Nanotech Compound Helps Convert Waste Heat Into Electricity

Rock salt crystals (wlodi/Wikimedia Commons)

Researchers at Northwestern University have placed nanocrystals of rock salt into lead telluride, a compound of lead and tellurium, creating a material that can harness electricity from heat-generating items more efficiently than has been reported in the past. The results of the study are published by the journal Nature Chemistry (paid subscription required).

The new material that exhibits greater thermoelectric performance is expected to enable the conversion of 14 percent of waste heat into electricity, considered a scientific first. Chemists, physicists, and material scientists at Northwestern collaborated to develop the material. Potential sources of waste heat where this process could apply include vehicle exhaust systems, industrial processes and equipment, and sun light.

Chemistry professor Mercouri Kanatzidis, co-author of the study, and his team dispersed nanocrystals of rock salt (SrTe) into the material lead telluride (PbTe). Previous research involving nanotechnology in bulk material improved the energy conversion efficiency of lead telluride, but also an increase in scattering of electrons, which reduced overall conductivity. Kanatzidis also holds an appointment with the material sciences division at Argonne National Laboratory in Argonne, Illinois.

In this study, the Northwestern team offers the first example of using nanostructures in lead telluride to reduce electron scattering and increase the energy conversion efficiency of the material. Kanatzidis says the automotive, chemical, brick, and glass industries, as well as other industries that uses heat to make products could make their system more efficient with this discovery.

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