Promising high temperature thermoelectric properties of dense Ba2Co9O14 ceramics

Abstract Layered cobalt oxides have shown high thermoelectric properties. The n  = 1 member of the Ba n +1 Co n O 3 n +3 (Co 8 O 8 ) family, Ba 2 Co 9 O 14 , a new layered cobalt oxides family with Co(II) and Co(III) in the CdI 2 layers, has been synthesized by solid state reaction and sintered as dense ceramics (relative density ∼ 93%) by Spark Plasma Sintering. It presents promising p-type thermoelectric properties at high temperature. The dimensionless figure of merit ZT is 0.032 at 660 K and 0.04 at 1000 K, which is about one quarter to one third of the ZT value of Ca 3 Co 4 O 9 ceramics.