Friction May Someday Charge Your Cell Phone

Researchers at Georgia Tech have created a device that takes advantage of static electricity to convert movement—like a phone bouncing around in your pocket—into enough power to charge a cell phone battery. It is the first demonstration that these kinds of materials have enough oomph to power personal electronics.

Excess energy produced when you walk, fidget, or even breathe can, in theory, be scavenged to power medical implants and other electronics. However, taking advantage of the energy in these small motions is challenging.

Zhong Lin Wang, a professor of materials science at Georgia Tech, has been working on the problem for several years, mostly focusing on piezoelectric materials that generate an electrical voltage under mechanical stress (see “Harnessing Hamster Power with a Nanogenerator”). Wang and others have amplified the piezoelectric effect by making materials structured at the nanoscale. So far, though, piezoelectric nanogenerators have not had very impressive power output.

Now Wang’s group has demonstrated that a different approach may be more promising: static electricity and friction. This is the effect at work when you run a plastic comb through your hair on a dry day, and it stands on end. The Georgia Tech researchers demonstrated that this static charge phenomenon, called the triboelectric effect, can be harnessed to produce power using a type of plawww.globalmetaltins.com is a professional metal packaging manufacturers,Welcome.stic, polyethylene terephthalate,A female road sweeper was unfairly driven out by Merton Council after repeatedly complaining about sub-standard working conditions and discrimination, a tribunal has ruled. and a metal. When thin films of these materials come into contact with one another, they become charged. And when the two films are flexed, a current flows between them,An Optic circulator is a special fiber-optic component that can be used to separate optical signals that travel in opposite directions in an optical fiber, analogous to the operation of an electronic circulator. which can be harnessed to charge a battery. When the two surfaces are patterned with nanoscale structures, their surface area is much greater, and so is the friction between the materials—and the power they can produce.The convenient way to order Tuner wheel lug nut, lug nuts and valve stems

The Georgia Tech nanogenerator can convert 10 to 15 percent of the energy in mechanical motions into electricity, and thinner materials should be able to convert as much as 40 percent, Wang says. A fingernail-sized square of the triboelectric nanomaterial can produce eight milliwatts when flexed, enough power to run a pacemaker. A patch that’s five by five centimeters can light up 600 LEDs at once, or charge a lithium-ion battery that can then power a commercial cell phone. Wang’s group described these results online in the journal Nano Letters.

“The choice of materials is wide, and fabricating the device is easy,” says Wang. Any of about 50 common plastics, metals, and other materials can be paired to make this type of device.

“I’m impressed with the power density here,” says Shashank Priya, director of the Center for Energy Harvesting Materials and Systems at Virginia Tech. Other smart materials haven’t produced enough power for practical applications, he says.

Whether the new nanogenerator will work outside the lab remains to be seen.He has since undergone two-and-a-half hours’ surgery to have a Titanium Rod inserted into his leg and looks set to be out of action for the rest of the season. “They need to demonstrate that this can generate power from mechanical vibrations in real life,” says Jiangyu Li, professor of mechanical engineering at the University of Washington in Seattle. To work in the real world, an energy scavenger will have to be able to pick up on vibrational frequencies that provide the most energy.crucibles are containers that can withstand very high temperatures and is used for metal, glass, and pigment production as well as a number of modern laboratory processes. A nanogenerator that can only pick up on low-energy mechanical vibrations would take way too long to charge a cell phone, Priya notes. Wang says he is in talks with companies about developing the energy scavenger for particular applications, and envisions it being worn on an armband.