Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Synthesis and Characterization of High Nickel Content Cathode Materials for High Performance and Capacity Reach in Li-Ion Batteries(Izmir Institute of Technology, 2022) Uğur, Turgut; Karabudak, EnginDue to their high energy density, low self-discharge properties, nearly negligible memory effect, high open-circuit voltage, and extended service life, lithium-ion batteries continue to gain interest as a promising energy storage technology. In the automotive industry, high-energy lithium-ion batteries have become the preferred power source for electric vehicles and hybrid electric vehicles in recent years. With the development of lithium-ion battery technology, several materials have been used into the cathodes and anodes in order to improve performance. LiNiCoAlO4, LiMn2O4, LiNiMnCoO4, Li4Ti5O12 and LiFePO4are five lithium-ion batteries that are commonly utilized in commercial EVs today. NMC cathode material is one of the most effective lithium-ion battery materials for balancing specific qualities. The battery cathode of NMC is strengthened with a specific ratio of three synthetic components (Nickel, Manganese and Cobalt). Depending on the proportions of these three chemical constituents, battery performance can vary. Synthesis, characterisation, and electrochemical studies of cathode materials with a high Nickel content were performed in this project in an effort to boost the specific capacity and durability of Li-ion batteries. In these preliminary studies, the synthesis and characterization of Ni(OH)2 structures, which serve as a starting material for the synthesis of cathode materials with a high Nickel content, was also a goal. In the research, the spherical Ni(OH)2 structure was effectively synthesized, and excellent electrochemical results were achieved. SEM and XRD analyses were performed on the resulting products.Master Thesis Synthesis and Characterization of Aluminum Doped To Extend Cathode Life in Li-Ion Batteries(01. Izmir Institute of Technology, 2021) Tekin, Onur; Karabudak, EnginLithium-ion batteries have an important place in meeting the energy needs and are of greater importance than their cognates, thanks to their characteristics as secondary batteries. Volumetric and gravimetric energy densities are the main features that carry lithium-ion batteries to the top. Lithium-ion batteries consist of different parts: cathode, anode, separator and electrolyte. While the anode materials are generally based on silicon, carbon and tin, the cathode materials include layered LiCoO2, spinel LiMn2O4, olivine LiFePO4, layered LiNi0,8Co0,15Al0,05O2(NCA) and layered LiNiCoMnO2 (NMC). Nmc and nca cathode materials stand out due to their high energy densities. Of course, lithium-ion batteries also have some disadvantages. A prime example of this is the capacity reductions it experiences with the increasing number of cycles. The main reasons for the decrease in capacity are; The transformation of the layered structure into spinel structure, the contamination of the Lio structure on the cathode to the electrolyte structure as a result of the side reactions that occur, damage the stable structure of the electrolyte and lead to Li loss. Metal oxide surface modification methods come to the fore in studies conducted to prevent these disadvantages. In this study, nmc structure was synthesized by reprecipitation method. Xrd, and sem analyzes of the obtained structure were taken. Al2O3 surface modification method was applied on the cathode surface. Cyclic voltammetry analyzes of the nmc structures with and without the modification applied were made with the help of potentiometry and the results were compared.Master Thesis Development of 3d Printed Spectroscopy Instrumentation for Medical Applications(01. Izmir Institute of Technology, 2020) Kanlı, Ali İhsan; Karabudak, EnginThe aim of this thesis is technically to produce a national production basement on analytical device manufacturing. In addition, recent advances in the evaluation of absorbance, reflection and fluorescence spectrum measurements in the UV-VIS range (vascular volume, oxygenation, extra cellular matrix, metabolic redox states, cellular proliferation) give us valuable measurements about the diagnosis, prognosis and treatment of some cancer types. Thus for every doctor and for every medical laboratory a cheap, portable, handy, and enough accurate UV-VIS spectrometer has become an up to date demand. Therefore production of an analytical VIS-spectrometer is planned as a first step on the way of our aim, by using our laboratory facilities and by using very common optical, electronical, mechanical components in the market around. Optical box design was get