The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Energies

Nataliya Yarema¹  Myroslava Prokhorenko¹  Daniel Lindberg²  Mykola Moroz³  Pavlo Demchenko⁴  Oleksandr Reshetnyak⁵  Leena Hupa⁶  Fiseha Tesfaye⁶ 

[1] Department of Cartography and Geospatial Modeling, Lviv Polytechnic National University, 79013 Lviv, Ukraine;Department of Chemical and Metallurgical Engineering, Aalto University, Kemistintie 1, 02150 Espoo, Finland;Department of Chemistry and Physics, National University of Water and Environmental Engineering, 33028 Rivne, Ukraine;Department of Inorganic Chemistry, Ivan Franko National University of Lviv, 79005 Lviv, Ukraine;Department of Physical and Colloid Chemistry, Ivan Franko National University of Lviv, 79005 Lviv, Ukraine;Johan Gadolin Process Chemistry Centre, Åbo Akademi University, 20500 Turku, Finland;

关键词: silver-based compounds;    thermoelectric materials;    phase equilibria;    thermodynamic properties;    Gibbs energy;    EMF method;   

DOI  :  10.3390/en14051314

来源: DOAJ

【 摘 要 】

Equilibrium phase formations below 600 K in the parts Ag₂Te–FeTe₂–F_1.12Te–Ag₂Te and Ag₈GeTe₆–GeTe–FeTe₂–AgFeTe₂–Ag₈GeTe₆ of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe₂, Ag₂FeTe₂, and Ag₂FeGeTe₄ compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag⁺ conducting solid-electrolyte ‖R[Ag⁺]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag+] is the buffer region for the diffusion of Ag⁺ ions into the PE. From the observed results, thermodynamic quantities of AgFeTe₂, Ag₂FeTe₂, and Ag₂FeGeTe₄ were experimentally determined for the first time. The reliability of the division of the Ag₂Te–FeTe₂–F_1.12Te–Ag₂Te and Ag₈GeTe₆–GeTe–FeTe₂–AgFeTe₂–Ag₈GeTe₆ phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe₂, Ag₂FeTe₂, and Ag₂FeGeTe₄ in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag₂FeGeTe₄ in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition.

【 授权许可】

Unknown