Effect of triple fillers on thermoelectric properties of p-type skutterudites

Experiments were carried out to investigate the effect of triple fillers on the thermoelectric properties of p type skutterudites. We have synthesized the samples by hot pressing nano powders made by ball milling annealed ingots of Ca$_{\mathrm{x}}$Ce$_{\mathrm{y}}$Nd$_{\mathrm{y}}$Fe$_{3.5}$Co$_{0.5}$Sb$_{12}$. By tuning the concentration of Ca, Ce, and Nd, we have achieved a lower thermal conductivity $\sim$ 2 W m$^{-1}$ K$^{-1}$ at room temperature and $\sim$ 2.6 W m$^{-1}$ K$^{-1}$ at 530 $^{\circ}$C), leading to a peak ZT of about 1.1 at 475 $^{\circ}$C. The observed lower thermal conductivity can be attributed due to a broad range of phonon scattering due to multiple fillers.