The discovery of a novel mechanism by a team of researchers that further suppresses thermal conductivity in thermoelectric materials will aid in the development of new standards for the manufacture of high-performance thermoelectric materials.
A schematic diagram. In intermetallic compounds with tunnel spaces in the crystal structure (Na-X-Sn compounds, where X is Al, Ga, In, or Zn), Na atoms in the tunnel vibrate (rattling) with large amplitude along the elongation direction of the tunnel, and the local interatomic distance of these Na atoms. It was found that the lattice thermal conductivity decreases in compounds where the local interatomic distance (dNa-Na) of these Na atoms is closer. This is a new mechanism of thermal conductivity reduction caused by the strong correlation of the atomic chain-like rattling atoms in the tunnel with each other. Image Credit: Takahiro Yamada et al.
On December 17th, 2022, the research was published in Advanced Materials.
Thermal conductivity, or the ability to control how easily heat is transferred through a material, has a variety of uses in daily life, including improving the performance of electronic devices, insulating homes, improving energy efficiency in automobiles, and generating more power.
Thermal management technology is gaining more attention from scientists as a way to efficiently use thermal energy and address a variety of heat-related issues.
The atomic chains strongly correlated with one another and vibrated with a large amplitude, or “rattled,” when the research team inserted them into tunnel spaces within intermetallic compound crystal structures.
Strong experiments and theoretical calculations showed that as the correlation between rattling atoms got stronger, the reduction in thermal conductivity was greater.
Since advancements in thermoelectric materials require lower thermal conductivity, our discovery can provide new guidelines for engineering improved thermoelectric materials.
Takahiro Yamada, Study Co-Author and Professor, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
Professor Hisanori Yamane (IMRAM), Professor Masato Yoshiya [at the time of research] (Graduate School of Engineering, Osaka University), Associate Professor Hiroshi Takatsu and Professor Hiroshi Kageyama (Graduate School of Engineering, Kyoto University), Chief Senior Research Scientist Dr. Takuji Ikeda (Research Institute for Chemical Process Technology, National Institute of Advanced Industrial Science and Technology) and Senior Research Scientist Dr. Hideaki Nagai (Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology) also participated in the research.
Journal Reference:
Yamada, T., et al. (2022) Correlated Rattling of Sodium-Chains Suppressing Thermal Conduction in Thermoelectric Stannides. Advanced Materials. doi:10.1002/adma.202207646.