11 documents found, page 1 of 2
High-performance thermoelectric oxides: processing approaches and composition d...
Kovalevsky, Andrei; Constantinescu, Gabriel; Lopes, Diogo; Zakharchuk, Kiryl V.; Rasekh, Shahed; Yaremchenko, Aleksey A.; Ferreira, Nuno M.; Xie, WenjieOxide materials represent a promising alternative to traditional thermoelectrics, by providing a possibility to operate at high temperatures, resulting in a higher Carnot efficiency. Although their conversion efficiency is considerably lower, their known structural and microstructural versatility can open new horizons for thermoelectric applications. This work reviews some representative cases of engineering th...
Exploring the strategies towards enhancing the thermoelectric performance in ox...
Kovalevsky, Andrei; Constantinescu, Gabriel; Lopes, Diogo; Ferreira, Nuno M.; Zakharchuk, Kiryl; Paulino, Tiago; Zúquete, Joana; Suarez, DianaOxide materials are currently considered a promising alternative to traditional thermoelectrics. Moderate charge carrier mobility stemming from strong covalent and ionic bonding, combined with relatively high thermal conductivity, represent known disadvantages of these materials for thermoelectric applications. However, oxides offer a possibility to operate at high temperatures, resulting in a higher Carnot eff...
Redox-promoted tailoring of the high-temperature electrical performance in Ca3C...
Constantinescu, Gabriel; Sarabando, Artur R.; Rasekh, Shahed; Lopes, Diogo; Sergiienko, Sergii; Amirkhizi, Parisa; Frade, Jorge R.This paper reports a novel composite-based processing route for improving the electrical performance of Ca3Co4O9 thermoelectric (TE) ceramics. The approach involves the addition of metallic Co, acting as a pore filler on oxidation, and considers two simple sintering schemes. The (1-x)Ca3Co4O9/xCo composites (x = 0%, 3%, 6% and 9% vol.) have been prepared through a modified Pechini method, followed by one- and t...
Exploring the high-temperature electrical performance of Ca3-xLaxCo4O9 thermoel...
Constantinescu, Gabriel; Rasekh, Shahed; Amirkhizi, Parisa; Lopes, Daniela V.; Vieira, Miguel A.; Kovalevsky, Andrei V.; Diez, Juan C.; Sotelo, AndresAliovalent substitutions in Ca3Co4O9 often result in complex effects on the electrical prop-erties and the solubility, and impact of the substituting cation also depends largely on the prepara-tion and processing method. It is also well-known that the monoclinic symmetry of this material’s composite crystal structure allows for a significant hole transfer from the rock salt-type Ca2CoO3 buffer layers to the hex...
Microstructural aspects affecting the performance of thermoelectric oxides: sel...
Kovalevsky, Andrei V.; Arias-Serrano, Blanca I.; Constantinescu, Gabriel; Zakharchuk, Kiryl; Rasekh, Shahed; Ferreira, Nuno M.; Xie, WenjieOxide materials represent certain advantages as compared to traditional thermoelectric materials, including stability at high temperatures and versatility regarding the gas atmosphere composition. Microstructural aspects play a crucial role in the performance of oxides, often dominating even over chemical composition effects. Thus, engineering the microstructure in these materials represents a powerful tool tow...
Specific microstructural effects on the performance of thermoelectric oxides
Kovalevsky, Andrei V.; Arias-Serrano, Blanca I.; Mikhalev, Sergey M.; Constantinescu, Gabriel; Zakharchuk, Kiryl V.; Sergiienko, Sergii A.Oxide materials possess notable high-temperature and chemical stability, thus representing certain advantages over traditional thermoelectrics. The thermoelectric performance of oxides is strongly affected by the microstructure, often even dominating over the chemical composition effects. Thus, engineering the microstructure in these materials represents a powerful tool towards improving their thermoelectric pe...
Exploring the high-temperature electrical performance of Ca3−xLaxCo4O9 thermoel...
Constantinescu, Gabriel; Rasekh, Shahed; Amirkhizi, Parisa; Lopes, Daniela V.; Vieira, Miguel A.; Kovalevsky, Andrei V.; Diez, Juan C.; Sotelo, AndresAliovalent substitutions in Ca3Co4O9 often result in complex effects on the electrical properties and the solubility, and impact of the substituting cation also depends largely on the preparation and processing method. It is also well-known that the monoclinic symmetry of this material’s composite crystal structure allows for a significant hole transfer from the rock salt-type Ca2CoO3 buffer layers to the hexag...
Unravelling the effects of calcium substitution in BaGd2CoO5 Haldane gap 1D mat...
Nasani, Narendar; Kovalevsky, Andrei V.; Xie, Wenjie; Rasekh, Shahed; Constantinescu, Gabriel; Weidenkaff, Anke; Pukazhselvan, D.; Fagg, Duncan P.Ecobenign and high-temperature-stable oxides are considered a promising alternative to traditional Bi2Te3-, Bi2Se3-, and PbTe-based thermoelectric materials. The quest for high-performing thermoelectric oxides is still open and, among other challenges, includes the screening of various materials systems for potentially promising electrical and thermal transport properties. In this work, a new family of acceptor...
Electrical performance tuning in thermoelectric Ca3Co4O9 materials by transitio...
Constantinescu, Gabriel; Rasekh, Shahed; Mikhalev, Sergey; Kovalevsky, AndreiThis work reports on the effects on high-temperature thermoelectric (TE) properties in bulk, polycrystalline p-type Ca3Co4O9 ceramics, after employing a composite approach consisting of metallic particles additions and two simple sintering schemes. The added Fe, Co and Ni particles are expected to act as porosity fillers upon oxidation in air and provide improved grain connectivity, changing the microstructural...
Redox-promoted tailoring of the high-temperature electrical performance in Ca3C...
Constantinescu, Gabriel; Sarabando, Artur R.; Rasekh, Shahed; Lopes, Diogo; Sergiienko, Sergii; Amirkhizi, Parisa; Frade, Jorge R.This paper reports a novel composite-based processing route for improving the electrical performance of Ca3Co4O9 thermoelectric (TE) ceramics. The approach involves the addition of metallic Co, acting as a pore filler on oxidation, and considers two simple sintering schemes. The (1-x)Ca3Co4O9/xCo composites (x = 0%, 3%, 6% and 9% vol.) have been prepared through a modified Pechini method, followed by one- and t...