Physicists Build Circuit That Generates Clean, Limitless Power from Graphene

https://news.uark.edu/articles/54830/physicists-build-circuit-that-generates-clean-limitless-power-from-graphene

by piercebot • 6 years ago

148 86 6 years ago

news.uark.edu

GRBurst• 6 years ago

Also https://phys.org/news/2020-10-physicists-circuit-limitless-p... from here https://news.ycombinator.com/item?id=24665381

Jugurtha• 6 years ago

What does 'limitless' mean, physically?

gilrain• 6 years ago

'bullshit'

Synaesthesia• 6 years ago

I think it's going to be able to essentially deliver a very small current virtually indefinitely.

simias• 6 years ago

That's how I understand it as well. It harvest the brownian motion of atoms in graphene.

I definitely don't know enough about this subject to judge the plausibility of the claim but "graphene" and "limitless power" in the same headline does trigger a few red flags.

cowpig• 6 years ago

If I'm understanding the article correctly, a very tiny piece of graphene can pick up a very tiny amount of energy from the random jiggles at the atomic scale.

Presumably, those jiggles are always going to be there, unless somehow earth becomes a cold, dead place.

So imagine the solar panel on your calculator didn't need light, just a temperature above absolute zero.

gus_massa12• 6 years ago

This is exactly what the press release say, but this is impossible due the the Second Law of Thermodynamics. So (select at least one)

1) The press release is wrong

2) The research article is wrong

3) The Second Law of thermodynamics is wrong.

[As a fast explanation, if the grapheme membrane and the lamp in the animation are at the same temperature, then the electrons in the lamp will get an equivalent amount of random jiggles and will counter the effect described in the article. (There may be also a similar problem with the diodes, capacitor, etc.)]

aduitsis2• 6 years ago

Naive question, wouldn't this (converting Brownian motion into electricity) violate the 2nd law of thermodynamics?

(edit, this is explicitly addressed further in the article: That's an important distinction, said Thibado, because a temperature difference between the graphene and circuit, in a circuit producing power, would contradict the second law of thermodynamics. "This means that the second law of thermodynamics is not violated, nor is there any need to argue that 'Maxwell's Demon' is separating hot and cold electrons," Thibado said.)

jl2718• 6 years ago

This sounds like a mangled explanation. It seems to me, somewhat naively, that the resonator must be held at a higher temperature than the rest of the circuit to produce work on the load.

aduitsis2• 6 years ago

I think some minuscule amount of energy is taken from the thermal bath (the environment is considered a thermal bath - you can take heat from it and it's so big its temperature won't budge), converted into electricity and then back to heat in the load resistor. They all remain in the same temperature if I'm not gravely mistaken.

xt002• 6 years ago

It’s more like “limitless power from heat transferred into graphene from an external power source”. So it’s a special type of a thermo electric generator basically.

ssivark• 6 years ago

Thank you; awful title.

ArtWomb• 6 years ago

Only in the load resistor. Electron flux in the graphene membrane appears to be solely due to geometry. This curvature does not necessarily need to be buckled via heat energy. It could be mechanical or electrical, if I understand things correctly...

More detail in this video clip with UArk's Paul Thibado:

https://www.youtube.com/watch?v=wrleMqm3HiU

I think what this research opens up is the possibility of "optimal" harvesting. There is some resonant frequency, some circuit configuration yet to be discovered that is perhaps self-sustaining. They've chosen "stochastic thermodynamical" circuits because its low hanging fruit. But it seems really exciting to me. Almost like a third class of energy production after solar and hydrogen (where 99% of research funds are allocated). Ocean wave energy harvesting perhaps?

In any case, congrats to the researchers on their painstaking hard work ;)

Fluctuation-induced current from freestanding graphene: toward nanoscale energy harvesting

https://arxiv.org/abs/2002.09947

IgorPartola3• 6 years ago

This does sound promising. Is it possible to run this process in reverse a la a heat pump to create an AC with no moving parts? Or is this purely a one way process?

keanebean86• 6 years ago

Could they add this to waste heat pipes in power plants to extract more energy?

xt002• 6 years ago

Yea that video is helpful and it looks like mechanical energy or thermal could be used to deform the graphene film to do some work on that film which them stores it. So it seems like what’s happening is that thermal energy is being used to put energy into the free standing graphene lattice. Then as it extends in length due to the film heating, it stores energy almost like inflating a balloon, then it touches one of the electrodes nearby and the electrons in this unique material transfer charge to the other electrode and causes the film to contract so a portion of the charge was transferred away, and it contracts then can repeat the process. So it’s a small motor that harvests either mechanical or thermal energy. But given the tiny size, it would seem like thermal might be the dominant thing since the membrane would probably need some sort of mass to benefit from random movements. Or the graphene would need to be extremely flexible. But not totally sure..

