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Effect of temperature on electrochemical parameters of Li-S battery
Bečan, Jan ; Skala, Kateřina (referee) ; Jaššo, Kamil (advisor)
This bachelor's thesis deals with the production of lithium-sulfur battery and the effect of changing temperatures on its electrochemical parameters. The theoretical part is focused on primary and secondary batteries and their historical evolution, anode and cathode materials for lithium-ion batteries and next-generation batteries. The practical part is focused on preparing the electrode material for lithium-sulfur battery, completion of electrochemical cell and measuring the values of cycling charge/discharge at different temperatures.
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Low temperature fuel cell for ultra-light-plane
Hladiš, Lukáš ; Brázdil, Marian (referee) ; Pospíšil, Jiří (advisor)
This thesis deals with the concept of propulsion for ultralight plane with using fuel cells technology. Here are described the individual kinds of fuel cells and possible fuel. Furthermore it is listed the calculation of low-temperature fuel cell H2 - O2 with polymeric membrane (PEM). The thesis includes also a part with the design drawings of the proposed solutions.
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Characterisation for the cold field-emission sources intended for electron microscopy
Vašíček, Martin ; Tománek, Pavel (referee) ; Grmela, Lubomír (advisor)
This work deals with the theoretical foundations of electron emission into vacuum, various types of emissions, focused on the cold-emission and Schottky emission and the principle of quantum tunneling. The next part deals with the technical implementation of electron sources with a detailed study of the methodology of laboratory production of cathodes by electrochemical etching and construction of electron microscopes, using field-emission sources. This work also contains methods for measuring, processing and evaluation of electrical characteristics of emission sources.
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Design and properties of low-frequency amplifier with vacuum valves
Piroha, Ladislav ; Musil, Vladislav (referee) ; Šandera, Josef (advisor)
The purpose of the bachelor’s thesis is explanation of theory and construction of low frequency tube audio amplifier with UV meter. Main focus is on history and development of vacuum circuits from its early beginning, on electrical parameters and applied physical principles. Explanation of operating characteristics of amplifier classes and comparison of vacuum tube sound acoustic performance against transistor amplifier one. Finally, there is build description of single ended amplifier class A.
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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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Deposited layers based on lead and cobalt for Li-ion batteries
Dorotík, David ; Libich, Jiří (referee) ; Máca, Josef (advisor)
The diploma thesis deals with the principles of operation of lithium ion batteries and their properties when using deposited thin films. The thesis is mainly focused on the formation of thin films using the electrolytic method and subsequently testing the properties of the thin film in an electrochemical cell. The test criteria are mainly the value of the capacity of the prepared electrode and the impact of cycling on the electrode layer itself, where the deposited layer is assessed before cycling and after cycling on an SEM microscope..
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Fuel cells and their use
Horák, Stanislav ; Klimeš, Lubomír (referee) ; Štětina, Josef (advisor)
This bachelor’s thesis deals with background research of fuel cells and their use. The first part of this thesis is familiar with the basic principle and fuel cell constructions, as well as the types of fuel cells, with which we meet today. Another part deals with the thermodynamic calculation of the fuel cell including the production of hydrogen. At the end of the thesis are taken into account the advantages and disadvantages of the fuel cells and examples of their use.
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Stability of cathode materials for Li-ion accumulators
Janíček, Zdeněk ; Libich, Jiří (referee) ; Sedlaříková, Marie (advisor)
This diploma thesis focuses on study of positive electrode materials for Li-Ion batteries. Our aim are intercalation materials whose are really perspective materials whose are widely used in this case. The theoretical part of my thesis focus on basic study of Li-ion batteries and their parameters. We studied charging and discharging processes. AFM and SEM were used as additional techniques for study LiCoO2 a Li0,975K0,025CoO2. We tested lifetime and stability of electrode as a perspective material for electrode for Li-ion batteries.
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New materials for Li-ion batteries with conversion mechanism
Petr, Jakub ; Straková Fedorková, Andrea (referee) ; Sedlaříková, Marie (advisor)
This thesis is interested in new materials for lithium – ion batteries. Two different samples were investigated, one intercalation and one conversion cathode material. The theoretical part is focused to the structure of cells, their advantages and disadvantages compared to other secondary batteries. Also other materials used in batteries are described. The practical part describes the preparation of cathode materials for subsequent testing by scanning elektron microscopy and thermogravimetric analysis. In conclusions two different materials were evaluated and compared with each other.
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