from an internet open source and printed in our laboratory by 3D-printer (Stratasys-Objet 30). A general purpose plastic mounting box (15x9x5 cm) is used for electronic part of the spectrometer. These two box is adjusted to each other to become as a single cabinet for spectrometer. Optical components are mounted, aligned and coupled to electronic circuit. PC and Microcontroller programs are written and loaded in our laboratory. During the calibration of our device, its performance is compared with the technical specifications of commercial VIS-spectrometers. As a last step; the produced device is used and tested in our laboratory.Master Thesis Development of Multi Metal Oxide Photo-Electrodes for Energy Applications(Izmir Institute of Technology, 2020) Özkahraman, Ecem Ezgi; Karabudak, EnginWater splitting via artificial photosynthesis uses only sunlight and water to produce hydrogen and oxygen. Hydrogen can be used as a green energy source. To be able this reaction to occur there is a catalyst needed as reaction center. Platinum and Iridium are the state-of-art catalyst used for water splitting reactions. The goal of this study is to develop an earth abundant, highly stable and efficient catalyst as an alternative to noble metal catalysts. For this purpose, ABO3 type perovskites was chosen to study for their abundancy and proven electrochemical efficiencies. BSCF was chosen as the starting point of this study because it is known for its great catalytic activity compared to state-of-art catalysts such as Iridium Oxide. To enhance the stability and catalytic activity of synthesized perovskite oxides, several foreign atoms (dopants) were introduced to their structure from B-site. Each perovskite was synthesized by the EDTA-Citrate complexing Sol-Gel method. Also, for dopants, cost-efficient and electron conductive elements was chosen in each study. As HER catalysts, manganese, zinc, and copper were introduced to BSCF structure as dopant, while for OER, silver was used as a dopant. In this study, catalytic activities and stabilities were tested by electrochemical methods. All electrochemical measurements were performed in alkaline media by three-electrode configurations. Perovskite oxides were prepared by the coating of their inks on Ni foam substrates by drop coating for HER and OER activity measurements by electrochemical methods. For the bulk and surface characterization of synthesized perovskite oxide powders, SEM, XRD, XPS, and BET analysis was performed.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 Development of Micro-Optical Furnace With Atmospheric Control for Research Purposes(Izmir Institute of Technology, 2018) Kıvanç, Mehmet; Karabudak, EnginIn this thesis, a desktop temperature controlled laboratory type micro-optical chamber system has been developed which can be used for vertical agricultural experiments to observe the development of plants with different wavelengths according to different atmospheric and temperature values using LED light sources. The main purpose of this thesis is to develop a laboratory type easy-to-use device that can control the ideal atmosphere and temperature to perform experimentally the effect of light rays of different wavelength to observe its development of the plant placed in the chamber. In this study, a chamber with rectangular prism geometry was created to prevent the negative effects of harmful insects on plants. Second, a fan system is formed to allow air circulation inside the chamber. Then, a heating unit with electrical resistance system was developed in order to increase or decrease the ambient temperature of the plants. In addition, a control unit with an electronic temperature control circuit is formed to control the atmospheric air circulation and temperature in the chamber. Using the completed system, it was concluded that it is possible to monitor the chamber using LED light sources with different wavelengths to monitor plant growth behaviors in the temperature and atmospheric controlled chamber. In this respect, the changes in the ambient temperature and LED light sources with different wavelengths can be practically used to monitor the growth behavior of the respective plants in chamber.Master Thesis Developing Mobile, Electronic and Positioning Applications for Emergency Situations Inside the Hospital(Izmir Institute of Technology, 2018) Keskin, Özge Sevin; Sürmeli, Nur Başak; Karabudak, Engin; Karabudak, Engin; Sürmeli, Nur BaşakThe aim of this project is to prevent mortality by providing emergency response on time. The communication inside the hospital is provided via developing application for Android and Ios operating system. The content of application is suitable for everyone’s use. The