|About this Abstract
||MS&T22: Materials Science & Technology
||Energy Materials for Sustainable Development
||Calcium Cobaltate Based Composite Ceramics for Thermoelectric Energy Harvesting
||Armin Feldhoff, Zhijun Zhao, Mario Wolf, Matthias Jakob, Oliver Oeckler, Richard Hinterding
|On-Site Speaker (Planned)
The p-type Ca3Co4-xO9+δ combines a high power factor with a low thermal conductivity. To enhance the thermoelectric properties, we investigated the influence of individually adding perovskite-related oxides such as the mixed ionic-electronic conductor La2NiO4+δ or the large bandgap semiconductor Na2Ca2Nb4O13 to obtain sintered composite ceramics. All three oxides are characterized by layered structures and therefore anisotropic transport properties. To benefit from a preferred orientation in a textured green body, gained by uniaxially pressing, the added oxides were synthesized as large anisotropic plate-like crystals in the size of several microns using molten-ﬂux synthesis. Analyses of the composite ceramics revealed the influence of the added phases on the thermoelectric properties and enabled the identification of reaction products at heteromaterial interphases. Multiphase composite ceramics with enhanced thermoelectric properties resulted. Compared to pure Ca3Co4-xO9+δ, in the temperature range of 373 to 1073 K, the average thermoelectric figure could be improved by up to 28%.