Posted on 08/02/2021 6:03:43 PM PDT by BenLurkin
A team of scientists from Northwestern University and Seoul National University in Korea now has demonstrated a high-performing thermoelectric material in a practical form that can be used in device development. The material—purified tin selenide in polycrystalline form—outperforms the single-crystal form in converting heat to electricity, making it the most efficient thermoelectric system on record. The researchers were able to achieve the high conversion rate after identifying and removing an oxidation problem that had degraded performance in earlier studies.
A key application target is capturing industrial waste heat—such as from power plants, the automobile industry and glass- and brick-making factories—and converting it to electricity.
Thermoelectric devices are already well defined...but what makes them work well or not is the thermoelectric material inside. One side of the device is hot and the other side cold. The thermoelectric material lies in the middle. Heat flows through the material, and some of the heat is converted to electricity, which leaves the device via wires.
The material needs to have extremely low thermal conductivity while still retaining good electrical conductivity to be efficient at waste heat conversion. And because the heat source could be as high as 400-500 degrees Celsius, the material needs to be stable at very high temperatures. These challenges and others make thermoelectric devices more difficult to produce than solar cells.
The efficiency of waste heat conversion in thermoelectrics is reflected by its "figure of merit," a number called ZT. The higher the number, the better the conversion rate. The ZT of single-crystal tin selenide earlier was found to be approximately 2.2 to 2.6 at 913 Kelvin. In this new study, the researchers found the purified tin selenide in polycrystalline form had a ZT of approximately 3.1 at 783 Kelvin. Its thermal conductivity was ultralow, lower than the single-crystals.
(Excerpt) Read more at phys.org ...
Cool 😎
That would be nice if they could take the heat from a cell phone and channel it in to the battery.
This would be handy for wood burning stoves in off grid / grid down situations.
Then people could get more talk time by shoving their phone up their...
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