The GRAPHENE mega thread - because it's technology you need to know about!

What is GraphExeter?

Russo describes the material as “like a lasagne”, with FeCl3 molecules sandwiched between the single layers of graphene. These molecules donate additional charge carriers, which are responsible for the huge decrease in sheet resistance compared with pristine graphene.

The researchers discovered the material while exploring a different potential application of graphene altogether. “We were interested in whether it could be used to make magnetic memory in graphene,” says Russo. Iron chloride molecules are ferroelectric, so incorporating them seemed a promising approach. Although this is still an open avenue of research within the group at Exeter, it soon became apparent that the material had other very readily exploitable attributes.

As well as its high conductivity, GraphExeter has 85% transparency and is stable up to 100% humidity and 150 °C. It is also easy to fabricate with a large surface area using chemical-vapour-deposition (CVD)-grown graphene, and resists degradation for more 1000 bending cycles to a radius of curvature of 3 mm.

Source: Nanotechweb.org, July 19, 2016 - Graphene composite enables metre-sized flexible displays

So that is what GraphExeter is and how it is made! That (*points at quote*) is how you explain a new material that nobody has ever heard of before. Nice to show a thumb-print-size screen being bent but to not explain how it is made is just a shame. So this is scalable... neat! A wrap around a column monitor screen. This is an advertiser's dream! I wonder when these will be for sale?

A layer of material—be it steel, dough, or graphene—is spread out flat. Then, the material is doubled over on itself, pounded or rolled out, and then doubled over again, and again, and again.
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In this research, rather than folding the material, the team cut the whole block—itself consisting of alternating layers of graphene and the composite material—into quarters, and then slid one quarter on top of another, quadrupling the number of layers, and then repeating the process. But the result was the same: a uniform stack of layers, quickly produced, and already embedded in the matrix material, in this case polycarbonate, to form a composite.

In their proof-of-concept tests, the MIT team produced composites with up to 320 layers of graphene embedded in them. They were able to demonstrate that even though the total amount of the graphene added to the material was minuscule—less than 1/10 of a percent by weight—it led to a clear-cut improvement in overall strength.

Phys.org, July 20, 2016 - Borrowing from pastry chefs, engineers create nanolayered composites.

I was thinking, "Why not do a Samurai sword with graphene?" That is kind of how they are made: sprinkle carbon on the cutting blade while it is heated up, fold it over, hammer flat, repeat. It is the same as filo dough: roll out flat, spread butter over it, fold, and repeat.

Anyhoo, the people at MIT said this method keeps each layer separate and they do not short out (between layers). They are also thinking of using CNTs and shaved graphene (like tiny shaved cheese spirals) and making into threads of layered material. They do not even go edge to edge with a complete layer of graphene! They just used "1/10th a percent by weight" in creating their layered material (same source).

See, home ec class pays off if you pay attention!

When a laser light irradiates crystals or molecules, it scatters and shifts colors. That scattered light can be detected in the form of a Raman spectrum, which serves almost as a fingerprint for every Raman-active irradiated system.
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The team chose three types of fluorescent dye molecules for their experiments. Fluorescent dyes, which are frequently used as markers in biological experiments, are particularly hard to detect in Raman spectroscopy because the fluorescence tends to wash out the signal. However, when the dye is added to the graphene or N-doped graphene [Nitrogen-doped] substrate, the photoluminescence—fluorescence—is quenched.
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By controlling nitrogen doping we can shift the energy gap of the graphene, and the shift creates a resonance effect that significantly enhances the molecule's vibrational Raman modes," said lead author Simin Feng.

Source: Phys.org, July 22, 2016 - Ultrasensitive sensor using N-doped graphene.

This was done with regular graphene but they figured out that selectively doping graphene with nitrogen increases the reflected light and cools down the dye's tendency to over wash the reflection--a 2-fer! That is pretty smart!

But now I am thinking of top ramen...

News from the DOE and Oak Ridge National Laboratory.

"We heated commercially available boron nitride in a furnace to 800 degrees Celsius to expand the material's 2D layers. Then, we immediately dipped the material into liquid nitrogen, which penetrates through the interlayers, gasifies into nitrogen, and exfoliates, or separates, the material into ultrathin layers."

