Electrical and Transport Properties of Ceramic Oxides for Potential Thermoelectric Power Generation Applications

摘要

Over the past several years, there has been a resurgence of interest in the investigation of new and novel materials for potential thermoelectric refrigeration and power generation applications. Potential thermoelectric materials must possess a high thermopower, a low resistivity and a low thermal conductivity. We will present a review of thermoelectric phenomena and the current state of the art in thermoelectric refrigeration and power generation materials. Our focus in this talk will be on results in bulk materials. Specific to this conference, a system of ceramic oxide thermoelectric materials based on NaCo_2O_4, have been generating a lot of recent interest. Due to its large thermopower and low resistivity, this ceramic oxide material, NaCo_2O_4, is a promising and attractive candidate for potential thermoelectric applications. This is especially interesting given that NaCo_2O_4, is a ceramic compound with high decomposition temperature and chemical stability in air and without toxic elements involved. The effects of microstructure, mainly grain size, and dopant concentration, sintering temperature and holding time on the thermoelectric properties, such as Seebeck coefficient, electrical and thermal conductivity will be discussed. Since, the results on the NaCo_2O_4, system were reported there have been investigations of several other thermoelectric oxide materials, with the bulk of this work originating from Japanese researchers. A review of previous work on the ceramic oxide system of thermoelectric materials will be presented which will include results on both polycrystalline and single crystal materials.