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    SYNTHESIS OF FLOWER-SHAPED COPPER FERRITE WITH COPPER AND IRON EXTRACTED FROM THE DIFFERENT ACID TREATMENTS OF CHALCOPYRITE FOR SUPERCAPACITOR ELECTRODE APPLICATION
    (2022-12) Mbebou, El Moctar
    Supercapacitors are one of the important energy storage systems that emerged as an alternative to lithium-ion batteries. The development of their electrodes is one of the important scientific study areas that has gained momentum in recent years. In this context, many syntheses have been carried out so far by considering the charge storage mechanisms of the electrodes. These are based on the principle of physical and chemical attachment of ions on the electrode surfaces. The physical attachment of the ions is related to the surface area of the electrode, and the chemical attachment is related to the oxidation/reduction mechanisms occurring on the surface. Two different components have generally been used in the studies to perform these operations. However, a single-component component that can perform both tasks is designed in this thesis. For this purpose, nano-sized metal oxide synthesis was carried out on the nickel foam current collector electrode surface from a natural mineral. Chalcopyrite containing copper and iron elements, which can give an easy redox reaction, was chosen as a mineral. First, chalcopyrite mineral was treated with 10-20-30-40 ppm concentrations of HCl, H2SO4, and HNO3 acids to extract copper and iron. Atomic absorption spectroscopy (AAS) was used to determine copper and iron concentrations in each solution. Afterward, the obtained results were compared with acid-free extraction, and optimization was achieved. After that, the highest copper and iron extraction was determined as 492 ppm with 446 ppm of HNO3 acid. The second step aims to produce copper ferrite-based electrodes with this solution containing the highest concentration of copper and iron. This synthesis process was carried out on the surface of the nickel foam used in the productions. After that, FTIR, XRD, TEM, and SEM techniques were used to describe the generated electrodes in terms of the chemical bond structures, crystal planes, and microstructures, respectively. Then, the electrochemical performance of the produced electrode was determined using cyclic voltammetry (CV) and galvanostatic charge-discharge measurements (GCD) with a three-electrode setup. The obtained characterization results showed that the flower-shaped CuFe2O4 was successfully synthesized on the nickel foam surface despite some impurities. Electrochemical results showed that the electrode has a battery-type charging mechanism, and the highest specific capacitance is 525 mF/cm2 at 2 mA/cm2 current density. In addition, this electrode's energy and power densities at a current density of 2 mA/cm2 were calculated as 8.9 mWh/cm2 and 233 mWh/cm2. As a result, it has been discovered that copper and iron extraction from chalcopyrite can be conducted at higher rates than their counterparts in the literature while using a low-cost component such as nitric acid. Furthermore, it has been established that the solution developed here can create high-performance electrodes for supercapacitors, a key component of energy storage devices. The electrochemical performances of the produced electrodes were seen to be promising for supercapacitors in this context; nonetheless, it was decided that additional research is required to determine whether this is the case.