Fabrication and performance of an oxide thermoelectric power generator

A box-type thermoelectric power generation module was fabricated using polycrystalline oxide materials, γ-Na_0.70CoO₂ (p-type) and Ca_0.92La_0.08MnO₃ (n-type). The present module (25 mm×25 mm×15 mm) implements two p-n couples connected in series and supplied the maximum electric power of 7.6 mW to an external load resistor under the condition of hot side temperature, T_h=345°C, and temperature difference, 281°C. The module was sufficiently tough for repeated heat cycles up to T_h=345°C in air. After a continuous operation at T_h=345°C for 10 days, the maximum electric power decreased to 5.6 mW due to the increase in electric resistivity of γ-Na_0.70CoO₂.