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KAIST develops low-cost, large-area piezoelectric nanogenerator

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May 22, 2012

KAIST's nanocomposite piezoelectric generator produces electricity from vibrational and me...

KAIST's nanocomposite piezoelectric generator produces electricity from vibrational and mechanical energy (Image: KAIST)

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Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have created a new piezoelectric nanogenerator that promises to overcome the restrictions found in previous attempts to build a simple, low-cost, large scale self-powered energy system.

Piezoelectric materials can convert vibrational and mechanical forces from, for example, wind and waves, into an electric current. This property has been harnessed to create better microphone transducers and, in more recent years, to harvest energy from clothing, shoes, and even traffic.

Last year, a team led by Dr. Zhong Lin Wang announced it had created the world's first piezoelectric nanogenerator and, shortly after, also announced the first self-powered nanodevice complete with a wireless transmitter. Now Wang and his team have announced further progress in creating a low-cost, large-scale nanogenerator which is also simple to manufacture.

The team produced a composite by mixing piezoelectric nanoparticles, carbon nanotubes and reduced graphene oxide in a matrix of polydimethylsiloxane (PDMS). The nanogenerator was then fabricated by process of spin-casting.

"The generator is mainly made of plastics and zinc oxide, so the materials are environmentally friendly," says Wang.

Bending the nanogenerator produces a difference of potential between the two electrodes (I...
Bending the nanogenerator produces a difference of potential between the two electrodes (Image: KAIST)

Despite its relative simplicity, the composite generates a much higher power density than other devices with a similar structure and has an energy conversion efficiency of seven percent. Wang told us that if the nanogenerator were to be embedded in a pair of shoes, an average-build person could generate around 3W just by walking. For reference, that would be roughly enough to power an iPad 2 (if you wanted to power the new iPad, however, you'd have to either pick up your pace or put on a few pounds).

Preliminary durability studies have confirmed that, even after thousands of cycles in which the material was repeatedly bent and released, the nanogenerator consistently produced the same amount of electric current, with no noticeable degradation in performance.

As Wang points out, the applications of such a technology are very broad and could include biosensing, medical devices, environmental and health monitoring, defense technology, and - why not - the Internet of Things.

A Paper (PDF) detailing the findings was featured in the April online issue of the journalWiley Advanced Materials.

Source: KAIST

About the Author
Dario Borghino Dario studied software engineering at the Polytechnic University of Turin. When he isn't writing for Gizmag he is usually traveling the world on a whim, working on an AI-guided automated trading system, or chasing his dream to become the next European thumbwrestling champion.   All articles by Dario Borghino
11 Comments

Hmmm...embed them in tire treads to replace the alternator?

SteveZ
22nd May, 2012 @ 09:19 am PDT

So if the cost is low, it would be awesome for under road construction. With all the traffic we have in cities and highways, imagine all the power that could be generated. Additionally, it could assist in powering a maglev roadway system.

yinfu99
22nd May, 2012 @ 09:27 am PDT

Could these nano generators if imbedded into electric car tyres produce enough energy to charge the cars batteries as it moved? If so then there would be no need for charging points.

Cliff Estensen
22nd May, 2012 @ 10:08 am PDT

@Cliff Estensen: That would generate maybe a few hundred watts, nowhere near what a vehicle needs to sustain its motion. It would extend the life of the vehicle though, and would be a good addition to solar vehicles.

Joel Detrow
22nd May, 2012 @ 12:06 pm PDT

re; Cliff Estensen

Perpetual motion would be nice but the laws of thermodynamics say it is impossible so at the very least it would be highly unlikely. It would probably produce less energy than the increased rolling resistance would consume. Using the material in the suspension on the other hand promises benefits as would using it in motor mounts as well.