Nanosheets of boron nitride could be used in separation and catalysis, such as transforming carbon monoxide to carbon dioxide in gasoline-powered engines. They also may act as an absorbent to mop up hazardous waste. Zhu said the team's controlled gas exfoliation process could be used to synthesize other 2D nanomaterials such as graphene,
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[Zhu said], "The surface area of the boron nitride nanosheets is 278 square meters per gram, and the commercially available boron nitride material has a surface area of only 10 square meters per gram.

Source: EurekAlert.org, July 25, 2016 - New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials.

Building one material to build another... seems like that happens often. And if you are interested in both being used at the same (sandwiched) it would seem you have saved a step! And the size increase is pretty impressive! If that can be done with graphene, then your closer to a full sheet sized. No chemicals means less defects in grphene (ripples, wrinkles, holes, etc) because it is not contracting as much.

Hope this does work for graphene as well!

Cemtrex's Chairman and CEO, Saagar Govil (@SaagarGovil) , commented, "In the coming decade we anticipate the greenhouse gas reduction market to grow substantially and hence want to strengthen our position within this space by developing additional cutting edge technologies." "We want to have a stake in the production of the graphene nanoparticles and are looking at ways to accomplish this, using sustainable and ecofriendly methods," continued Mr. Govil.

PRNewswire, July 15, 2016 - Cemtrex to Setup a Research Pilot Plant for Production of Graphene

Yet again, from a financial reposting service, there is a story about graphene. This was 10 days ago but I had never heard of them and ran across a story announcing "breakthrough" but no actual details. So looked up the company itself. The news 7/25 is about the stock price jump up 25%. The PR says they want to "capture flue gasses" and generate graphene "nanoparticles" but no mention on what/how they will do both. Is this just speculation or did they figure out how to make money out of thin air? IDK, because there are no details.

So remember the name, cemtrex, as there is major stock movement around them. 35% in the past four weeks!

Graphene 3D Lab Inc... pleased to announce that, as of today, it will begin selling a new cutting-edge functionalized single-layer graphene oxide material under the trade name of "ORG-GO". The introduction of this material is an important step in addressing one of the key roadblocks on graphene commercialization: the effective dispersion of graphene materials in resins and solvents traditionally used in large-scale manufacturing. This new material can be easily dissolved in a variety of organic solvents and one can achieve ultrahigh concentrations. ORG-GO also boasts outstanding thermal stability.

Graphene 3D Labs, July 28, 2016 - G raphene 3D Lab Introduces New Type of Single Layer Graphene Material.

And at 125 $US per 100 mg you can have soluble graphene oxide for all your 3D printing needs! Actually, that is not too bad of a price as you do not need much of the stuff to get the much touted "stronger than steel" effects. The bike frame uses 0.01% of total weight so you really do not a whole lot. And the oxide is easier to manufacture.

One more (tiny) step towards our graphene future (now if I could only get the spell check to quit spelling everything "grapheme"...)

Previous theoretical studies have suggested that films with a cubic structure and ionic bonding could spontaneously convert to a layered hexagonal graphitic structure in what is known as graphitization. For some substances, this conversion has been experimentally observed. It was predicted that rock salt NaCl could be a compound with graphitisation tendencies. Graphitisation of cubic compounds could produce new and promising structures for applications in nanoelectronics. However, no theory has accounted for this process with an arbitrary cubic compound or made predictions about its conversion into graphene-like salt layers.
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The compounds within the scope of this study can all have a hexagonal, "graphitic" G phase (the red in the diagram) that is unstable in 3-D bulk but becomes the most stable structure for ultrathin (2-D or quasi-2-D) films. The researchers identified the relationship between the surface energy of a film and the number of layers in it for both cubic and hexagonal structures. They graphed this relationship by plotting two lines with different slopes for each of the compounds studied. Each pair of lines associated with one compound has a common point that corresponds to the critical slab thickness that makes conversion from a cubic to a hexagonal structure energetically favourable. For example, the critical number of layers was found to be close to 11 for all sodium salts and between 19 and 27 for lithium salts.

