Advancing green energy: synthesis of Li-doped MgFe2O4 nanoporous ferrite for sustainable hydroelectric cells and eco-friendly power generation

Abstract

In this work, a novel hydroelectric cell (HEC) was developed for green electricity generation. This HEC leverages the unique properties of lithium-substituted magnesium ferrite, facilitating water molecule dissociation on octahedrally coordinated unsaturated surface cations and oxygen vacancies. The phase formation was characterized using X-ray diffraction (XRD), revealing crystallite sizes ranging from 36.36 nm to 60.89 nm, sufficient for the reaction. Surface morphology and porosity were examined using field emission scanning electron microscopy (FESEM), showing grain sizes between 100 and 300 nm with optimized porosity. Elemental composition was analyzed using energy-dispersive X-ray spectroscopy (EDAX), and chemical bonding was explored using Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Additionally, Brunauer–Emmett–Teller (BET) isotherm analysis revealed a high specific surface area of approximately 3.2 m²/g with an average pore size of 25 nm, providing more active sites for electrochemical reactions. Magnetic properties with magnetization upto 27.7 emu/g and low coercivity were assessed using a vibrating sample magnetometer (VSM), while the electrochemical behaviour was studied through electrochemical impedance spectroscopy (EIS) showing that impedance of the cell decreases from 10⁷ Ω to 10 Ω during the reaction. Performance evaluation showed that water dissociates into hydroxide and hydronium ions whenby sprinkled. Confined hydronium ions within the nanopores generate an electric field that accelerates the dissociation process, enhancing the ionic current. The resulting voltage and electric current are produced through the oxidation of the Zn electrode by hydroxide ions and the reduction of H₃O⁺ at the Ag electrode. The developed HEC, with an area of 19.6 cm², achieves a maximum output power of 15 mW, a short-circuit current of 50 mA, and a voltage of 1.23 V. This HEC demonstrates consistent and repetitive performance, offering a promising and efficient alternative for renewable energy generation.