Effect on the Properties of Different Preparation Processes in Ca3Co4O9 Thermoelectric Material

Ca₃Co₄O₉ samples were prepared by pressureless sintering, hot-pressing sintering (HP) and spark plasma sintering (SPS), and the effect of different preparation processes on the thermoelectric properties of Ca₃Co₄O₉ were systematically studied. The results show that comparing with the pressureless sample, samples produced by the HP and SPS method have similar Seebeck coefficient, higher electrical conductivity and thermal conductivity. Electrical conductivity of HP and SPS samples improved much more than the increase of thermal conductivity on the effect of ZT value, so integrated thermoelectric properties: pressureless sample <;HP sample <;SPS sample.