Slowburn
22nd May, 2012 @ 12:19 pm PDT

I would place them in the Ocean and let the waves do the generation for on land use

John Sweet
22nd May, 2012 @ 05:40 pm PDT

I'm with John Sweet, (you beat me to it) create an artificial reef with these to catch wave action and produce power in addition to creating a safer harbor area.

kellory
22nd May, 2012 @ 07:53 pm PDT

Artificial reefs have this problem of stuff growing things on it. I would build wave guides that channel the force of the wave into a catchment that once filled dumps the water onto this generator with a self cleaning filter so when the water recedes it flushes the filter. Think of those japanese water feature pitchers they fill up then they tip over

MasterG
23rd May, 2012 @ 01:02 am PDT

Every time I see one of those huge American flags flapping in a stiff breeze, I think, "That thing should be made of piezoelectric material". Simple and beautiful. Imagine a replacing a huge wind farm with Red White & Blue!

Matthew Bailey
23rd May, 2012 @ 09:31 am PDT

@ Joel Detrow

The laws of thermodynamics don't say perpetual motion is impossible. They say it is impossible in a closed system. Earth, however, is NOT a closed system. We are open to the entire universe. Also, earth itself is a very nearly portrayal of perpetual motion at its finest! It's been spinning for the past at least 6 billion years seemingly uninterrupted. We are floating around in a vast sea of energy, just because you're sitting at home on the couch doesn't mean the natural state of things is at rest. NOOO it's ENERGETIC, everything around you is moving at an incredible rate!! Particles on a molecular level bouncing off one another in an unlimited sea of energy which is just constantly changing states. Energy can neither be created nor destroyed; This does not account for the fact that energy is everywhere in unlimited quantities (and don't try saying in a complete vacuum there is no energy, because the Cassimir Effect proves there is always energy). Sorry for the long rant, I had hoped to share some ideas I've had for piezoelectric energy generation to add to the many fantastic ideas already thought up here!

Lining the underside of train cars, the interior walls of engine compartments in all modes of transportation as well as anything with a loud vibrating motor, lining the interior walls of large factories, lampposts in busy cities could power themselves, large buildings in city centres could line the exterior walls (would cut down on wind noise in large buildings), Lining the interior walls of server farms which are extremely loud. With regards to the server farms and engine bays and engines themselves we could build them out a revolutionary new multiferroic alloy called Ni45Co5Mn40Sn10 which converts heat directly into usable electricity via magnetics. Furthermore we could use the floating wind turbines coated with a thin layer of this and a thin photovoltaic skin to provide 3 forms of "free" electricity from just 1 product! Also forgot to mention the footprint required to tether 1 of these is the same size as the footprint needed to tether 50 of these! Thankfully there are countless ways to collect enough energy to power the worlds machines, I haven't even begun to scratch the surface on all the technologies available but can tell you, it was Nikola Tesla's work which sparked my immense interest in this subject.

Joel Bauman
23rd May, 2012 @ 12:13 pm PDT

I think you can have artificial muscles using the same effect in reverse (not sure if the materials are the same) ie you have a composite material, place a voltage across its material components and it bends into a shape "for that voltage", have them thin enough, layer them, have some low friction material between layers => extremely strong, no "moving" components, efficient (??) muscle, great for exo-skeletons, robots etc, probably dreaming here but insects i think have the highest efficiency muscle and highest ratio or power / per weight as a "motor", perhaps this is one way to get something like that.

The more you have different medium changes you have for energy => Efficiency starts plummeting, as each change in energy form (ie mechanical to heat to pressure to angular or whatever) is where I think most of the efficiency is lost at (storing energy for long periods in the same state has its own issues (ie capacitors, fly-wheels etc), but transferring it into a different form => efficiency of conversation is the main hurdle - this is where percentage lost as heat happens ) so if u can go directly from electricity to "muscle" without using cogs, chains or mechanical stuff as a lead up to the "true mechanical work" you want to do => more efficient, at least in layman theory.

Of course I could be wrong ...

Andrew Kubicki
24th May, 2012 @ 01:44 am PDT
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