WORLD_ENDS_SOON• 6 years ago

I'm completely out of my area of expertise here (I can mostly follow the press release but I can't understand that much of the actual paper outside of the introduction), but your comment about resonant frequencies reminded me of of some recent research on layering graphene at a "magic angle" to produce special fractal moire patterns that have special physical properties. I wonder if that work can be combined with the work here. To a non expert like myself, it seems like there is a lot of really exciting research in this area at the moment.

vitus• 6 years ago

In the 1950s, physicist Léon Brillouin published a landmark paper refuting the idea that adding a single diode, a one-way electrical gate, to a circuit is the solution to harvesting energy from Brownian motion. Knowing this, Thibado’s group built their circuit with two diodes for converting AC into a direct current (DC).

So, they built a full-wave rectifier (albeit with only 2 instead of, say, 4 diodes)? Pretty neat to see electrical engineering fundamentals at work.

(also, for any who wanted specifics: article is at https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0... ; abstract contains a couple of circuit diagrams)

edit: updated link, thanks for pointing that out

yourapostasy2• 6 years ago

Remove the semicolon at the end of the above link to get to the actual journal paper; paper is behind the APS paywall.

Working link for the lazy:

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...

nayuki• 6 years ago

Is this based on the physics of the Seebeck effect to generate a voltage from a temperature difference? https://en.wikipedia.org/wiki/Thermoelectric_effect#Seebeck_...

kwhitefoot• 6 years ago

If this is representative of press releases from universities it's no wonder that people can't tell the difference between free energy scams and real physics.

Sounds like nonsense to me but the article is so badly written that it's hard to tell. In fact it is hard to be sure whether they have actually created a prototype or merely simulated it.

tgsovlerkhgsel• 6 years ago

If this is representative of press releases from universities

If you want reporting that accurately represent science, in my experience, the university press releases are even worse than the worst mainstream shit-tier media.

gspr• 6 years ago

It's super sad. My boss was once at the center of one of these big press release splashes at the university I worked. She said it was almost more of a burden than a boon, because the attention it attracted was almost all of the wrong kind. And among the right kind of people, she had to spend time and effort excusing the embarassing and ridiculous press release.

I wonder if universities understand that they're sometimes harming their own people with these things.

barney54• 6 years ago

The incentives for the PR team is to make news. They don’t have to spend a ton of time cleaning up the mess of misleading press releases.

vsskanth• 6 years ago

I am guessing the clickbait title is to make the article widely shared and attract funding.

Probably have to read the journal paper to get accurate details.

PicassoCTs• 6 years ago

In all honesty funding is given by institutions and people who evaluate the goal they spend there money on. So this sort of attention gathering, should be pre-filtered out by all serious sources of funding.

So what remains is a prestige, attention metric of the university.

karaterobot• 6 years ago

It's kind of funny that the person writing the press release thought it was their job to just spice up the headline a little bit by claiming they'd discovered a source of unlimited clean energy.

tsimionescu• 6 years ago

The idea of harvesting energy from graphene is controversial because it refutes physicist Richard Feynman’s well-known assertion that the thermal motion of atoms, known as Brownian motion, cannot do work. Thibado’s team found that at room temperature the thermal motion of graphene does in fact induce an alternating current (AC) in a circuit, an achievement thought to be impossible.

So it sounds like, if this really works, it may have some impact on our general understanding of thermodynamics or the properties of Brownian motion?

gus_massa12• 6 years ago

If it works as described in the press release, this is a direct trip to Stockholm to pick the Nobel Prize. I can't read the research paper now.

My guess is that there is a temperature difference between the grapheme and the resistor. In that case it's a normal experiment, perhaps with some tweak, but not a groundbreaking experiment. The power generated by the device is tiny (not "unlimited"), and there are a lot of similar devices.

Sometimes the experiment is interesting in some niche (this experiment is related to tunnel microscopy) but this is totally overhyped.

Animats• 6 years ago

If it works as described in the press release, this is a direct trip to Stockholm to pick the Nobel Prize.

There are too many PR announcements like that in the nanotechnology and battery areas. It's either Nobel Prize material or nothing, and you can't tell from the article.

No power numbers. Are they talking about generating a picowatt or something like that?

