A Holey Graphene Electrode framework that enables highly efficient charge delivery – Making Better Batteries for the Future


Holey Graphene II grapheneThis visualisation shows layers of graphene used for membranes. Credit: University of Manchester

A team of researchers affiliated with institutions in the U.S., China and the Kingdom of Saudi Arabia has developed a new type of porous graphene electrode framework that is capable of highly efficient charge delivery. In their paper published in the journal Science, the group describes how they overcame traditional conflicts arising between trade-offs involving density and speed to produce an electrode capable of facilitating rapid ion transport. Hui-Ming Cheng and Feng Li with the Chinese Academy of Sciences offer a Perspective piece on the work done by the team in the same journal issue, and include some opinions of their own regarding where such work is likely heading.

In a perfect world, batteries would have unlimited energy storage delivered at speeds high enough to power devices with unlimited needs. The phaser from Star Trek, for example, would require far more power and speed than is possible in today’s devices.

While it is unlikely that such technology will ever come about, it does appear possible that batteries of the future will perform much better than today, likely due to nano-structured materials—they have already shown promise when used as material due to their unique properties. Unfortunately, their use has been limited thus far due to the ultra-thin nature of the resulting electrodes and their extremely low mass loadings compared to those currently in use. In this new effort, the researchers report on a new way to create an electrode using that overcomes such limitations.

The electrode they built is porous, which in this case means that it has holes in it. Those holes, as Cheng and Li note, allow better charge transport while also offering improved capacity retention density. The graphene framework they built, they note, offers a superior means of electron transport and its porous nature allows for a high ion diffusion rate—the holes force the ions to take shortcuts, reducing diffusion.

Cheng and Li suggest the new work is likely to inspire similar designs in the search for better electrode materials, which they further suggest appears likely to lead to new electrodes that are not only practical, but have high mass loadings.

Explore further: New graphene framework bridges gap between traditional capacitors, batteries

More information: Hongtao Sun et al. Three-dimensional holey-graphene/niobia composite architectures for ultrahigh-rate energy storage, Science (2017). DOI: 10.1126/science.aam5852

Abstract
Nanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) because of the increasing ion diffusion limitations in thicker electrodes.

We report the design of a three-dimensional (3D) holey-graphene/niobia (Nb2O5) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport.

By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications.

 

“Holey” graphene improves battery electrodes – May be ‘The Holy Grail’ of Next Generation Batteries 



May 12, 2017

Electrodes containing porous graphene and a niobia composite could help improve electrochemical energy storage in batteries. This is the new finding from researchers at the University of California at Los Angeles who say that the nanopores in the carbon material facilitate charge transport in a battery.

By fine tuning the size of these pores, they can not only optimize this charge transport but also increase the amount of active material in the device, which is an important step forward towards practical applications.


Niobia and holey graphene composite with tailored nanopores

Batteries and supercapacitors are two complementary electrochemical energy-storage technologies. They typically contain positive and negative electrodes with the active electrode materials coated on a metal current collector (normally copper or aluminium foil), a separator between the two electrodes, and an electrolyte that facilitates ion transport.

The electrode materials actively participate in charge (energy) storage, whereas the other components are passive but nevertheless compulsory for making the device work.

Batteries offer high energy density but low power density while supercapacitors provide high power density with low energy density.

Although lithium-ion batteries are the most widely employed batteries today for powering consumer electronics, there is a growing demand for more rapid energy storage (high power) and higher energy density. Researchers are thus looking to create materials that combine the high-energy density of battery materials with the short charging times and long cycle life of supercapacitors.

Such materials need to store a large number of charges (such as Li ions) and have an electrode architecture that can quickly deliver charges (electrons and ions) during a given charge/discharge cycle.

Increasing the mass loading of niobia in electrodes

Nanostructured materials fit the bill here, but unfortunately only for electrodes with low areal mass loading of the active materials (around 1 mg/cm2). “This is much lower than the mass of the passive components (around 10 mg/cm2 or greater),” explains team leader Xiangfeng Duan. “As a result, in spite of the high intrinsic capacity or rate capability of these new nanostructured materials, the scaled area capacity or areal current density of nanostructured electrodes rarely exceeds those of today’s Li-ion batteries.

Thus, these electrodes have not been able to deliver their extraordinary promise in practical commercial devices.

