Thermoelectric Performance Enhancement in BiSbTe Alloy by Microstructure Modulation via Cyclic Spark Plasma Sintering with Liquid Phase

Abstract

The widespread application of thermoelectric (TE) technology demands high‐performance materials, which has stimulated unceasing efforts devoted to the performance enhancement of Bi2Te3‐based commercialized thermoelectric materials. This study highlights the importance of the synthesis process for high‐performance achievement and demonstrates that the enhancement of the thermoelectric performance of (Bi,Sb)2Te3 can be achieved by applying cyclic spark plasma sintering to BixSb2–xTe3‐Te above its eutectic temperature. This facile process results in a unique microstructure characterized by the growth of grains and plentiful nanostructures. The enlarged grains lead to high charge carrier mobility that boosts the power factor. The abundant dislocations originating from the plastic deformation during cyclic liquid phase sintering and the pinning effect by the Sb‐rich nano‐precipitates result in low lattice thermal conductivity. Therefore, a high ZT value of over 1.46 is achieved, which is 50% higher than conventionally spark‐plasma‐sintered (Bi,Sb)2Te3. The proposed cyclic spark plasma liquid phase sintering process for TE performance enhancement is validated by the representative (Bi,Sb)2Te3 thermoelectric alloy and is applicable for other telluride‐based materials.

A comprehensive review on Bi2Te3‐based thin films: Thermoelectrics and beyond

“…This indicates that it is very challenging to tune effectively the electronic properties in Bi 2 Te 3 ‐based thin films, similar to the drastic variations in the electronic properties found in their bulk counterparts. [ 12–14,27–29 ] So far, three important aspects regarding the transport properties could be identified in Bi 2 Te 3 ‐based thin films. (1) Atomic defect engineering: defect formation energy calculations and advanced experimental characterizations have revealed [ 101,119–123 ] that vacancies at the anion sites (V Se and V Te ) and anti‐site defects at both anion and cation sites (Bi Te , Sb Te , and Te Bi ) have the lowest formation energies and thus are the dominant atomic defects in thin Bi 2 Te 3 ‐based films.…”

Key properties of inorganic thermoelectric materials—tables (version 1)

“…Besides, band structure engineering through proper substitution of the framework atoms or tuning the vacancy concentration on the framework sites and the guest atom concentrations inside the polyhedral cages with novel synthetic techniques, e.g. low-temperature redox reactions [353,354] melt-centrifugation [44,314] or liquid phase sintering [355,356] may potentially lead to enhanced thermoelectric properties. Leveraging high-throughput calculations and data mining [357][358][359][360], the selection process of inorganic clathrates can be accelerated, and unexplored clathrate phases may be uncovered with high thermoelectric performance.…”

Synergistic modulation of the thermoelectric performance of melt-spun p-type Mg2Sn via Na2S and Si alloying

“…4 The total thermal conductivity, denoted as k, is composed of the lattice (k L ) and electronic (k e ) thermal conductivity, and may also be contributed by the bipolar conduction (k B ) at elevated temperatures. For practical applications of thermoelectric technology, unceasing efforts have been devoted to the performance enhancement of a variety of materials, especially metal tellurides (e.g., Bi 2 Te 3 , 5,6 GeTe, 7,8 PbTe, [9][10][11] and SnTe 12,13 ). Accordingly, various effective concepts have been stimulated and developed, such as band modulation, defect engineering, and nanostructuring.…”