Beneficiated cassiterite (SnO2) from mining tailings-to- clean renewable energy storage material: unlocking the potential sustainability

Abstract Research on developing sustainable materials for devices to store clean energy has become crucial. This study explores the use of naturally occurring cassiterite (SnO2), a rare metal oxide mineral, as a material for electrodes in supercapacitors. The mineral is found in mining tailings of the Igla Be–Sn deposit (Egypt’s Central Eastern Desert) mined from pegmatitic granite and greisen zones. The mineral (3.59% mass) was beneficiated using a sequence of sorting, magnetic, and gravity separation. The physico-chemical characterization indicated stoichiometric SnO2 of nanoscale grains with high crystallinity, porous structure, and many electroactive sites. Using a three-electrode configuration with a 6M KOH electrolyte, the electrochemical performance was assessed via cyclic voltage measurements, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The cassiterite-based electrode shows specific capacitance of 54.97 F g−1 and a capacity of 30.23 C g−1 under an electrical density of 1 A g−1, and capacitive storage (retention) of 293.8% over 3000 cycles, which paired with enhanced charge transfer and ion diffusion characteristics. Cassiterite from Igla mining tailings has been proven to be a sustainable substitute for traditional electrode materials in clean energy storages due to the developed electrode’s electrical efficacy, the enormous amount of Igla Sn tailings, and the economical and environmentally friendly recovery techniques used.