectric loss. Alternating current conductivity increased with frequency following Jonscher’s power law, reaching 3.68 × 10⁻⁶ S/cm. The use of cassava starch enabled the synthesis of phase-pure cobalt ferrite ceramics with properties that can be tuned through synthesis conditions and chelating agent concentration, in accordance with green chemistry principles.
