Heat-to-electricity materials advance

PASADENA, Calif., May 4 (UPI) -- New materials hold the promise of efficiently converting waste heat, such as from auto exhaust, into electricity, researchers say.

Jeffrey Snyder and colleagues from the California Institute of Technology report in the journal Nature this week they altered the chemical composition of materials to boost their thermoelectric efficiency.

Most thermoelectric materials have a "figure of merit," a measure of overall performance, of less than 1, while values of 1.5 or higher are needed for many applications. These higher values can be reached by nanostructuring, but Snyder's team achieved similar gains more simply by carefully controlling the composition of a bulk material.

They say they engineered the desired combination of thermal and electrical properties into an alloy of lead, tellurium and selenium, producing a substance with a thermoelectric figure of merit of 1.8.