ICT2014 Abstracts

Up-to-date, the thermoelectric performance of p-type skutterudites lags that of the corresponding n-type materials. In this work, we report improved thermoelectric performance of triple filled p-type skutterudites. The samples were synthesized by hot pressing nano-powder made by ball milling annealed ingots of Ca_xCe_yNd_yFe_4-zCo_zSb₁₂ with varying concentration of x, y, and z. By suitably tuning the fillers concentration and Fe/Co ratio, we achieved a lower thermal conductivity (~2 W m^-1 K^-1 at room temperature and ~2.6 W m^-1 K^-1 at 535 ^oC) and a high power factor (~35 mW cm^-1 K^-2 at 475 ^oC), leading to a peak ZT of about 1.1 at 475 ^oC. The observed lower thermal conductivity can be attributed to a broad range of phonon scattering due to multiple fillers and the enhanced mobility due to the lightness of Ca leading to a high power factor.