A manufacturing process that produces long strips of high-quality graphene | Hacker News Reader

A manufacturing process that produces long strips of high-quality graphene

news.mit.edu

257 pointsfahd77756 comments

Many applications of Graphene are already on the market (ex. lighter and stiffer bicycle frames, bicycle tires, sports equipment, electronic inks and paints etc). However, these are based on lower quality Graphene powders or nanoplatelets (essentially a commodity at this point) which are used as an additive to a starting epoxy or resin material.

Chemical Vapor Deposition (CVD) is the method used to produce the highest quality graphene (usually on Copper). Several companies (Graphenea etc) have scaled up CVD and continue to work towards much lower $ / m^2 targets in the near future.

The main challenge in the industry is currently the transfer step. Current methods to transfer Graphene from growth substrate to target substrate are inefficient and not amenable to high volume manufacturing.

"Roll to Roll" (what the paper is referring to) aims to solve this - companies like Samsung, LG, and Sony have been exploring Roll to Roll systems for flexible electronics/display applications.

After flexible applications, the next step is to enable CMOS compatibility / transfer to Silicon wafers. I'm the co-founder of a company in Austin that is working towards this.

Thanks for making this very informative comment! It was very interesting.

Can you give an insider's perspective on graphene's supercapacitor applications, if any? What does it mean in practice?

I realize given your disclaimer at the end if there are those kinds of applications you will want to promote them versus listing shortcomings, but if you would at least allude to the shortcomings too I would really appreciate the honesty: I saw a lot of articles about its supercap applications when graphene began to be synthesized but haven't heard much since (and it's not in your short list in your first sentence at all).

In theory, you achieve high power and long charge-discharge lifetimes with graphene-based supercapacitors

The Graphene Flagship is focused on developing methods for combining few-layer graphene and silicon nanoparticles to obtain high performance silicon-graphene anodes.

These new methods need to be cost- effective, scalable and compatible with commercial battery electrode fabrication methods (current bottlenecks). Progress continues to be made in scaling up capacity and size. Flexible graphene supercapacitors were on display at the recent Mobile World Congress

You might've seen this from Samsung - https://news.samsung.com/global/samsung-develops-battery-mat...

Thanks!

How do these low quality graphene products you mentioned compare to carbon fiber?

And How does graphene compare to carbon fiber in general? Will we make airplanes and spacecraft out of it someday?

Vs. Carbon Fiber, it depends on the application and intended use case

Re: aerospace, from a recent report, "Graphene can give multifunctional benefits to composites, including increased mechanical properties and conductivity. To protect against lightning strikes, the composite structures of aircraft contain metal meshes or have embedded conduc- tive wires. Graphene-containing composites could provide lightning-strike protection with the advantage of a simplified production process and weight reduction.

This year, a team comprising engineers and scientists from Airbus, Aernnova and Grupo Antolin have developed a prototype aircraft component using a graphene- based composite material. A section of the horizontal tail plane leading edge (HTPLE) of the Airbus A350 XWB was manufactured using industry standard resin transfer moulding of a graphene-based composite. The performance of this prototype compo- nent will be validated through electrical, mechanical and impact testing during the Core 2 phase."

How large is the "crowd" in the field (companies, research labs, conferences) ?

EU's biggest research initiative is the Graphene Flagship - https://en.wikipedia.org/wiki/Graphene_Flagship

Major Conferences - Graphene Week, Mobile World Congress (Barcelona + SF), National Graphene Association (inaugural conference was Oct 2017)

Major universities in the US - UT Austin, UPenn, MIT, Stanford, Rice, Berkeley. Lot of activity in Korea, Japan, and China

Companies - Various companies on growth side. Lot of companies doing work in composites and coatings. Various startups looking into supercap, audio, sensor, battery, and water filtration applications

My Materials Engineering Undergrad thesis (in 2010) was on synthesizing graphene for Li-Ion battery applications. It was interesting stuff at the time but I haven't kept up with the research. Our lab was using ESRP (electrostatic spray reductive precipitation) I'm sure by now a lot of other better techniques.

All I can really remember from my thesis was I had a throwaway line describing graphene as a single layer of hybridized SP2 Bonded carbon atoms and examiner spent what felt like 15 mins of my allotted defense time grilling me about it (in reality it was probably only 1 or 2 mins but I was so freaking nervous at the time felt like it was dragging on forever)...

there an english dude on youtube, robert murray smith, he setup a "little" lab then factory to produce storage using graphene or close. <hyperbole>Caps and the likes. Do you know him ? I wonder how good he can be with his reduced size operation.

