|
|
XRD characterization of electrodes and electrode materials for electrochemical power sources
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The thesis describes available choices of methods for research of electrochemical power source electrode strcture by x-ray diffraction spectroscopy. At first there is a theoretical computation of difractogram. Then there are discussed possibilities of in-situ and ex-situ techniques as background research. Practical part of thesis compares theoretical assumptions to measurements of lithium and sodium cells, including analyze of crystallographic phases and lattice constants. As a conclusion, there are discussed possibilities of subsequent research.
|
|
|
Design and testing of XRD holder for post-mortem analysis of li-ion battery electrodes performed in an inert atmosphere
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The work describes the design and manufacturing of a test device for post-mortem measurements of electrodes of electrochemical cells using X-ray diffraction spectroscopy. The theoretical part describes the diffractometer Rigaku Miniflex 600, for which the product is intended. At the same time, an overview of solutions in various applications is processed here in the form of a recherche. The practical part documents the current development of a new cell, on which tests were performed. Here is an overview of the influence of gases and insulating materials on the resulting data, especially distortion and attenuation. Subsequently, a new design with improved hermetic insulation and sample displacement error correction is described. The principle of operation of the manufactured cell, including the control unit and software, is elaborated in the form of technical documentation. Finally, the functionality is verified by comparing the diffractograms of the powder standards and the graphite electrodes.
|
|
|
Review of In-situ and Ex-situ Techniques for Characterization of Li-ion Batteries
Klvač, Ondřej ; Kazda, Tomáš
This paper describes the analytical techniques andsample preparation methods used in in-situ and ex-situ investigationsof Li-ion batteries (LIBs). The introduction briefly describesthe current state of Li-ion batteries and their aging mechanisms.The article is further divided into a description of ex-situ and insitutechniques. Ex-situ techniques include a detailed descriptionof sample preparation for repeatable results using Broad IonBeam (BIB) polisher. In-situ techniques are described in theform of a report of selected published experiments. The paper isfurther extended with our experiments involving ex-situ analysesof cylindrical and flat cell types using BIB in planar modeand cross-section mode. In the case of in-situ experiments, thedesign of the cell inside the SEM chamber is described. Twoexperiments have been performed - on the surface of a MEMSchip, and also using a micromanipulator as a current collectorof the investigated electrode.
|
|
|
Parasitic infections tortoises of genus \kur{Testudo} with a focus on apicoplexa
ŽAHOUREK, Jakub
This bachelor thesis deals with the spectrum and frequency of parasitic infections in Testudo tortoises in breeding in the Czech Republic. In the first section of the theoretical part I focus on the biology, biogeography, ecology, and morphology, the understanding of which is important for breeding these very special animals. Further on, I mention the specific methodology of breeding linked to the demands of tortoises of their environment, nurture, and behavioural manners. In the second section of the theoretical part I focus on parasites that often infect herbivorous reptiles. In my thesis, I have focused on parasites within the Apicomplexa phylum that are currently being paid significantly closer attention in veterinary medicine. 143 samples of droppings gathered throughout 2020 by twelve different breeders have been examined. Samples were examined using sedimentation and flotation method together with which Sheater sugar solution was used. Out of a total of 92 % samples were marked as positive with developmental stages of parasitic elements also known as helmints. Out of the gathered data, I constructed a spectrum of parasites of the complete family and individual species including their frequency and strength of infection in individual parasites.
|
|
|
The Design Of Sample Holder For Xrd Measurements In Inert Atmosphere With Displacement Error Correction
Klvač, Ondřej
This article describes a designed of a holder for post-mortem XRD measurements of Li-ion, Na-ion and Li-S electrodes, which need to be performed in the inert atmosphere. The first part describes the measurement method and problems arising during the measurements of the samples. Subsequently, the design and construction of a new cell with hermetic insulation and sample displacement error correction possible during the operation of the diffractometer is described. Finally, the inert gas attenuation within the cell is theoretically calculated. The calculation is verified by practical measurements, and alternatives are proposed to improve the signal-to-noise ratio.
|
|
|
Ex-Situ Xrd Characterization Of Electrodes For Electrochemical Power Sources
Klvač, Ondřej
The article describes a theoretical method of a research of graphite electrodes in an electrochemical cell where the problem is with the preferred orientation and a thin layer. As a result, only a reflection (002) is visible. However, there is a possibility to determine crystallographic parame-ters from these peaks because of the effect of a destructive and constructive interference caused by intercalated lithium atoms. At the same time, the work shows that Kapton is not a suitable material for ex-situ cell production, as samples have been destroyed by air humidity. Finally, a circular ex-situ cell was made and tested with the pure sodium. This modification reduces a rate of degradation of the samples.
|
|
|
Design and testing of XRD holder for post-mortem analysis of li-ion battery electrodes performed in an inert atmosphere
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The work describes the design and manufacturing of a test device for post-mortem measurements of electrodes of electrochemical cells using X-ray diffraction spectroscopy. The theoretical part describes the diffractometer Rigaku Miniflex 600, for which the product is intended. At the same time, an overview of solutions in various applications is processed here in the form of a recherche. The practical part documents the current development of a new cell, on which tests were performed. Here is an overview of the influence of gases and insulating materials on the resulting data, especially distortion and attenuation. Subsequently, a new design with improved hermetic insulation and sample displacement error correction is described. The principle of operation of the manufactured cell, including the control unit and software, is elaborated in the form of technical documentation. Finally, the functionality is verified by comparing the diffractograms of the powder standards and the graphite electrodes.
|
|
|
XRD characterization of electrodes and electrode materials for electrochemical power sources
Klvač, Ondřej ; Chladil, Ladislav (referee) ; Čech, Ondřej (advisor)
The thesis describes available choices of methods for research of electrochemical power source electrode strcture by x-ray diffraction spectroscopy. At first there is a theoretical computation of difractogram. Then there are discussed possibilities of in-situ and ex-situ techniques as background research. Practical part of thesis compares theoretical assumptions to measurements of lithium and sodium cells, including analyze of crystallographic phases and lattice constants. As a conclusion, there are discussed possibilities of subsequent research.
|
guest ::