Phys.org, Aug 1, 2016 - Scientists find a way of acquiring graphene-like films from salts to boost nanoelectronics

What can't graphene do? Now it is a verb! The creation of the 2D world is happening before our eyes. Strange that they are odd numbers and not multiples of 3. 11, 19, and 27 are not random numbers. Wonder if that has anything to do with packing molecules? May have to go read up on that one. They do have to put the salt under pressure until it stabilizes in the hexagonal state. Wonder what they are going to layer with these new materials?

Anyway, graphene showed them the way!

They replaced the underlying silica with boron nitride, a crystalline material that's chemically sluggish and has a smooth surface devoid of electronic bumps and pits. By using this substrate and the anisotropic etching technique, the group successfully made graphene nanoribbons that were only one-layer thick, and had well-defined zigzag edges.

"This is the first time we have ever seen that graphene on a boron nitride surface can be fabricated in such a controllable way," Zhang explained.

The zigzag-edged nanoribbons showed high electron mobility in the range of 2000 cm2/Vs even at widths of less than 10nm—the highest value ever reported for these structures—and created clean, narrow energy band gaps, which makes them promising materials for spintronic and nano-electronic devices.

Source: Phys.org, Aug 1, 2016 - Swapping substrates improves edges of graphene nanoribbons.

So "white praphene" to the rescue! Let the fabrication begin! Having well defined edges and a repeatable method of creating graphene nanoribbons is yet one more step to the 2D computing future.

BAC has worked with Haydale Composite Solutions on the trial, which used graphene-enhanced carbonfibre, and decided to focus on the rear arches because of their size and complexity, which allowed the material and manufacturing process to be thoroughly tested. The test car, with the graphene arches fitted, was showcased at the Science in the City festival in Manchester.
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“These initial materials have shown some major increases in impact and thermal performance coupled with improved surface finish, and it’s pleasing to see these attributes being demonstrated on such a high-performance vehicle as the Mono [said Haydale director of aerospace and defense].

Source: Autocar.co (.uk), Aug 1, 2016 - BAC Mono is first to use 'revolutionary' graphene material.

A race car with graphene from Haydale! And it is out on the test track. They said that graphene will be offered in future BAC products as options for customers. Wonder when F1 will start using products? After all the nose sections lost last weekend in Indy Car they may need this sooner rather than later.

Nice to see real world applications of graphene!

The [MIT] researchers fastened the layers of [carbon fiber] composite materials together using carbon nanotubes... They embedded tiny "forests" of carbon nanotubes within a glue-like polymer matrix, then pressed the matrix between layers of carbon fiber composites. The nanotubes, resembling tiny, vertically-aligned stitches, worked themselves within the crevices of each composite layer, serving as a scaffold to hold the layers together.

In experiments to test the material's strength, the team found that, compared with existing composite materials, the stitched composites were 30 percent stronger, withstanding greater forces before breaking apart.

Source, Phys.org, Aug 3, 2016 - Method to reinforce carbon nanotubes could make airplane frames lighter, more damage-resistant.

I actually looked back to see if this had been posted because it sounds familiar. Nothing noticeable. Then I remembered it was a story on CNT on how the scientists "swirled" dissolved carbon to create "forests" of vertical CNTs. At the time of that announcement all I thought was neat but did not post the story. So using that method they put the vertical CNTs in the epoxy and layered more carbon fiber over that layer. CNTs are small enough to not crack the carbon fiber and provide a vertical attachment to the horizontal carbon fiber. Several layers later they have stronger carbon fiber.

This method is scalable as producing graphene in whole sheets has not been worked out. Immediate thought went to aircraft usage and reducing overall weight and therefore fuel consumption and pollution. Seeing as the first graphene drone flew a few weeks ago both are welcome news!

Way to go MIT! And really! What are they feeding those people over there?

Major manufacturing news!

[Cedar Ridge Research's] process for generating a floating continuous graphene film builds upon the traditional chemical vapor deposition (CVD) method. The process involves generating an even plasma distribution to produce a glow discharge of ionized carbon atoms at a desired rate that controls the continuous growth of a graphene film suspended over an alternating polarity magnetic structure having a sufficient gradient to float graphene in a stable manner. The free-floating growth process requires virtually no raw materials or surface preparation and eliminates the metal etching and transfer issues that lead to atomic-scale flaws that reduce efficiency. Graphene film produced using this process can be free of undulations, grain boundaries or defects that may cause uneven build-up of the graphene into a polycrystalline structure.

