|
|
Expanded and Flake Natural Graphite as Negative Electrode Material in Lithium-ion Cell
Paulovics, Petr ; Kazda, Tomáš (referee) ; Libich, Jiří (advisor)
This diploma thesis deals with an issue of lithium-ion batteries, primarily with negative (anode) electrode materials. Natural graphite in two forms, namely flake and expanded graphite, is used in the thesis as active electrode material. It is concerned with study of their capacity and output characteristics depending on the pressing pressure and discharging current. The first part of thesis consists of theory and describes basic principles and the composition of lithium-ion batteries. Materials, their characteristics used in production and theoretical description of measurement techniques are presented then. The second part of the thesis is focused on production, assembling and measurement of the characteristics of the produced electrodes. The aim of the thesis is finding the effects of changes of pressing pressure on the capacity, stability during cycling and stability at higher loads.
|
|
|
Layered Transition Metal Hydroxides: Delamination and Properties
Hyklová, Barbora ; Lang, Kamil (advisor) ; Zima, Vítězslav (referee) ; Bujdák, Juraj (referee)
Charles University Faculty of Science Study programme: Inorganic Chemistry Mgr. Barbora Hyklová Layered Transition Metal Hydroxides: Delamination and Properties Extended abstract Supervisor: Ing. Kamil Lang CSc., DSc. Supervisor-Consultant: RNDr. Jan Demel PhD. Prague, 2017 Layered transition-metal hydroxides have attracted increasing attention as promising active electrode materials for electrochemical energy storage and conversion device due to facile preparation and modification, good tunability, high capacitance capability, fast reversible redox reactions, and cost effectiveness. Many reported hierarchical architectures based on nickel and cobalt hydroxides are composed of bulky nanoplatelet-like aggregates; however, the nanomorphology and behavior of the separated hydroxide nanosheets is much less known. Figure 1. Scheme of layered nickel or cobalt hydroxide delamination and subsequent restacking on conductive HOPG support. In this respect, the dissertation thesis reports characterization and electrochemical performance of nickel, nickel-cobalt, and cobalt hydroxide nanosheets, synthesized by an economical and environmentally friendly method based on delamination of corresponding layered hydroxides in water (Figure 1). For this purpose, lactate and nitrate layered hydroxides were prepared by two...
|
|
|
Application of Molecular Simulations in Complex Structural Analysis of Layered Materials
Veteška, Marek ; Pospíšil, Miroslav (advisor) ; Demel, Jan (referee) ; Tokarský, Jonáš (referee)
Title: Application of Molecular Simulations in Complex Structural Analysis of Layered Materials Author: RNDr. Marek Veteška Department: Department of Chemical Physics and Optics Supervisor: RNDr. Miroslav Pospíšil, Ph.D., Dept. of Chemical Physics and Optics Abstract: Techniques of molecular simulations were used together with experimental measurements (X-ray diffraction, thermogravimetry, infrared spectroscopy, elemental analysis and others) to clarify the structure properties of various types of layered materials. The structure of Zn-Al-layered double hydroxide intercalated by pyrenetetra- sulfonate acid was solved. Depending on the relative humidity, the samples showed different arrangements with three planes of water molecules and with either one or two planes of pyrenetetrasulfonate anions. At the same time considerable variability of anions arrangement was demonstrated. The adsorption behavior of natural montmorillonite and montmorillonite modified by tetramethylammonium cations in relation to aniline and phe- nol was explored. Adsorption features differed according to both the type of adsorbed molecules and the type of adsorbents. An important role was played by the plane of water molecules right above the surface which medi- ated adsorption of anilines. The water plane area was reduced by...
