New alloy to boost energy conversion by 25 percent

WASHINGTON - Automobiles, and even large-scale power generating facilities may someday operate far more efficiently thanks to a new alloy that enables a 25 percent improvement in the ability of a key material to convert heat into electrical energy.

The alloy was developed by US Department of Energy’s Ames Lab.

“What happened here has not happened anywhere else,” said Evgenii Levin, associate scientist at Ames Lab and co-principal investigator, speaking of the significant boost in efficiency documented by the research.

So-called thermoelectric materials that convert heat into electricity have been known since the early 1800s, the journal Advanced Functional Materials reports.

One well-established group of thermoelectric materials is composed of tellurium, antimony, germanium and silver, and thus is known by the acronym TAGS.

In the nearly two centuries since the discovery of TAGS, practical applications have been limited due to its low efficiency, according to an Ames Lab statement.

All that changed in 2010 when Ames researchers found that adding just one percent of the rare-earth elements cerium or ytterbium to a TAGS material was sufficient to boost its performance.

The team is yet to understand exactly why such a small compositional change in the material is able to profoundly affect its properties.

However, they theorize that doping the TAGS material with either of the two rare-earth elements could affect several possible mechanisms that influence thermoelectric properties.