The process also enables processing of the graphene during its production including using lasers to draw conductive circuit board traces, applying other atoms using stereo lithography to build nanostructures, and activating carbon and mixing impurities to produce semiconductors.

Nanowerk news, Aug. 8, 2016 - A pioneering patent for free-floating graphene production technology.

Defect free, mono-layer graphene sheets?! That are created by floating the atoms into place? That is pretty crazy but a cool idea! Glad that somebody figured that out because normal CVD requires a substrate then removal which can introduce defects in the sheet. The other part of the news is that while being made the carbon can be doped with other materials which is important for creating 2D electronics (which is also mentioned the "lasers" and "etching" comment). Nearly lost is the comment at the end of the article, this process is "scalable".

Is this the starting gun to the 2D race and our graphene future??

Another manufacturing news item.

The adaptation of chemical vapor deposition (CVD) production of graphene so that it’s compatible with roll-to-roll processing is transforming graphene manufacturing.
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Now researchers at Hong Kong Polytechnic University and Peking University have developed a technique that accelerates the process so that the growth happens at 60 micrometers per second—far faster than the typical 0.4 µm per second. The key to this 150-fold speed increase was adding a little oxygen...

...placed [on] an oxide substrate 15 micrometers below the copper foil.

IEEE Spectrum, Aug. 9 , 2016 - Single-Crystal Graphene Films Grown More Than 100 Times as Fast as Previously Possible.

A second manufacturing method for making single-crystal graphene in two days. Single-crystals will have their places as will whole sheet graphene. The layering upon other 2D materials, as noted previously, will benefit from this particular improvement.

Even the article quips about the arrival of the "killer app" for graphene! There was a news story (probably another press release actually) about a paint company using graphene in its primer. Specialized products are nice but until it is in my grubby little hands there is a gap!

Still production improvement means one step out of the laboratory into the real world.

Researchers… have managed to produce quantum dots out of graphene. And according to the multinational team, these dots offer a bold new promise for quantum computing.

So, what’s new? The researchers discovered that quantum dots made from graphene possess four quantum states at a given energy level, unlike semiconductor quantum dots, which have only two.

“In conventional semiconductors, there is only the spin of the electrons,” explained Florian Libisch, the assistant professor at TU Wein who led the research, in an e-mail interview with IEEE Spectrum. “With graphene, there is a second conserved quantity called “pseudospin.” Both of these symmetries together yield 2 x 2 = 4 quantum states.”
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“Using our graphene quantum dots, you could think of storing two qubits in the four-fold near-degenerate states—which would make a coherent interaction between these two qubits much more well controlled than the interaction of two two-fold degenerate states,”
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According to the researchers, it should be possible to fit many graphene quantum dots on a small chip for use in quantum computing.

IEEE Spectrum, Aug. 23, 2016 – Grap hene Doubles Up on Quantum Dots' Promise in Quantum Computing.

Ooohhhh! Cool news on a couple fronts! A quantum dot holding 2 q-bits in strong coherence means they do not need extra q-bits for error correcting. Typical usage is 12 q-bits to make 5 q-bits with coherence and error correction (that is the strategy the MIT quantum computer uses). So now you can line up graphene quantum dots in a row. Reading spin, setting energy levels, error correcting, are being done at the super cooled level so it is now a matter of combining the knowhow with the new material.

Gee, a quantum computer made of graphene quantum dots sound like science fiction but might be around the corner!

[ETA: Third manufacturing announcement in a month]

Researchers discovered a procedure to restore defective graphene oxide structures that cause the material to display low carrier mobility. By applying a high-temperature reduction treatment in an ethanol environment, defective structures were restored, leading to the formation of a highly crystalline graphene film with excellent band-like transport. These findings are expected to come into use in scalable production techniques of highly crystalline graphene films.