|
|
|
Interaction of aminoacids with phospholipid monolayers
Kukharchuk, Alexandra ; Roeselová, Martina (advisor) ; Pospíšil, Miroslav (referee)
The aim of the thesis is to get insight into the interactions between amino acids with a hydrophobic side- chain and a phospholipid monolayer on the water-air interface via molecular dynamics. There were three simulations performed: a) simulation of leucine in aqueous solution, b) simulation of leucine at the solution - air interface c) simulation of leucine solution with DPPC phospholipid monolayer at its surface. These simulations demonstrate that leucine shows surface activity and tendency to aggregate, particularly at the water surface. This tendency also remains in the presence of DPPC monolayer. In addition, intercalation of leucine between DPPC molecules was observed, leading to creation of small pores in the DPPC monolayer. The results of the simulation with leucine were compared with the results of a previously done analogous simulation with phenylalanine. The comparison showed that phenylalanine penetrates into the DPPC monolayer more than leucine, however the depth of penetration between DPPC molecules is almost the same for both amino acids. Powered by TCPDF (www.tcpdf.org)
|
|
| |
|
|
Natural Graphite as Negative Electrode Material for Lithium-Ion Batteries
Paulovics, Petr ; Jahn, Michal (referee) ; Libich, Jiří (advisor)
This bachelor thesis deals with an issue of lithium-ion batteries. It is focused on the negative (anode) electrode materials, dealing with the study of their electrochemical properties. The aim was to study the capacity characteristics of active electrode materials based on natural graphite. Mainly it was assessed the relationship morphology electrode material and the pressing pressure due to the electrochemical properties of the capacitive electrode. The first part of the thesis contains a theoretical introduction to the negative electrode materials with focuses on the composition and overall analysis of the lithium-ion cell. The second part is focuses on the manufacture, assembly and measurement of lithium-ion cells.
|
|
|
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.
|
|
|
Negative Electrode for Lithium-Ion Batteries
Libich, Jiří ; Vanýsek, Petr (referee) ; Straková Fedorková, Andrea (referee) ; Vondrák, Jiří (advisor)
The dissertation thesis deals with investigation of electrode materials for Lithium-ion batteries. The main aim of investigation was focused to materials for negative electrode of Litihum-ion batteries. These negative electrode materials operate on intercalation principle. Object of interest are carbonaceous materials, especially their graphite forms. Graphite plays host role in lithium ion – graphite interactions that provides LiC6 compound. As a result of that investigation can be considered improving of graphite materials from stability, irreversible capacity and other parameters points of view. This kind of investigation takes an important part in field of elementary investigation work engaged to the next generation of Lithium-ion batteries. The work also describes the fire safety issue of Lithium-ion batteries along with compatibility of negative electrode materials and aprotic electrolytes.
|
|
|
Materials and Components for Lithium-Ion Power Sources
Jirák, Tibor ; Kadlec, Jaromír (referee) ; Paidar,, Martin (referee) ; Vondrák, Jiří (advisor)
The dissertation thesis deals with electrode materials and components for lithium-ion power sources. The thesis works with two different kinds of materials, concretely nanostructured Li4Ti5O12 with spinel basis and LiCoO2 with layered structure. The electrochemical properties, structure and element analysis and utilization possibilities in electrochemical industry of new technological electrode material Li4Ti5O12 were investigated. The influences of admixtures and electrolytes on characteristics of electrode materials with aforesaid active masses were also examined. Low cost price, environmental safety and obtained results of electrochemical measurements and structure analysis refer to wide possibilities of usage electrode material Li4Ti5O12 in the field of electrochemistry.
|
|
|
Investigation of intercalation of alkaline metals in electrochromic devices
Kortyš, Petr ; Špičák, Petr (referee) ; Svoboda, Vít (advisor)
This work deals with investigation of intercalation of alkaline metals in electrochromic devices by the help of the quartz crystal microbalance method. The general aim is to investigate the influence of molar mass and resistance on properties of vanadium pentoxide and tungsten trioxide electrochromic films. The main measuring method used for investigating of interacalation of sodium and lithium ions into these films is the cyclic voltammetry. Drawn graphs reveals that sodium and lithium ions shows different qualities during intercalation, particularly in participation of solvent, therefore, in the influence of molar mass and in structural changes in the films.
|
guest ::
