New guidelines for oxide thermoelectrics: redox tuning and controlled interactions

Abstract

Development of thermoelectrics for high-temperature applications imposes several essential requirements on the material properties. In some energy-conversion scenarios the cost and thermal stability requirements may dominate over efficiency issues, making abundant, hightemperature-stable and low-toxic oxides an interesting alternative TEs. The talk will feature some promising strategies to design performing oxide-based thermoelectrics. Particular attention will be given to the approaches where the inherent redox flexibility of oxides is invoked for tailoring the TE properties through in-situ formation of nanocomposites with enhanced performance. Another strategy is based on a self-forming nanocomposite concept for ZnO-based thermoelectrics, where a controllable interplay between exsolution of the nanophases and modification of the host matrix suppresses the thermal transport, while imparting the high electrical performance. The mechanisms behind the observed enhancement in thermoelectric properties and specific pathways towards high TE performance in oxides will be proposed and discussed.