emergency call button makes it easy to call, and if the button is disabled, the heart rate rhythm starts for emergency intervention. This application is associated with bluetooth low energy systems in terms of help to locate the patient. Beacon systems provide data transfer through bluetooth by this means location is detected without internet. The project will be tested primarily at the laboratory following these steps. If it succeeds statistically, the project will be tried at the Tepecik Education and Research Hospital. The success of the project will be reviewed depends on the scenarios in the hospital.Master Thesis On the Pathway of Whole Blood Analysis by Portable Atr-Ir and Chemometrics(Izmir Institute of Technology, 2017) Koç, Mert; Karabudak, EnginCurrently, the number of patients per state hospital in Turkey is too high. Doctors need point of care(PoC) tests like blood analysis, to diagnose his/her patients. Patients is firstly examined by a doctor. If the doctor needs blood analysis, then patient gives blood to blood laboratory. After a certain time, the results are given to the patient and he/she meets with the doctor again to show the results. This causes too much time loss. In addition, these analyses are not performed in some small healthcare centers and cause extra time loss, which is another major problem in the health care system. Electrochemical, spectrophotometric and enzymatic analysis methods are mostly used for blood analysis. The sum of glucose, urea, triglycerides, cholesterol, albumin and total protein tests cost for 7TL. Blood samples are taken separately about 2-5ml volume for each test and preliminary procedures are required. On the other hand, ATR-IR spectrometry is a technique that does not require preliminary sample preparation, less sample volume, cheap and results in shorter time. Studies have been carried out in the literature which have shown positive results on glucose, urea, triglycerides, cholesterol, albumin and total protein in blood, plasma and serum using ATR technique. The six components in blood have importance in the diagnosis of a disease at the patient. The aim of this thesis is a preliminary study to determine the glucose, urea, triglyceride, cholesterol, albumin and total protein concentrations in 1 minute, 1 u of blood, using disposable crystals and less than 1 dollar in the doctor's room by direct analysis of the blood using ATR-IR spectrometry and using chemometrics algorithms to predict them from the spectral data.Master Thesis 3d-Printed Multiprobe Analysis System for Solar Fuel Research; Design, Fabrication and Testing(Izmir Institute of Technology, 2016) Harmanlı, İpek; Karabudak, Engin; Ebil, ÖzgençMethods of generating electricity with unlimited, clean and cheap energy from solar energy are tried to be investigated and developed in practical and theoretical academic fields. Especially, photocatalytic water splitting (PWS) systems have been identified as the main method in this study as well as in many studies due to the advantages provided by production of solar fuels from water. In this research, a study was carried out on the alternatives of the both used experimental set-up and used photocatalytic material for PWS systems. A study has been carried out on both the used experimental setup and the used photocatalytic material alternatives in PWS systems. As an alternative experimental setup that allows small volume analysis for PWS by Unisense gas microsensors, a mini photoreactor was designed using 3-D drawing and printing techniques and its usability was tested for PWS applications. Moreover, some characterization results for the electronic band structure and the band gap of the lead (II) trioxovanadate (V) chloride [PbVO3Cl] crystal, which was discovered by Eanes and co-workers in 2007 at IZTECH, was introduced in this study by not only theoretical (DFT approximations; LDA, GGA and HSE06) but also experimental (XRD, Diffuse Reflectance Method- Tauc Plot, Raman Spectroscopy, Four Probe) methods. Also, its estimated theoretical price and its potential for future application in tandem solar fuel device as a photoanode in combination with Si photocathode was calculated and discussed. The results showed that the designed mini photoreactor system is an open to development apparatus that is suitable for PWS, besides, PbVO3Cl has an "indirect transition" band structure and a band energy of ~ 2.2 eV. Although it did not give an effective result in PWS applications done by the designed mini photoreactor, it can be said that it is a semiconductor which is worth studying and developing in detail for other researches in this field due to the compatibility of its band energy amount and optical properties for PWS.