Enhancement of thermoelectric figure of merit in binary-phased La 0.3Ce0.37Fe3CoS12-PbTe materials

To enhance the Seebeck coefficient and reduce the thermal conductivity while maintaining a satisfied electrical conductivity, a disordered structure was introduced into the La0.3Ce0.37Fe3CoSb12 crystalline by adding a low-melting-point lead telluride (PbTe). The results suggest that the disordered structure created by the melted PbTe at 870K can be partly preserved into the La0.3Ce0.37Fe3CoSb12 materials at room temperature. With the existence of the disordered structure the Seebeck coefficient at 773K is increased from 143μVK−1 to 265μVK−1, while the thermal conductivity is reduced from 2.12Wm−1K−1 to 1.60Wm−1K−1, nevertheless the electrical conductivity is dropped from 78,000Ω−1m−1 to 23,500Ω−1m−1. A figure of merit of 0.95 at 773K is observed for the material containing 40% PbTe.