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Breakthrough Material Could Suck Electrical Juice From Car Exhaust, Light Bulbs

Scientists have known about pyroelectricity for years, but it's always been too inefficient to be useful. A new breakthrough changes this, making it plausible to extract power from your car exhaust.

A team at the Weinberg College of Arts and Sciences led by Mercouri Kanatzidis dispersed nanocrystals of SrTe rock salt into lead telluride (PbTe). Previous efforts in this sort of experiment have improved the electrical conversion efficiency of PbTe—a known pyroelectric material—but also blocked the free movement of electrons through the composite material, meaning they're less conductive and thus less useful as electrical power generators.

The innovation here was to figure out how to infuse the nanoscale crystals into the PbTe in a way that actually reduced electron scattering. As a result, Kanatzidis' team has produced a material that could convert up to 14% of its input heat into useful electricity.

As an upshot, they've created a relatively inexpensive way to "reclaim" some of the heat that normally goes to waste in all sorts of unexpected devices: You could adjust how electrically efficient a lightbulb is, gather power from the hot gas exhaust of a car, harness all sorts of industrial processes to act as power generators—basically anywhere waste heat is created and normally is just left to dissipate. The environmental impact of the invention (assuming the plusses are better than the eco cost of production of the material) are potentially very large.

Image of PbTe microstructure via G. Ramanath.

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