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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nízkoteplotní palivový článek pro ultralehký letoun / Low temperature fuel cell for ultra-light-plane

Hladiš, Lukáš January 2013 (has links)
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.
2

Studium interakce CO a N2 s anodovými katalyzátory palivových článků s polymerní membránou / Study of CO and N2 Interaction with Anode Catalysts of Proton-Exchange Membrane Fuel Cells

Fusek, Lukáš January 2019 (has links)
Poisoning of the catalyst seems to be one of the most serious problems preventing a widespread commercialization of fuel cell technology. This thesis focuses on the effect of CO poisoning and hydrogen dilution by nitrogen on performance of fuel cells with low platinum content. Catalysts were deposited by magnetron sputtering directly on membrane etched by plasma. Alloys with different platinum-ruthenium ratio were used to mitigate the CO poisoning. We found that presence of nitrogen has almost negligible effect on the fuel cell performance. On the other hand, CO, even in small concentrations, caused a significant drop in power density. PtRu with atomic ratio 2:1 and 1:1 showed the best CO tolerance.
3

Stabilita katodového materiálu pro LI-ion akumulátory / Stability of cathode materials for Li-ion accumulators

Janíček, Zdeněk January 2014 (has links)
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.
4

Nové materiály pro Li-iontové baterie pracující na principu konverze / New materials for Li-ion batteries with conversion mechanism

Petr, Jakub January 2014 (has links)
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.
5

Přírodní expandovaný a vločkový grafit jako záporná elektroda lithium-iontového článku / Expanded and Flake Natural Graphite as Negative Electrode Material in Lithium-ion Cell

Paulovics, Petr January 2018 (has links)
This diploma thesis deals with an issue of lithium-ion batteries, primarily with negative (anode) electrode materials. Natural graphite in two forms, namely flake and expanded graphite, is used in the thesis as active electrode material. It is concerned with study of their capacity and output characteristics depending on the pressing pressure and discharging current. The first part of thesis consists of theory and describes basic principles and the composition of lithium-ion batteries. Materials, their characteristics used in production and theoretical description of measurement techniques are presented then. The second part of the thesis is focused on production, assembling and measurement of the characteristics of the produced electrodes. The aim of the thesis is finding the effects of changes of pressing pressure on the capacity, stability during cycling and stability at higher loads.
6

Pokročilé uhlíkové struktury jako materiál pro Na-ion akumulátory / Advanced carbon structures as a material for Na-ion batteries

Bečan, Jan January 2021 (has links)
This diploma thesis deals with the description of individual types of batteries. The first part is focused to primary and secondary batteries, materials for their positive and negative electrodes with a focus on lithium-ion batteries and their changes over time. The next section focuses on a more detailed description of sodium-ion batteries, used electrode materials and to their problems. Practical part is focesed to preparing of electrode materials and to completing of measuring electrochemical cell and to discribing of measuring methodes and to evaluation of measured data.
7

Deponované vrstvy na bázi olova a kobaltu pro Li-ion akumulátory / Deposited layers based on lead and cobalt for Li-ion batteries

Dorotík, David January 2021 (has links)
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..
8

Nové materiály pro Li-iontové baterie pracující na principu konverze / New materials for Li-ion batteries with conversion mechanism

Petr, Jakub January 2014 (has links)
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.
9

Připrava a charakterizace keramických aktivních materiálů pro sodno-iontové akumulátory / Preparation and characterisation of ceramic electroactive materials for Na-ion batteries

Vaněk, Martin January 2016 (has links)
Hlavním cílem této práce je charakterizace vzorků titanátů, jako materiálů pro sodíko-iontové (Na-ion) akumulátory. Syntéza některých vzorků je součástí této práce. Charakterizace je zaměřena na elektrochemické vlastnosti, složení a morfologii použitých materiálů. První část se zabývá lithium-iontovými (Li-ion) akumulátory. Byly vybrány, protože jsou ve vědeckých článcích dobře popsány a základní funkční princip je aplikovatelný také na Na-ion akumulátory. Materiály používáné pro katody, anody a elektrolyty následují po krátké části shrnující parametry a konstrukci Li-ion akumulátorů. Následující kapitola je zaměřena na sodíko-iontové akumulátory. Srovnání sodíku a lithia je následováno materiály používanými pro elektrody a elektrolyty (s důrazem na anodové materiály). Třetí část popisuje analytické metody použité pro charakterizaci elektrod a materiálů. Jedná se o elektrochemickou charakterizaci (cyklická voltametrie a galvanostatické cyklování s potenciálovým omezením), morfologii (rastrovací elektronová mikroskopie) a složení (X-ray difrakční spektroskopie). Poslední dvě kapitoly obsahují syntézu a charakterizaci sodného titanátu a charakterizaci dvou vzorků TiO2. Výsledky této práce jsou shrnuty v závěru.
10

Teplotní závislost kapacity negativní elektrody pro sodno – iontové akumulátory / Temperature dependence of negative electrode capacity for sodium - ion batteries

Šátek, Dominik January 2021 (has links)
This work focuses on sodium-ion batteries. It describes the basic principles of accumulators, focusing more on secondary cells, their electrodes, especially negative electrodes. The work is lightly based on the basics of lithium-ion batteries. The practical part of the work is the production of negative electrodes Na2Ti3O7, which are further measured at three different temperatures. These measurements are then evaluated.

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