Somebody like EVworld should publish "1, 5 and 10 years ago today in energy announcements".

zaroth• 6 years ago

So apparently this is the “small device eliminates need for AC” that I see advertised everywhere! </s>

But in all seriousness, it seems this converts ambient heat (not a heat differential) directly into electricity. Therefore it must necessarily cool its surroundings by the equivalent energy extracted?

So it’s a kind of air conditioner which doesn’t use electricity to move heat but rather converts heat directly to electricity? I thought we “knew” this was impossible...

philplckthun• 6 years ago

“People may think that current flowing in a resistor causes it to heat up, but the Brownian current does not. In fact, if no current was flowing, the resistor would cool down,” Thibado explained. “What we did was reroute the current in the circuit and transform it into something useful.”

Based on this I understood that it'd indeed cool down and create a heat gradient if it wasn't doing any work, but the difference it'd create is instead used to induce a current, which means it probably wouldn't cool down as long as that potential is used in this way instead (?)

Mountain_Skies• 6 years ago

If it works, it'd be a great cooler for electronics that could put back into the circuit some of the electricity that had been turned into heat. CPU and GPU coolers could become built into the structure of the ICs themselves.

bencollier49• 6 years ago

So how much energy would you harvest by using these en masse to reduce the temperature of the earth by around 2.5 degrees centigrade? (I appreciate this is highly unlikely to be possible).

kossTKR• 6 years ago

Can this be scaled up to provide power that isn't just a gimmick in the grand scheme of things?

r-bryan• 6 years ago

Without getting all quantum about it, it seems to work by configuring the graphene as one electrode (or both) of a capacitor. As the graphene flaps in the breeze (actually Brownian motion, I assume), the changing geometry will change the capacitance. If there is a charge on the cap, then the voltage would flap too, inversely (Q = CV). A changing voltage would tend to push about a current (i.e. charge motion). If their diodes somehow have a negligible forward voltage drop, then brief moments of higher voltage on the flappy cap would push increments of charge onto the storage cap (the one to the right of the diodes) until the storage cap voltage rose to equal the peak flappy voltage (minus the diode voltage drop). When the storage capacitance is greater than the flappy graphene capacitance, the stored energy will be greater than the tiny increments (energy = 1/2 CV^2). Then every so often the storage cap could be switched to drive some load.

So why would there be a charge in the flappy capacitor? Well, a bias voltage is applied by this battery in the circuit. Ahem, before invoking any principles of thermodynamics, I'd like to see some detailed measurements, or even careful theory, of the current out of the battery and back into the battery, particularly w.r.t. the instantaneous voltages (P = VI), to prove that the time-average power delivered by the battery is precisely zero, or at least far lower than that putatively transferred to the load (light bulb in the animation). Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.

There is some precedent for semiconductor thermal magic in the Peltier junction. It makes one end colder and the other end hotter by applying electric watts to it, with no moving parts aside from the electrons and holes recombining, or something. But nobody sees thermodynamics being violated or extended there.

But here the magic is to take away thermal energy from one place, the flappy graphene (thereby cooling it) and moving the energy to the light bulb (thereby heating it). It seems you could then use any old heat engine to extract work by letting the heat flow from the resulting hotter place back to the colder place, getting "limitless power" for free from your perpetual motion machine. Conceivably it's a sort of heat pump that gets some multiplier above the battery power. But I think the burden of proof is on the Arkansas folks to explain how this can be. If I had more energy (no pun intended, really) right now I'd try to find the paper that the press release is based on, to see if there's a little more truth there.

Meanwhile, I doubt it.

MauranKilom2• 6 years ago

Otherwise it's behold, we found a high-resistance path for our battery to run a light bulb.

It's like a nano Rube Goldberg!

Paper is here btw: https://arxiv.org/abs/2002.09947

sradman• 6 years ago

The abstract of the paper Fluctuation-induced current from freestanding graphene [1]:

At room temperature, micron-sized sheets of freestanding graphene are in constant motion, even in the presence of an applied bias voltage. We quantify the out-of-plane movement by collecting the displacement current using a nearby small-area metal electrode and present an Ito-Langevin model for the motion coupled to a circuit containing diodes. Numerical simulations show that the system reaches thermal equilibrium and the average rates of heat and work provided by stochastic thermodynamics tend quickly to zero. However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath. The exact power formula is similar to Nyquist's noise power formula, except that the rate of change of diode resistance significantly boosts the output power, and the movement of the graphene shifts the power spectrum to lower frequencies. We have calculated the equilibrium average of the power by asymptotic and numerical methods. Excellent agreement is found between experiment and theory.

[1] https://journals.aps.org/pre/abstract/10.1103/PhysRevE.102.0...

mannykannot5• 6 years ago

"However, there is power dissipated by the load resistor, and its time average is exactly equal to the power supplied by the thermal bath."

