At the beginning of this thesis, a review of zinc-air batteries, their electrocatalysts, and the challenges related to this battery, as well as the research done by other researchers, was done. The purpose of this thesis is a comparative investigation of the electrochemical performance of Fe-Co/Kb catalysts and 30 wt% Pt/C in the presence of zinc oxide and carbonate impurities. At first, the surface microstructure of the catalysts was studied by linear scanning microscope technique and it was concluded that Fe-Co/Kb has particles with very small to large sizes and has more surface area and porosity. The specific surface of the catalysts was measured and the specific surface of Fe-Co/Kb is about 5 times higher than Pt/C due to the use of ketjen black. The electrochemical activity of the catalysts was studied in a three-electrode system. To investigate the effect of zinc oxide and carbonate impurities, different amounts of these impurities were added to the potassium hydroxide electrolyte. Using cyclic voltammetry and linear scanning voltammetry, it was observed that for Fe-Co/Kb, the cell potential was from -0.15 V vs. Ag/AgCl to -0.05 V, and for platinum catalyst from -0.3 V, it has changed to -0.2 V. That is, the impurities have partially improved the kinetics of oxygen reduction. Chronoamperometry was carried out to check the current density concerning the time at certain potentials and it was observed that for the non-noble metal catalyst at the potential of -0.12 V by adding zinc oxide, the current density changed from 27 to 65 and 40 mA/cm2, respectively. found, and in the case of the platinum catalyst, it was changed from 8.4 to 6.6 and 20 mA/cm2, respectively, at the potential of -0.3. Electrochemical impedance was carried out to check the contact resistance and charge transfer resistance on the surface of the catalysts in reducing potentials and for Fe-Co/Kb, Rohm with the addition of zinc oxide and carbonate increased from 49.44 to 44.04 and 56.04 Ohm; In this case, the impurities decreased the ohmic resistance of the battery, and in the case of platinum, by adding zinc oxide and carbonate, it changed from 25.42 to 43.52 and 16.74 Ohm, the carbonate impurity decreased the ohmic resistance. In the next part, two air batteries were made based on Fe-Co/Kb catalysts and 30% Pt/C by weight. Battery discharge tests were performed at different current densities. Based on the results, the batteries had similar performance. At a potential of 1 V, the power density of 240 mW/cm2 and the current density of 300 mA/cm2 were observed for the Fe-Co/Kb catalyst, and for the platinum catalyst, the power density was 250 mW/cm2 and the current density was 320 mA/cm2. The battery discharge test was performed at a current density of 20 mA/cm2 and the battery based on Fe-Co/Kb catalyst for 1 hour and 15 minutes and the battery based on the platinum catalyst for 1 hour and 40 minutes showed a potential drop. Based on this, the performance of the battery based on the non-noble metal catalyst was eva‎luated as comparable to the battery based on the platinum catalyst.

محمد ژياني

محمد محمدي

محمد محسن مومني، حسن حداد زاده