Shaking around some crumpled balls of tinfoil may not seem like a very productive action. But surprisingly, it can generate enough electricity to power a small LED light. At least that’s what an experiment recently described in the journal Advanced Science shows.
The crinkled foil balls rattling around are part of a tubular contraption called a triboelectric nanogenerator that the researchers constructed to harness the energy of movement. Here, by playing with the charges generated through contact electrification and electrostatic induction (think static electricity), mechanical energy can be converted into electricity.
The first such device to use this type of physics for power comes from a 2012 study by Zhong Ling Wang from the Chinese Academy of Sciences in Beijing and his colleagues. Similar ideas, like taking the mechanical energy generated by soundwaves and turning them into power, have also been around for a decade or so.
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Since then, that idea has been iterated upon many times, with different research groups switching out the materials and trialing various designs. Such technology could have applications for smart homes, multi-purpose clothing, and other remote sensors.
This recent version in Advanced Science proposes foil balls as a way to both generate electricity but also recycle used aluminum foil that would otherwise go into the bin.
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According to the paper, this device “primarily comprises an acrylic substrate, a charge-inducing polytetrafluoroethylene (PTFE) layer, aluminum top and bottom electrodes, and crumpled aluminum foil.” The foil balls, which are positively charged, shuttle electrons from one electrode to another as they’re shaken.
This mechanism, interacting with the air around it, can produce an electric field that plays an important role in the charging and discharging cycle, seen commonly in batteries. This process can produce just a little bit of juice.
While this tiny amount of energy may never be able to power serious electronics like a flatscreen TV, it could be integrated into a light, portable charger. The researchers tested it on smaller devices like 500 light-emitting diodes (LEDs) and 30-W commercial lamps, and it performed well.
Watch the device at work below: