Synthesis, Characterization and Optimization of New Thermoelectric Materials

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F18%3A00328412" target="_blank" >RIV/68407700:21340/18:00328412 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Synthesis, Characterization and Optimization of New Thermoelectric Materials

Popis výsledku v původním jazyce

Thermoelectric (TE) materials allow direct conversion between heat and electricity. The aim of this thesis was to try to improve the thermoelectric performance of three different families of materials working in different temperature ranges, and to better understand the link between the various physical properties (electrical, thermal, magnetic) generally measured in a broad temperature range (5-700 K) and the observed microstructure/chemical composition. The materials were synthesized by powder metallurgy techniques and densified by spark plasma sintering (SPS) or obtained from partner laboratories. The major part of our studies concern the tetrahedrite family of materials, derived from the mineral tetrahedrite, (Cu,Ag)10(Zn,Fe)2(Sb,As)4S13, whose promising thermoelectric properties in the mid-temperature range were only recently discovered. In a first approach, the TE properties of eight natural tetrahedrites of different origin are studied. It is shown that they all behave rather predictably and uniformly. Then, the properties of mixtures of natural and synthetic tetrahedrites produced either by ball milling or simply by hand grinding are determined. It is evidenced that the former, high-energy process yields nanoscale particles of the two phases, which form a solid solution during the sintering; the latter, low-energy process preserves the two-phase nature after the sintering, resulting in inferior TE performance. Because arsenic is a common substituent in natural specimens, several As-substituted tetrahedrites are synthesized and characterized. It is shown that the TE properties are only weakly influenced by the substitution of As for Sb. Besides tetrahedrites, calcium manganese oxides and conductive polymers are also studied.

Název v anglickém jazyce

Synthesis, Characterization and Optimization of New Thermoelectric Materials

Popis výsledku anglicky

Thermoelectric (TE) materials allow direct conversion between heat and electricity. The aim of this thesis was to try to improve the thermoelectric performance of three different families of materials working in different temperature ranges, and to better understand the link between the various physical properties (electrical, thermal, magnetic) generally measured in a broad temperature range (5-700 K) and the observed microstructure/chemical composition. The materials were synthesized by powder metallurgy techniques and densified by spark plasma sintering (SPS) or obtained from partner laboratories. The major part of our studies concern the tetrahedrite family of materials, derived from the mineral tetrahedrite, (Cu,Ag)10(Zn,Fe)2(Sb,As)4S13, whose promising thermoelectric properties in the mid-temperature range were only recently discovered. In a first approach, the TE properties of eight natural tetrahedrites of different origin are studied. It is shown that they all behave rather predictably and uniformly. Then, the properties of mixtures of natural and synthetic tetrahedrites produced either by ball milling or simply by hand grinding are determined. It is evidenced that the former, high-energy process yields nanoscale particles of the two phases, which form a solid solution during the sintering; the latter, low-energy process preserves the two-phase nature after the sintering, resulting in inferior TE performance. Because arsenic is a common substituent in natural specimens, several As-substituted tetrahedrites are synthesized and characterized. It is shown that the TE properties are only weakly influenced by the substitution of As for Sb. Besides tetrahedrites, calcium manganese oxides and conductive polymers are also studied.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

<a href="/cs/project/GB14-36566G" target="_blank" >GB14-36566G: Multidisciplinární výzkumné centrum moderních materiálů</a><br>

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů