Rare Earth and Thermoelectricity
Automobiles, military vehicles, even large-scale power generating facilities may someday operate far more efficiently thanks to a new alloy developed at Ames Laboratory. A team of researchers that is funded by the DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering and the Defense Advanced Research Projects Agency, has achieved a 25 percent improvement in the ability of a key material to convert heat into electrical energy.
“What happened here has not happened anywhere else,” says Evgenii Levin, associate scientist at Ames and co-principal investigator on the effort, speaking of the significant boost in efficiency documented by the research. Along with Levin, the team included Bruce Cook, co-principal investigator; Joel Harringa; Sergey Bud’ko; Klaus Schmidt-Rohr, and Rama Venkatasubramanian, director of the Center for Solid State Energetics at RTI International in North Carolina.
Thermoelectric materials that convert heat into electricity have been known since the early 1800s. One well-established group of materials is composed of tellurium, antimony, germanium and silver, and thus is known by the acronym “TAGS.” Thermoelectricity is based on the movement of charge carriers from their heated side to their cooler side, just as electrons travel along a wire.
The process, known as the Seebeck effect, was discovered in 1821 by Thomas Johann Seebeck, a physicist who lived in what is now Estonia. A related phenomenon observed in all thermoelectric materials is known as the Peltier effect, named after French physicist Jean-Charles Peltier, who discovered it in 1834. The Peltier effect can be utilized for solid-state heating or cooling with no moving parts.
In the nearly two centuries since the discovery of the Seebeck and