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Inverse vulcanised sulphur as an electroactive material for lithium-sulphur and sodium-sulphur batteries
Trochta, David ; Kazda, Tomáš (referee) ; Čech, Ondřej (advisor)
This thesis deals with the study of lithium-sulfur and sodium-sulfur batteries, which are designed for use at room temperatures. Both of these systems are interesting mainly due to their high theoretical capacity and low environmental impact, thus greatly outperforming lithium-ion batteries. The weakness of these new technologies is their low lifespan and the associated rapid loss of battery capacity. To increase the lifespan, elemental sulfur in this work was replaced by sulfur with an amorphous structure, synthesized by an inverse vulcanization process that has been optimized in various ways. In addition to the optimization of the inverse vulcanization technology window, the effect of the addition of carbonaceous additives during the synthesis was also investigated. In this work, a series of samples of inverse vulcanized sulfur with different ratios of input precursors were prepared and also with different additives. X-ray diffraction was used to confirm the amorphous structure of the material, which also excludes the presence of crystalline sulphur. The results of Raman spectroscopy were also presented, demonstrating the possibility of using this method to determine semi-quantitative ratios of the input precursors. Electrodes for electrochemical cells were fabricated from selected samples. The homogeneity of the distribution of the electroactive material on the electrode was investigated using a scanning electron microscope and elemental mapping by energy dispersive spectroscopy technique. The electrochemical characterization of the inversely vulcanized sulfur electrodes was carried out by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic potential limited cycling.
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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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Numerical modelling of Li-S batteries
Mezera, Petr ; Jaššo, Kamil (referee) ; Mačák, Martin (advisor)
This work deals with modeling and simulation of Li-S batteries in Matlab. The work describes the properties of these batteries, their construction and the problems associated with their development. Furthermore, experimental techniques and their importance for numerical modeling of batteries are discussed. Different types of battery modeling are described in the work, then numerical models for simulations are analyzed in more detail. The procedure for making the Li-S battery is described and the measurements made on it are described. The measured data has been adapted for use in several different ECMs. Finally, models of a replacement circuit for the Li-S battery were built. One model accounted for the polynomial equations and the other the resulting circuit. The latter used linear interpolation and was more accurate.
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Study of electrode materials for post-lithium ion systems
Kekelák, Miroslav ; Jaššo, Kamil (referee) ; Kazda, Tomáš (advisor)
This bachelor thesis deals with studying electrode materials for post-lithium ion systems. The theoretical part describes the principle, history and construction of lithium-ion battery cells. A separate chapter is dedicated to the materials of positive and negative electrodes for lithium-ion batteries. The third chapter is dedicated to the principles of new generation lithium-air and sodium-ion batteries. The last chapter of theoretical part is dedicated to lithium-sulfur batteries, which describes their principle, history, used electrode materials and the influence of binders. The experimental part is dedicated to the preparation of the electrode material of lithium-sulfur accumulator in combination with water-soluble binders and their measurement using electrochemical methods.
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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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Advanced systems of Li-Ion accumulators
Lexová, Kristýna ; Langerová, Petra (referee) ; Mihai, Hana (advisor)
S rostoucí potřebou energie pro přenosnou elektroniku a elektrická vozidla se problematika úschovy elektrické energie stává stále významnější. Tato bakalářská práce poskytuje přehled elektrochemických zdrojů energie, a to zejména lithno-iontových akumulátorů a nejpoužívanějších materiálů pro kladnou elektrodu. Práce pojednává také o vývoji vysokonapěťových katodových materiálů, včetně systému lithium-síra. Experimentální část této práce popisuje zhotovení několika vzorků kladných elektrod, a porovnává jejich elektrochemické vlastnosti.
