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Study of Metal Oxides and Hydroxides in Aqueous Solutions
Špičák, Petr ; Trnková, Libuše (referee) ; Kadlec, Jaromír (referee) ; Kazelle, Jiří (advisor)
This dissertation work deals with analysis of nickel hydroxide phases, their oxidation compounds, their stability and degradation mechanisms of electrochemically more active alpha phase on standard beta phase. The active material was prepared by both methods, electrodeposition and chemical precipitation. Main analysis method was Electrochemical Quartz Crystal Microbalance in combination with common analytical methods (cyclic voltammetry, potenciometry) can resolute between alpha and beta phases and quantitatively describe differences in main reaction by monitoring mass changes in the active material. Poor stability of the ?-Ni(OH)2 were improved by adding cations with valence two three and four into the structure instead of Ni atoms. The most important role plays cobalt and its hydroxide. Totally new way is to use titanium in combination with other cations. In electrolyte the most significant addition is LiOH, which has beneficial influent on cycle ability, stability in strong alkaline medium and cycle life.
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Investigation of mass changes by piezoelectric resonator
Kužílek, Jakub ; Svoboda, Vít (referee) ; Špičák, Petr (advisor)
An operation deals with a concept of the new cell for measuring weight changes with high precision through the use of quartz crystal micro-scales called QCM. The new cell is destined for crystal resonators which diameter is 14mm. The resonators are produced in the Czech Republic. A price is the greatest advantage of crystal resonators in comparison with original crystals. The next positive is higher mechanical tolerance which is outgoing of a guest-size. The cell designed by this way is tested in electrochemical system where a deposition of metallic copper in crystal is happening. A homologation of accuracy is judged by Faraday’s law and using Sauerbrey equation for quartz crystal microbalance in cyclic voltammetry measurement method.
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Study of Metal Oxides and Hydroxides in Aqueous Solutions
Špičák, Petr ; Trnková, Libuše (referee) ; Kadlec, Jaromír (referee) ; Kazelle, Jiří (advisor)
This dissertation work deals with analysis of nickel hydroxide phases, their oxidation compounds, their stability and degradation mechanisms of electrochemically more active alpha phase on standard beta phase. The active material was prepared by both methods, electrodeposition and chemical precipitation. Main analysis method was Electrochemical Quartz Crystal Microbalance in combination with common analytical methods (cyclic voltammetry, potenciometry) can resolute between alpha and beta phases and quantitatively describe differences in main reaction by monitoring mass changes in the active material. Poor stability of the ?-Ni(OH)2 were improved by adding cations with valence two three and four into the structure instead of Ni atoms. The most important role plays cobalt and its hydroxide. Totally new way is to use titanium in combination with other cations. In electrolyte the most significant addition is LiOH, which has beneficial influent on cycle ability, stability in strong alkaline medium and cycle life.
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|
|
Investigation of mass changes by piezoelectric resonator
Kužílek, Jakub ; Svoboda, Vít (referee) ; Špičák, Petr (advisor)
An operation deals with a concept of the new cell for measuring weight changes with high precision through the use of quartz crystal micro-scales called QCM. The new cell is destined for crystal resonators which diameter is 14mm. The resonators are produced in the Czech Republic. A price is the greatest advantage of crystal resonators in comparison with original crystals. The next positive is higher mechanical tolerance which is outgoing of a guest-size. The cell designed by this way is tested in electrochemical system where a deposition of metallic copper in crystal is happening. A homologation of accuracy is judged by Faraday’s law and using Sauerbrey equation for quartz crystal microbalance in cyclic voltammetry measurement method.
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