'Tribo-electric,' the buzzword of the future?

Mar 04, 2014 by Richard Ingham
A hand-held triboelectric generator for harvesting energy from human motions. Credit: Drs. Guang Zhu and Zhong Lin Wang, Beijing Institute of Nanoenergy and Nanosystems and Georgia Tech

Out at sea, gentle waves provide power for thousands of homes. In cities, dancefloor moves generate electricity for nightclubs. In the countryside, hikers use leg power to recharge their phones.

It is an alluring goal of clean, reliable power free from geo-political risks—and scientists in the United States said Tuesday it lies within reach, thanks to a smart way to harvest energy called tribo-.

Researchers at the Georgia Institute of Technology said they had built a simple prototype device that converts stop-start movement into power.

Waves, walking and dancing—even rainfall, computer keys or urban traffic—could one day be harnessed to drive sensors, mobile gadgets or even electricity plants, they contend.

Zhong Lin Wang, a professor of materials science and engineering, described the invention a "breakthrough."

"Our technology can be used for large-scale energy harvesting, so that the energy we have wasted for centuries will be useful," he told AFP by email.

"Tribo-electric" is a modern term with ancient roots—from the Greek word for "rub."

Its electricity is created from friction between two substances causing a charge of electrons to be transferred from one to the other.

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Powering spot lights through harvesting energy from tap water flow by the triboelectric generator. Credit: Drs. Guang Zhu and Zhong Lin Wang, Beijing Institute of Nanoenergy and Nanosystems and Georgia Tech

It commonly happens, for instance, when plastic-soled shoes are in contact with a nylon carpet, causing the snap of static discharge when one's hand touches a metal doorknob.

Because tribo-electric is so unpredictable, it has been generally shunned as a power source.

The preferred method has been magnetic induction—a turbine driven by nuclear- or fossil-powered steam or water.

Powering spot lights through harvesting energy from air flow by the triboelectric generator. Credit: Drs. Guang Zhu and Zhong Lin Wang, Beijing Institute of Nanoenergy and Nanosystems and Georgia Tech

But, in a new study published in the journal Nature Communications, Wang's team said they had overcome key hurdles to converting a haphazardly-generated electrical charge into current.

Their prototype comprises a disc about 10 centimetres (four inches) across, designed to show the potential from a small, portable generator moved by ambient energy.

Inside are two circular sheets of material, one an electron "donor" and the other an electron "receiver," brought together through rotary movement.

If the sheets are separated, one then holds an isolated by the gap between them.

Sandwiched between the two discs is a third disc with electrodes, which bridges the gap and helps a small current to flow.

Powering spot lights through harvesting energy from tap water flow by the triboelectric generator. Credit: Drs. Guang Zhu and Zhong Lin Wang, Beijing Institute of Nanoenergy and Nanosystems and Georgia Tech

At a top speed of 3,000 revolutions per minute, the device generated 1.5 watts.

This gave it an energy efficiency of 24 percent, three times greater than piezoelectric, the previously best source of mechanical electricity harvesting—and as efficient as magnetic-induction turbines.

It can run on a gentle wind or tap water, or "random jerky motions," including human movement, to provide the rotation, Wang said.

"As long as there is mechanical action, there is power that can be generated."

The prototype used copper for the rotator and gold for the electrodes in lab tests, but these could easily be substituted for low-cost synthetics, he said.

The team is working on ways to scale up tribo-electric energy for harvesting power from the ocean.

Explore further: Vibration energy the secret to self-powered electronics

More information: Paper: dx.doi.org/10.1038/ncomms4426

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User comments : 12

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ogvorker
2.1 / 5 (10) Mar 04, 2014
Ah, wonderful -- another free & clean energy source we will never see manifest

Are these people who think they can change the energy paradigm delusional or just ill-informed? So hard to tell...
Bonia
Mar 04, 2014
This comment has been removed by a moderator.
MR166
1.5 / 5 (6) Mar 04, 2014
"This gave it an energy efficiency of 24 percent, three times greater than piezoelectric, the previously best source of mechanical electricity harvesting—and as efficient as magnetic-induction turbines."

