A study of electrodes for thermoelectric oxides

Oxide module studies for thermoelectric energy harvesting at a high temperature were performed in this study. Considering the degradation of the electrode properties by oxidation at normal operating temperatures in air, a silver electrode (Ag) was selected for use in this study. Two types of contact problems causing a severe loss in electrical power generation were investigated: potential barriers at the interfaces, and inter-diffusion problems. Also, two types of thermoelectric modules were fabricated using Ag electrodes: a module with n-type CaMnO₃ and p-type Ca₃Co₄O₉ oxides and another module with n-type (ZnO)₇In₂O₃ and p-type Ca₃Co₄O₉ oxides. The measured power density values were compared with the values calculated from the materials properties.