Effects of spark plasma sintering conditions on the anisotropic thermoelectric properties of bismuth antimony telluride

Abstract

Bismuth antimony telluride (BixSb2-xTe3, 0.4 < x< 0.6) is one of the best and most-used p-type semiconductor materials for near-room-temperature thermoelectric power generation. In this work, p-type Bi0.4Sb1.6Te3 samples were prepared under various conditions (temperature, holding time, and ramp-rate) using spark plasma sintering (SPS). The effects of SPS conditions on the anisotropic thermoelectric properties and microstructure evolutions were systematically investigated. The change of sintering temperature showed stronger influence than other sintering parameters to the resulting thermoelectric properties. Samples sintered over the temperature range between 653 K and 773 K showed significant differences in the degrees of orientations. The change was mainly caused by grain growth and re-orientation. Despite of the anisotropy, zT value as high as 1.2 to 1.3 was achieved over the temperature range of 300 to 360 K by directly using commercial power sintered at 723 and 773 K. The sintering profiles and microstructure evolutions during SPS were illustrated and the thermoelectric properties as a function of the degrees of orientations were shown and discussed in detail

Enhanced figure of merit in nanostructured (Bi,Sb)2Te3 with optimized composition, prepared by a straightforward arc-melting procedure

“…6b inset). These values are comparable with those found in literature for the Bi-Sb-Te system 24 , 25 , 27 , 35 , 39 , 40 . We have calculated the electronic contribution to the thermal conductivity, using a Lorentz number of 1.6 × 10 –8 27 , and found that the lattice contribution at room temperature is about 85.3% in Bi 0.35 Sb 1.65 Te 3 .…”

Crystallographically Textured Nanomaterials Produced from the Liquid Phase Sintering of BixSb2–xTe3 Nanocrystal Building Blocks

“…More conventional processes, such as hot press and spark plasma sintering, have been also effective in producing Bi2Te3-xSex and BixSb2-xTe3 polycrystalline materials with significant degrees of crystallographic alignment. 13,14 Combining these methodologies with micropowders produced by ball milling, polycrystalline pellets with relatively thick layered structures, ca. 0.5-1 μm, have been obtained.…”

Progress in Polymer Thermoelectrics

“…The main reason for this is, of course, the higher thermoelectric performance of BiTe. The ZT value of BiTe is around 1 [22]. ZT values of p-type and n-type polymers are generally clearly below 1 or even below 0.1.…”

“…It was also shown, that in-plane thermal conductivity of these ilms increases with electrical conductivity [21]. For comparison, spark plasma sintered BiTe compounds also show a relatively low thermal conductivity of 0.8 W/(m K) for cross-plane and 1.2 W/(m K) for in-plane measurements [22]. For nanostructured thermoelectric materials, thermal conductivity can be even lower [23].…”