Study finds topological materials could boost the efficiency of thermoelectric devices

What if you could run your air conditioner not on conventional electricity, but on the sun's heat during a warm summer's day? With advancements in thermoelectric technology, this sustainable solution might one day become a reality.

Thermoelectric devices are made from materials that can convert a temperature difference into electricity, without requiring any moving parts—a quality that makes thermoelectrics a potentially appealing source of electricity. The phenomenon is reversible: If electricity is applied to a thermoelectric device, it can produce a temperature difference. Today, thermoelectric devices are used for relatively low-power applications, such as powering small sensors along oil pipelines, backing up batteries on space probes, and cooling mini-fridges.

But scientists are hoping to design more powerful thermoelectric devices that will harvest heat—produced as a byproduct of industrial processes and combustion engines—and turn that otherwise wasted heat into electricity. However, the efficiency of thermoelectric devices, or the amount of energy they are able to produce, is currently limited.

Now researchers at MIT have discovered a way to increase that efficiency threefold, using "topological" materials, which have unique electronic properties. While past work has suggested that topological materials may serve as efficient thermoelectric systems, there has been little understanding as to how electrons in such topological materials would travel in response to temperature differences in order to produce a thermoelectric effect.

In a paper published this week in the Proceedings of the National Academy of Sciences, the MIT researchers identify the underlying property that makes certain topological materials a potentially more efficient thermoelectric material, compared to existing devices.