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Determining the health status of the primary Li cell
Černík, Michal ; Vanýsek, Petr (referee) ; Bača, Petr (advisor)
This paper discusses the issue of determining the health and state of charge of cells and batteries. These parameters are an important component in all applications involving cells and batteries, in terms of their effectiveness and protection of personnel and the cells themselves. The method of electrochemical impedance spectroscopy, the method of relaxation time distribution and the design of an equivalent replacement circuit are explained and implemented in detail. LiSOCl2 type primary cells were used to implement these methods. The results demonstrated the functionality of the relaxation time distribution method and pointed out the shortcomings of the equivalent replacement circuit design method.
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Preparation of a laboratory exercise focusing on hydrogen energy storage
Mistrová, Jana ; Vanýsek, Petr (referee) ; Bača, Petr (advisor)
This diploma thesis describes the preparation of a laboratory experiment focused on hydrogen storage capacity. The experiment deals with hydrogen production, fuel cells, the evaluation its efficiency and hydrogen consumption within a fuel cell. The first part of the thesis is devoted to the energy storage systems, particularly chemical energy storage and hydrogen production. The next part explores fuel cell technologies. Following this, the thesis describes the experiment's preparation, equipment, and fuel cell activation. The final part focuses on the laboratory materials and the report.
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UHV-EC transfer system for electrochemical surface science studies
Jakub, Zdeněk ; Vanýsek, Petr (referee) ; Bartošík, Miroslav (advisor)
This thesis deals with the combined ultra-high vacuum (UHV) and electrochemical (EC) studies of selected iron oxide surfaces, namely Fe3O4(001) and -Fe2O3(012). The state-of- the-art knowledge regarding these surfaces is briefly reviewed, and importance of understanding these materials in the electrochemical environment is discussed. The design of the transfer system between UHV and EC environment is presented; individual features of the system are thoroughly discussed and the system is used for testing the stability of the Fe3O4(001) (2×2)R45° surface reconstruction in ambient conditions. The experimental results presented in this thesis show that the Fe3O4(001) (2×2)R45° reconstruction, utilized as an adatom array for single atom catalysis studies, survives both exposure to air and to liquid water, if the exposure is achieved in well-controlled fashion. Further, this thesis presents the first-ever atomic scale scanning tunneling microscopy (STM) study of the -Fe2O3(012) surface, which is important for photoelectrochemical water splitting. STM images of two surface reconstructions of the -Fe2O3(012) surface known to date are presented. A bulk terminated model of the (1×1) reconstruction is confirmed and a novel surface structure model for the (2×1) reconstructed surface is proposed. Adsorption studies of H2O and O2 on the (2×1) reconstructed surface are documented by timelapse STM.
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Effect of environment on the photocatalytic properties of copper oxides
Šmatlo, Filip ; Vaněk, Jiří (referee) ; Vanýsek, Petr (advisor)
V této práci byl popsán princip fotokatalýzy. Práce se soustřeďuje na kovové oxidy, které mají široké využití ve fotokatalytických aplikacích. Bylo také popsáno různé použití fotokatalytických materiálů. Tato práce se zaměřuje zejména na využití fotokatalytických materiálů pro rozklad organických vodu znečisťujících látek. Popsaný fotokatalyzátor je oxid měďný, který má velmi dobré vlastnosti pro rozklad organických látek pomocí fotokatalýzy. Schopnost rozkladu organických látek oxidu měďného byla popsána na rozkladu organického barviva methylová oranž.
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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.
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Design of a photovoltaic power system with battery storage for household purposes in area of Brno-mesto
Vrana, Martin ; Vanýsek, Petr (referee) ; Vaněk, Jiří (advisor)
Táto bakalárska práca sa zameriava na rešerš technológií obsiahnutých v návrhu fotovoltického systému, ako sú solárne panely, nabíjateľné akumulátory, a systémy na premenu elektrickej energie. Následne sú tieto informácie využité na návrh hybridného a sieťového fotovoltického systému pre rodinný dom nachádzajúci sa v lokalite Brno-Mesto. Plán realizácie je nájsť cenovo výhodné riešenie s rozumným časom návratnosti, ktoré prevažne pokryje energetický odber domácnosti. Takisto sú náklady každého zo systémov znížene o dostupné štátne dotácie podľa parametrov každej inštalácie. Sieťový systém je lacnejší ako hybridný systém, pretože systém neobsahuje drahé batérie. Preto má nižšiu dobu návratnosti šiestich rokov, v porovnaní so siedmimi rokmi v prípade hybridného systému. Hybridný systém je výhodný, pretože umožňuje lokálne ukladanie energie a poskytuje záložné napájanie v prípade výpadku prúdu. Dodávateľ elektriny umožňuje uložiť prebytočnú energiu vyrobenú systémami do virtuálnej batérie, z ktorej je možné počas roka čerpať v čase nedostatočnej výroby energie. V kombinácii so súčasnými vysokými cenami energie majú oba systémy relatívne krátke obdobie finančného bodu zvratu v porovnaní so systémami v minulosti. Finálny výber typu inštalovaného systému je na klientovi.
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Monitoring of Electrode Changes of Negative Electrode for Lead-Acid Batteries by Operando Confocal Microscopy
Hálová, Hana ; Vanýsek, Petr (referee) ; Chladil, Ladislav (advisor)
The thesis is focused on the laser microscopy observation of the negative electrode for lead-acid batteries during their cycling. The surface changes are evaluated during both deep cycling and PSoC (Partial State of Charge) cycling. The mode leads to gradual degradation of the negative electrode – mostly because of irreversible sulfation. The speed of the sulfation can be influnced by additives of the negative active mass added already during production process. The active mass was firstly examined by electron microscope and X-ray diffractometer. The crystal growth during cycling was observed using confocal microscope Olympus Lext OLS4100.
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Charakterizace vlastností perovskitovských fotovoltaických článků
Salaukou, Aleh ; Vanýsek, Petr (referee) ; Novák, Vítězslav (advisor)
This work deals with photovoltaic cells based on perovskite. The theoretical part describes the basic properties of perovskite structure, its composition and its using in solar cells. In addition, the work provides basic information about photovoltaic and silicon solar panels. Information on photovoltaic cell measurement methods such as impedance spectroscopy, photoimpedance spectroscopy, and load curve method are also presented here. Practical part of the Bachelor work deals with the application of measuring methods described in the theoretical part, the determination of equivalent circuits and discussions about the results obtained.
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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.
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Impedance spectroscopy characterization of perovskite solar cell materials
Křečková, Jitka ; Vanýsek, Petr (referee) ; Novák, Vítězslav (advisor)
The Master‘s thesis deals with the topic of perovskite solar cells with the main focus on the materials used for the active layer. In the introductory part, the electrical and optical properties of halide perovskites are described and specific examples of perovskite crystals are introduced. The description of impedance and photoimpedance measurement methods used for characterization of perovskite solar cells is also included in the thesis. The measurement of electrochemical impedance spectroscopy was conducted on four perovskite crystals and equivalent circuit was formed to fit the obtained data. Parameters of the circuit elements were acquired using the fitting method and were further evaluated in experimental part of this thesis.
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