Says Who?

https://www.green...turbine/

I see 61% here.

It is an interesting device that may serve a purpose but I cannot see it producing kilowatts of power in any normal application.

It is obvious to me that these articles are written to fulfill government grant requirements. They received a grant to research renewable energy devices and that is how the device is presented.

vlaaing peerd
5 / 5 (2) Mar 05, 2014
the "sustainable dance floor" a project between Club Watt (nightclub in Rotterdam) and the university of Delft in 2008 showed that each person on the dancefloor is capable of generating 20W/h.

So for every 1000 people "in da club" that's a pretty nice 20Kwh!
EnricM
5 / 5 (3) Mar 05, 2014
Ah, wonderful -- another free & clean energy source we will never see manifest

Are these people who think they can change the energy paradigm delusional or just ill-informed? So hard to tell...


Yes. what a pity :_(

meanwhile in Holland people continue dancing: http://eriks.nl/n...nsvloer/

Pity that this dance floor never existed... in your alternative universe at least, in mine you can buy one of these if you have enough cash.
MR166
2 / 5 (4) Mar 05, 2014
Enric if you really think that producing energy from people walking or dancing can supply useful energy to the grid you are delusional. They will just get tired that much sooner. The same goes for generators in roads, all you will do is decrease the vehicles gas mileage by more than any energy produced.

Conventional generators are more efficient at producing power from wave or tide action.

I would like to see cheap renewable energy as much as anyone but I get really angry when people try to tell me that a device can do something that that is not practical.
indio007
not rated yet Mar 05, 2014
Smack a Tesla Turbine on this.
Jimee
not rated yet Mar 05, 2014
I know so much more than everyone else that I can't be bothered. Don't even try. Yawn
dedereu
not rated yet Mar 06, 2014
This look like a modern improved version of very old electricity made by cat skin on glass or any other things .
Rimino
Mar 06, 2014
This comment has been removed by a moderator.
dedereu
not rated yet Mar 06, 2014
There is two steps, charge difference creation which gives a constant current generator and after sliding charge separation mechanical work made against electrostatic forces between opposite charges, which can be large giving very high voltage like Van de Graaff generator if the current is large.
The reported efficiency seems a real breaktrough able to make an industrial revolution.
http://iopscience...5402.pdf
based on pyramid-patterned PDMS thin film.
It is not cear how fast is the friction wearing out, which must be very slow ???
Otherwise, too fast worn out, it will not be useful,
It must resist many billion of fast tribo friction charge separations with no degradation ????.
MR166
not rated yet Mar 06, 2014
I see this device as useful in small niche applications but it can hardly revolutionize power generation. I cannot see someone using this sort of generator to charge a personal device other than in emergencies. Also, most static generators are very sensitive to moisture so the device will have very tough packaging requirements.
katesisco
1 / 5 (1) Mar 08, 2014
Wonderful indeed! Just a bit more and we will catch up with the past! Those geometric figures on the Nazca plain, walkers recharging the energy pits!! The ley lines in Britian, again sources of electrical energy lost to us the egotistical futurists.
Of course, this was applicable during one of the long delay magnetic reversals of the sun.
Just imagine, the magnetic field Earth was imbued inside held up the water veil, and allowed the smarter us to exist on mountain tops exposed to cosmic radiation. While down below the rest of us existed in the moment like dogs (who don't have it so bad after all). Now that we are the same, all of us capable of future planning but not it seems understanding the past, we compete daily for the benefit of none.
And eye Venus greedily as each magnetic delay of the solar reversal cycle allows more energy to be expended and the 50 mile cloud deck of Venus fall onto the surface. Soon the water veil of Venus will exist and life .....
a_n_k_u_r
not rated yet Mar 10, 2014
They should embed something like this in speed breakers.

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