Preparation and Thermoelectric Properties of (Ca1-x-yKxBiy)3Co4O9 Ceramic
The precursor of (Ca1-x-yKxBiy)3Co4O9 was synthesized by sol-gel method using nitrate salts as raw materials and citrate acid as agent. The final product was obtained after the precursor was calcined at 800°C for 4 h. The polycrystalline bulk samples were fabricated by a conventional sintering process at 900°C for 12 h. XRD and SEM were used to characterize the microstructures and the composition of the samples. The transport properties of the samples at room temperature were determined by measuring electrical conductivity and Seebeck coefficient. The Bi and K-doped samples show an excellent transport properties even at room temperature. The value of power factor of (Ca0.90K0.075Bi0.025)3Co4O9 reaches 1.42×10-4Wm-1K-2 at 293K, close to the performance of pure Ca3Co4O9 at 1000K.
Wei Pan and Jianghong Gong
H. M. Hu et al., "Preparation and Thermoelectric Properties of (Ca1-x-yKxBiy)3Co4O9 Ceramic", Key Engineering Materials, Vols. 368-372, pp. 559-561, 2008