Researchers Uncover Mechanism Behind Low Thermal Conductivity

Researchers at the Queensland University of Technology (QUT) have made a significant discovery regarding low thermal conductivity in certain materials. This finding, which is crucial for applications in energy conversion, insulation, and gas storage, reveals a structural mechanism that explains why some materials can effectively block heat. The research, published in the journal Nature Communications, identifies how uneven compositions in materials lead to exceptionally low thermal conductivity.

The first author of the study, Siqi Liu, stated that the results challenge traditional models that do not take into account the importance of microstructural features. “People used to think low thermal conductivity in uneven materials was just due to how the different parts were mixed,” Liu explained. “But we found it’s actually caused by tiny defects, called edge dislocations, that scatter heat more when they’re randomly arranged.”

Key Findings on Thermal Properties

The research team focused on a widely used thermoelectric alloy, Bi0.4Sb1.6Te3, using advanced electron microscopy and scanning thermal probe techniques to analyze the compound’s composition and thermal properties at the atomic level. Liu noted that their findings indicated materials with randomly mixed zones rich in bismuth and antimony blocked heat more effectively than those with a more ordered structure. This effectiveness arises from the scattering of edge dislocations in multiple directions, which disrupts heat flow.

Team leader Professor Zhi-Gang Chen highlighted the broader implications of this discovery. “By understanding how these dislocations form and align, we can better engineer materials for energy applications,” he said. “This structural insight provides a new design principle for low thermal conductivity materials beyond traditional defect engineering.”

The researchers believe their work could have significant applications across various industries. Liu emphasized that the findings could enhance the efficiency of thermoelectric generators and lead to the development of superior thermal insulators. “This work gives us a new tool to control heat flow at the atomic level,” he added.

Collaboration and Future Directions

The full research team, all affiliated with the QUT Center for Material Science, includes Dr. Wei-Di Liu, Dr. Wanyu Lyu, Yicheng Yue, Dr. Han Gao, Dr. Meng Li, Dr. Xiao-Lei Shi, and Professor Zhi-Gang Chen, with contributions from James D. Riches at QUT’s Central Analytical Research Facility and Dmitri Golberg, a distinguished professor at the QUT School of Chemistry and Physics.

As industries increasingly seek efficient energy solutions, this research paves the way for innovative materials tailored to specific thermal properties, potentially revolutionizing how heat management is approached in technology and energy sectors.