p-type La xFe 3CoSb 12 thermoelectrics by using a melt-spinning process]]>

摘要

AbstractIn this work we improved the thermoelectric figure of meritZTin a LaxCoFe3Sb12(x?=?0.80, 0.85, 0.90) skutterudite system by applying a conductivity ratio (electrical to thermal) control method based on the phonon-glass electron-crystal (PGEC) approach. Polycrystalline bulks of LaxCoFe3Sb12were prepared by melt-spinning and subsequent spark plasma sintering. Based on the thermoelectric transport properties and microstructural analysis, we found that large amount of La-filler (x?≥?0.9) in the LaxCoFe3Sb12system is necessary to increase the conductivity ratio required to improve the thermoelectric properties in the LaxCoFe3Sb12system. Resultantly, the maximumZTvalue of 0.87 was obtained at 723?K in the heavily filled La0.9CoFe3Sb12. We discuss our results on the basis of the filling level dependence of the rattling effect and on the formation of the skutterudite single phase. We also confirm that a large amount of La-filling level is necessary to meet the electrical neutrality condition of thep-type LaxCoFe3Sb12skutterudite system.Highlights?Nanocrystalline of LaxCoFe3Sb12samples were prepared by melt-spinning and SPS sintering.?The conductivity ratio is a critical parameter to determine thermoelectric performance.?Large amount of La filler is necessary to increase the conductivity ratio.?Rattling effect by La filler is confirmed to be the main mechanism for phonon scattering.]]>