Thermoelectric performance of Ni compensated cerium and neodymium double filled p-type skutterudites

We have synthesized Ni compensated Ce and Nd double filled p-type skutterudites CexNdxFe3.7Ni0.3Sb12 with x = 0.35, 0.40, 0.45, and 0.5 by a melting-quenching-annealing method. The samples were made by directly hot pressing the hand ground powder at 650 degrees C for 5 minutes at a pressure of about 80 MPa. Since Ni has two more electrons than Fe, a lower power factor and a stronger bipolar effect in thermal conductivity are expected at higher temperature. In the experiments, we have demonstrated that by suitably tuning the Fe-Ni ratio and filler concentration, we can achieve both a higher power factor (similar to 35 mu W cm(-1) K-2 at 535 degrees C) and a lower thermal conductivity (similar to 2.1 W m(-1) K-1 at room temperature and similar to 2.7 W m(-1) K-1 at 535 degrees C) in Ce0.4Nd0.4Fe3.7Ni0.3Sb12. A peak thermoelectric figure-of-merit of similar to 1.1 at 475 degrees C is achieved in Ce0.4Nd0.4Fe3.7Ni0.3Sb12.