Physically extracted and concentrated niobium oxide minerals from Abu-Dob mineralization (Eastern Desert of Egypt) as sustainable electrode's material for supercapacitor applications

Abstract

Recently, due to the global energy crisis and the anti-carbon movement, research on synthetic rare earth metal oxide-based supercapacitors has gained attraction. Niobium oxide minerals concentrate from the Abu-Dob mineralized pegmatite (Eastern Desert of Egypt), with an average niobium penta-oxide (Nb₂O₅) content of 4.9 % mass, was evaluated as a supercapacitor electrode. The purified Nb oxide minerals by gravity concentration, magnetic separation, and lastly froth flotation are primarily fergusonite-Y, with less common nioboixiolite-([]), aeschynite-Y and ferrocolumbite, as evident by XRD, FTIR and EDX analysis. An excellent performance of the niobium oxide as electrode material, possessing a quick rate of ion transfer and diffusion between the electrolyte and the electrode surface, long-term cyclic stability. This is evident by a high specific capacitance of 205 F/g at current density 1 A/g, with low R_s and R_ct, high capacity retention rates (182 % after 3000 cycles at 3 A g⁻¹). The abundant Nb minerals at Abu-Dob, low-cost beneficiation methods and efficient electrochemical characteristics call for further research into similar mineralization in Egypt as a potential geological raw material for supercapacitor applications. This adds value to Egyptian natural geological resources, particularly in the renewable energy industry, while also achieving global sustainable development goals.