
A manufacturing process that produces long strips of high-quality graphene - fahd777
https://news.mit.edu/2018/manufacturing-graphene-rolls-ultrathin-membranes-0418
======
AChamarthy
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.

~~~
logicallee
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).

~~~
AChamarthy
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...](https://news.samsung.com/global/samsung-develops-battery-material-
with-5x-faster-charging-speed)

~~~
logicallee
Thanks!

------
ChuckMcM
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.

~~~
jws
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...](https://en.wikipedia.org/wiki/Desalination#Energy_consumption)

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

~~~
Retric
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...](https://electrek.co/2017/11/16/cheapest-electricity-on-the-planet-
mexican-solar-power/)

------
chiefalchemist
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.

~~~
NegativeLatency
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.

~~~
xyzzyz
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.

~~~
DmenshunlAnlsis
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.

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cslarson
Space elevators?

~~~
fudged71
Not viable, graphene isn't strong enough.

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

~~~
marcosdumay
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.

~~~
MertsA
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.

~~~
eloff
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.

------
goombastic
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.

------
marshray
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?

~~~
MertsA
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.

~~~
DmenshunlAnlsis
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.

~~~
burfog
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.

------
knicholes
Sounds like Bill Gates may finally get his unbreakable condom.

~~~
TeMPOraL
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.

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

~~~
rdruxn
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.

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

