Enhanced thermoelectric performance of dual-element-filled skutterudites BaxCeyCo4Sb12

Single-phase polycrystalline dual-element-filled skutterudites BaxCeyCo4Sb12 (0 < x < 0.4, 0 < y < 0.1) are synthesized by the melting-quenching-annealing and spark plasma sintering methods. The electrical conductivity, Seebeck coefficient, thermal conductivity and low-temperature Hall data of these compounds are reported. Our results suggest that there is essentially no difference in electrical transport properties between the dual-element-filled BaxCeyCo4Sb12 and single-element-filled BayCo4Sb12 systems. The Ba-Ce co-filling is more effective in lattice thermal conductivity reduction than Ba single filling in the temperature range of 300-850 K. Very low lattice thermal conductivity values less than 2.0 W m(-1) K-1 are obtained at room temperature. Consequently, enhanced thermoelectric figure of merits (ZT) for these dual-element-filled CoSb3 skutterudites are achieved at elevated temperatures, in particular ZT=1.26 at 850 K for Ba0.18Ce0.05Co4Sb12.02. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.