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Hydrogen fuel cells
Kejval, Dan ; Kučera, Pavel (referee) ; Píštěk, Václav (advisor)
The replacement of the current fuels and engines presents one of the most important tasks not only for vehicle manufacturers but also in the energy industry. Whole world is trying to limit the production of greenhouse gasses which pollute the environment and switch to sources that will not produce any harmful emissions as fast as possible. One of these are hydrogen fuel cells, which are the focus of the thesis and explains how hydrogen is produced and stored. It shows the principle on which they work, what designs currently exist and also evaluates their efficiency. According to temperature and material of the electrolyte they can be divided into various types which offer a wide range of performances and their use. Thanks to that, this device began to spread both in the Czech Republic, where the effort is to firstly expand public transportation to include busses using the hydrogen fuel cells and at foreign vehicle manufacturers where carmakers such Toyota and Hyundai already mass-produce passenger cars, trucks or buses with this source of electricity.
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Evaluation Of Temperature Influence on Lead-Acid Battery Properties
Langer, Martin ; Zimáková, Jana (referee) ; Bača, Petr (advisor)
This work deals with lead-acid batteries, their properties and individual types that are available on the market. The temperature dependences of the battery parameters at different ambient temperatures and at different discharging and charging modes are measured here. The theoretical part of the work deals with electrochemical cells in general, description of their main parts and principles of operation. The work analyzes the types of batteries used, their advantages and negatives. In the case of a lead-acid battery, its internal structure and the function of the electrodes and the electrolyte are taken into account. Furthermore, a description of individual possible negative phenomena that take place in lead-acid batteries and contribute to the end of their service life is included. In the practical part, 6 batteries are tested at different charging currents, which provides information about their behavior both during discharge and at the time of charging. During the experiments, testing is not only performed at room temperature, but the batteries are also exposed to high temperatures up to 75 ° C.
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Electrolytes for sodium - ion batteries using ionic liquids
Suský, Stanislav ; Zatloukal, Miroslav (referee) ; Máca, Josef (advisor)
The content of this work deals with a theoretical search of sodium-based batteries. The first part of the work contains an introduction to the issue of batteries, contains basic concepts, principles of secondary batteries. In the second part, the basic three divisions of sodium batteries according to the design principles are discussed in more detail. He also deals with the theory of ionic liquids. Their mechanical, thermal and electrical properties and the method used to measure electrolytes are described here. The practical part describes the measurement procedure, displays the recorded measured values and their evaluation.
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Characterization of electrochemical properties of magnesium batteries in electrolyte modification
Honč, Jiří ; Doskočil, Leoš (referee) ; Wasserbauer, Jaromír (advisor)
This thesis deals with novel electrolytes for magnesium batteries. Prepared electrolytes were composed of affordable solvents and chemicals, which can be handled at normal laboratory conditions. Specifically, solutions of tetrahydrofurane and dimethylsulfoxide with magnesium chloride, aluminium chloride, nitrilotriacetic acid and disodium ethylenediaminetetraacetic acid, were prepared. To determine electrolyte ability of magnesium stripping and deposition, the cyclic voltammetry was used. The kinetics of electrochemical reactions in terms of polarization resistance was studied by electrochemical impedance spectroscopy. Based on scanning electron microscopy and EDS analysis, the effect of atmospheric oxygen and humidity on magnesium electrode corrosion during cycling was discussed.
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Study of Electric and Dielectric Properties of Ionic Liquids
Altšmíd, Jakub ; Boušek, Jaroslav (referee) ; Mikula, Milan (referee) ; Nešpůrek, Stanislav (advisor)
Dizertační práce je zaměřena na studium elektrických a dielektrických vlastností iontových kapalin. Iontové kapaliny mohou nacházet uplatnění v široké škále aplikací, především pak v elektrotechnice. Teoretická část se věnuje popisu základních vlastností iontových kapalin a možností jejich uplatnění v kondenzátorech a elektrochemických senzorech plynů. Experimentální část se věnuje použitým metodám charakterizace vlastností iontových kapalin, jsou zde popsány teoretické poznatky o dielektrické spektroskopii včetně metod stanovení fyzikálních vlastností a vyhodnocení experimentálních dat. Experimentální část je rozdělena na dvě základní části. První se věnuje studiu iontových kapalin pro použití jako elektrolytu v kondenzátorech, druhá část se věnuje studiu vlastností připravených experimentálních senzorů na NO2, zejména vlivem vlastností iontových kapalin na sledované parametry senzoru.
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Gel polymer electrolytes with nanoparticles
Szotkowski, Radek ; Sedlaříková, Marie (referee) ; Jahn, Michal (advisor)
This master‘s thesis concerns gel polymer electrolytes formed on a methyl methacrylate base with selected types of nanoparticles. In the thesis are also analyzed the methods for measuring electrochemical properties. The practical portion deals with sample preparations of gel polymer electrolytes with different contents of alkaline salt in a solvent, creating gels with different nanoparticle content and comparing gel polymer electrolytes polymerized with heat and UV radiation. The thesis deals with the evaluation of these samples from the viewpoint of electrical conductivity and potential windows as well as thermal analysis of selected samples.
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Hydrogen production
Kunický, Ondřej ; Šnajdárek, Ladislav (referee) ; Poláčik, Ján (advisor)
Bachelor thesis deals with the production of hydrogen by electrolysis. The introductory part describes the basic properties of hydrogen, the possibilities of its storage and transport, hydrogen safety, the hydrogen economics, and the impact on the environment. Greater attention is then paid to the current possibilities of using hydrogen and its production from fossil and renewable sources. The next part of this thesis deals with possibilities of increasing the efficiency of electrolysis and the control of its performance. At the end, there is a practical measurement of electrolyser and a calculation of the efficiency of hydrogen production by electrolysis.
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Applications of ionic liquids in electrolytes for amperometric gas sensors and Li-ion batteries.
Nádherná, Martina ; Opekar, František (advisor) ; Samec, Zdeněk (referee) ; Zima, Jiří (referee)
Mgr. Martina Nádherná PhD. Thesis Applications of ionic liquids in electrolytes for amperometric gas sensors and Li-ion batteries SUMMARY The dissertation presents the results of preparation and characterisation of new aprotic electrolytes based on ionic liquids for the solid-state electrochemical gas sensors and for the electrochemical energy storage devices - secondary lithium-ion batteries. In the part dealing with the solid-state amperometric sensor for NO2 research was aimed at development of new solid electrolyte. This electrolyte is developed as a system of ionic liquid embedded in the structure of a polymer, when the ionic liquid joints the properties of a solvent and a dissolved salt. The electrolyte therefore does not contain any volatile component and is long-term chemically and electrochemically stable. Several series of electrolytes were prepared with different polymers or macromonomers and imidazolium-based ionic liquids. The composition, especially the polymer-IL ratio was optimized. The electrolytes were successfully tested in a solid-state NO2 sensor with a gold minigrid serving as the indicating electrode. The research included the determination of basic electrochemical parameters and study of the sensor behaviour under different conditions. The influence of atmosphere humidity,...
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