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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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Preparation and characterisation of ceramic electroactive materials for Na-ion batteries
Vaněk, Martin ; Libich, Jiří (referee) ; Čech, Ondřej (advisor)
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.
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Determination of the most suitable ratio of cathode materials for the lithium-sulfur battery system
Benešová, Petra ; Kazda, Tomáš (referee) ; Jaššo, Kamil (advisor)
This master's thesis deals with a topic of determination of the most suitable ratio of cathode materials for the lithium-sulfur systems. The first two chapters provide a general introduction to the topic of electrochemical energy sources and present the commonly used primary and secondary battery systems with emphasis on their characteristics and applications. The core of the theoretical part is dedicated to lithium-ion and lithium-sulfur batteries, their working principles along with the benefits or drawbacks related to the particular systems, and widely used materials. The experimental part briefly comments on determining the suitable electrode paste preparation method, the subsequent main part is focused on evaluation of electrochemical performance of cells using different ratios of cathode materials. Five samples of cathode materials were prepared, where the sulfur ratio is in range from 64 to 88 wt. %. Finally, the comparison of all prepared ratios in terms of their electrochemical properties is provided.
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Synthesis and characterization of sulfurized polymers for electrochemical power sources
Svoboda, Lukáš ; Kazda, Tomáš (referee) ; Čech, Ondřej (advisor)
Batteries based on lithium-sulfur technology have the potential to increase the amount of stored energy in comparison with current lithium-ion systems while maintaining the same weight. Achieving this goal is possible due to the high theoretical energy density of sulfur, which exceeds the values of other materials used in batteries. However, these batteries suffer from several failing, which still hinder the practical use. The use of amorphous sulfur instead of its crystalline form might lead to increasing of durability and charge efficiency. Inverse vulcanization of sulfur seems to be the perspective method for the preparation of polymer sulfur because it prevents its recrystallization and stabilizes amorphous sulfur. The aim of this thesis is the preparation and study of properties of materials made of inverse vulcanized sulfur.
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Advanced carbon structures as a material for Na-ion batteries
Bečan, Jan ; Čech, Ondřej (referee) ; Kazda, Tomáš (advisor)
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.
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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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Effect of compaction pressure to the electrochemical properties of the electrodes for Li-S accumulators
Jaššo, Kamil ; Tichý, Jiří (referee) ; Kazda, Tomáš (advisor)
The purpose of this diploma thesis is to describe the impact of compaction pressure on the electrochemical parameters of lithium-sulfur batteries. Theoretical part of this thesis contains briefly described terminology and general issues of batteries and their division. Every kind of battery is provided with a closer description of a specific battery type. A separate chapter is dedicated to lithium cells, mainly lithium-ion batteries. Considering various composition of lithium-ion batteries, this chapter deeply analyzes mostly used active materials of electrodes, used electrolytes and separators. Considering that the electrochemical principle of Li-S and Li-O batteries is different to Li-ion batteries, these accumulators of new generation are included in individual subhead. In the experimental part of this thesis are described methods used to measure electrochemical parameters of Li-S batteries. Next chapter contains description of preparing individual electrodes and their composition. Rest of the experimental part of my thesis is dedicated to the description of individual experiments and achieved results.
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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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Advanced carbon structures as a material for Na-ion batteries
Bečan, Jan ; Čech, Ondřej (referee) ; Kazda, Tomáš (advisor)
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.
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Determination of the most suitable ratio of cathode materials for the lithium-sulfur battery system
Benešová, Petra ; Kazda, Tomáš (referee) ; Jaššo, Kamil (advisor)
This master's thesis deals with a topic of determination of the most suitable ratio of cathode materials for the lithium-sulfur systems. The first two chapters provide a general introduction to the topic of electrochemical energy sources and present the commonly used primary and secondary battery systems with emphasis on their characteristics and applications. The core of the theoretical part is dedicated to lithium-ion and lithium-sulfur batteries, their working principles along with the benefits or drawbacks related to the particular systems, and widely used materials. The experimental part briefly comments on determining the suitable electrode paste preparation method, the subsequent main part is focused on evaluation of electrochemical performance of cells using different ratios of cathode materials. Five samples of cathode materials were prepared, where the sulfur ratio is in range from 64 to 88 wt. %. Finally, the comparison of all prepared ratios in terms of their electrochemical properties is provided.
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