Heat is everywhere around us. In the engines of our cars, in the processors of our computers, in industrial pipes. And most of it is simply wasted, dispersed into the environment. The thermoelectric has long promised to capture this lost energy, but has always been held back by a fundamental dilemma: how to conduct electricity without also conducting heat?
Now, a team led by Fabian Garmroudi of Los Alamos National Laboratory has found a surprisingly effective answer. By combining two materials With incompatible lattice structures but compatible electronic properties, the team has created a hybrid that defies the conventions of materials physics and doubles the thermoelectric efficiency. How? Let's take a look together.
The challenge of conflicting properties
Effective thermoelectric materials (solid-state semiconductors that convert heat into electricity) must conduct electricity efficiently while minimizing heat transfer. This, as noted, presents a special challenge: materials that conduct electricity well typically also conduct heat well.
How do you explain Garmroudi: “In solid matter, heat is transferred both by mobile charge carriers and by vibrations of atoms in the crystal lattice.” It’s a problem that has frustrated researchers for decades, limiting the practical applications of this promising technology.
In thermoelectric materials, we mainly seek to suppress heat transport through lattice vibrations, since they do not contribute to energy conversion.
This insight led the team towards a completely new approach, just announced in a press release. Instead of modifying a single material, why not combine two with complementary characteristics?
The thermoelectric intuition that changes the rules of the game
The innovation was born during the research stay of Garmroudi in Tsukuba, Japan, supported by the Lions Award and realized at theNational Institute for Materials Science as part of his work at theTechnical University of Vienna.
Under intense heat and pressure, he fused two distinct powders: one made from an iron-based alloy with vanadium, tantalum e aluminum (Fe₂V₀.₉₅Ta₀.₁Al₀.₉₅), and the other from a mixture of bismuth-antimony (Bi₀.₉Sb₀.₁). The result? A compact hybrid material with truly promising thermoelectric potential: once again, the most elegant solutions come from unexpected combinations.
What makes the approach particularly brilliant is that the two materials do not fuse at the atomic level. Due to their different chemical and mechanical properties, the bismuth-antimony component selectively accumulates at the micrometer-sized interfaces between the crystals of the FeVTaAl alloy. In simple words? Imagine having two completely different types of LEGO bricks that cannot fit together. When you try to join them under pressure and heat, instead of mixing and fusing completely, they remain separate. The bismuth-antimony (one type of brick) does not mix with the iron alloy (the other type of brick), but instead sits precisely in the spaces between the crystals of the iron alloy, creating microscopic “boundaries.”
It is precisely in these border regions that the magic happens: electrons can easily pass from one material to the other (good electrical conduction), while thermal vibrations are blocked (poor thermal conduction). It is like having a filter that lets electricity pass but blocks heat: exactly what is needed for record-breaking thermoelectric efficiency.
Exceeding the 50's standard
“This discovery brings us much closer to our goal of developing a thermoelectric material that can compete with commercially available compounds based on bismuth telluride,” he concludes. Garmroudi. “The targeted decoupling of heat and charge transport allowed the team to increase the efficiency of the material by more than 100 percent. "
Bismuth telluride, introduced in the 50s, is still considered the gold standard for thermoelectric materials. However, new hybrid materials offer an important advantage: they are significantly more stable and more affordable.
This breakthrough could transform the way we power the Internet of Things, especially microsensors and other miniature electronics. Imagine a future where waste heat from industrial plants, vehicles, or even the human body could be harvested and transformed into usable electrical energy.
Now it’s a real possibility thanks to this pioneering research that challenges the limits of what we thought was possible in materials physics.
