Microscopic Nanowires Convert Waste Heat into Electrical Energy more Effectively


A piston engine from a car. / Photo by: Getty Images


Sometimes in a thermodynamic process, released heat from a motor like a steam engine can go to waste. While certain generators can recycle some waste heat, their productivity remains low. Scientists at the University of Warwick found a better way to convert waste heat into electricity. They used atomically thin nanowires to perform the conversion in a more efficient way.

Seebeck effect is a kind of thermoelectric effect wherein a component or device converts heat directly into electrical energy. This effect is the common core function of thermoelectric generators in power plants. The generators recycle the waste heat to provide additional electrical power to the facilities. However, these machines have an average efficiency between 5 and 30 percent.

To improve future TEGs, scientists at Warwick University developed thin nanowires based on thermoelectric materials. In the study, the scientists investigated the crystallization process of tin telluride, a semiconductor, in extremely narrow carbon nanotubes.

Their investigation resulted in the formation of the templates of the thin thermoelectric nanowires. When they experimented on the conductivity of the templates, the materials showed that their conductive properties were better if their sizes were smaller. So, they systematically produced tin telluride templates with a size of one to two atoms in diameter to deliver a better thermoelectric process.

“In contrast to three-dimensional material, isolated nanowires conduct less heat and more electricity at the same time. These unique properties yield unprecedented efficiency of heat-to-electricity conversion in one-dimensional materials,” explained Dr. Andrij Vasylenko, the first author of the study from the department of physics at the Warwick.

The study findings suggest potential opportunities in creating new models of thermoelectric generators and exploring for non-toxic yet suitable materials for thermoelectrics. The materials may also be applied to automotive TEGs to improve the fuel efficiency of vehicles.