Recent Progress in Nanostructured Oxide TE Materials for Power Generation at High Temperatures

Thermoelectric (TE) materials, which can convert waste heat into electricity, could play an important role in a global sustainable energy solution and environmental problems. Metal oxides have been considered as potential TE materials for power generation that can operate at high temperatures on the basic of their advantages over chemical and thermal robustness, nontoxic and cheap composed elements. Among oxide materials, layered-cobaltites such as NaCo2O4 and Ca3Co4O9 have recently attracted much attention due to their unusual high TE figure of merit with single crystals, ZT ≈ 1 at 1000 K (ZT = S2σT/κ , where S, σ, T and κ are the Seebeck coefficient, electrical conductivity, absolute temperature and thermal conductivity, respectively). We have fabricated high-quality oxide TE materials based on Ca3Co4O9 by optimizing the method for synthesis, modifying the compositions and by nanostructuring. This report will focus on the high temperature TE properties of heavy ions doping nanostrcutred Ca3Co4O9 oxides, which exhibit promising ZT, implying suitable polycrystalline oxide TE materials for power generation from waste heat.