Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Modelling and Simulation of Zinc-Air Batteries(01. Izmir Institute of Technology, 2024) Ebil, Özgenç; Ebil, Özgenç; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyRenewable energy sources are key components of a sustainable future. However, most of the renewable energy sources have intermittent natures, that can significantly affect the stability of grids. Thus, Energy Storage Systems (ESS) are introduced to store the energy produced for later use. Even though there are various ESS candidates, batteries are superior candidates due to technological readiness. Batteries still suffer from disadvantages that prevent their mass adoption as ESS for grid-scale applications. As an ESS, a battery that can last long cycles, have high power densities, and material availability should be designed and commercialized. Commercial batteries such as lead-acid and Li-ion batteries still suffer from material availability, environmental friendliness, or feasibility. Therefore metal-air batteries, especially zinc-air batteries (ZAB), have significant potential due to their high-power densities, material abundance, and technological readiness. However, ZABs are not ready enough to be commercialized as grid-scale ESS due to their low cycle lives due to aging mechanisms. Therefore, more research should be conducted to improve the rechargeability of a ZAB. However, experimental procedures are time and resource-consuming. To tackle this, accurate mathematical models and simulations should be implemented. In this study, the electrochemical behavior of zinc-air batteries was simulated with Finite Element Analysis (FEM) method. The motivation of the work was to demonstrate the feasibility of a simple 1-D zinc-air battery model to investigate the effect of various phenomena on the battery capacity and charge-discharge cycles. The results were compared to literature and experimental values to evaluate the model's accuracy.Master Thesis Development of Carbon-Free Zinc-Air Batteries(01. Izmir Institute of Technology, 2024) Ebil, Özgenç; Ebil, Özgenç; 03.02. Department of Chemical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyZinc-air batteries are thought to be among the greatest substitutes for present energy storage systems because of their high energy densities (~1000 Wh/kg), affordability, and safety. However, zinc-air batteries face several problems, such as carbon corrosion, pore-clogging, and electrode passivation. The main cause of these problems is carbon in the air electrode. Therefore, carbon should be eliminated from the air electrode to enhance its performance. This thesis aims to synthesize an electrocatalyst for air electrodes for secondary carbon-free zinc-air batteries within the scope of the M-Era.NET 'AMAZE' project. Initially, manganese oxide was selected as an electrocatalyst and synthesized using a co-precipitation method with different parameters such as concentration, pH, temperature, and precursor materials. The best MnxOy was obtained with a solution pH and temperature of 9.5 and 60°C, respectively. The main precursor for the catalyst was KMnO4, with a ratio of KMnO4:HCl as 20:4 by volume. α-MnO2 with a surface area of 85.68 m2g-1 was obtained. In addition, onset overpotentials for oxygen reduction and oxygen evolution reactions with 650mV and 271mV, respectively, and a maximum current density of 10.5 mA.cm-2 were obtained. Nickel and cobalt additions were evaluated to improve ORR and OER activity. Catalyst with MnxNiyCozOt(1:0.5:0.5) composition performed better than other samples and had the highest surface area (172.06 m2g-1), ORR and OER potentials of 463mV and 700mV, respectively, and current density of 96 mA.cm-2.