“To take full advantage of these new materials, we must increase the mass loading to a level comparable to or higher than the mass of the passive components. To satisfy the energy storage requirement of an electrode with 10 times higher mass loading requires the rapid delivery of 10 times more charge over a distance that is 10 times greater within a given time. This is a rather challenging task and has proven to be a critical roadblock for new electrode materials.

“We have now addressed this very issue of how we can increase the mass loading of niobia (Nb2O5) in electrode structures without compromising its merit for ultrahigh-rate energy storage,” he continues. “Electrodes with intrinsically high capacity or high rate capability in practical devices require a new architecture that can efficiently deliver sufficient electrons or ions.

We have designed a 3D holey-graphene-Nb2O5 composite with excellent electron and ion transport properties for ultrahigh-rate energy storage at practical levels of mass loading (greater than 10 mg/cm2).”

Porous structure facilitates rapid ion transport

“The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties and its hierarchical porous structure facilitates rapid ion transport,” he adds. “What is more, by systematically tailoring the porosity in the holey graphene backbone, we optimize charge transport in the composite architecture to simultaneously deliver areal capacity and high-rate capability at practical levels of mass loading – something that is a critical step forward towards commercial applications.”

The researchers made their mechanically strong 3D porous composites in a two-step synthesis technique. “We uniformly decorate Nb2O5

Decreasing the fraction of inactive materials

The in-plane pores in the holey graphene sheet function as ion transport “shortcuts” in the hierarchical porous structure to facilitate rapid ion transport throughout the entire 3D electrode and so greatly improve ion transport kinetics and access to ions on the surface of the electrode, Duan tells nanotechweb.org.

Spurred on by these results, the researchers say they will now try to incorporate high-capacity active materials such as silicon and tin oxide to further increase output energy levels in electrochemical cells. “Extremely high mass-loaded electrodes (for example, five times that of practical mass loading, or 50 mg/cm2) could also help decrease the fraction of inactive materials in a device and so simplify the process to make these cells.”


So What’s Next?

Team GNT writes: For the Researchers to take ‘the next step’ further exploration of best outcome and integration of new structured  materials must be completed. And then …

  • Proof of Concept
  • Proof of Scalability 
  • Competitive Market Integration Analysis
  • Manufacturing Platform and Market Distribution 

A lot of hard work! But work that will be well worth the effort if the emerging technology can meet all of the required. Milestones! The current rechargeable battery market is a $112 Billion Market!



The research is detailed in Science DOI: 10.1126/science.aam5852.
Belle Dumé is contributing editor at nanotechweb.org

Chemically tailored graphene advances Potential for use in Semiconductors


Graphene chemicallytaSection of a graphene network with chemically bound hydrogen atom: the spectral vibrational signature of the single carbon-carbon bonds adjacent to the bound hydrogen atom is highlighted in different colors. Credit: Frank Hauke, FAU

Graphene is considered as one of the most promising new materials. However, the systematic insertion of chemically bound atoms and molecules to control its properties is still a major challenge. Now, for the first time, scientists of the Friedrich-Alexander-Universität Erlangen-Nürnberg, the University of Vienna, the Freie Universität Berlin and the University Yachay Tech in Ecuador succeeded in precisely verifying the spectral fingerprint of such compounds in both theory and experiment. Their results are published in the scientific journal Nature Communications.

Two-dimensional consists of single layers of carbon atoms and exhibits intriguing properties. The transparent material conducts electricity and heat extremely well. It is at the same time flexible and solid. Additionally, the electrical conductivity can be continuously varied between a metal and a semiconductor by, e.g., inserting chemically bound atoms and molecules into the graphene structure – the so-called functional groups. These unique properties offer a wide range of future applications as e.g. for new developments in optoelectronics or ultrafast components in the semiconductor industry. However, a successful use of graphene in the semiconductor industry can only be achieved if properties such as the conductivity, the size and the defects of the graphene structure induced by the functional groups can already be modulated during the synthesis of graphene.

