High thermoelectric performance BiSbTe alloy with unique low-dimensional structure

Abstract

We report a detailed description of an innovative route of a melt spinning (MS) technique combined with a subsequent spark plasma sintering process in order to obtain high performance p-type Bi0.52Sb1.48Te3 bulk material, which possesses a unique low-dimensional structure. The unique structure consists of an amorphous structure, 5–15 nm fine nanocrystalline regions, and coherent interfaces between the resulting nanocrystalline regions. Measurements of the thermopower, electrical conductivity, and thermal conductivity have been performed over a range of temperature of 300–400 K. We found that MS technique can give us considerable control over the resulting nanostructure with good thermal stability during the temperature range of 300–400 K and this unique structure can effectively adjust the transport of phonons and electrons, in a manner such that it is beneficial to the overall thermoelectric performance of the material, primarily a reduction in the lattice thermal conductivity. Subsequently, this results in a maximum figure of merit ZT value of 1.56 at 300 K for p-type Bi0.52Sb1.48Te3 bulk material. This ZT value is over a 50% improvement of that of the state of the art commercial Bi2Te3 materials. We also report results of thermal cycling of this material for over one hundred cycles between 300–400 K. Our work offers an innovative route for developing high performance bismuth telluride based alloys and devices, which have even broader prospects for commercial applications. This technique may also be applicable to other thermoelectric materials.

ZT Enhancement in Solution-Grown Sb(2−x)BixTe3 Nanoplatelets

“…Further, it is 50 % lower than nanostructured bulk Sb 1.5 Bi 0.5 Te 3 obtained by ball-milling [3] and 15 % lower than a melt-spun nanostructured bulk sample [4]. As discussed below, some of this decrease results from a simultaneous decrease in electric conductivity (σ) (see Fig.…”

“…From the first reports in the 1950s until today, the dimensionless thermoelectric figure of merit (ZT) of such materials at room temperature has been improved threefold. From 0.5 for pure Bi 2 Te 3 bulk samples [1] [4] with "coherent interfaces", advances in semiconductor manipulation have yielded impressive results in this ecologically highly promising field. ZT is estimated to require a value of 3 to be competitive with conventional cooling devices and to open up novel pathways for efficient and greener power generation.…”

“…To allow a quantitative comparison of transport properties with the previous reports mentioned above [3,4], it is important to account for different degrees of porosity in the measured samples. Where Poudel et al and Xie et al measured samples with 100 % and 96 % relative density, respectively, the material presented in this work shows relative densities of only 83 to 86 %.…”

Управление Температурными Полями В Процессе Искрового Плазменного Спекания Термоэлектриков

“…В последнее десятилетие были опубликованы работы о принципиальных достижениях в разработке высокоэффективных наноструктурирован-ных термоэлектриков. Так, например, было заявлено, что в наноструктурированных материалах на основе соединений Bi−Sb−Te получены значения ZT = 1.4 при T = 373 K и ZT = 1.2 при комнатной температу-ре [5,6]. Увеличение термоэлектрической добротности наноструктурированных термоэлектриков может быть связано с туннелированием носителей через зазор меж-ду нанозернами, дополнительным рассеянием фононов на границах нанозерен и энергетической фильтрацией носителей через барьеры [7][8][9].…”

A temperature-variant method for performance modeling and economic analysis of thermoelectric generators: Linking material properties to real-world conditions

“…[23] (2) BiSbTe [24], (3) SiGe [25], and (4) Ti À dopedðZr; Hf ÞNiSn half-Heusler alloy [26]. These materials were selected because they represent the latest cutting-edge developments in research of thermoelectric materials.…”