Synthesis and Thermoelectric Properties of Ceramics Based on Bi 2 Ca 2 Co 1.7 O y Oxide

Layered ceramics based on bismuth–calcium cobaltite with varied cobalt oxide contents is synthesized by the solid-phase method, the ceramics phase composition is determined, and the microstructure, thermal expansion, electroconductivity, and thermal electromotive force are investigated. The formation of just one compound, ternary oxide composed of Bi2Ca2Co1.7O y , is established within the quasi-binary Bi2Ca2O5–CoO z system. The effect of the cobalt oxide content on the Bi2Ca2Co x O y ceramics’ microstructure and physicochemical properties is analyzed. The single-phased ceramic sample Bi2Ca2Co1.7O y demonstrated the highest power factor value among all the investigated samples—26.0 μW/(m K2) at a temperature of 300 K. This sample showed the lowest value of the thermal linear expansion coefficient of 9.72 × 10–6 K–1.