Synergistic Optimization of Electrical–Thermal–Mechanical Properties of the In-Filled CoSb₃ Material by Introducing Bi_0.5Sb_1.5Te₃ Nanoparticles

Abstract

How to realize the synergistic optimization of electrical–thermal–mechanical properties of thermoelectric materials is a key challenge. Using the Bi0.5Sb1.5Te3 nanoparticle as a mixed agent provides an effective way to address this challenge. Here, Bi0.5Sb1.5Te3/In0.25Co4Sb12 nanocomposites with different contents of Bi0.5Sb1.5Te3 nanoparticles were successfully prepared by ultrasonic dispersion combined with spark plasma sintering. Phase and microstructure characterization presented that Te nanoparticles were precipitated from Bi0.5Sb1.5Te3 during the SPS sintering process. Transport measurement results showed that the electrical conductivity was increased due to the increased carrier concentration induced by the charge transfer between Te nanoparticles and the matrix. The Seebeck coefficient was also increased due to the selected electron scattering and increased scattering factor. The lattice thermal conductivity was dramatically suppressed because of the enhanced phonon scattering induced by the Bi0.5Sb1.5Te3 nanoparticles and in situ-precipitated Te nanoparticles and increased dislocations. As a result, a higher average ZT value of 1 was obtained in the range of 300–700 K by the decoupling of the electrical and thermal transport properties for the nanocomposite with 0.1 wt % of Bi0.5Sb1.5Te3 nanometer suspension. Furthermore, the flexural strength, fracture toughness, and hardness of the nanocomposites were also improved significantly. This work demonstrates that using the Bi0.5Sb1.5Te3 nanoparticle as a mixed agent can realize the synergistic optimization of electrical–thermal–mechanical properties of the In-filled CoSb3 thermoelectric material.

Alloying engineering for thermoelectric performance enhancement in p-type skutterudites with synergistic carrier concentration optimization and thermal conductivity reduction

“…The S was significantly decreased above 650 K, which is attributed to the bipolar conduction induced by intrinsic excitation [11]. To further understand the mechanisms of the variation in S, a charge carrier scattering distance independent of the energy and degenerate approximation was assumed.…”

“…Skutterudite compounds, as important energy conversion materials, have potential applications in the fields of waste heat recovery and space power generation owing to their excellent TE performances at intermediate temperatures [6][7][8] and excellent mechanical strengths [9][10][11]. The candidates doped or filled the CoSb 3 -and FeSb 3 -based skutterudites are appropriate for n-and p-type legs of TE devices, respectively [12][13][14][15].…”

Structure Optimization and Multi-frequency Phonon Scattering Boosting Thermoelectrics in Self-Doped CoSb3-Based Skutterudites

“…As a commercial thermoelectric material in the mid-temperature region, the CoSb 3 -based skutterudites have attracted broad attention for the symmetric body-centered cubic crystal structure, high band degeneracy, as well as high thermal stability. , However, its application is plagued by the ultra-high κ L (∼7.5 W m –1 K –1 at room temperature), thus poor zT (∼0.05 at 723 K) and low thermoelectric efficiency . Recently, attempts have been made to advance its thermal performance including introduction of solid solution alloy by doping, − filling atom (such as alkaline-earth atoms, − rare-earth atoms, − alkaline metals, , and group IIIA elements − ), special structures (dislocation arrays, micro-/nanopores, and nano-core–shell structures), − and the nanoscale second phase (such as InSb, GaSb, AgSbTe 2 , and Bi 0.5 Sb 1.5 Te 3 ). Based on the insights gained into the above strategies, as well as the electronic and phonon transport of CoSb 3 materials, excellent thermoelectric properties have been achieved, including zT of ∼1.9 at 835 K in (R, Ba, Yb) y Co 4 Sb 12 (R = Sr, La, Mm, DD, SrMm, SrDD) and ∼1.8 at 823 K in (In, Sr, Ba,Yb) y Co 4 Sb 12 …”

Energy band and charge-carrier engineering in skutterudite thermoelectric materials

“…The binary CoSb 3 skutterudite TE material has high thermal conductivity and low ZT value due to the covalent bonding between the framework atoms. [21] Phonon engineering such as low dimensionalization, [22][23][24] the introduction of nano second phase, [25][26][27][28] nanointerfaces or nanopores, [29][30][31] phonon resonance scattering induced by filler [17,32,33] has been adopted to reduce remarkably the thermal conductivity of CoSb 3 materials, which significantly improves their ZT values. Although the thermal conductivity can be significantly reduced by adjusting the microstructure of the CoSb 3 material at the nanomesoscopic scale, it is also accompanied by deterioration of electrical conductivity of the material.…”