Preparation and thermoelectric properties of p-type filled skutterudites CeyFe4−xNixSb12

In this study, a series of p-type filled skutterudite compounds CeyFe4−xNixSb12 (x = 0-1.5; y = 1-0.3) have been successfully prepared by a conventional melting, quenching, annealing followed by spark plasma sintering technique and their high temperature thermoelectric properties are systematically examined. The results indicate that the introduction of Ni dopants exerts little influence on the electronic structure of CeyFe4−xNixSb12 compounds near top valence band but will cause severe bipolar diffusion effect. The carrier concentration can be facilely adjusted over a broad region through the synergetic regulation of Ce filling fraction and Ni doping amount, thus providing much space for power factor optimization. We also demonstrate that partial filling is an effective way of blocking the phonon propagation. Consequently, the thermoelectric performance is significantly enhanced over a wide temperature range via a moderate Ni doping because of the simultaneous optimization of electron and phonon transport.