High temperature thermoelectric properties of oxide Ca9Co12O28

The electrical conductivity, Seebeck coefficient and thermal conductivity of oxide Ca 9 Co 12 O 28 with Ca 2 Co 2 O 5 -type structure are 84 S cm –1 , 118 µV K –1 and 1.73 W m –1 K –1 respectively at 700 °C, and its figure of merit is 0.67×10 –4 K –1 , showing that Ca 9 Co 12 O 28 is a potential material for high temperature thermoelectric energy conversion.