Synthesis of Mg2Si1−xSnx solid solutions as thermoelectric materials by bulk mechanical alloying and hot pressing

Song, Ruizhuo; Aizawa, Tatsuhiko; Sun, Jichang

doi:10.1016/j.mseb.2006.09.011

Cited by 76 publications

(48 citation statements)

References 17 publications

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“…Historically, Mg 2 Sn material has been investigated less than its analogous compound Mg 2 Si for thermoelectric applications due to its lower ZT (22)(23)(24)(25). Most of the research has been focused on the alloy of Mg 2 Si-Mg 2 Sn with a peak ZT value of ∼1 at 500°C (26)(27)(28). Recently, different groups have improved the peak ZT value to 1.1-1.3 by adjusting the x value in the Mg 2 Si 1−x Sn x solid solution (14,29,30).…”

Section: ·Kmentioning

confidence: 99%

“…Recently, different groups have improved the peak ZT value to 1.1-1.3 by adjusting the x value in the Mg 2 Si 1−x Sn x solid solution (14,29,30). The challenges in preparing and handling these materials were the high vapor pressure and chemical activity of Mg. Methods of direct comelting with subsequent annealing, and solid-state reaction with subsequent annealing and Bridgman method were reported to synthesize Mg 2 Si-Mg 2 Sn alloys (22)(23)(24)(25)(26)(27)(28)(29)(30). Powder metallurgy route, e.g., ball milling plus hot pressing, was widely used to fabricate a variety of high-performance thermoelectric bulk materials such as Bi 2 Te 3 (6,31), PbTe (32), PbSe (33), and skutterudites CoSb 3 (16,34).…”

Section: ·Kmentioning

confidence: 99%

“…In fact, ball milling was reported to synthesize Mg 2 Si and its alloys Mg 2 Si-Mg 2 Sn (35)(36)(37)(38). However, the reported ZT was lower than 0.7 (27,38), which may be due to the difficulty in avoiding oxidization of Mg. Here, we report a successful synthesis of an Sn-dominated composition Mg 2 Sn 0.75 Ge 0.25 through ball milling and hot pressing to achieve a ZT of 1.4 at 450°C and power factor PF of 55 μW·cm −1 ·K −2 at 350°C.…”

Section: ·Kmentioning

confidence: 99%

See 2 more Smart Citations

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

Liu

Kim

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

199

131

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Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg 2 Sn-based material, Mg 2 Sn 0.75 Ge 0.25 , is a good example to meet the dual requirements in efficiency and output power. It was found that Mg 2 Sn 0.75 Ge 0.25 has an average ZT of 0.9 and PF of 52 μW·cm ·K−2 over the temperature range of 25-450°C, a peak ZT of 1.4 at 450°C, and peak PF of 55 μW·cm·K −2 at 350°C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with T h = 400°C and T c = 50°C to be of 10.5% and 6.6 W·cm −2 under a temperature gradient of, respectively.thermoelectrics | magnesium | tin | power factor | output power T hermoelectric power generation from waste heat is attracting more and more attention. Potential fuel efficiency enhancement by recovering the waste heat is beneficial for automobiles and many other applications (1, 2). In addition, solar thermoelectric generator provides an alternative route to convert solar energy into electrical power besides the photovoltaic conversion (3). Thermoelectric generator (TEG) can be regarded as a heat engine using electrons/holes as the energy carrier. The conversion efficiency of a TEG is related to the Carnot efficiency and the material's average thermoelectric figure of merit ZT (4):where ZT = (S 2 σ/κ)T, and S, σ, κ, and T are Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively. Pursuing high ZT has been the focus of the entire thermoelectric community by applying various phonon engineering via nanostructuring approaches to reduce the thermal conductivity (5-7), or by exploring new compounds with intrinsically low thermal conductivity, such as compounds having complex crystalline structure, local rattlers, liquid-like sublattice, and highly distorted lattice (8-11). However, for practical applications, efficiency is not the only concern, and high output power density is as important as efficiency when the capacity of the heat source is huge (such as solar heat), or the cost of the heat source is not a big factor (such as waste heat from automobiles, steel industry, etc.). The output power density ω is defined as the output power W divided by the cross-sectional area A of the leg, i.e., ω = W/A, which is related to power factor PF = S 2 σ by the following:Eq. 2 contains two main parts: square of the temperature difference divided by leg length, and material power factor PF = S 2 σ.Clearly, to achieve higher power density for a given heat source, we have to either increase the power factor PF or decrease the leg length. However, decreasing the leg length could cause severe consequences such as increase of large heat flux that will incr...