> Several companies (Graphenea etc) have scaled up CVD and continue to work towards much lower $ / m^2 targets in the near future.

What is the approximate commercial cost of CVD-produced graphene sheets?

https://www.graphenea.com/collections/graphene-products/prod...

Wow, cool. I imagine in volume it's within a factor of two or so of that?

Nordic?

One of the applications for graphene membranes that I am watching for are large scale desalination plants. It has been shown to work for small membranes and if you had enough surface area you could build a desalinator that was using not much more energy than the energy to pump the water around.

It looks like maybe a factor of 3 or so energy efficiency improvement is available for desalination. Current efficient processes are around 3kWh/m³†. The thermodynamic limit is about 1kWh/m³‡. That can be improved a little if you pump more seawater, there is a tradeoff there.

Treatment of fresh water is around 1kWh/m³, so it gets into the ballpark for freshwater treatment, though I presume some of the freshwater treatment needs to be performed on the desalinated seawater.

This places seawater as an equal to river or lake water for watering humans, but still expensive for watering crops; at 1kWh/m³, there would be about $1.50 of water in a $3.50 bushel of corn.

␄

† wikipedia: https://en.wikipedia.org/wiki/Desalination#Energy_consumptio...

‡ About page 12 of this presentation: http://www.nwri-usa.org/documents/Elimelech_000.pdf

At ~10-15 m^3 per bushel (2000 - 3000 gallons) the lowest cost intermittent electricity is under 2c/kwh. So that's closer to 20-30 cents per 3.50$ bushel of corn for energy at minimum. Though presumably there would be many other costs on top of pure energy especially if you are not operating 24/7.

https://electrek.co/2017/11/16/cheapest-electricity-on-the-p...

Primarily the concern was "drinking water" for people aka the urban water requirement (which includes drinking, washing, cooking, sanitation, and urban scale irrigation)

I suppose it helps the seasteading picture as well but I haven't really thought much about that.

Mostly if you can disconnect urban water planning from agricultural water planning it allows you to do things differently. Especially when it comes to water transport projects for coastal cities.

Wow, that's a great presentation.

I wonder how one can stumble upon more presentations/summary reports like that on current state of other globally important issues.

How would you dispose of this stuff? I presume it doesn't decompose. Mind you, there's not high volume any time soon. I only curious about lifecycle.

It should burn pretty cleanly (as it's just carbon), but who knows what it would be mixed with in an actual application. Could be mixed with all kinds of plastics and resins that are nasty when burnt.

Graphite is "just carbon" too, but you cannot simply burn it by putting a lit flame to it -- it's simply not hot enough to combust it. To put it in perspective, graphite is frequently used as a crucible to melt aluminum in. Aluminum won't melt in your home fireplace (it's not hot enough), but graphite crucible will easily hold molten aluminum without combusting itself.

Graphite is also used to make rocket exhaust nozzles; it is really thermally stable stuff. Diamond by contrast is much easier to burn. The good news is that if you want to dispose of graphene, just stick it with a lot of other graphene and make pencils. It’s not as though we worry about disposing of pencil “leads” after all.

It should burn with all the side products of most artificial carbon chains (aromatics and poisonous carbon oxides). Those aren't hard to deal with, but don't expect it to burn cleanly.

It should also be hard to burn. It will probably require some water vapor to burn at all, and do it slowly.

I'm not sure I understand how you arrived at your first point. It seems to me that at a suitable temperature and oxygen content atmosphere, it should burn about as clean as natural gas. Why would you expect otherwise?

I also do not understand your second point. Surely, it is oxygen that is the missing ingredient in the burn rather than water vapor. What does water vapor provide to increase the rate of combustion?

About the first point, you are expecting total combustion of a solid. That is hard to achieve. By your theory coal should also burn cleanly, and it evidently doesn't.

With enough temperature and a high oxygen pressure, graphene will burn cleanly. But also will your furnace, and my bet is that both will do so at roughly the same temperature and pressure.

About the second point, oxygen does not react well with graphite because it's entire surface does not let its electrons go very easily. Graphene has similar properties. Water does catalyze the burning of graphite, it may very well do that to graphene too.

Coal has lots of other stuff mixed in to carbon: notably sulfur, and up to 10% of non-burning minerals (ash), often containing significant amounts of radioactive uranium and thorium.

Pure carbon (as in graphene) should burn much more cleanly, provided abundant oxygen.

Why dispose them? They’re a great carbon sink and as long as we don’t make short graphene chains I think they’re also not toxic for the environment. The process described uses methane (greenhouse gas) and if the process would be done with renewable energy it could even perhaps be carbon negative?

