Preparation and thermoelectric properties of semiconducting Zn4Sb3

Hot-pressed samples of the semiconducting compound beta-Zn4Sb3 were prepared and characterized by X-ray and microprobe analysis. Some physical properties of beta-Zn4Sb3 were determined and its thermoelectric properties measured between room temperature and 650 K. Exceptionally low thermal conductivity values were obtained in the 300-650 K temperature range and the room temperature lattice thermal conductivity was estimated at 6.5 W cm(-1) K-1. High thermoelectric figures of merit (ZTs) were obtained between 450 and 670 K and a maximum of about 1.3 was obtained at a temperature of 670 K, the highest known at this temperature. The stability of the compound was investigated by several techniques, including thermogravimetric studies. The results showed that the samples were stable under argon atmosphere and static vacuum up to about 670 K and up to 520 K in dynamic vacuum. The high thermoelectric performance of beta-Zn4Sb3 in the 300-670 K temperature range fills the existing gap in the ZT spectrum of p-type state-of-the-art thermoelectric materials between Bi2Te3-based alloys and PbTe-based alloys. This material, relatively inexpensive, could be used in more efficient thermoelectric generators for waste heat recovery and automobile industry applications, for example. (C) 1997 Elsevier Science Ltd. All rights reserved.