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Electrode Materials for Li-S Batteries
Jaššo, Kamil ; Almáši,, Miroslav (referee) ; Syrový,, Tomáš (referee) ; Kazda, Tomáš (advisor)
This thesis is focused on the research of electrode materials for lithium-sulphur (Li-S) batteries, with an emphasis on the optimization of the process of preparation of positive electrodes through the modification of the individual technical steps of the manufacturing process and the selection of a suitable binder. The theoretical part of the thesis is devoted to terminology and battery issues with emphasis on Li-S batteries, their working principle, shortcomings, critical parameters for commercialization and existing research in this field. The practical part of the thesis deals with the influence of the compression pressure used in the production of positive electrodes on the electrochemical properties of the resulting Li-S cells. In the next part of the thesis, the influence of the binder used on the resulting electrochemical properties is investigated. In the following sections, the influence of the thickness of the electrode material layer and the ratio of its individual components (C/S) on the resulting electrochemical properties of the Li-S cell is analyzed. On the basis of the measured results, the optimum conditions for the preparation of the positive electrodes of the Li-S cells have been identified with respect to the individual technical steps of the manufacturing process.
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Inverse vulcanised sulphur as an electroactive material for lithium-sulphur and sodium-sulphur batteries
Trochta, David ; Kazda, Tomáš (referee) ; Čech, Ondřej (advisor)
This thesis deals with the study of lithium-sulfur and sodium-sulfur batteries, which are designed for use at room temperatures. Both of these systems are interesting mainly due to their high theoretical capacity and low environmental impact, thus greatly outperforming lithium-ion batteries. The weakness of these new technologies is their low lifespan and the associated rapid loss of battery capacity. To increase the lifespan, elemental sulfur in this work was replaced by sulfur with an amorphous structure, synthesized by an inverse vulcanization process that has been optimized in various ways. In addition to the optimization of the inverse vulcanization technology window, the effect of the addition of carbonaceous additives during the synthesis was also investigated. In this work, a series of samples of inverse vulcanized sulfur with different ratios of input precursors were prepared and also with different additives. X-ray diffraction was used to confirm the amorphous structure of the material, which also excludes the presence of crystalline sulphur. The results of Raman spectroscopy were also presented, demonstrating the possibility of using this method to determine semi-quantitative ratios of the input precursors. Electrodes for electrochemical cells were fabricated from selected samples. The homogeneity of the distribution of the electroactive material on the electrode was investigated using a scanning electron microscope and elemental mapping by energy dispersive spectroscopy technique. The electrochemical characterization of the inversely vulcanized sulfur electrodes was carried out by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic potential limited cycling.
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Numerical modelling of Li-S batteries
Mezera, Petr ; Jaššo, Kamil (referee) ; Mačák, Martin (advisor)
This work deals with modeling and simulation of Li-S batteries in Matlab. The work describes the properties of these batteries, their construction and the problems associated with their development. Furthermore, experimental techniques and their importance for numerical modeling of batteries are discussed. Different types of battery modeling are described in the work, then numerical models for simulations are analyzed in more detail. The procedure for making the Li-S battery is described and the measurements made on it are described. The measured data has been adapted for use in several different ECMs. Finally, models of a replacement circuit for the Li-S battery were built. One model accounted for the polynomial equations and the other the resulting circuit. The latter used linear interpolation and was more accurate.
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Modification Of The Production Of Positive Electrodes For Lithium-Sulfur Batteries
Jaššo, Kamil
The rapid development of electrical wearable devices and electric cars is forcing battery industry into developing more efficient and economic energy storage systems. One of the attractive candidates among these systems are Li-S batteries. These next-generation high-energy rechargeable batteries are promising mainly thanks to their high theoretical energy density and low cost. However, the safety concerns of lithium anode, insulating properties of sulfur and rapid drop of capacity during cycling due to dissolution of polysulfides are key limitations of practical use. A cell composed of metal lithium anode and carbon doped sulfur cathode in environment of *LiTFSI:LiNO3 DME:DOL electrolyte can be considered a basic lithium-sulfur cell. This type of lithium-sulfur cell is used in many scientific publications. This paper discusses the production of positive electrodes for lithiumsulfur cells and modifications of their production.
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