|
|
Study of the properties of the advanced materials for the cathodes of the lithium-ion accumulators
Pustowka, Pavel ; Tichý, Jiří (referee) ; Kazda, Tomáš (advisor)
This thesis in its first part deals especially with characteristic of lithium ion accumulators in terms of their structure, electrochemical properties and also features of the most commonly used cathode materials. Especial attention is given to the high-voltage cathode material LiNi0,5Mn1,5O4 which cell voltage is close to 5V. The second practical part deals with the preparation of cathode materials based on LiNi0,5Mn1,5O4 with different temperatures in the second stage of annealing and analyzing them in terms of structure and electrochemical properties using appropriate measuring methods.
|
|
|
Modification of Cathode Materials for Lithium-Ion Accumulators
Kazda, Tomáš ; Studničková, Marie (referee) ; Vanýsek, Petr (referee) ; Vondrák, Jiří (advisor)
This doctoral thesis deals with properties of cathode materials for Lithium-Ion accumulators. The theoretical part consists of an overview of the cathode materials and a brief introduction into the very wide area of Lithium-Ion accumulators. The goal of this work was to study the LiCoO2 cathode material and to prepare some modifications of it by doping with other elements. This work was then extended with the study of the new generation of high-voltage cathode materials. The aim of this part was to study their synthesis, their physical and electrochemical properties and the influence of used electrolytes on their electrochemical stability. The work then focuses on the influence of doping these materials and the influence of another part of the battery – the separator – on the overall properties of these types of cathode materials. The results show that doping the LiCoO2 cathode material with sodium and potassium lead to an enhancement of some electrochemical properties as stability during cycling or stability at higher loads and also the long-term stability during aging is better. The LiNi0,5Mn1,5O4 high voltage material was synthetized in both its forms in comparable or even better quality compared with the results from foreign laboratories. The synthesis process was watched in-situ by SEM, thanks to which a unique study of the ongoing changes during synthesis was done. Also the best suitable electrolytes for this material were identified from the viewpoint of stability at high voltages, which is important for the future practical use. Doping of the material with chromium resulted in better stability and capacity both during cycling at standard conditions and at higher temperature and load. A significant impact of the separators on the overall electrochemical properties of the cathode materials was proved, which could be a big benefit for their future usage.
|
|
|
Modification of cathode material based on nickel and manganese for Li-ion cell
Bukáčková, Ivana ; Vondrák, Jiří (referee) ; Kazda, Tomáš (advisor)
This bachelor´s thesis deals with cathode materials for lithium batteries with cell voltage approaching 5V. The first part of the thesis is devoted to the characteristics of Li-ion batteries, electrochemical reactions and properties of electrode materials. She also pays attention to the preparation and measurement of materials LiNi0,5Mn1,5O4, LiNi0,45Mn1,55O4 and LiNi0,55Mn1,45O4. Observed material was measured by electron microscopy, elemental analysis and galvanostatic method,
|
|
| |
|
| |
|
|
Study of the properties of the advanced materials for the cathodes of the lithium-ion accumulators
Pustowka, Pavel ; Tichý, Jiří (referee) ; Kazda, Tomáš (advisor)
This thesis in its first part deals especially with characteristic of lithium ion accumulators in terms of their structure, electrochemical properties and also features of the most commonly used cathode materials. Especial attention is given to the high-voltage cathode material LiNi0,5Mn1,5O4 which cell voltage is close to 5V. The second practical part deals with the preparation of cathode materials based on LiNi0,5Mn1,5O4 with different temperatures in the second stage of annealing and analyzing them in terms of structure and electrochemical properties using appropriate measuring methods.
|
|
|
Modification of cathode material based on nickel and manganese for Li-ion cell
Bukáčková, Ivana ; Vondrák, Jiří (referee) ; Kazda, Tomáš (advisor)
This bachelor´s thesis deals with cathode materials for lithium batteries with cell voltage approaching 5V. The first part of the thesis is devoted to the characteristics of Li-ion batteries, electrochemical reactions and properties of electrode materials. She also pays attention to the preparation and measurement of materials LiNi0,5Mn1,5O4, LiNi0,45Mn1,55O4 and LiNi0,55Mn1,45O4. Observed material was measured by electron microscopy, elemental analysis and galvanostatic method,
|
|
|
Modification of Cathode Materials for Lithium-Ion Accumulators
Kazda, Tomáš ; Studničková, Marie (referee) ; Vanýsek, Petr (referee) ; Vondrák, Jiří (advisor)
This doctoral thesis deals with properties of cathode materials for Lithium-Ion accumulators. The theoretical part consists of an overview of the cathode materials and a brief introduction into the very wide area of Lithium-Ion accumulators. The goal of this work was to study the LiCoO2 cathode material and to prepare some modifications of it by doping with other elements. This work was then extended with the study of the new generation of high-voltage cathode materials. The aim of this part was to study their synthesis, their physical and electrochemical properties and the influence of used electrolytes on their electrochemical stability. The work then focuses on the influence of doping these materials and the influence of another part of the battery – the separator – on the overall properties of these types of cathode materials. The results show that doping the LiCoO2 cathode material with sodium and potassium lead to an enhancement of some electrochemical properties as stability during cycling or stability at higher loads and also the long-term stability during aging is better. The LiNi0,5Mn1,5O4 high voltage material was synthetized in both its forms in comparable or even better quality compared with the results from foreign laboratories. The synthesis process was watched in-situ by SEM, thanks to which a unique study of the ongoing changes during synthesis was done. Also the best suitable electrolytes for this material were identified from the viewpoint of stability at high voltages, which is important for the future practical use. Doping of the material with chromium resulted in better stability and capacity both during cycling at standard conditions and at higher temperature and load. A significant impact of the separators on the overall electrochemical properties of the cathode materials was proved, which could be a big benefit for their future usage.
|
guest ::
