A new thermoelectric material has emerged from a University of Michigan lab. Pierre Ferdinand P. Poudeu, assistant professor of material science and engineering, has developed a material whose ability to convert heat into power is 200 percent higher.
Poudeu engineered an alloy of titanium zirconium, nickel and tin which, he says, is not very good in thermoelectric purposes in its original state. However, after introducing individual atoms of nickel (imagine how he did that) into the material, he made it 43 percent more conductive and with much better thermoelectric properties.
The nickel atoms formed what Poudeu describes as quantum dots—nanoscale structures that follow the laws of quantum, rather than classical, physics. He said that the structures are so small that lining a million would be needed for them to be visible with the naked eye.
Usually, scientists used to dope semiconductors to achieve good thermoelectric behavior, but sometimes doping the material can work against the purpose, by hampering the heat-to-electricity conversion.
“This concept is new and exciting,” Poudeu said. “We think it can be adapted to other materials as well and pave the way for improved thermoelectric materials intended for high-performance energy conversion applications.
“If we want to build generators that convert waste heat to electricity and that are capable of replacing current technology, thermoelectric materials with much higher efficiency need to be discovered. We’ll have to about double the efficiency typically achieved today.”
When they will be much more efficient than today, thermoelectric materials will be able to help cars and power plants recover some of their lost energy and will play a big role in cooling systems, because if you apply electricity to them, one side cools while the other heats up. They’re behind those portable fridges you take away in your summer vacation but need to power them from the car’s lighter socket.