Rattler-seeded InSb nanoinclusions from metastable indium-filled In0.1Co4Sb12 skutterudites for high-performance thermoelectrics

The synthesis and thermoelectric properties of In0.1−xCo4Sb12−x skutterudite-based nanocomposites with xInSb nanoinclusions are reported. The nanoinclusions reduce the thermal conductivity of the composites considerably compared with nanoinclusion-free In0.1Co4Sb12. Unequivocal evidence is provided demonstrating that the InSb nanoinclusions found in some of the highest reported thermoelectric figure of merit (ZT) skutterudites are synthesized in situ from filler atoms diffusing out of the icosahedral void-sites, and the kinetics of their synthesis is enhanced strongly by mechanical attrition. Moreover, a procedure designed to maximize the concentration of InSb nanoinclusions is reported, and can be employed to create void-site-filled and optimally doped skutterudite-based InSb-nanocomposites with exceptional ZT.