Abstract :
[en] Since decades, thermoelectricity is deeply studied as no-waste energy source. Thermoelectric (TE) materials allow the direct transformation of a heat source into an electrical current (Seebeck effect). TE conversion is very attractive as it is the strongest candidate for producing electricity from waste heat energy sources (automobiles, incinerators, boilers, …). For TE applications at high temperatures, oxide compounds like In2O3, Ca3Co4O9, Bi2Sr2Co2Ox or CaMnO3, have attracted attention, in particular due to their natural oxidation resistance. However, the performances of actual TE oxides must be improved for manufacturing efficient TE generators. For that purpose, an accurate control of micro and nanostructure is required for optimizing the electrical and/or thermal transport properties of TE materials. This can be achieved through the development of innovative powder synthesis techniques, like sol-gel process.
In this study, we report on the impact of the use of sol-gel processing techniques on the microstructure (grain size, homogeneity, porosity) of two promising oxide TE compounds and their resulting TE properties. The two studied oxide compounds are the n-type metal doped indium oxide In2-xGexO3 and p-type Bi2Sr2Co2Ox cobaltites.