Trend for Thermoelectric Materials and Their Earth Abundance

The low crustal abundance of materials such as tellurium (Te) (0.001 ppm by weight), antimony (Sb) (0.2 ppm), and germanium (Ge) (1.4 ppm) contributes to their price volatility as applications (competing with thermoelectrics) continue to grow, for example, cadmium telluride photovoltaics, antimony-lead alloy for batteries, and Ge for fiber optics and infrared optical technologies. Previous consideration of material scarcity has focused on Te-based thermoelectrics. Here, we broaden the analysis to include recent high-figure-of-merit () materials such as skutterudites, Zintl phase compounds, and clathrates that employ Sb, ytterbium (2.8 ppm), and Ge. The maximum demonstrated for each particular alloy exhibits an empirical dependence on the crustal abundance, , such that = (-) , where is in the range from 0.05 to 0.10. This analysis shows that no material with crustal abundance of 30 ppm (similar to 4 x 10(18) metric tons) has greater than 0.8.