Significant enhancement in Seebeck coefficient and power factor of Ca3Co4O9 thermoelectric ceramics by SiC addition

Abstract

The ceramics of Ca3Co4O9/xwt.% SiC (x = 0, 2, 3, 5, 7 and 10) have been prepared by using a solid state reaction method. The effects of SiC on the structure and thermoelectric performance of Ca3Co4O9 have been systematically investigated. The results show that major phase is the Ca3Co4O9, and the grain-oriented structure (00l) appears in the Ca3Co4O9/xwt.% SiC. Compared with a pure Ca3Co4O9 sample, the electrical resistivity of the SiC adding samples decreases with the SiC content at room temperature. Seebeck coefficient (S) increases from 52.52 μV/K (pure Ca3Co4O9) to 232.45 μV/K (Ca3Co4O9/10 wt% SiC) at 800 °C. The power factor (P) of Ca3Co4O9/10 wt% SiC samples shows the maximum values 247.926μW/K2m at 51.73 °C, which is 28.8 times larger than the power factor of pure Ca3Co4O9.