Boron-Mediated Grain Boundary Engineering Enables Simultaneous Improvement of Thermoelectric and Mechanical Properties in N-Type Bi2 Te3.

Powder metallurgy introduces small structures of high-density grain boundaries into Bi2 Te3 -based alloys, which promises to enhance their mechanical and thermoelectric performance. However, due to the strong donor-like effect induced by the increased surface, Te vacancies form in the powder-metallurgy process. Hence, the as-sintered n-type Bi2 Te3 -based alloys show a lower figure of merit (ZT) value than their p-type counterparts and the commercial zone-melted (ZM) ingots. Here, boron is added to one-step-sintered n-type Bi2 Te3 -based alloys to inhibit grain growth and to suppress the donor-like effect, simultaneously improving the mechanical and thermoelectric (TE) performance. Due to the alleviated donor-like effect and the carrier mobility maintained in our n-type Bi2 Te2.7 Se0.3 alloys upon the addition of boron, the maximum and average ZT values within 298-473 K can be enhanced to 1.03 and 0.91, respectively, which are even slightly higher than that of n-type ZM ingots. Moreover, the addition of boron greatly improves the mechanical strength such as Vickers hardness and compressive strength due to the synergetic effects of Hall-Petch grain-boundary strengthening and boron dispersion strengthening. This facile and cost-effective grain boundary engineering by adding boron facilitates the practical application of Bi2 Te3 -based alloys and can also be popularized in other thermoelectric materials.

[1]  M. Wuttig,et al.  Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density , 2021, Advanced Energy Materials.

[2]  W. M. Rainforth,et al.  Facile route to bulk ultrafine-grain steels for high strength and ductility , 2020, Nature.

[3]  Jun Luo,et al.  Tailoring the chemical bonding of GeTe-based alloys by MgB2 alloying to simultaneously enhance their mechanical and thermoelectric performance , 2021 .

[4]  Xiaozhou Liao,et al.  Ultra‐High Thermoelectric Performance in Bulk BiSbTe/Amorphous Boron Composites with Nano‐Defect Architectures , 2020, Advanced Energy Materials.

[5]  Heping Xie,et al.  Leveraging Deep Levels in Narrow Bandgap Bi0.5Sb1.5Te3 for Record‐High zTave Near Room Temperature , 2020, Advanced Functional Materials.

[6]  M. Wuttig,et al.  Exceptionally High Average Power Factor and Thermoelectric Figure of Merit in n-type PbSe by the Dual Incorporation of Cu and Te. , 2020, Journal of the American Chemical Society.

[7]  J. Zou,et al.  Advanced Thermoelectric Design: From Materials and Structures to Devices. , 2020, Chemical reviews.

[8]  G. J. Snyder,et al.  Weighted Mobility , 2020, Advanced materials.

[9]  J. Shuai,et al.  Manipulating the Ge Vacancies and Ge Precipitates through Cr Doping for Realizing the High-Performance GeTe Thermoelectric Material. , 2020, Small.

[10]  M. Kanatzidis,et al.  High-Performance Thermoelectrics from Cellular Nanostructured Sb2Si2Te6 , 2020, Joule.

[11]  G. J. Snyder,et al.  Revealing nano-chemistry at lattice defects in thermoelectric materials using atom probe tomography , 2020 .

[12]  Heping Xie,et al.  Simultaneous enhancement of the thermoelectric and mechanical performance in one-step sintered n-type Bi2Te3-based alloys via a facile MgB2 doping strategy. , 2019, ACS applied materials & interfaces.

[13]  Han Gao,et al.  Anisotropy Control–Induced Unique Anisotropic Thermoelectric Performance in the n‐Type Bi 2 Te 2.7 Se 0.3 Thin Films , 2019, Small Methods.

[14]  Xinbing Zhao,et al.  Evolution of the Intrinsic Point Defects in Bismuth Telluride Based Thermoelectric Materials. , 2019, ACS applied materials & interfaces.

