In the laboratories of Clemson University in South Carolina, the creation of a hybrid thermoelectric material sets the stage for new forms of electricity in the future.
How is a thermoelectric material defined?
Thermoelectric materials are those materials that can directly convert heat into electricity, that is when a temperature difference creates an electric potential or vice versa.
At the basis of this behavior there are several phenomena, depending on the “direction” in which the property of the matter under consideration acts:
- Peltier effect: the creation of a flow of heat from an electric current;
- Seebeck effect: the creation of a voltage from a temperature difference;
- Thomson effect: reversible heating or cooling inside a conductor when there is both an electric current and a temperature gradient.
All materials can be defined as thermoelectric, but usually, the variation is so small that it is not taken into consideration, as it is unusable.
The new thermoelectric material
An associate professor at College of Science’s Department of Physics and Astronomy, Jian He, has joined forces with collaborators from China and Denmark, involving scientists from Shanghai Jiaotong University, the Shanghai Institute of Ceramics and SUSTech in China, and Aarhus University in Denmark to create a new, potentially revolutionary, high-performance thermoelectric compound.
His work began with the analysis of the atomic structure of materials or the way in which atoms arrange themselves in space and time. From this perspective, solid materials are divided into crystalline or amorphous: in crystals, atoms are arranged in an ordered and symmetrical pattern, while amorphous materials have randomly distributed atoms.
Instead, the international team has created a new one-of-a-kind hybrid compound.
The researchers created this hybrid material by intentionally mixing elements from the same group on the periodic table, but with different atomic sizes. Specifically, they used the atomic size discrepancies between sulfur and tellurium and between copper and silver to create a new compound (Cu1-xAgx)2(Te1-ySy) in which crystalline and amorphous sublattices intertwine into a single crystal-amorphicity duality. The new compound showed excellent thermoelectric performance.
“If you have a unique or peculiar atomic structure, you would expect to see very unusual properties because properties follow structure.” said Jian He.
“The new material performs well, but more important than that is how it achieves that level of performance. (…) Traditionally, thermoelectric materials are crystals. Our material is not pure crystal, and we show we can achieve the same level of performance with a material with a new atomic structure.”
It’s expected that the new material will begin to influence applications in 10 to 20 years, but in the meantime the future of this research is bright!