Influence of Addition of Alumina Nanoparticles on Thermoelectric Properties of Higher Manganese Silicide

2012 ◽  
Vol 1490 ◽  
pp. 127-132 ◽  
Author(s):  
Takashi Itoh ◽  
Naoki Ono

ABSTRACTHigher manganese silicide (HMS) is a low-cost and eco-friendly thermoelectric material available for recovering waste heat of 500 to 900 K. In this research, we tried to uniformly disperse the alumina nanoparticles (ANPs) in the HMS matrix to reduce the thermal conductivity and to improve the thermoelectric performance. Influence of addition of ANPs on the thermoelectric properties was investigated. It was confirmed that ANPs were uniformly dispersed in the HMS grain boundary. The lattice thermal conductivity was reduced by adding ANPs. As a result, the maximum thermoelectric performance of ZT=0.58 was achieved at about 800 K by adding 1 vol% of ANPs. The performance of ANPs-added HMS was improved about 25 %.

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yatir Sadia ◽  
Mor Elegrably ◽  
Oren Ben-Nun ◽  
Yossi Marciano ◽  
Yaniv Gelbstein

The world energy crisis had increased the demand for alternative energy sources and as such is one of the topics at the forefront of research. One way for reducing energy consumption is by thermoelectricity. Thermoelectric effects enable direct conversion of thermal into electrical energy. Higher manganese silicide (HMS, MnSi1.75) is one of the promising materials for applications in the field of thermoelectricity. The abundance and low cost of the elements, combined with good thermoelectric properties and high mechanical and chemical stability at high temperatures, make it very attractive for thermoelectric applications. Recent studies have shown that Si-rich HMS has improved thermoelectric properties. The most interesting of which is the unusual reduction in thermal conductivity. In the current research, transmission (TEM) and scanning (SEM) electron microscopy as well as X-ray diffraction methods were applied for investigation of the govern mechanisms resulting in very low thermal conductivity values of an Si-rich HMS composition, following arc melting and hot-pressing procedures. In this paper, it is shown that there is a presence of sub-micron dislocations walls, stacking faults, and silicon and HMS precipitates inside each other apparent in the matrix, following a high temperature (0.9 Tm) hot pressing for an hour. These are not just responsible for the low thermal conductivity values observed but also indicate the ability to create complicate nano-structures that will last during the production process and possibly during the application.


Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Muchun Guo ◽  
Fengkai Guo ◽  
Jianbo Zhu ◽  
Li Yin ◽  
Qian Zhang ◽  
...  

CaMg2Bi2-based compounds, a kind of the representative compounds of Zintl phases, have uniquely inherent layered structure and hence are considered to be potential thermoelectric materials. Generally, alloying is a traditional and effective way to reduce the lattice thermal conductivity through the mass and strain field fluctuation between host and guest atoms. The cation sites have very few contributions to the band structure around the fermi level; thus, cation substitution may have negligible influence on the electric transport properties. What is more, widespread application of thermoelectric materials not only desires high ZT value but also calls for low-cost and environmentally benign constituent elements. Here, Ba substitution on cation site achieves a sharp reduction in lattice thermal conductivity through enhanced point defects scattering without the obvious sacrifice of high carrier mobility, and thus improves thermoelectric properties. Then, by combining further enhanced phonon scattering caused by isoelectronic substitution of Zn on the Mg site, an extraordinarily low lattice thermal conductivity of 0.51 W m-1 K-1 at 873 K is achieved in (Ca0.75Ba0.25)0.995Na0.005Mg1.95Zn0.05Bi1.98 alloy, approaching the amorphous limit. Such maintenance of high mobility and realization of ultralow lattice thermal conductivity synergistically result in broadly improvement of the quality factor β. Finally, a maximum ZT of 1.25 at 873 K and the corresponding ZTave up to 0.85 from 300 K to 873 K have been obtained for the same composition, meanwhile possessing temperature independent compatibility factor. To our knowledge, the current ZTave exceeds all the reported values in AMg2Bi2-based compounds so far. Furthermore, the low-cost and environment-friendly characteristic plus excellent thermoelectric performance also make the present Zintl phase CaMg2Bi2 more competitive in practical application.


2020 ◽  
Vol 8 (6) ◽  
pp. 3431-3437 ◽  
Author(s):  
Bing Shan ◽  
Siqi Lin ◽  
Zhonglin Bu ◽  
Jing Tang ◽  
Zhiwei Chen ◽  
...  

Ternary Cu4Ge3Se5 with a disordered zinc blende structure shows a low intrinsic lattice thermal conductivity and potential thermoelectric performance.


Author(s):  
Zheng Chang ◽  
Kunpeng Yuan ◽  
Zhehao Sun ◽  
Xiaoliang Zhang ◽  
Yufei Gao ◽  
...  

With the ability of altering the inherent interatomic electrostatic interaction, modulating external electric field strength is a promising approach to tune the phonon transport behavior and enhance thermoelectric performance of...


2015 ◽  
Vol 3 (40) ◽  
pp. 10525-10533 ◽  
Author(s):  
Felix Fahrnbauer ◽  
Stefan Maier ◽  
Martin Grundei ◽  
Nadja Giesbrecht ◽  
Markus Nentwig ◽  
...  

The precipitation of skutterudite-type crystallites in germanium antimony tellurides yields intriguing materials with respect to their thermoelectric performance, especially due to a very low phononic part of the lattice thermal conductivity.


Author(s):  
Jonathan Skelton

Thermoelectric generators (TEGs) convert waste heat to electricity and are a leading contender for improving energy efficiency at a range of scales. Ideal TE materials show a large Seebeck effect,...


Author(s):  
Zihang Liu ◽  
Wenhao Zhang ◽  
Weihong Gao ◽  
Takao Mori

Discovering materials with the intrinsically low lattice thermal conductivity κlat is an important route for achieving high thermoelectric performance. In reality, the conventional synthetic approach, however, relies on trial and...


RSC Advances ◽  
2021 ◽  
Vol 11 (25) ◽  
pp. 15486-15496
Author(s):  
Enamul Haque

The layered structure, and presence of heavier elements Rb/Cs and Sb induce high anharmonicity, low Debye temperature, intense phonon scattering, and hence, low lattice thermal conductivity.


2001 ◽  
Vol 16 (3) ◽  
pp. 837-843 ◽  
Author(s):  
Xinfeng Tang ◽  
Lidong Chen ◽  
Takashi Goto ◽  
Toshio Hirai

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.


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