Scientists at Northwestern University in Evanston, Illinois say they have found a better way to turn waste heat into electricity by improving "thermoelectric" devices.
Until now, thermoelectrics were too inefficient or expensive for widespread use.
According to a report in the latest issue of the journal Nature, a material called tin selenide has an unusual combination of properties that make it particularly good at converting heat into electric current. Tin selenide is a good conductor of electricity but a poor conductor of heat.
Scientists say the new device could be a step toward making a more efficient hybrid car that would use fuel to directly create electricity rather than the less-efficient current process of running a gasoline motor to power a generator.