United States, China team explore energy harvesting

April 18, 2015 by Nancy Owano weblog
United States, China team explore energy harvesting
Credit: ACS Nano

Six authors have described their work in harvesting energy in a paper titled "Ultrathin, Rollable, Paper-Based Triboelectric Nanogenerator for Acoustic Energy Harvesting and Self-Powered Sound Recording." Translation: A paper microphone may help charge your cellphone. Jacob Aron in New Scientist wrote about their work; he said one benefit of such a microphone is that it could harvest acoustic energy to top up a phone charge on the go. The team, from the Georgia Institute of Technology in the U.S. and Chongqing University and Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, China, published their paper in ACS Nano last month.

The scientists developed a rollable, paper-based triboelectric nanogenerator with 125 μm thickness. It can deliver maximum power density of 121 mW/m2 and 968 W/m3 under a sound pressure of 117 dBSPL. (The amount of power the provides depends on its size, but it's around 121 milliwatts per square meter.)

What is a nanogenerator? Interviewed last year by Paul Weiss, Zhong Lin Wang of Georgia Tech said: "A nanogenerator is a device that utilizes piezoelectrics, triboelectrics, or paraelectrics, or all three of them, to convert mechanical action, thermal action, or other action into electricity for powering small electronic devices, mostly by converting mechanical energy." As for the triboelectric nanogenerator (TENG), he explained that this uses the electrostatic charge "created due to the triboelectrification process as a driving force for electron flow to an external load. Using this process today, we can achieve 55 percent energy conversion efficiency, the best so far."

Again, Aron translated what Zhong Wang of the Georgia Institute of Technology in Atlanta and colleagues actually did to their paper. "They used a laser to zap a grid of microscopic holes in the paper, then coated one side in copper and laid it on top of a thin sheet of Teflon, joining the two sheets at one edge. Sound waves vibrate the two sheets in different ways, causing them to come in and out of contact. This generates an electric charge, similar to the one made when your rub a balloon on your hair, which can charge a phone slowly."

The microphone is the size of a postage stamp. Aron said, "The amount of power the microphone provides depends on its size, but it's around 121 milliwatts per square meter. 'It can be made into any size you like,' says Wang, though he admits a stamp-sized microphone fitted to your phone would only provide a small amount of power rather than fully charging your phone."

The authors of the said it can be implemented onto a commercial cell phone for acoustic from human talking. Aron, meanwhile, also wrote about another potential application—the recycling of sound energy from the environment, where one could get "free electricity from the 'waste' sounds all around us."

The authors said the concept and design could be applied to a variety of circumstances for energy harvesting or sensing purposes. Some examples they gave would be toward wearable and flexible electronics, military surveillance, jet engine noise reduction, a low-cost implantable human ear and wireless technology applications.

Via NewScientist

Explore further: Device captures energy from walking to recharge wireless gadgets

More information: Ultrathin, Rollable, Paper-Based Triboelectric Nanogenerator for Acoustic Energy Harvesting and Self-Powered Sound Recording ACS Nano, Article ASAP, Publication Date (Web): March 19, 2015. DOI: 10.1021/acsnano.5b00618

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18 comments

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MR166
1 / 5 (4) Apr 18, 2015
Is "Recharge Your Cell Phone" some sort of code phrase that needs to be attached to every paper?

The power measurement of 117db is ludicrous considering 120 db is capable of instantanious noise induced hearing loss, 100 db is a jackhammer at 1m and long term 85db exposure can create hearing loss.

MR166
1 / 5 (5) Apr 18, 2015
I swear that you must be eligible for some sort of government grant if your paper includes "Recharge Your Cell Phone" somewhere in the body of the paper.
someone11235813
not rated yet Apr 18, 2015
I think finding a better way than bulky batteries to recharge your phone will be an instant contract worth squillions form Apple so maybe it's code for any research due to the iPhone, it could even be a paid subliminal ad.

I was thinking the same thing having as my KRK VXT6's sitting on my desk have an spl of 111 db and I'd not want them anywhere near that.
MR166
1 / 5 (2) Apr 18, 2015
Every 10 DBspl is 10x the power level. Thus at normal conversation of 60 DB this device would put out 1 million times less or about 121 nano watts /square meter. Now you have to fit this in a cell phone so it is a lot less than a square meter. So lets be generous and say the device could generate 1 nanowatt in practice.

