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Preparation of electrodes of Li-S batteries using inversely vulcanized sulfur
Trochta, David ; Kunický, Daniel (referee) ; Čech, Ondřej (advisor)
This work focuses on research of lithium-sulfur batteries, which are a promising battery type due to their theoretically high capacity and low environmental impact. Steering away from the commonly used elementary sulfur as the electroactive material of the cathode, inversely vulcanized sulfur with amorphic structure was utilized instead, while the manufacturing process of which was improved and optimized during the research. A series of samples of inversely vulcanized sulfur was synthesised, each containing a different ratio of the input precursors. X-ray diffraction was used to verify the amorphic structure of the material, which simultaneously also ruled out the presence of crystalline sulfur. Additionally, this work presents the results of Raman spectroscopy. At the same time, the possibility of utilization of Raman spectroscopy to identify the exact quantitative ratios of the used precursors was presented for the first time. Specific samples were also handpicked to undertake a dissolution test involving procedural solvents. Electrodes for electrochemical cells (Li-S battery) were manufactured based upon the knowledge gathered. The distribution homogeneity of the electroactive material of the electrode was observed through creation of an elemental map using the EDS technique. Electrochemical characterization of the selected inversely vulcanized sulfur electrode samples was measured using various methods: cyclical voltammetry, electrochemical impedance spectroscopy and galvanostatic cycling with potential limitation.
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Study of the influence of separator modification on the properties of Li-S batteries
Řehák, Petr ; Jaššo, Kamil (referee) ; Kazda, Tomáš (advisor)
This thesis deals with the development and current issues of Li-ion and Li-S accumulators, especially the separators. In the theoretical part is described history of Li-ion batteries, their properties and materials for the positive electrode. Li-S batteries and their problems are also described in this diploma thesis. In the practical part, electrochemical methods were described, and several separator samples with various modifications were created. These samples were then photographed using an SEM electron microscope and evaluated using electrochemical methods.
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Preparation Of Electrodes Of Li-S Batteries Using Inversely Vulcanized Sulfur
Trochta, David
This paper focuses on manufacturing of Li-S batteries, which in theory have higherenergy density than the currently most popular Li-ion battery. Before putting the Li-S battery onthe market, several problems which prevent its practical use have to be solved. These issues includeshort longevity, which could be solved by manufacturing the electrode using inversely vulcanizedsulfur. This method could eliminate the immediate issue and enable the rise of the Li-S battery onthe market.
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Numerical Modelling Of Li-S Chemistry
Mačák, Martin
This work presents a custom electrochemical model of a lithium-sulfur cell implemented into Ansys Fluent software. The model was used to analyse cyclic voltammetry at differently sized particles, which represented porous cathodes. The results indicate that the cyclic voltammetry response of the whole porous sulfur cathode could be solved as a response of a single particle, which might lead to a simplification of numerical simulations and in result, to accelerating their optimizing process.
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Preparation of electrodes of Li-S batteries using inversely vulcanized sulfur
Trochta, David ; Kunický, Daniel (referee) ; Čech, Ondřej (advisor)
This work focuses on research of lithium-sulfur batteries, which are a promising battery type due to their theoretically high capacity and low environmental impact. Steering away from the commonly used elementary sulfur as the electroactive material of the cathode, inversely vulcanized sulfur with amorphic structure was utilized instead, while the manufacturing process of which was improved and optimized during the research. A series of samples of inversely vulcanized sulfur was synthesised, each containing a different ratio of the input precursors. X-ray diffraction was used to verify the amorphic structure of the material, which simultaneously also ruled out the presence of crystalline sulfur. Additionally, this work presents the results of Raman spectroscopy. At the same time, the possibility of utilization of Raman spectroscopy to identify the exact quantitative ratios of the used precursors was presented for the first time. Specific samples were also handpicked to undertake a dissolution test involving procedural solvents. Electrodes for electrochemical cells (Li-S battery) were manufactured based upon the knowledge gathered. The distribution homogeneity of the electroactive material of the electrode was observed through creation of an elemental map using the EDS technique. Electrochemical characterization of the selected inversely vulcanized sulfur electrode samples was measured using various methods: cyclical voltammetry, electrochemical impedance spectroscopy and galvanostatic cycling with potential limitation.
|
|
|
Study of the influence of separator modification on the properties of Li-S batteries
Řehák, Petr ; Jaššo, Kamil (referee) ; Kazda, Tomáš (advisor)
This thesis deals with the development and current issues of Li-ion and Li-S accumulators, especially the separators. In the theoretical part is described history of Li-ion batteries, their properties and materials for the positive electrode. Li-S batteries and their problems are also described in this diploma thesis. In the practical part, electrochemical methods were described, and several separator samples with various modifications were created. These samples were then photographed using an SEM electron microscope and evaluated using electrochemical methods.
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