Perseverance, NASA’s 2020 Mars rover, is powered by something very desirable here on Earth: a thermoelectric device, which converts heat to useful electricity. On Mars, the heat source is the radioactive decay of plutonium, and the device’s conversion efficiency is 4-5%. That’s good enough to power Perseverance and its operations but not quite good enough for applications on Earth. 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. The polycrystalline tin selenide could be developed for use in solid-state thermoelectric devices in a variety of industries, with potentially enormous energy savings. 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. More than 65% of the energy produced globally from fossil fuels is lost as waste heat. https://phys.org/news/2021-08-material-ecofriendly-solution-energy.html
