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Sodium-ion batteries: research of carbon based negative electrode materials
Homolka, Tomáš ; Máca, Josef (referee) ; Libich, Jiří (advisor)
This work focuses on the research of hard carbon as a promising negative electrode material for sodium-ion batteries. The first part deals with electrochemical cells and their development in general. Then lithium-ion cells, their history and the materials currently used are mentioned. The next section discusses sodium-ion cells, their development so far, current issues and differences compared to lithium-ion cells, as they appear to be one of the promising post-lithium technologies with the potential for rapid commercialization. In the practical part, properties of some material samples are tested with a focus on their capacity and coulombic efficiency.
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Compatibility of negative electrode materials at system of lithium-ion battery
Šikuda, Milan ; Sedlaříková, Marie (referee) ; Libich, Jiří (advisor)
This thesis deals with a study of lithium-ion batteries. It is focused into negative electrode materials and electrolytes. In this thesis is presented synthesis, electrochemical properties, possibilities to improving negative electrode materials as LTO (Lithium Titanate Oxid) and graphite. These electrode materials were investigated with respect to their compatibility at electrolytes with carbonate solvents, Sulfolane and DMF (DiMethylFormamide) in detail. The main aim of this thesis is to characterize electrode materials and electrolyte properties depending on wide range of temperatures and their comparison for the purpose of achievement of the best solution. The thesis is divided into two main parts. The theoretical part of thesis describes composition, process of synthesis and analysis of lithium-ion cell. Practical part contains measuring and evaluating of charge-discharge and irreversible capacity characteristics related to variety of environmental temperatures.
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Flame retardant treated thermosets for composite materials used in transport industry
Novotný, Kamil ; Kučera, František (referee) ; Poláček, Petr (advisor)
First part of this bachelor‘s thesis contains a literature review, which describes basic mechanisms of flame retardancy, distribution of flame retardants into groups based on their composition and commercially available compounds. Experimental part studied the change of thermal stability and flammability of a thermoset resin with the adition of flame retardants. Change in mechanical properties of the resin was investigated as well. Epoxy resin was selected as a specimen of the resin group due to its excellent properties, which make it widely used in transportation industry. The main disadvantage of epoxy is its high flammability. The effect of two low cost, eco-friendly, easily applicable flame retardants was observed, namely expanded graphite and magnesium hydroxide. Materials were evaluated by a burning test, tensile test and thermogravimetric analysis. Overall, the additives caused a decrease in mechanical properties. Material with a combination of both compounds was found to be the least flammable, but had the worst mechanical properties.
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Carbon materials for power sources
Tichý, Jiří ; Novák, Vítězslav (referee) ; Barath, Peter (advisor)
This work deals with carbon materials and using them in alternative energy sources. Object of this work was prepared electrodes with carbon materials and investigate their electrical properties. The practical part objects of the carbon materials, their properties and application in fuel cells and Ni-Cd batteries. Analysis describes the electrochemical processes in electrode materials with carbon as conductive element.
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Negative Electrode for Lithium-Ion Batteries
Libich, Jiří ; Vanýsek, Petr (referee) ; Straková Fedorková, Andrea (referee) ; Vondrák, Jiří (advisor)
The dissertation thesis deals with investigation of electrode materials for Lithium-ion batteries. The main aim of investigation was focused to materials for negative electrode of Litihum-ion batteries. These negative electrode materials operate on intercalation principle. Object of interest are carbonaceous materials, especially their graphite forms. Graphite plays host role in lithium ion – graphite interactions that provides LiC6 compound. As a result of that investigation can be considered improving of graphite materials from stability, irreversible capacity and other parameters points of view. This kind of investigation takes an important part in field of elementary investigation work engaged to the next generation of Lithium-ion batteries. The work also describes the fire safety issue of Lithium-ion batteries along with compatibility of negative electrode materials and aprotic electrolytes.
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Negative Electrode for Sodium-ion batteries
Šimek, Antonín ; Jaššo, Kamil (referee) ; Libich, Jiří (advisor)
This bachelor thesis contains general introduction to the issue of batteries, their basic principles and distribution. It is mainly focused on the research of electrode materials for negative electrodes of sodium-ion batteries, which do not use lithium for their function. Thesis is also focused on lithium-ion batteries, because their development is closely linked to sodium-ion batteries. The practical part mainly contains the synthesis and characteristics of sodium metatitanate, which is used as active material in negative electrode mass.
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Application of graphite in thermal management of microelectronics
Havlíček, Václav ; Mačák, Martin (referee) ; Vyroubal, Petr (advisor)
Tato práce je zaměřena na zlepšení tepelného managementu mikroelektroniky implementací materiálů na bázi uhlíku, přesněji grafitových fólií, do tepelné architektury mikroelektroniky. Práce začíná vysvětlením současných metod chlazení a výzev v oblasti mikroelektroniky. Poté přechází k běžně používaným materiálům - hliníku a mědi a přidává do výběru i uhlíkové alotropie. Ve druhé části tato práce obsahuje několik příkladů použití pyrolytické grafitové fólie v tepelném managementu mikroelektroniky, prokazuje jeho použitelnost a analyzuje přínosy pro šíření tepla, tepelnou vodivost při dodržení elektrické izolace a možné využití ve flexibilní elektronice.
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Study of intercalation properties of electrode materials based on expanded graphite
Vencelides, Lukáš ; Máca, Josef (referee) ; Libich, Jiří (advisor)
The diploma thesis deals with the issue of electrochemical cells and deals in detail with lithium-ion batteries. The thesis describes the history of development of lithium-ion batteries, basic information about lithium and basic types of electrochemical cells. The work is devoted in detail to the description of characteristics and operating principle of lithium-ion batteries with emphasis on the negative electrode and negative electrode materials. Of the negative electrode materials, both the most widely used material graphite and modern materials with a great potential for the future are described. In the measurement methods the work describes methods CV, GCPL and EIS. Great emphasis is placed on the explanation of the principle of the function of electrochemical impedance spectroscopy and its application in measurement of electrochemical properties of materials used in lithium-ion batteries. There is also described the procedure of calculation of diffusion coefficients using the results of electrochemical impedance spectroscopy. In the practical part, two methods are used to calculate the diffusion coefficients of lithium ions into the negative electrode made of expanded flake graphite using the results of a series of electrochemical measurements.
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Chemorezistive gas sensor
Venkrbec, Lukáš ; Pytlíček, Zdeněk (referee) ; Prášek, Jan (advisor)
This thesis deals with the detection of gases. Based on the research, the theoretical part is devoted to the principles and construction of chemical gas sensors, especially the chemoresistive gas sensors, mainly with the active layer consisting of metal oxides and carbon nanotubes. In the second half of the theoretical part the carbon nanostructures, their properties and the methodology of preparation are reviewed. The experimental part deals with the type of support structure, preparation of the active layer and the method of its deposition and he principle of detection. In the results and discussion, the thesis focuses on the detailed processing of the results and the evaluation of the response ammonia, the impact of the modifications and procedures. In the end, the results obtained are compared, both with each other and with the relevant literature.
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