Nanoscale oxide thermoelectrics

The renaissance of thermoelectrics has been bolstered by the contemporary call for energy harvesting technologies. The potential use of thermoelectrics for direct conversion of waste heat into electricity is gaining momentum and oxides are envisaged as the most promising materials for high temperature applications. Nevertheless, prior to the commercial deploying of this technology, the efficiency of thermoelectric oxides needs to be perfected. Inevitably, the large thermal conductivity of oxides needs to be reduced. Several strategies are currently being explored, including sol-gel processing of oxide thermoelectrics. The higher density of interfaces in nanoceramics fabricated from sol-gel processed powders is regarded as an effective approach to enhance phonon scattering, and thereby reduce thermal conductivity. In this chapter, the fundamentals of thermoelectrics are presented alongside the most promising oxides for the fabrication of thermoelectric modules for energy harvesting. Potential benefits of using sol-gel processed powders are highlighted and the current state-of-art all-oxide thermoelectric modules are presented. Finally, we proposed the exploration of hexagonal perovskites.