[15]  M. Wuttig,et al.  Understanding the Structure and Properties of Sesqui‐Chalcogenides (i.e., V2VI3 or Pn2Ch3 (Pn = Pnictogen, Ch = Chalcogen) Compounds) from a Bonding Perspective , 2019, Advanced materials.

[16]  M. Wuttig,et al.  Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism , 2019, Advanced Functional Materials.

[17]  Cham Kim,et al.  Concurrent defects of intrinsic tellurium and extrinsic silver in an n-type Bi2Te2.88Se0.15 thermoelectric material , 2019, Nano Energy.

[18]  David J. Singh,et al.  Complex Band Structures and Lattice Dynamics of Bi2Te3‐Based Compounds and Solid Solutions , 2019, Advanced Functional Materials.

[19]  Volker L. Deringer,et al.  A Quantum‐Mechanical Map for Bonding and Properties in Solids , 2018, Advanced materials.

[20]  Huijin Jin,et al.  Attaining reduced lattice thermal conductivity and enhanced electrical conductivity in as-sintered pure n-type Bi2Te3 alloy , 2018, Journal of Materials Science.

[21]  Haijun Wu,et al.  Thermoelectric SnTe with Band Convergence, Dense Dislocations, and Interstitials through Sn Self-Compensation and Mn Alloying. , 2018, Small.

[22]  H. Ng,et al.  Solution-processed n-type Bi2Te3−xSex nanocomposites with enhanced thermoelectric performance via liquid-phase sintering , 2018, Science China Materials.

[23]  Haijun Wu,et al.  Synergistic Compositional–Mechanical–Thermal Effects Leading to a Record High zT in n‐Type V2VI3 Alloys Through Progressive Hot Deformation , 2018, Advanced Functional Materials.

[24]  Byungkyu Kim,et al.  Impurity-free, mechanical doping for the reproducible fabrication of the reliable n-type Bi2Te3-based thermoelectric alloys , 2018 .

[25]  T. Mori.  Novel Principles and Nanostructuring Methods for Enhanced Thermoelectrics. , 2017, Small.

[26]  Terry M. Tritt,et al.  Advances in thermoelectric materials research: Looking back and moving forward , 2017, Science.

[27]  Xinbing Zhao,et al.  Enhancing room temperature thermoelectric performance of n-type polycrystalline bismuth-telluride-based alloys via Ag doping and hot deformation , 2017 .

[28]  Haijun Wu,et al.  Enhancing Thermoelectric Performance of n-Type Hot Deformed Bismuth-Telluride-Based Solid Solutions by Nonstoichiometry-Mediated Intrinsic Point Defects. , 2017, ACS applied materials & interfaces.

[29]  G. J. Snyder,et al.  Self‐Tuning n‐Type Bi2(Te,Se)3/SiC Thermoelectric Nanocomposites to Realize High Performances up to 300 °C , 2017, Advanced science.

[30]  Tiejun Zhu,et al.  Compromise and Synergy in High‐Efficiency Thermoelectric Materials , 2017, Advanced materials.

[31]  M. Wuttig,et al.  Simultaneous optimization of electrical and thermal transport properties of Bi0.5Sb1.5Te3 thermoelectric alloy by twin boundary engineering , 2017 .

[32]  Liu Yong,et al.  New trends, strategies and opportunities in thermoelectric materials: A perspective , 2017 .

[33]  J. Ghatak,et al.  Ultrahigh Average Thermoelectric Figure of Merit, Low Lattice Thermal Conductivity and Enhanced Microhardness in Nanostructured (GeTe)x (AgSbSe2 )100-x. , 2017, Chemistry.

[34]  K. Khor,et al.  Minority Carrier Blocking to Enhance the Thermoelectric Performance of Solution-Processed BixSb2-xTe3 Nanocomposites via a Liquid-Phase Sintering Process. , 2017, ACS applied materials & interfaces.

[35]  Q. Yan,et al.  Enhanced thermoelectric performance of solution-derived bismuth telluride based nanocomposites via liquid-phase Sintering , 2016 .