As the "thermal bath" is supplying power, this seems consistent with it being a Carnot-equivalent heat engine.

There is certainly nothing in physics that prevents the extraction of energy from an environment in which the temperature fluctuates - devices that do so to keep mechanical clocks running indefinitely have been around for some time.

http://atmosadam.com/howitworks.html

gus_massa12• 6 years ago

The clock in your link uses the temperature fluctuations, for example if it hot during the day and cool during the night. So you can have a flux of heat from the hot part to the cold part, and extract a small part as useful energy.

If we take the press release at face value, in this device there is no difference of temperature. So if the Second Law of Thermodynamics is correct it is not possible to extract some useful energy to do something interesting, like turning on the lamp in the animation.

gus_massa12• 6 years ago

Ignoring the horrible horrible horrible title ...

This can only work if there is a temperature difference between the grapheme membrane and the load resistor (the lamp in the animations). Other wise, it breaks the Second Law of Thermodynamics.

The problem is not that it breaks some remark from Feynman, the problem is that if there is no temperature difference, it breaks the Second Law of Thermodynamics and in particular an example in an explanation of Feynman.

ag56• 6 years ago

Doesn’t the article explicitly say that is not the case?

Though the thermal environment is performing work on the load resistor, the graphene and circuit are at the same temperature and heat does not flow between the two.

I’m not a physicist or even an educated layman, can you explain your comment more?

gus_massa12• 6 years ago

I read that part a few times, but it makes no sence.

I prefer another quote

What we did was reroute the current in the circuit and transform it into something useful.

Let's suppose that they get some "useful" energy to turn on the lamp like in the animation or power a small device.

Let's suppose that you use it to power a laser and send a beam that heat some object far away. As a side effect, you are extracting energy from the device with the graphene in the lab so it will get cooler.

So the net effect is that the device in the lab gets cooler and the object far away get hotter. So you have a flux of heat. But if the other object is hotter, you have a lux of heat from in the wrong direction, that is impossible according to the Second Law.

There are a million ways to rewrite this https://en.wikipedia.org/wiki/Second_law_of_thermodynamics in more abstract or more concrete ways. With some oversimplifications, another is that you need at least two heat baths and the efficiency of the device to transform heat from the "hot" bath to of "useful" energy can be calculate using the temperatures of the baths. When the difference of temperature is zero, the efficiency is zero and the device can produce no "useful" energy. Or in other words, with only one heath bath, you can produce no "useful" energy.

wongarsu• 6 years ago

At least it doesn't break conservation of energy. The second law of thermodynamics is already kind of suspect in that random fluctuations break it all the time on a microscopic level. It's closer to a statistical observation.

Turning heat into usable energy without temperature differential is still an extraordinary claim that demands extraordinary evidence, but I wouldn't dismiss it out of hand

blablabla123• 6 years ago

The second law requires to take the average over a sufficiently long amount of time though.

sandworm101• 6 years ago

So it converts heat into work without a temperature gradient? That is the real revolution. I wonder if this could scale into a cooling solution for chips.

itsshreyarora• 6 years ago

I read the words "limitless power" and assumed it is crap. In case it it not, please reply to this comment, and I will give the article a read. There is no reason for you to do this, but thanks in advance, kind strangers.

wtracy• 6 years ago

The article is indeed garbage.

It smells like there's actually some interesting research being done here using graphene to extract energy from the ambient environment (possibly harvesting the work done as the graphene expands during hearing?) but the press release was written by someone who does not understand the subject at all.

wolfi1• 6 years ago

this is the doi of the paper: https://doi.org/10.1103/PhysRevE.102.042101

andi9992• 6 years ago

If the title of this post were true, the paper would have been published in nature instead.

jostmey• 6 years ago

While I share your disappointment in the quality of the press release, Nature is by no means the bar for measuring significance. I've been both accepted and rejected by Nature, I've seen colleagues accepted and rejected by Nature, and I've found results published outside of Nature, Cell, Science more reproducible!

andi9992• 6 years ago

I fully agree. But I still think if you could show violation of 2nd maw of thermodynamics and potentially solving all of human energy needs, I believe you would submit it to nature (or science). At least as signaling for getting funding for your trillion dollar startup commercializing the result.

stephc_int13• 6 years ago

Isn't it some kind of antenna?

I might be completely wrong here, but I don't see that much of a difference, antennas are also "harvesting" power in some ways.

Physicists Build Circuit That Generates Clean, Limitless Power from Graphene

Related Stories