Wooden floors infused with silicon and metal ions can generate enough electrical energy from human footsteps to light LED bulbs. Researchers hope that they could provide a green energy source for homes.
Some materials can generate an electrical charge when they come into contact with another such material and so are then separated, because of a phenomenon called the triboelectric effect. Electrons are transferred in one object to some other and generate a charge. Materials that have a tendency to donate electrons are referred to as tribopositive and the ones that have a tendency to receive them are known as tribonegative.
Guido Panzarasa at ETH Zürich in Switzerland and his colleagues discovered that although wood sits in the middle of this spectrum and doesn’t readily pass electrons, it is usually altered to generate larger charges. The team infused one panel of wood with silicon, which accumulates electrons on connection with an object. Another panel was infused with nanocrystals of zeolitic imidazolate framework-8 (ZIF-8), a compound containing metal ions and organic molecules, and these crystals have a tendency to lose electrons. They called this impregnation process “functionalisation”.
The team discovered that this treatment made a device that contained both wooden panels 80 times better than standard wood at transferring electrons, meaning it had been powerful enough to light LED bulbs when human footsteps compressed these devices and brought both wooden panels into contact.
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Panzarasa said: “The task is making wood that’s in a position to attract and lose electrons. The functionalisation approach is fairly simple, and it could be scalable on an professional level. It’s only a matter of engineering.”
The engineered wood was fitted with electrodes that the charge could be directed, and the team discovered that a 2-centimetre-by-3.5-centimetre sample that was put under 50 newtons of compression – an order of magnitude significantly less than the force of a human footstep – could generate 24.3 volts. A more substantial sample that was around how big is an A4 little bit of paper was able to produce enough energy to operate a vehicle household LED lamps and small gadgets such as for example calculators.
Panzarasa and his team now desire to develop chemical coatings for wood that are more green and easier to manufacture.
Journal reference: Matter , DOI: https://www.doi.org/10.1016/j.matt.2021.07.022
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