scholarly journals Thermoelectric Properties of Cu2SnSe3-Based Composites Containing Melt-Spun Cu–Te

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 971
Author(s):  
Degang Zhao ◽  
Lin Wang ◽  
Di Wu ◽  
Lin Bo

In this study, the Cu–Te alloy ribbons containing nanocrystalline structures were prepared by melt spinning (MS), and were composed of Cu2−xTe, Cu2Te, Cu3−xTe, and CuTe phases. Crystal grains on both sides of the ribbons were uniformly distributed and the grain size of the contact surface was about 400 nm. The Cu–Te powder was incorporated into the Cu2SnSe3 powder by the ball milling process and the Cu–Te/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). With the amount of Cu–Te powder increasing, the carrier concentration of the Cu–Te/Cu2SnSe3 composite increased, while the carrier mobility and electrical conductivity initially increased and then decreased. Compared to the Seebeck coefficient of the Cu2SnSe3 matrix, the Seebeck coefficient of the Cu–Te/Cu2SnSe3 samples increased slightly. Moreover, the Cu–Te/Cu2SnSe3 composites had lower thermal conductivity and lattice thermal conductivity over the whole temperature range. The lattice thermal conductivity of the 0.8 vol.% Cu–Te/Cu2SnSe3 composite achieved the lowest value of 0.22 W/m·K, which was 78% lower than that of the Cu2SnSe3 matrix. The maximum figure of merit of the 0.8 vol.% Cu–Te/Cu2SnSe3 composite was 0.45 at 700 K.

2020 ◽  
Vol 10 (14) ◽  
pp. 4963 ◽  
Author(s):  
Ki Wook Bae ◽  
Jeong Yun Hwang ◽  
Sang-il Kim ◽  
Hyung Mo Jeong ◽  
Sunuk Kim ◽  
...  

Herein we report a significantly reduced lattice thermal conductivity of Sb-doped Hf0.35Zr0.35Ti0.3NiSn half-Heusler alloys with sub-micron grains (grain size of ~300 nm). Polycrystalline bulks of Hf0.35Zr0.35Ti0.3NiSn1−xSbx (x = 0.01, 0.02, 0.03) with a complete single half-Heusler phase are prepared using temperature-regulated melt spinning and subsequent spark plasma sintering without a long annealing process. In these submicron-grained bulks, a very low lattice thermal conductivity value of ~2.4 W m−1 K−1 is obtained at 300 K due to the intensified phonon scatterings by highly dense grain boundaries and point-defects (Zr and Ti substituted at Hf-sites). A maximum thermoelectric figure of merit, zT, of 0.5 at 800 K is obtained in Hf0.35Zr0.35Ti0.3NiSn0.99Sb0.01.


2018 ◽  
Vol 913 ◽  
pp. 811-817 ◽  
Author(s):  
Di Wu ◽  
Ji Ai Ning ◽  
De Gang Zhao ◽  
Xue Zhen Wang ◽  
Na Liu

In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.


2009 ◽  
Vol 66 ◽  
pp. 17-20 ◽  
Author(s):  
Mei Jun Yang ◽  
Wei Jun Luo ◽  
Qiang Shen ◽  
Hong Yi Jiang ◽  
Lian Meng Zhang

Nanocomposites and heavy doping both are regarded as effective way to improve materials’ thermoelectric properties. 0.7at% Bi-doped Mg2Si nanocomposites were prepared by spark plasma sintering. Results of thermoelectric properties tests show that the doping of Bi atom effectively improves the electrical conductivity of Mg2Si,and the nanocomposite structures are helpful to reduce thermal conductivity and increase Seebeck coefficient, hence improving the thermoelectric performance. A maximum dimensionless figure of merit of 0.8 is obtained for the Bi-doped Mg2Si nanocomposite with 50 wt % nanopowder inclusions at 823K, about 63% higher than that of Bi-doped Mg2Si sample without nanopowder inclusions and 119% higher than that of microsized Mg2Si sample without Bi-doped, respectively.


Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 643 ◽  
Author(s):  
Bhuvanesh Srinivasan ◽  
David Berthebaud ◽  
Takao Mori

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.


2013 ◽  
Vol 06 (05) ◽  
pp. 1340006 ◽  
Author(s):  
JINGSHU XU ◽  
CHENGUANG FU ◽  
JIAN XIE ◽  
XINBING ZHAO ◽  
TIEJUN ZHU

The p-type skutterudite compounds of ( Pr 0.25 Nd 0.75)x Fe 3 CoSb 12 (x = 0.67–0.78) have been successfully synthesized by levitation melting followed by annealing and spark plasma sintering. The thermoelectric properties have been characterized by the measurements of Seebeck coefficient, electrical conductivity and thermal conductivity in the temperature range from 300 K to 850 K. The improvement in the thermoelectric properties was realized due to the reduction in the lattice thermal conductivity when the voids were partially filled by Pr 0.25 Nd 0.75. The maximum ZT value of ~ 0.83 for ( Pr 0.25 Nd 0.75)0.76 Fe 3 CoSb 12 was obtained at 700 K.