Phys.org, Aug 25, 2016 - A promising route to the scalable production of highly crystalline graphene films.

Another production method is found! Although it is hard to tell what exactly they mean by "defective structures were restored" the picture at the article makes it clear: the defects are minimized using this production method. I really wish people not make announcements like this in the passive voice. Crystalline graphene is the be all and end all form for specific applications including displays and processing chips. The "defective structures" have so far kept graphene oxide from being little more than a neat lab trick. Now they can make it defect free.

So this is the third announcement in two weeks on producing graphene. So... still waiting on my iPod battery replacement!

We have a date! And a cool product using carbon nanotubes...

Fujitsu announced that it has licensed Nantero's carbon nanotube-based NRAM (Non-volatile RAM) and will participate in a joint development effort to bring a 256Mb 55nm product to market in 2018.
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Other products also suffer limited endurance thresholds, whereas Nantero's NRAM has been tested up to 10^12 (1 trillion) cycles. The company stopped testing endurance at that point, so the upper bounds remain undefined.
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The NRAM carbon nanotubes are 2nm in diameter. Much like NAND, fabs arrange the material into separate cells. NAND employs electrons to denote the binary value held in each cell (1 or 0), and the smallest lithographies hold roughly a dozen electrons per cell. NRAM employs several hundred carbon nanotubes per cell, and the tubes either attract or repel each other with the application of an electrical current, which signifies an "on" or "off" state. NRAM erases (resets) the cells with a phonon-driven technique that forces the nanotubes to vibrate and separate from each other. NRAM triggers the reset process by reversing the current, and it is reportedly more power efficient than competing memories (particularly at idle, where it requires no power at all).

Source: Tomshardware.com, Sept. 1, 2016 - Fujitsu To Mass-Produce NRAM Carbon Nanotube Memory In 2018.

Sorry but the PC World link did not pull up for me so I settled for the first one that did. This is cool beans right here! So the CNTs touch each other to allow current to flow (like touching two wires together). The phonon (sound, I think) is used to separate the connection. They will either be connected or not which means it is truly non-volatile memory! And CNTs are operable up to 800 °C so heat will not be an issue. The fact they stopped at a trillion cycles (on-off toggles) is freaking amazing! And most importantly is that they set a date. If I had one, I would put a mini-kernel on it to boost boot time to be instant on!

Maybe this will be ready before the launch of the James Webb Space Telescope!

[Suprem] Das and [Jonathan] Claussen came up with the idea of using lasers to treat the graphene [after inkjet printing circuits]...

And it worked: They found treating inkjet-printed, multi-layer graphene electric circuits and electrodes with a pulsed-laser process improves electrical conductivity without damaging paper, polymers or other fragile printing surfaces.

"This creates a way to commercialize and scale-up the manufacturing of graphene," Claussen said.

Phys.org, Sept. 1, 2016 - Engineers treat printed graphene with lasers to enable paper electronics.

Lasers. The answer was "lasers". When inkjet printed the entire paper, substrate, and graphene ink required one more step to set the ink and get the desired electrical properties. Unfortunately, that usually damages everything except the graphene. So now they can print and lase and keep the paper and substrate (or anything else) from being damaged.

One more manufacturing advance!

Yet another three-for Thursday!

The easiest way to make large quantities of graphene is to exfoliate graphite into individual graphene sheets by using chemicals. The downside of this approach is that side reactions occur with oxygen - forming graphene oxide that is electrically non-conducting, which makes it less useful for products.

Removing oxygen from graphene oxide to obtain high-quality graphene has been a major challenge over the past two decades for the scientific community working on graphene. Oxygen distorts the pristine atomic structure of graphene and degrades its properties.

Chhowalla and his group members found that baking the exfoliated graphene oxide for just one second in a 1,000-watt microwave oven, like those used in households across America, can eliminate virtually all of the oxygen from graphene oxide.

Phys.org, Sept. 1, 2016 - Researchers use microwaves to produce high-quality graphene.

Microwaves. The answer was "microwaves." Free-floating graphene, ethanol CVD, lasers, microwaves... enough! Put that d@mn battery in my grubby little hands already!

