|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
guest ::
