Effects of Ag Addition on Thermoelectric Properties of LaCoO3 Ceramics

LaCoO3 powder was prepared by a polyacrylamide gel method, and then composed with Ag by liquid phase method. LaCoO3/xAg(x=0, 0.05, 0.10, 0.20) composite ceramics were sintered by a traditional pressureless sintering technique after being shaped through cold isostatic pressing. Effects of Ag addition on thermoelectric properties of LaCoO3 ceramics were investigated at room temperature. The results Indicate that Ag particles are dispersed in the LaCoO3 matrix as the second phase, the electrical conductivity(sigma) and thermal conductivity(kappa) of the composites are larger than those of LaCoO3, and increase with Ag content. Meanwhile, Seebeck coefficient(S) of the composites increases firstly and then decreases with increasing in Ag content. Since the enhancement of sigma is more significant, the values of power factor and ZT are improved by the addition of Ag.