Bloch orbital engineering and high-entropy alloying for high performance thermoelectric materials design

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20486
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0401:Materials engineering, chemical engineering, and related fields
• Research Institution: National Institute for Materials Science
• Principal Investigator: IWASAKI Yutaka 国立研究開発法人物質・材料研究機構, ナノアーキテクトニクス材料研究センター, 研究員 (20964232)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: 熱電材料 / 金属間化合物 / ホイスラー合金 / 第一原理計算

Outline of Final Research Achievements

In order to synthesize thermoelectric materials with high thermal and chemical stability and excellent mechanical properties for use in thermoelectric power generation devices for medium- and low-temperature waste heat recovery, we searched for alloy-based materials with a suitable band structure for thermoelectric materials based on orbital analysis using first principles calculations. As a result, a dimensionless figure of merit of 0.5 was obtained at 973 K for Ru(Al,Si)γ with a chimney ladder phase.The second was an iron-based alloy with an irregular structure that achieved lower thermal conductivity than the competing iron-based Heusler alloy due to its defect-rich structure. The other is a nickel-based alloy that exhibits a high power factor comparable to that of iron-based Heusler alloys.

Free Research Field

材料科学

Academic Significance and Societal Importance of the Research Achievements

本研究によって、実用化に資する熱電材料の候補物質を見つけることができた。特に今回合成したチムニーラダー相Ru(Al,Si)γは、類似構造をもつ物質群においてn型で高性能が得られた報告が少ない材料系であるが、その中でも熱電材料にとって好適な低い熱伝導率と高い出力因子し、高い無次元性能指数を実現することができた。