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An international team of scientists from the United States, Canada, Egypt, and Ireland has developed a snow-based triboelectric nanogenerator (TENG) that generates electricity from falls of snow. The snow-TENG, described in the newspaper Nano Energy, can produce a power density of 0.2mW / m2and an open circuit voltage of up to 8V. The unit also functions as a self-powered sensor to monitor snowfall rate, accumulation depth, wind direction and speed in snowy environments. icy.
Snow-TENG: a) to control and detect biomechanical movements by attaching a snow TENG to different parts of the human body; (b) measuring the electrical power of a TENG snow device using the snowfall mode when it is attached to (i) the shoulder, (ii) the wrist and (iii) the knee; (c-i) a photograph of the snow-TENG device assembled and attached to the bottom of a snow boot as a self-powered biomechanical sensor; (c-ii) the electrical outlets of the snow-TENG when the wearer makes different movements – running, jumping, walking and walking. Image credit: Ahmed et al, doi: 10.1016 / j.nanoen.2019.03.032.
The snow-TENG is small, thin and flexible, like a sheet of plastic, and generates loads through static electricity.
"The static electricity results from the interaction of a material that captures the electrons and another that gives up electrons. You separate the charges and create electricity from scratch, said Professor Richard Kaner, senior author, of the University of California at Los Angeles and the University of Tanta in Egypt.
The snow is positively charged and yields electrons. Silicone – a material similar to synthetic rubber composed of atoms of silicon and oxygen, associated with carbon, hydrogen and other elements – is negatively charged. When snow falls on the silicone surface, the charge captured by the device generates electricity.
"The snow is already loaded, so we thought, why not bring another material with the opposite charge and extract the charge to create electricity?" Said co-author, Maher El-Kady, researcher at the University of California at Los Angeles.
"While the snow likes to give away electrons, the performance of the device depends on the efficiency of the other material to extract these electrons. After testing a large number of materials, including aluminum foil and teflon, we found that silicone produced more load than any other material. "
"About 30% of the Earth's surface is covered with snow every winter, during which time solar panels often do not work," he said.
"The accumulation of snow reduces the amount of sunlight reaching the solar panels, limiting the power output of the panels and making them less efficient."
"The new device could be integrated into solar panels to provide continuous power when it snows."
The snow-TENG can be used to monitor winter sports, such as skiing, to evaluate and improve more accurately the performance of an athlete when he runs , walk or jump. It is also possible to identify the main movement patterns used in cross-country skiing, which can not be detected with a smart watch.
The device could usher in a new generation of self-powered portable devices to track athletes and their performance. It can also send signals indicating whether a person is moving. He can tell when a person walks, runs, jumps or walks.
The researchers used 3D printing to design the device, which features a silicone layer and an electrode to capture the charge.
"We believe that the device could be manufactured at low cost, given the ease of manufacture and availability of silicone," said Professor Kaner.
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Abdelsalam Ahmed et al. 2019. All printable triboelectric nanogenerators. Nano Energy 60: 17-25; doi: 10.1016 / j.nanoen.2019.03.032
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