Someday, you may be able power your electronics just by moving around. A new nanogenerator that acts like a second skin and harvests energy from human motions can easily generate enough power to light 20 small LEDs.
at the Chinese Academy of Sciences in Beijing and her colleagues built a specialised material out of a layer of hydrogel sandwiched between a stretchy plastic material called elastomer, and then coated in silicone rubber to keep the hydrogel from drying out. The final bonded material is just under 0.4 millimetres thick and almost transparent.
To generate energy, the material is pressed up against skin. Electrons flow from the skin into the lower elastomer layer, pushing positive ions through the hydrogel and into the upper elastomer layer. When the material is bent or stretched and then released, the movement of oppositely-charged layers creates an electrical current.
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The nanogenerator can provide up to 135 milliwatts of power per square metre of plasticky material. It would take about 40 hours to completely charge an iPhone using a metre of generator material at peak power production.
Do the twist
The researchers were able to light 20 small green LEDs with electricity from the material just by pressing, stretching, bending or twisting it.
It could be used in wearable tech such as shirts with soft circuits integrated into the fabric, but first the size requirements will have to be scaled down, says at Queen鈥檚 University in Ontario, Canada. Wearing a square metre of this tight and nonbreathable material would be uncomfortable, let alone the few square metres you鈥檇 need for most practical applications.
If the researchers can scale it down, Vertegaal says that it could have biomedical uses as well. 鈥淵ou could make a bandage that generates its own electricity and also has some kind of interface with the skin that allows it to sense something like your blood pressure,鈥� he says.
ACS Nano
Read more: Radio powered by your own sweat hints at future of wearables
