Microstructure and thermoelectric performance of n-type Co 4 Sb 11.3 Te 0.5 Se 0.2 skutterudite synthesized via microwave heating

Abstract

The Te-/Se-doped n-type Co 4 Sb 11.3 Te 0.5 Se 0.2 skutterudite thermoelectric bulk was successfully fabricated by the combination of microwave synthesis and spark plasma sintering technique. The microstructure and the electrical and thermal transport properties have been systematically investigated. The experimental results show that nearly single-phase skutterudites grow in merely 5 min microwave heating. The average matrix grain size of Co 4 Sb 11.3 Te 0.5 Se 0.2 is ∼2 μm. The carrier concentration and mobility of Co 4 Sb 11.3 Te 0.5 Se 0.2 are 1.943×10 20 n/cm -3 and 23.17 cm 2 V -1 s -1 , respectively. The maximum Seebeck coefficient is -204 μVK -1 . The lattice and total thermal conductivity from room temperature to 773K are 2.11∼3.32 and 2.88∼3.78 Wm -1 K -1 , respectively. The highest ZT of 0.59 of Co 4 Sb 11.3 Te 0.5 Se 0.2 was achieved at 673 K. The present synthetic method is superior especially in term of the synthesis efficiency.