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Section: ·Kmentioning

confidence: 99%

Section: ·Kmentioning

confidence: 99%

Section: ·Kmentioning

confidence: 99%

See 1 more Smart Citation

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

Liu

Kim

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

199

131

View full text Add to dashboard Cite

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“…9) Due to the high vapor pressure, the oxidation of Mg, as well as the different melting points of Mg, Si, Sn, it is extremely difficult to synthesize the pure compounds and control the structure and properties. Thus, the solid state reaction combined with SPS sintering is introduced to synthesize these solid solutions, involving the low temperature and large diffusion velocity of SPS at the low temperature.…”

Section: -7)mentioning

confidence: 99%

Preparation and Thermoelectric Properties of Bi-Doped Mg2Si0.8Sn0.2 Compound

et al. 2010

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The Bi-doped Mg 2 Si 0:8 Sn 0:2 single phase compound is prepared by a solid state reaction (SSR)-spark plasma sintering (SPS) method. The effect of the Bi content on the thermoelectric properties of the Bi-doped Mg 2 Si 0:8 Sn 0:2 compound is mainly investigated. The results show that the thermoelectric properties of the obtained samples are sensitive to the Bi content. With the increase in Bi content, the electrical conductivity () and Seebeck coefficient () of the samples are increased, while the thermal conductivity () is decreased slightly between 300 K and 850 K. When the Bi content is greater than 3.0 at%, the sample shows a maximum figure of merit (ZT) value (1:17 AE 0:05) at 850 K.

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“…The efficiency of thermoelectric power generation is governed by the Carnot efficiency and dimensionless figure of merit (ZT) of 30 the material. ZT is defined as ZT = (S 2 σ/κ)T, where S, σ, κ, and T are the Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively.…”

Section: Introductionmentioning

confidence: 99%

New insight into the material parameter B to understand the enhanced thermoelectric performance of Mg₂Sn_1−x−yGe_xSb_y

Liu

Zhou

et al. 2016

Energy Environ. Sci.

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Historically, material parameter B incorporating weighted mobility and lattice thermal conductivity has guided the exploration of novel thermoelectric materials. However, the conventional definition of B neglects the bipolar effect which can dramatically change the thermoelectric energy conversion efficiency at high temperatures. In this paper, a generalized material parameter B * is derived, which connects weighted mobility, lattice thermal conductivity, and band gap. Broader ContextThermoelectric conversion involves the transport of electrons and phonons. It has been very challenging to synergistically tune the macro thermoelectric transport parameters: electrical conductivity, thermal conductivity, and Seebeck coefficient as these properties are coupled 20 to each other. Recently, we have achieved a significant enhancement in the thermoelectric performance of Mg 2 Sn by partially substituting Sn with Ge and doping Sb. The new material Mg 2 Sn 0.728 Ge 0.25 Sb 0.022 has a high average ZT (0.9) and power factor (52 μW cm −1 K −2 ) in the temperature range of 25-450 °C, with favourably high efficiency and large output power density. The ZT improvement is understood through a generalized material parameter B * , which connects weighted mobility, lattice thermal conductivity, and band gap. A higher B * is desired for higher ZT. The new parameter will help guide the optimizations of known materials by synergistically tailoring 25 these fundamental parameters to enhance their thermoelectric performance, and the search of new materials by using it as new scale.

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Synthesis of Mg2Si1−xSnx solid solutions as thermoelectric materials by bulk mechanical alloying and hot pressing

Cited by 76 publications

References 17 publications

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

Preparation and Thermoelectric Properties of Bi-Doped Mg<SUB>2</SUB>Si<SUB>0.8</SUB>Sn<SUB>0.2</SUB> Compound

New insight into the material parameter B to understand the enhanced thermoelectric performance of Mg₂Sn_1−x−yGe_xSb_y

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Synthesis of Mg2Si1−xSnx solid solutions as thermoelectric materials by bulk mechanical alloying and hot pressing

Cited by 76 publications

References 17 publications

n-type thermoelectric material Mg 2 Sn 0.75 Ge 0.25 for high power generation

n-type thermoelectric material Mg 2 Sn 0.75 Ge 0.25 for high power generation

Preparation and Thermoelectric Properties of Bi-Doped Mg<SUB>2</SUB>Si<SUB>0.8</SUB>Sn<SUB>0.2</SUB> Compound

New insight into the material parameter B to understand the enhanced thermoelectric performance of Mg2Sn1−x−yGexSby

Contact Info

Product

Resources

About

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

New insight into the material parameter B to understand the enhanced thermoelectric performance of Mg₂Sn_1−x−yGe_xSb_y