The future of easy cell phone charging: static electricity?

Researchers have been looking for a way to harness the energy in our movements to power our devices. A new way of harvesting friction and static electricity may be the key.

There's been a lot of talk of capturing the energy we create while doing every tasks (such as typing on your cell phone or rolling your suitcase ) to power things.

While it seems like these actions could provide an endless supply of power for our devices, the problem is that they don't provide enough electricity to really give our phones the juice they need.

But a new breakthrough could power your phones with static electricity and friction.

How it works

The professor who's been working on this problem, Zhong Lin Wang, a professor of materials science at Georgia Tech, started by focusing on "piezoelectric" materials. These are the materials that can create energy from things like typing on your cell phone or rolling your suitcase. But because of their low power output, Wang instead turned to the triboelectric effect (commonly called static electricity).

The way he captures the energy is by using thin films of a type of plastic called polyethylene terephthalate and a metal. When put put in contact with each other, they become charged, and flexing them created a current that can be used to charge a battery.

The trick to boosting the amount of power they produce is to pattern the surface of each with nanoscale structures, which increases the amount of surface area of the two materials and also raises the friction level.

The nanogenerator he developed can convert up to 15% of the energy in motion into electricity, but Wang estimates that thinner materials could get a conversion rate of 40%. This would make it possible for a fingernail-sized square of the material to power a pacemaker, and a two-inch-by-two-inch square could charge a cell phone.

Another benefit is that you could use any number of about 50 common plastics, metals or other materials to make this device.

“I’m impressed with the power density here,” Shashank Priya, director of the Center for Energy Harvesting Materials and Systems at Virginia Tech, told Technology Review.

But whether or not this will work outside the lab is still a question: a real-life version would need to pick up high-energy vibrations. A nanogenerator that can only grasp low-energy vibrations will take too long to charge a cell phone.

Technology Review reports, "Wang says he is in talks with companies about developing the energy scavenger for particular applications, and envisions it being worn on an armband."

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via: Technology Review

photo: Pieter Kuiper/Wikimedia

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