[36]  Jingfeng Li,et al.  Thermoelectric performance enhancement in n-type Bi2(TeSe)3 alloys owing to nanoscale inhomogeneity combined with a spark plasma-textured microstructure , 2016 .

[37]  Tiejun Zhu,et al.  New Insights into Intrinsic Point Defects in V2VI3 Thermoelectric Materials , 2016, Advanced science.

[38]  Qi Zhang,et al.  Thermoelectric Devices for Power Generation: Recent Progress and Future Challenges   , 2016 .

[39]  Marco Buongiorno Nardelli,et al.  Convergence of multi-valley bands as the electronic origin of high thermoelectric performance in CoSb3 skutterudites. , 2015, Nature materials.

[40]  J. Eckert,et al.  Effect of boron on microstructure and mechanical properties of multicomponent titanium alloys , 2015 .

[41]  Tiejun Zhu,et al.  Tuning Multiscale Microstructures to Enhance Thermoelectric Performance of n‐Type Bismuth‐Telluride‐Based Solid Solutions , 2015 .

[42]  Gang Chen,et al.  Nanocomposites for thermoelectrics and thermal engineering , 2015 .

[43]  G. J. Snyder,et al.  Dense dislocation arrays embedded in grain boundaries for high-performance bulk thermoelectrics , 2015, Science.

[44]  Xianli Su,et al.  Mechanically Robust BiSbTe Alloys with Superior Thermoelectric Performance: A Case Study of Stable Hierarchical Nanostructured Thermoelectric Materials , 2015 .

[45]  G. J. Snyder,et al.  Characterization of Lorenz number with Seebeck coefficient measurement , 2015 .

[46]  Han Li,et al.  High-Temperature Mechanical and Thermoelectric Properties of p-Type Bi0.5Sb1.5Te3 Commercial Zone Melting Ingots , 2014, Journal of Electronic Materials.

[47]  Dawei Liu,et al.  BiSbTe‐Based Nanocomposites with High ZT: The Effect of SiC Nanodispersion on Thermoelectric Properties , 2013 .

[48]  J. Eckert,et al.  Influence of boron and oxygen on the microstructure and mechanical properties of high-strength Ti66Nb13Cu8Ni6.8Al6.2 alloys , 2013 .

[49]  Heng Wang,et al.  Band Engineering of Thermoelectric Materials , 2012, Advanced materials.

[50]  Xinbing Zhao,et al.  Improving thermoelectric properties of n-type bismuth–telluride-based alloys by deformation-induced lattice defects and texture enhancement , 2012 .

[51]  Richard W Siegel,et al.  A new class of doped nanobulk high-figure-of-merit thermoelectrics by scalable bottom-up assembly. , 2012, Nature materials.

[52]  Qingjie Zhang,et al.  Investigation of the sintering pressure and thermal conductivity anisotropy of melt-spun spark-plasma-sintered (Bi,Sb)_2Te_3 thermoelectric materials , 2011 .

[53]  Qian Zhang,et al.  Thermoelectric Property Studies on Cu‐Doped n‐type CuxBi2Te2.7Se0.3 Nanocomposites , 2011 .

[54]  Terry M. Tritt,et al.  Identifying the specific nanostructures responsible for the high thermoelectric performance of (Bi,Sb)2Te3 nanocomposites. , 2010, Nano letters.

[55]  L. Bell.  Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems , 2008, Science.

[56]  Weishu Liu,et al.  Enhanced thermoelectric and mechanical properties in textured n-type Bi2Te3 prepared by spark plasma sintering , 2008 .

[57]  M. Dresselhaus,et al.  High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys , 2008, Science.

[58]  G. J. Snyder,et al.  Complex thermoelectric materials. , 2008, Nature materials.

[59]  D. Miracle,et al.  Grain refinement of cast titanium alloys via trace boron addition , 2005 .

[60]  Xing Zhang,et al.  Bismuth telluride nanotubes and the effects on the thermoelectric properties of nanotube-containing nanocomposites , 2005 .

[61]  F. D. Rosi,et al.  Compound tellurides and their alloys for peltier cooling—A review , 1972 .