Synergetic improvement strategy on thermoelectric performance of CuAlO2 compacts

Abstract We fabricated Sr and Ca-doped CuAlO 2 compacts from the mixed powder of CuO, Cu 2 O, Al 2 O 3 , and SrO or CaO by multi-pass hot pressing followed by spark plasma sintering (SPS). The XRD results showed the reaction of CuO, Cu 2 O and Al 2 O 3 was rather complete and only CuAlO 2 single phase was formed when the additive amount of SrO or CaO was appropriate. Multi-pass hot pressing increased the relative density and the usage of plate-like Al 2 O 3 as reaction raw material enhanced the orientation degree. In spite of performance improvement conflicts through elemental doping, density increase and orientation improvement, the measurement on the thermoelectric performance indicated that the electrical resistivity, Seebeck coefficient, power factor, dimensionless figure of merit ( ZT ) were improved to varying degrees through the synergetic action of elemental doping, density increase, and orientation control. The highest power factor and ZT of the Ca-doped CuAlO 2 compacts reached 1.54 × 10 −4 W m −1 K −2 and 0.015 at 973 K, respectively. The thermoelectric performance was higher than those of CuAlO 2 at the same temperature in published work before.