Thermoelectric Properties of Nano/microstructured p-Type Bi0.4Sb1.6Te3 Powders Fabricated by Mechanical Alloying and Vacuum Hot Pressing

Abstract

Two kinds of Bi 0.4 Sb 1.6 Te 3 powder with different particle and grain sizes were fabricated by high-energy ball milling. Powder mixtures with varied weight ratios were consolidated by vacuum hot pressing (HP) to produce nano/ microstructured composites of identical chemical composition. From measurements of the Seebeck coefficient, electrical resistivity, and thermal conductivity of these composites, a figure of merit (ZT) value of up to 1.19 was achieved at 373 K for the sample containing 40% nanograin powder. This ZT value is higher than that of monolithic nanostructured Bi 0.4 Sb 1.6 Te 3 . It is further noted that the ZT value of this sample in the temperature range of 450 K to 575 K is in the range of 0.7 to 1.1. Such ZT characteristics are suitable for power generation applications as no other material with a similar high ZT value in this temperature range has been observed until now. The achieved high ZT value can probably be attributed to the unique nano/ microstructure, in which the dispersed nanograin powder increases the number of phonon scattering sites, which in turn results in a decrease of the thermal conductivity while simultaneously increasing the electrical conductivity, owing to the existence of the microsized powder that can provide a fast carrier transportation network. These results indicate that the nano/microstructured Bi 0.4 Sb 1.6 Te 3 alloy can serve as a high-performance material for application in thermoelectric devices.

Flexible Bi2Te3/PEDOT nanowire sandwich-like films towards high-performance wearable cross-plane thermoelectric generator and temperature sensor array

“…The introduction of highly dense nano/micro-structured Bi 2 Te 3 nanocrystals is believed to provide fast carrier transport and improved electrical performance. 40–43 As shown in Fig. 1f, the Bi 2 Te 3 @PEDOT NW composite exhibits a sandwich-like assembled structure with a clear and tightly bonded interface between highly ordered stacked Bi 2 Te 3 nanocrystals and the nanoporous PEDOT NW scaffold (Fig.…”

Overview on thermoactive materials, simulations and applications

“…PbTe, Bi2Te3), Si-Ge alloys, rare earth chalcogenides and half-Heusler alloys [35][36][37][38]. It is also becoming more usual the enhancement of thermoelectric properties through doping [39,40], alloying [41,42] and material nanostructuring [43,44].…”

Development of Flexible Thermoelectric Cells and Performance Investigation of Thermoelectric Materials for Power Generation

“…Over the past 30 years, various alloys idealized around bismuth telluride have been researched and optimized for TE applications [6]. Recent studies have shown that high performing p-type Bi0.4Sb1.6Te3 materials have been manufactured via mechanical alloying (MA) and hot extrusion in the temperature range of 360°C -450°C.…”