Improved cryogenic thermoelectric performance of MgAgSb-based materials by modulation doping of Cu
| Project/Area Number |
20K22486
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0402:Nano/micro science, applied condensed matter physics, applied physics and engineering, and related fields
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| Research Institution | Shibaura Institute of Technology |
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Principal Investigator |
Miao Lei 芝浦工業大学, 工学部, 教授 (60455540)
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| Project Period (FY) |
2020-09-11 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | MgAgSb熱電材料 / 廃熱発電 / 放電プラズマ焼結 / 電気特性 / 熱伝導率制御 / ミクロ孔 / Cuドープ / thermoelectric / α-MgAgSb / micro-pores effects / low thermal conductivity / Cu / cold energy / modulation doping / ZT / thermoelectrics / cryogenic temperature / MgAgSb / cold energy utilization / 低温・冷凍熱源利用熱電技術 / p型Cuナノ粒子添加MgAgSb熱電材料 / 遊星ボールミリング合成法 / Cuナノ粒子変調添加法 / 熱電特性発現物理機構 |
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| Outline of Research at the Start |
熱電素子による低品位の低温・冷凍熱源から高効率熱発電実現のため、Cuナノ粒子添加p型MgAgSb熱電材料を高性能化する精密合成法と熱電特性発現機構を解明する。
基材のMgAgSbの合成に、低価格化を視野に、簡便な方法の一つである遊星ボールミリング合成法を適用し、その最適プロセスを見出す。
我々の先行研究で培われた方法を発展させたCu変調添加（modulation doping）法を用い、高濃度Cuナノ粒子添加サブミクロン領域をCu濃度の低いMgAgSb基材中に比較的均一分散する組織構造による高性能化を目指す。
また、熱電特性発現メカニズムを計算科学の援用により考察し高性能化の指針を得る。
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| Outline of Final Research Achievements |
MgAgSb-based alloy was successfully prepared via ordinary planetary ball milling and spark plasma sintering. The element Cu successfully doped into MgAgSb to cooperatively optimize the electrical transport properties. The main parameters including nominal composition of raw powders Mg, Ag, Sb, Cu doping ratio, SPS pressure and heat treating conditions have been optimized. As a result, the maximum PF value of 2111 μW/mK-2 at 523K for MgAg0.93Cu0.02Sb0.98 was about 18% increased than 1788 μW/mK-2 for the initial sample MgAg0.95Sb0.98, and a peak ZT ~ 1.08 at 473 K were achieved for the sample MgAg0.935Cu0.015Sb0.98@ 60 MPa. In addition, we explored the phase composition and micro-pores effects and found that a large number of micro-pores can strengthen phonon scattering to reduce the lattice thermal conductivity. Thus, thermoelectric properties of MgAgSb-based alloys can be enhanced by Cu doping into Ag site and micro-pores structures.
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| Academic Significance and Societal Importance of the Research Achievements |
熱電発電ではエントロピーの高い低品位の低中温熱源（LNGや石炭を燃料とする火力発電所や様々な産業プロセスからの100℃以下の大量廃熱、冷熱産業や人体を含めた様々な環境周囲からの200K-常温範囲の未利用熱など）から、高品質の電気エネルギーに変換できる技術で、通常のRankine サイクル利用の熱水蒸気発電システムに比較して、可動部分を少なくし単純化できる発電プラント構成にできる等の優位性から、省エネルギー・地球温暖化問題に寄与できるために大きな期待がかかる。今回研究した熱電素子は ZT ~ 1.08 ＠473 Kに達し、その学術的意義は高く、上記応用分野に充分適用可能で社会的意義も高い。
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Report
(3 results)
Research Products
(5 results)
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[Journal Article] Constructed Ge Quantum Dots and Sn Precipitate SiGeSn Hybrid Film with High Thermoelectric Performance at Low Temperature Region2022
Author(s)
Ying Peng, Lei Miao,* Chengyan Liu, Haili Song, Masashi Kurosawa, Osamu Nakatsuka, Song Yi Back, Jong Soo Rhyee, Masayuki Murata, Sakae Tanemura, Takahiro Baba, Tetsuya Baba, Takahiro Ishizaki, and Takao Mori
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Journal Title
Adv. Energy Mater.
Volume: 12
Issue: 2
Pages: 2103191-2103191
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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