Recovery of the intrinsic thermoelectric properties of CaMn0.98Nb0.02O3 in 2-terminal geometry using Ag infiltration

Abstract

Oxide based thermoelectric (TE) materials offer several advantages over currently used intermetallic alloys due to their chemical and thermal stability at high temperatures, non-toxic elements, low cost and ease of manufacture. However, incorporation of oxides into thermoelectric generators (TEGs) is hindered by factors such as the requirement for polycrystalline materials over single crystals and the large electrode/ceramic contact resistances. The latter significantly limits the performance efficiency of a working TEG. Here we report the TE properties of Ag infiltrated polycrystalline CaMn0.98Nb0.02O3 ceramics. We demonstrate that by using this route the intrinsic TE properties of this material are fully recovered in 2-terminal geometry through Ag infiltration, thereby overcoming the electrode TEG contact problem. This synthetic route provides opportunities for bridging the performance gap between the intrinsic TE and TEG device properties of oxides.

Microstructural Influence on Thermoelectric Properties of CaMnO3 Ceramics

“…Calcium Manganite, or CMO, is a perovskite ceramic with an orthorhombic crystalline structure, and n-type semiconductor characteristics, which has been the object of several studies [19][20][21][22] to improve its thermoelectric parameters. The synthesis process can improve the thermoelectric properties of the material.…”

Influence of Ag on the Properties of Ca0.9Yb0.1MnO3 Sintered Ceramics

“…Another way to enhance electrical properties in ceramic systems is to use metallic additions when both materials do not react under sintering conditions. One of the most useful metals for this purpose is Ag, which, besides enhancing electrical properties [23,24], is very good at improving mechanical properties [25,26,27]. Furthermore, even if Ag is molten at CaMnO 3 sintering temperatures, no Ag losses are expected, as demonstrated in previous research [26].…”