All kidding aside, there is a huge pure graphite mine in Australia and I bet they are extremely happy about this find. It will make their production of graphene so much easier. South Korea has already started ramping up their commercialization efforts. And there is the lab in Manchester and the Graphene Flagship in the EU. Which makes me ask, where is the US?

Graphene, coming to a store near you!

Scientists have been pursuing ways around this [mechanical sound production] by turning to a principle conceived of more than a century ago: thermoacoustics, the production of sound by rapidly heating and cooling a material rather than through vibrations...

The [South Korean] researchers developed a two-step (freeze-drying and reduction/doping) method for making a sound-emitting graphene aerogel. An array of 16 of these aerogels comprised a speaker that could operate on 40 Watts of power with a sound quality comparable to that of other graphene-based sound systems. The researchers say their fabrication method is practical and could lend itself to mass production for use in mobile devices and other applications. Because the speaker is thin and doesn't vibrate, it could fit snugly against walls and even curved surfaces.

Source: EurekAlert!, Sept. 7, 2016 - Bringing graphene speakers to the mobile market (video).

Speakers, huh? The other speakers use a sheet of graphene and high volume production of that product has not been figured out yet. So in walks the aerogel! The stuff is my favorite of the graphene products and I figure its use would be omnipresent. Arrayed 40w aerogel speakers... that is awesome!

Graphene itself will be used in concrete to prevent crumbling (and that bridge collapse). It is really amazing how very little is needed to increase strength in other materials. F1 cars should begin using this next year (as well as Indy cars). The use of aerogel as an insulation I figured would be the first major use. I guess I was wrong!

I wonder if they can make me a 4x12 guitar cab (8 ohms) say, about... 60w? A TEOT can dream!

Yet another method of producing defect free graphene... this time from Germany.

A common way to synthesize graphene is through chemical exfoliation of graphite. In this process, as explained by researchers, metal ions are embedded in graphite, which is made of carbon, resulting in what is known as an intercalation compound. The individual layers of carbon... are separated using solvents. The stabilized graphene then has to be separated from the solvent and re-oxidized. However, defects in the individual layers of carbon, such as hydration and oxidation of carbon atoms in the lattice, can occur during this process.

By adding the solvent benzonitrile, researchers discovered that the graphene can be removed without any additional functional groups forming—and it remains defect-free.

The method, they say, is low cost and efficient, and also comes with another advantage. The reduced benzonitrile molecule formed during the reaction turns red as long as it does not come into contact with oxygen or water...
[the color change] now... gives graphene and battery researchers a new way of measuring the charge state.

Source: Electronics360, Sept. 8, 2016 - Method to Produce Low-Cost, Defect-Free Graphene.

So there is the exfoliation process described and a new term "intercalation" (layers in a crystal lattice which graphene actually is--a 2D crystalline form of carbon (Double Jeopardy. "What is an 'allotrop'? Alex.")) . And where along the lines defects are reintroduced back into the graphene. The "by product" has a use too which is a double bonus. The charge state of functionalized graphene can be determined without having to pass a voltage through it which means if you are making graphee for use in a battery you can see which ones meet specs and which do not just by measuring the color.

I hope this means that the graphene battery revolution can start! I am getting tired of "just another year or so" being said over and over again.

Under a collaboration agreement, announced on Tuesday, Talga will supply graphene for testing in components producing JenaBatteries’ patented polymer flow battery, a type of redox flow battery suitable for commercial scale and grid applications.

Talga said its graphene would aim to reduce manufacturing costs and increase the performance and longevity of the flow battery components by using graphene’s renowned properties of conductivity, chemical inertness and impermeability.

Source: Mining Weekly, Sept. 13, 2016 - German battery group testing Talga’s graphene for flow batteries.

Flow batteries meet graphene! At least this is announced for real world applications. Both companies retain their IP rights while contributing to each other's product. I hope this partnership works and creates a viable flow battery for grid-level storage. Scotland just announced installing seven flow batteries at one of their wind farms for load balancing and providing off-peak power for peak time use. Those vanadium flow batteries are expected to last 12 years before replacement parts are needed. If graphene can add to that and make a flow battery last 15-20 (or more!) years then expect a drastic shift on power distribution.