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 Aluminum Doped To Extend Cathode Life in Li-Ion Batteries(01. Izmir Institute of Technology, 2021) Karabudak, Engin; Karabudak, Engin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyLithium-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) Karabudak, Engin; Karabudak, Engin; 04.01. Department of Chemistry; 04. Faculty of Science; 01. Izmir Institute of TechnologyThe 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.