In other words, the whole paper and research is pure BS as far as generating any real power.
MR166
1 / 5 (3) Apr 18, 2015
Papers like this just illustrate the government subsidized everything for free mentality that is pervasive in today's society. "Energy Harvesting" of things like sound or ambient RF fields is pure unadulterated BS because the power levels available to be harvested are so miniscule.
gkam
not rated yet Apr 18, 2015
Once again, the skeptics try to squelch progress, it seems.

Yeah, you folk laughed at wind and solar, too.
Jeffhans1
not rated yet Apr 18, 2015
Surface area is the key to overall absorption. Curled layers, Nonofoam substrates and similar should allow for meters of surface per square MM easily. Once computing power levels are reduced to what can be harvested at any given time, everything is essentially self powering. If you need a bit more, charge some superconductors.
MR166
1 / 5 (1) Apr 18, 2015
"Once again, the skeptics try to squelch progress, it seems.
Yeah, you folk laughed at wind and solar, too."

Gkam if you are trying to equate wind and solar to sound and ambient RF energy harvesting you are well off the mark and this huge error in magnitude of power available for a technology just highlights your ignorance and negates that any of your past claims of employment might be credible!
antialias_physorg
5 / 5 (3) Apr 18, 2015
The difference here is that it doesn't need to be vastly efficient. This is not a technology to replace power plants.
it only needs to be efficient enough to power gadgets...and gadgets are rapidly becoming more efficient. So with a bit more work inthis area and a bit mor work on gadgets coming the other way ther will be a time when the two meet.

But the main application here isn't cell phones. It's stuff embedded sensors (e.g. in roads, bridges, vehicles etc. where they monitor for microcracks). It's not a good idea to embed batteries as they have a limited lifetime and the only other alternative is a fixed powerline. With this stuff such sensors could work indefinitely and be much lower cost.
MR166
1 / 5 (1) Apr 18, 2015
"But the main application here isn't cell phones. It's stuff embedded sensors (e.g. in roads, bridges, vehicles etc. where they monitor for microcracks.)"

Well that is not what the paper claims, is it!!! This article is all about "Green Power" and the pure BS that surrounds it. How can I believe the papers that support solar and wind viability when papers like this support "Charging Your Cell Phone" from ambient sound waves?

If you want the skeptics to stop doubting the alternative power movement then stop supporting papers like this.
gkam
5 / 5 (1) Apr 18, 2015
166, you are only exposing your own ignorance. I suggest you loo up the term and see the state of the art, plus the potential advantages. Those of you not in the power field cannot discern between utility power and that for consumer products?

and: "just highlights your ignorance and negates that any of your past claims of employment might be credible!"??
------------

You have no basis for any judgment.
Tom_Andersen
not rated yet Apr 18, 2015
Hilarious.
MR166
1 / 5 (1) Apr 18, 2015
" Those of you not in the power field cannot discern between utility power and that for consumer products?"

Gkam you were the one who mentioned wind and solar as it relates to this thread!

Tell me genius, how exactly is this breakthrough going to "Charge a Cell Phone"!!!!!
MR166
1 / 5 (1) Apr 18, 2015
You know Gkam the answer is simple. IT CANNOT!!!! Admit the paper is "Peer Reviewed" BS who's only purpose is to get someone "Published" and we can end this argument like gentlemen.
betterexists
not rated yet Apr 19, 2015
I am going to get a set of Drums & beat the hell of their skins near my Cellphone Microphone....Well, I am waiting for that day!
bkregier
not rated yet Apr 20, 2015
Probably have better luck charging a cellphone through tribo-electric effects by wearing a polyester sweater.
thingumbobesquire
not rated yet Apr 21, 2015
Hmm. I think this research paper is generating more hot air than electricity...
MR166
1 / 5 (1) Apr 21, 2015
You know, if progressive "Hot Air" was a realistic energy source 97% of the papers posted on Phys.org would be superfulius.

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