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Low temperature Fuel Cells
Kazda, Tomáš ; Novák, Vítězslav (referee) ; Barath, Peter (advisor)
The Bachelor’s thesis is aimed at the low-temperature fuel cells and their usage in cars and mobile applications. In the theory part of this project is described the evolution of the fuel cells in last years and historically as well. Further there are described their functions and particular kinds of the fuel cells with aim at low-temperature cells. In the practical part of this thesis we were making different kinds of carbon mixtures. We have been doing measurements of mixtures on rotate disk electrode and in the experimental fuel cell. At the end of the work are experimentally evaluated different types of carbon materials with different contents of platinum depositing. The results are evaluated using electro analytical methods, using this evaluation to optimize the composition of the material used as electrode material in fuel cells.
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Comparison of different types of commercial lithium-ion batteries
Šindelářová, Anna ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
The master's thesis is devoted to the comparison of different types of lithium-ion batteries. Primarily, an introduction to electrochemical power sources and their division is described. Furthermore, the thesis deals only with lithium-ion batteries. In the theoretical part, the chapters discuss the history, the principle of operation and a detailed description of the main battery parts, including used materials. A comparison of commercially available lithium-ion cells with each other as well as with other types of batteries is also included in the theoretical part. The practical part deals with the cyclinf of lithium-ion cells and subsequent evaluation of the effect of temperature on the capacitance and current characteristics of these lithium-ion batteries.
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Utilization of fotovoltaic effect in combination with electrochromism
Šeda, Radek ; Kazda, Tomáš (referee) ; Jakubis, Ivan (advisor)
This thesis deals with the preparations of titanium and tungsten dioxide active electrochromic layers and simulation of link between electrochromic structures and photovoltaic cell. By means of electrodeposition, the active layers were made on the glass substrates ITO. These layers were subsequently analyzed, namely their intercalation properties. In this thesis, I tried to design the link between the electrochromic element and the photovoltaic cell. After this, functionality of this link was verified by software environment MATLAB Simulink.
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Study of the possibility of using Tesla's turbine as a source of energy
Šedina, Martin ; Maxa, Jiří (referee) ; Kazda, Tomáš (advisor)
The master thesis deals with the currently used types of water turbines and next part of the thesis deals with the theory of Tesla turbine. The theoretical part discusses water wheels, water turbines with their types and models which are described in the work. The thesis also discusses the construction of the Tesla turbine, its possibilities of using, inside principles and information about Tesla´s patent. The practical part contains the design of the Tesla turbine with modifications for increasing efficiency. The thesis describes production and assembly of turbine and the technology used for production of the turbine. There is also described how the turbine was measured and there are results of measurements of the turbine.
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Study of the properties of the advanced materials for the cathodes of the lithium-ion accumulators
Pustowka, Pavel ; Tichý, Jiří (referee) ; Kazda, Tomáš (advisor)
This thesis in its first part deals especially with characteristic of lithium ion accumulators in terms of their structure, electrochemical properties and also features of the most commonly used cathode materials. Especial attention is given to the high-voltage cathode material LiNi0,5Mn1,5O4 which cell voltage is close to 5V. The second practical part deals with the preparation of cathode materials based on LiNi0,5Mn1,5O4 with different temperatures in the second stage of annealing and analyzing them in terms of structure and electrochemical properties using appropriate measuring methods.
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Study of intercalation properties of negative electrode materials
Minda, Jozef ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
The bachelor thesis deals with the research of intercalating properties of negative electrode materials for lithium-ion and sodium-ion accumulators. The main focus of this work is on the kinetic aspects associated with the diffusion processes of lithium in graphitic negative electrode material and sodium in titanates materials in relation to the electrochemical parameters. By comparing the materials in terms of kinetic properties expressed by the diffusion coefficient with using of electrochemical impedance spectroscopy in the state of the base material and after creating the passive layer on the electrode, it is possible to determine the application possibilities of the materials and the dependence on the electrochemical parameters. In the thesis is designed a procedure for electrodes preparation, measurement and evaluation of monitored parameters. Within the experimental part, the structural and electrochemical parameters and diffusion coefficients of the studied materials are determined by the proposed method.
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Positive electrode for lůithium-ion batteries based on LiCoO2
Krištof, Petr ; Kazda, Tomáš (referee) ; Sedlaříková, Marie (advisor)
This diploma thesis deals with materials used by production ofcathodes of Lithium-ion batteries. Primary this thesis deals with LiCoO2material and its subsidizing of alkali metals. The first part deals with the charakteristic of Lithium-ion batteries, used materials, possibilities of doping and charging. The practical part concentrates on production of active substance of cathode and doping this substance by sodium and potassium. The methods of evaluation were used galvanostaticcycling and x-ray analysis (XRD).
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Modification of Cathode Materials for Lithium-Ion Accumulators
Kazda, Tomáš ; Studničková, Marie (referee) ; Vanýsek, Petr (referee) ; Vondrák, Jiří (advisor)
This doctoral thesis deals with properties of cathode materials for Lithium-Ion accumulators. The theoretical part consists of an overview of the cathode materials and a brief introduction into the very wide area of Lithium-Ion accumulators. The goal of this work was to study the LiCoO2 cathode material and to prepare some modifications of it by doping with other elements. This work was then extended with the study of the new generation of high-voltage cathode materials. The aim of this part was to study their synthesis, their physical and electrochemical properties and the influence of used electrolytes on their electrochemical stability. The work then focuses on the influence of doping these materials and the influence of another part of the battery – the separator – on the overall properties of these types of cathode materials. The results show that doping the LiCoO2 cathode material with sodium and potassium lead to an enhancement of some electrochemical properties as stability during cycling or stability at higher loads and also the long-term stability during aging is better. The LiNi0,5Mn1,5O4 high voltage material was synthetized in both its forms in comparable or even better quality compared with the results from foreign laboratories. The synthesis process was watched in-situ by SEM, thanks to which a unique study of the ongoing changes during synthesis was done. Also the best suitable electrolytes for this material were identified from the viewpoint of stability at high voltages, which is important for the future practical use. Doping of the material with chromium resulted in better stability and capacity both during cycling at standard conditions and at higher temperature and load. A significant impact of the separators on the overall electrochemical properties of the cathode materials was proved, which could be a big benefit for their future usage.
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Determination of the most suitable ratio of cathode materials for the lithium-sulfur battery system
Benešová, Petra ; Kazda, Tomáš (referee) ; Jaššo, Kamil (advisor)
This master's thesis deals with a topic of determination of the most suitable ratio of cathode materials for the lithium-sulfur systems. The first two chapters provide a general introduction to the topic of electrochemical energy sources and present the commonly used primary and secondary battery systems with emphasis on their characteristics and applications. The core of the theoretical part is dedicated to lithium-ion and lithium-sulfur batteries, their working principles along with the benefits or drawbacks related to the particular systems, and widely used materials. The experimental part briefly comments on determining the suitable electrode paste preparation method, the subsequent main part is focused on evaluation of electrochemical performance of cells using different ratios of cathode materials. Five samples of cathode materials were prepared, where the sulfur ratio is in range from 64 to 88 wt. %. Finally, the comparison of all prepared ratios in terms of their electrochemical properties is provided.
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