Thermoelectric properties of indium-filled InxRh4Sb12 skutterudites

This study reports the synthesis and characterization of polycrystalline indium-filled InxRh4Sb12 (0 ≤ x ≤ 0.2) skutterudites. The structural response to indium filling was monitored by whole pattern fitting of the powder X-ray diffraction data. Indium occupation of the oversized void-sites was verified by its unusually large thermal displacement parameter. The indium solubility limit approached 0.15. The principal thermoelectric properties were measured from 300 to 600 K. All samples are semiconducting. Indium void-site occupation reduced the lattice thermal conductivity of In0.15Rh4Sb12 30% at 300 K; however, the effect was subverted at elevated temperatures due to a coincident increase in bipolar thermal diffusion. The high-temperature thermoelectric figure of merits (ZT's) are low compared to the isostructural indium-filled InxCo4Sb12 skutterudites due to a striking sign change in the Seebeck coefficients at 400 K and relatively high thermal conductivities.

Indium-filled InxRh4Sb12 was synthesized. Principal thermoelectric properties were measured at elevated temperatures, thermal conductivity reduction was less than predicted.Figure optionsDownload as PowerPoint slideHighlights
► We synthesized the indium-filled Rh4Sb12 skutterudite.
► We measured the principal thermoelectric properties at elevated temperatures.
► Indium filling of the Rh4Sb12 skutterudite produces a reduction in thermal conductivity, while also producing a large bipolar thermal diffusion contribution to the total thermal conductivity.
► Indium filling of the Rh4Sb12 skutterudites does not produce a large reduction in thermal conductivity, counter to what has been predicted.