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Catalysts for positive electrode of hydrogen-oxygen fuel cell
Kováč, Martin ; Bača, Petr (referee) ; Novák, Vítězslav (advisor)
Master's thesis deals with new methods of preparing catalytic materials for positive electrode of an oxygen-hydrogen fuel cell and the influence of potassium permanganate or doping agent molar mass change on theirs attributes. Further it studies the use of proper measuring methods designed to qualify theirs attributes and the presentation of achieved results. In particular methods of linear sweep and cyclic voltammetry and the processing of data using Koutecky-Levich and Tafel plot and wave log analysis. Values of half-wave and onset potential and kinetic coefficient have been measured and calculated.
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Aprotic electrolytes for supercapacitors
Musílek, Václav ; Knotek, Tomáš (referee) ; Dvořák, Petr (advisor)
This master´s thesis deals different types of the aprotic electrolytes for supercapacitors and investigates by impedance spectroscopy to conductivity and method cyclic voltametry to measure dimension potential windows. Used aprotic solvents: propylencarbonate, dimethylsulfoxide, N, N dimethylformamide, ethylencarbonate, dimethylcarbonate, diethylcarbonate and acetonitrile. In the aprotic solvents were appended salts: LiClO4, NaClO4, KClO4, LiBF4, LiPF6, TEABF4 and TMABF4. From these compounds were prepared solutions with the different molar concentrations.
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Electrochemical sensor array
Šulc, Jakub ; Prášek, Jan (referee) ; Adámek, Martin (advisor)
In recent years (Of late year)microelectronic technology significantly affected in the field of sensor technology, especially in the field of electrochemical sensors. This thesis deals with design and construction of thick-film voltammetric sensors array. The reason for proposal of voltammetric sensors array is to increase of speed, increase the accuracy and extension possibilities measurement compared with common systems.By reason of increase of sensitivity of these sensors it is efficient use the potentiostat chip for measurement output signal. Created sensors must fulfill the specified parameters and also requirements of thick-film technology. Next step is design the basic blocks of electronic circuit used to evaluate the measured values.
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Properties electrodes materials for alcaline accumulators
Řihák, Lukáš ; Vrbický, Jiří (referee) ; Sedlaříková, Marie (advisor)
This thesis is involved in basical properties of electrode materials for alkaline accumulators. This thesis describes the possibilities of capacity stabilisation of nickel electrode to be stable for highest number of cycles. Thesis also consider modification of properties of electrode materials on the base of nickel hydroxide by using dopes (aluminum, manganese). Measuration proceeded on the thin film electrodes created by electrodeposition. Measuration of properties of electrodes proceeded by cyclic voltammetry and frequency analyzis.
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The influence of alcaline accumulators loading on their parameters
Čech, Ondřej ; Vrbický, Jiří (referee) ; Sedlaříková, Marie (advisor)
This master's thesis deals with alkaline battery characteristics and it has special consideration of nickel-cadmium cells. There are three main experimental parts in this paper. First one is concerned with positive electrode materials properties and is aimed to investigate impact of magnesium ions formed into nickel hydroxide electrode structure. Second part deals with battery charging/discharging and response measurement tool design. National Instruments hardware PXI modules for data acquisition was used and program in LabView environment was made. Last one is concerned with nickel-cadmium cell properties changes during increased temperature stressing. Investigation of cell self-charge changes during lithium hydroxide addition into electrolyte was made.
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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.
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Liquid electrolytes for supercapacitors
Bill, Jan ; Dvořák, Petr (referee) ; Sedlaříková, Marie (advisor)
This work deals with the preparation of liquid electrolytes from different types of aprotic solvents with the aim of their application as electrolytes in electrochemical supercapacitors. Different sorts of aprotic solvents have been chosen, in which the following forms of salts were used: LiBF4, LiClO4,LiPF6. In the next part of the work, the properties of these solvents were measured and the best electrolyte, according to the biggest possible capacity of the system, was chosen. In the theoretical part of this work, the physical principle of supercapacitors and their propeties are described. It deals with electrolytes, their division and with the properties that are appropriate for supercapacitors. The experimental part of the work describes the process of preparation of the samples of electrodes, electrolytes and the techniques of measuring their capacities.
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The design of electrochemical sensor with integrated potentiostat chip
Uhlár, Martin ; Novotný, Marek (referee) ; Adámek, Martin (advisor)
The research on electrochemical sensor applications in combination with application-defined electronic circuits is a very fast developing field of modern sensorics. Device designing of unique integrated systems with specific properties and parameters is now becoming the everyday practice for producers of devices based on the latest technology progress in microelectronics. In the process of realization of a new device type, the main objective consists in increasing the possibility of detecting very low concentrations of heavy metals in the given chemical solution, extending the signal-to-noise ratio, and measuring the potential of a sensor. The general aim of this Master’s thesis is to design the topology of a sensor based on the thick film technology, to materialize the sensor, and to make experimental measurement using the sensor prototype. The practical reason for basing the measurement on the application of this thick film sensor is to find out whether the operational integration of the sensor and the circuit has been achieved according to the original hypothesis. Importantly, it is also necessary to determine whether the reproducibility of measured results has been reached. The innovative aspect of the created device consists in the improvement of output characteristics given by the integration of ASIC (IMAM CHIP). The integration of ASIC on the surface of the sensor eliminates the huge parasitic influence that affects the accuracy of measurement.
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