Good point. Could it be e.g. reused as a structural element, or some kind of filling (e.g. for roads)?

Yes, there are some papers that suggest that adding graphene-like elements to for example concrete will make them stronger. I think that if we can find a carbon neutral process of creating graphene it could be a great additive and a carbon sink (finally making a useful product out of carbon). It can even be used to detect damages in concrete (electrical resistivity value reduces at maximum compressive load). Here is an interesting paper: www.mdpi.com/2071-1050/9/7/1229/pdf but there are more applications once you start looking.

Essentially paper with microscopic layer of 'ink' on it. Easier to dispose of than office paper I think.

Space elevators?

Not viable, graphene isn't strong enough.

Sources? Googling only returns a bunch of random threads with people insisting it's possible.

In theory any molecule that looks like a graphite layer should be enough. In practice there are plenty of concerns about the stability of the ones that aren't rolled into tubes (and some concern about those later ones too).

The result is, you'll see plenty of calculations telling it's possible. But it is probably not.

It definitely is with a tapered cable. The only question is if it could be done practically and if it would actually be worth the hassle. The self support length is for a cylinder of the material, with a cone there isn't a limit to the maximum self support length as the base just gets as wide as necessary to support the rest of it. But with graphene it's close enough that just a 10 to 1 difference in the cross-sectional area between the top of the cable and the bottom would be structurally sufficient. Since the area scales with the square of the radius a 10 to 1 difference is only sqrt(10) larger in diameter between the top and the bottom.

None of that answers whether the structural properties of graphene can be realized at the macroscopic level with such a massive cable. We don't know yet, because nobody has built something even close to that out of graphene.

Graphene has a break length of 4000 km (the length were it will break simply under it own weight) and a space elevator needs to be 35000 km long.

Next up is graphene pollution. All such new tech should also have tech that allows for natural decomposition and shouldn't probably be used until that is available as well.

I stopped reading at: "composed of carbon atoms joined in a pattern that makes the material extremely tough and impervious to even the smallest atom, helium."

Is helium really smaller than hydrogen?

Oddly enough yes Helium has a smaller atomic radius because the additional proton and electron complete that first electron shell and get pulled closer to the nucleus.

Helium is a strange bird. Every other element in liquid form will freeze if you drop the temperature enough, except Helium. You must greatly pressurize Helium for it to freeze. It is worth pointing out that while the atomic radius of Helium is smaller than Hydrogen, Helium is still the heavier element. It’s small radius and tendency to remain a gas or liquid makes it very useful in testing for leaks or as a purging gas.

Hydrogen is mighty weird too.

For leak testing, it can be better than helium because the molecule is lighter. This raises the speed for any given temperature, and thus increases the rates of diffusion and effusion.

A downside is that hydrogen can burrow right into solid metal, one atom (proton) at a time, and then merge back into diatomic molecules. This creates a sort of internal pressure in the material, making it brittle. Hydrogen embrittlement is a significant problem, particularly with titanium.

That's an understatement. Helium cooled below 2K loses literally all viscosity and will flow through porcelain like it's a sponge. Not only that, because there's literally zero viscosity, convection makes superfluid helium a great heat conductor. All of this was discovered back in the 30s. The man who discovered superfluid liquid helium must have truly thought he had gone insane.

Also, atomic Hydrogen is not very common around here (nor anywhere, I suppose)... H+ and H2, on the other hand...

Well, I'm not a physicist, but hydrogen gas is two atoms compared to 1 atom for helium gas.

  hydrogen gas is two atoms

... which makes it a molecule.

If you belive Wikipedia https://en.wikipedia.org/wiki/Atomic_radius then the atomic radius of Helium has never been measured, but it is predicted to be smaller than Hydrogen.

A google search says yes.

Sounds like Bill Gates may finally get his unbreakable condom.

And if he does, it would be great. An ultra-thin, unbreakable condom would be a huge improvement both in quality-of-life and public health.

Title is definitely overblown. Roll-to-roll production is still very much a small scale process. Linear change not stepwise

Piecemeal batch production to continuous roll-to-roll production is most definitely a step change.

Continuous production allows for mass production, quality monitoring, and progressively increase in width, in a way that is not possible with batch process

That said wasn't the state of the art production previously measured in single digit square centimeters?

This might just be my confirmation bias speaking, but MIT seems to put out a lot of moverblown and clickbait-y headlines about their research.

This is the case for every press release office for every research university, I'm afraid. Some just get broader attention.

Reply on news.ycombinator.com