2021 ◽  
pp. 2150089
Author(s):  
THAMMANOON KAPANYA ◽  
BINBIN JIANG ◽  
JIAQING HE ◽  
YANG QIU ◽  
CHANCHANA THANACHAYANONT ◽  
...  

The efficient strategies to minimize thermal conductivity in skutterudite materials are creating point defects along with nanosized grains. In this report, Sn and Se co-doped CoSb3 materials were synthesized through mixed-ball milling and spark plasma sintering techniques to utilize this strategy. Their phases, microstructure and thermoelectric properties were investigated under the content variation of Sn and Se in CoSb3 samples. The experimental results revealed that the Sn and Se were substituted at Sb sites in CoSb3 crystal structure and grain sizes were restricted to a hundred nanometer. The lattice thermal conductivity was reduced to 2.4[Formula: see text]W/mK at 298K. Interestingly, increasing Sn and Se doped content could further minimize the lattice thermal conductivity. The lowest value at room temperature is 1.79[Formula: see text]W/mK for CoSb[Formula: see text]Sn[Formula: see text]Se[Formula: see text] which was dramatically lower than pure CoSb3. Moreover, the increment of Sn and Se content also increased the electrical conductivity of doped samples, while the negative Seebeck coefficient sign tended to decrease. As expected, low electrical conductivity and substantial reduction in the Seebeck coefficient of doped samples at high measurement temperature, resulting in low power factor and low ZT values. It was clearly seen that the highest power factor of 880[Formula: see text][Formula: see text]W/mK2 was found at 516[Formula: see text]K in CoSb[Formula: see text]Sn[Formula: see text]Se[Formula: see text]. Furthermore, it also dominated the highest ZT value of 0.29 at 565 K, compared to the other Sn and Se co-doped samples. From these results, ball milling under dry conditions followed by wet conditions not only allowed a longer milling process but also generated a small fraction of pore which was a part of the reduction in thermal conductivity. Especially, the advantage of the existence of Sn and Se point defects and nanosized grains from this work will be escalated when it was applied to prepare materials that have high power factor values.


2010 ◽  
Vol 03 (04) ◽  
pp. 227-231 ◽  
Author(s):  
CUI YU ◽  
TIEJUN ZHU ◽  
KAI XIAO ◽  
JUNJIE SHEN ◽  
XINBING ZHAO

(Zr,Hf)NiSn -based half-Heusler thermoelectric materials have been prepared by melt spinning and spark plasma sintering to refine the grain size. The grain sizes of the melt-spun thin ribbons varied from ~500 nm to ~3 μm and no significant grain growth were found for the bulk samples compacted by spark plasma sintering. Nanoscale precipitates dispersed in the matrix were observed, which should be more metallic due to the increase of the electrical conductivity. The reduction of lattice thermal conductivity was observed due to the refined grain sizes.


2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).


2014 ◽  
Vol 2 (38) ◽  
pp. 15829-15835 ◽  
Author(s):  
Kriti Tyagi ◽  
Bhasker Gahtori ◽  
Sivaiah Bathula ◽  
A. K. Srivastava ◽  
A. K. Shukla ◽  
...  

Intrinsically ultra-low thermal conductivity and electrical transport in single-phase Cu2SbSe3 synthesized employing a solid state reaction and spark plasma sintering.


2012 ◽  
Vol 512-515 ◽  
pp. 1651-1654 ◽  
Author(s):  
Yu Kun Xiao ◽  
Zhi Xiang Li ◽  
Jun Jiang ◽  
Sheng Hui Yang ◽  
Ting Zhang ◽  
...  

P-type BiSbTe/RuO2 composite was fabricated using a combined process of melting and spark plasma sintering. The XRD patterns showed that RuO2 reacted with the matrix for the RuO2 content of 1.0 wt% and 4.0 wt% samples. The measured thermoelectric properties showed that the highest electrical conductivity was obtained for the sample with 2.0 wt% RuO2. The power factor (α2σ/κ) decreased with the increase of RuO2 below 450 K. The lattice thermal conductivity was lower than that of BiSbTe over the whole temperature range for BiSbTe/2.0 wt% RuO2.


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