Enhancement of thermoelectric figure of merit in binary-phased La0.3Ce0.37Fe3CoS12–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 870 K can be partly preserved into the La0.3Ce0.37Fe3CoSb12 materials at room temperature. With the existence of the disordered structure the Seebeck coefficient at 773 K is increased from 143 μV K−1 to 265 μV K−1, while the thermal conductivity is reduced from 2.12 W m−1 K−1 to 1.60 W m−1 K−1, nevertheless the electrical conductivity is dropped from 78,000 Ω−1 m−1 to 23,500 Ω−1 m−1. A figure of merit of 0.95 at 773 K is observed for the material containing 40% PbTe.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We fabricate a material with disordered and ordered structures. ► We create and preserve the disordered structure into materials. ► Disordered structure enhances the Seebeck coefficient largely. ► Disordered structure reduces the thermal conductivity obviously. ► The strategy can also be applied to other thermoelectric alloys.