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) Durak, Ege; Ebil, ÖzgençRenewable 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 Synthesis and Investigation of Quinone-Pyrrole Polymeric Materials for Zinc-Ion Batteries(01. Izmir Institute of Technology, 2024) Çanakçı, Utku Cem; Büyükçakır, OnurFosil yakıtların günümüzde yaygın kullanımı çevre üzerinde yıkıcı bir etkiye sahiptir. Bu durum, çevre dostu alternatif enerji kaynaklarının benimsenmesini zorunlu kılmıştır. Çinko-iyon piller, bu bağlamda önemli potansiyele sahip, gelişmekte olan yeni bir enerji depolama sistemi sınıfını temsil etmektedir. Bununla birlikte, bu teknolojiyi ilerletmekteki büyük zorluk, Zn2+ iyonlarını verimli ve geri dönüşümlü olarak barındırabilen katot malzemeleri geliştirmektir. Kinon bazlı konjuge polimerik malzemeler, redoks aktif yapıları, kolayca değiştirilebilen yapıları ve güçlü kimyasal ve termal kararlılıkları nedeniyle çinko-iyon pilleri için mükemmel katot seçenekleridir. Bu çalışmada, çinko-iyon pilleri (ÇİP'ler) için katot malzemeleri olarak kinon-pirol konjuge polimerik malzemeler (QRP'ler) sentezlendi. QRP'lerin içsel özellikleri, redoks merkezlerine etkili Zn2+ difüzyonunu kolaylaştırarak uzun vadeli döngü kararlılığını sağlar. QRP-1 ve QRP-2 sırasıyla 0.1 mA g-1 akım yoğunluğunda 180 mA h g-1 ve 134 mA h g-1 deşarj kapasitesi gösterdi. QRP'ler, 2.0 A g-1 akım yoğunluğunda 10000 döngü boyunca olağanüstü döngü kararlılığı göstererek, QRP-1 ve QRP-2 için sırasıyla 42 mA h g-1 ve 104 mA h g-1 olmak üzere oldukça yüksek final kapasiteleri elde edildi. Bu çalışmanın, kinon bazlı konjuge polimerik malzemelerin çinko-iyon piller için etkili katot malzemeleri olarak potansiyelini gösterdiğine ve enerji depolama alanında çalışan araştırmacılarının dikkatini çekeceğine inanıyoruz.Master Thesis Experimental Analysis of Inkjet Printed Multi Metal Oxide Photoelectrodes for Water Splitting Applications(Izmir Institute of Technology, 2020) Tekneci, Gülsüm Efsun; Karabudak, Engin; Adem, UmutRecently, scientific research studies focus on renewable energy solutions as well as energy efficiency in managing the upcoming climate crisis which manifests itself in the form of global warming. However, the chaotic nature of renewable energy sources caused energy storage technologies to gain importance. In addition to battery technologies consisting of lithium and post-lithium ion, zinc-air, nickel-zinc and lead-acid; artificial photosynthesis products such as hydrogen and methanol also show superiority in transportation. Especially hydrogen fuel is in the leading position with gravimetric energy density of approximately 140 MJ/kg. In this study, the experimental procedure is conducted and analyzed to produce cost-effective multi-metal oxide catalysts at high speed and efficiency with a combinatorial approach using inkjet printing technology to obtain hydrogen by splitting water. Considering the abundancies in nature, especially nickel, cobalt, iron, manganese, copper and chromium salts were preferred to obtain oxide derivatives. Inkjet printing experiments were conducted with the printer provided by Sağlık İzleme Sistemleri A.Ş.. The precision of the printed layers was examined and compared with the literature values. In cases involving differences from the literature value, possible causes are emphasized and solutions are suggested. Problems in transition from single metal oxide printed layers to more complicated multi-metal oxide prints have been examined and solutions have been proposed. As a result, this experimental study is aimed to provide foresight for large-scale (photo)electrocatalyst production with the utilization of inkjet printing.Master Thesis Zeolite Based Composites in Energy Storage(Izmir Institute of Technology, 1999) Negiş, Fikri; Ülkü, SemraIn this thesis, second phases were used for the zeolite-based composites with high thermal conductivity for energy storage applications. Natural zeolite, clinoptilolite received from large deposits in Turkey was used as matrix while aluminum, aluminum hydroxide and graphite were used as second phases for composite preparation.Composites of different compositions (from 10 to 40 wt% additive loading) were prepared by mixing different amount of second phases to the clinoptilolite.Powder mixtures were pelletized using poly vinyl alcohol as a binder. The use of the binder was necessary to obtain mechanically strong pellets. The thermal treatment temperature and press pressure were determined as 150°C and 60 bar for the pellet preparation. Powders were further characterized by thermo gravimetric analysis, differential thermal analysis and differential scanrung calorimetry. These characterizations have shown that three types of water is present in clinoptilolite: external water, loosely bound water and tightly bound water.Thermal conductivities of these composite pellets prepared were determined using hot plate method.Thermal conductivity of pure matrix cIinoptilolite pellets were measured as 0.26 W/mK. Thermal conductivity increased significantly by using aluminum as the second phase while it did not change much for graphite and aluminum hydroxide composites.For composites containing 40% aluminum or aluminum hydroxide or graphite, thermal conductivities of 1.18, 0.50, 0.43 W/mK were measured, respectively. Aluminum containing composites could be used as adsorbent bed materials and by this way, it may increase the performance of adsorption heat pumps.