Turning heat into electricity might sound like science fiction, but thermoelectric materials can do exactly that.
These special materials convert waste heat into usable electrical energy, making them ideal for powering tiny electronics like sensors in the growing Internet of Things.
However, improving their efficiency has always been a major challenge—until now.
An international research team led by Fabian Garmroudi has created a new type of thermoelectric material that solves a long-standing problem: how to let electricity flow easily while blocking heat.
Their work, published in Nature Communications, marks a big leap forward in the search for better, cheaper, and more stable thermoelectric materials.
In solid materials, heat travels in two main ways—through moving electrons and through vibrations in the atomic structure, known as lattice vibrations.
While the electrons help generate electricity, the vibrations only carry heat and reduce the material’s efficiency.
The goal has been to block these vibrations without slowing down the electrons.
Garmroudi and his team managed to do both by combining two very different materials. One is an alloy made of iron, vanadium, tantalum, and aluminum (Fe₂V₀.₉₅Ta₀.₁Al₀.₉₅). The other is a mix of bismuth and antimony (Bi₀.₉Sb₀.₁).
These powders were pressed together at high temperatures to form a compact material. Interestingly, because of their different physical properties, the two materials didn’t blend at the atomic level. Instead, the BiSb material settled at the borders between the crystals of the iron alloy.
This setup created an ideal effect. The mismatched structures of the two materials block heat vibrations from passing through, acting like a barrier to heat.
But since the electronic properties of the two materials are similar, electrons can still move smoothly—especially along the interfaces between the materials, where charge flows even faster.
This is thanks to a unique feature of the BiSb component called a “topological insulator,” which allows electricity to move along its surface with almost no resistance.
This clever combination more than doubled the efficiency of the material compared to previous designs. According to Garmroudi, it’s a big step toward replacing the current industry standard, bismuth telluride, which has been used since the 1950s. Unlike bismuth telluride, the new hybrid material is more stable and less expensive to produce.
Garmroudi developed the material during his research stay at Japan’s National Institute for Materials Science, working as part of a global collaboration.
With this innovation, scientists are one step closer to creating more efficient and accessible thermoelectric technology for everything from wearable gadgets to waste-heat recovery in industry.