In an international collaboration scientists led by Andreas Hirsch from the Friedrich-Alexander-Universität Erlangen-Nürnberg in close cooperation with Thomas Pichler from the University of Vienna accomplished a crucial breakthrough: using the latter’s newly developed experimental set-up they were able to identify, for the first time, vibrational spectra as the specific fingerprints of step-by-step chemically modified graphene by means of light scattering. This spectral signature, which was also theoretically attested, allows to determine the type and the number of in a fast and precise way. Among the reactions they examined, was the chemical binding of hydrogen to graphene. This was implemented by a controlled chemical reaction between water and particular compounds in which ions are inserted in graphite, a crystalline form of carbon.

Additional benefits

“This method of the in-situ Raman spectroscopy is a highly effective technique which allows controlling the function of graphene in a fast, contact-free and extensive way already during the production of the material,” says J. Chacon from Yachay Tech, one of the two lead authors of the study. This enables the production of tailored graphene-based materials with controlled electronic transport properties and their utilisation in .

Explore further: Low-cost and defect-free graphene

More information: Philipp Vecera et al. Precise determination of graphene functionalization by in situ Raman spectroscopy, Nature Communications (2017). DOI: 10.1038/ncomms15192

 

World’s first images of electric currents in Graphene released: Applications for Next Generation Electronics, Quantum Computing, Energy Storage (batteries), Flexible Displays & Bio-Chem Sensors.



Artist’s impression of a diamond quantum sensor. The ‘spotlight’ represents light passing through the diamond defect and detecting the movement of electrons. Electrons are shown as red spheres, trailed by red threads that reveal their path through graphene (a single layer of carbon atoms). Credit: David A. Broadway/cqc2t.org


Researchers at the University of Melbourne are the first in the world to image how electrons move in two-dimensional graphene, a boost to the development of next-generation electronics.

Capable of imaging the behaviour of moving electrons in structures only one atom in thickness, the new technique overcomes significant limitations with existing methods for understanding electric currents in devices based on ultra-thin materials.

“Next-generation electronic devices based on ultra-thin materials, including quantum computers, will be especially vulnerable to contain minute cracks and defects that disrupt current flow,” said Professor Lloyd Hollenberg, Deputy Director of the Centre for Quantum Computation and Communication Technology (CQC2T) and Thomas Baker Chair at the University of Melbourne.

A team led by Hollenberg used a special quantum probe based on an atomic-sized ‘colour centre’ found only in diamonds to image the flow of electric currents in graphene. The technique could be used to understand electron behaviour in a variety of new technologies.

“The ability to see how electric currents are affected by these imperfections will allow researchers to improve the reliability and performance of existing and emerging technologies. We are very excited by this result, which enables us to reveal the microscopic behaviour of current in quantum computing devices, graphene and other 2D materials,” he said.

graphenehydrWatch the video:

The Diamond Quantum Sensor is controlled by lasers.

Artist’s impression of a diamond quantum sensor. The ‘spotlight’ represents light passing through the diamond defect and detecting the movement of electrons. Electrons are shown as red spheres, trailed by red threads that reveal their path through graphene (a single layer of carbon atoms). Credit: David A. Broadway/cqc2t.org

“Next-generation electronic devices based on ultra-thin materials, including quantum computers, will be especially vulnerable to contain minute cracks and defects that disrupt current flow,” said Professor Lloyd Hollenberg, Deputy Director of the Centre for Quantum Computation and Communication Technology (CQC2T) and Thomas Baker Chair at the University of Melbourne.
We are very excited by this result, which enables us to reveal the microscopic behaviour of current in quantum computing devices, graphene and other 2D materials,” he said.

“Researchers at CQC2T have made great progress in atomic-scale fabrication of nanoelectronics in silicon for quantum computers. Like graphene sheets, these nanoelectronic structures are essentially one atom thick.
The success of our new sensing technique means we have the potential to observe how electrons move in such structures and aid our future understanding of how quantum computers will operate.”
In addition to understanding nanoelectronics that control quantum computers, the technique could be used with 2D materials to develop next generation electronics, energy storage (batteries), flexible displays and bio-chemical sensors.

“Our technique is powerful yet relatively simple to implement, which means it could be adopted by researchers and engineers from a wide range of disciplines,” said lead author Dr Jean-Philippe Tetienne from CQC2T at the University of Melbourne.

“Using the magnetic field of moving electrons is an old idea in physics, but this is a novel implementation at the microscale with 21st Century applications.”

The work was a collaboration between diamond-based quantum sensing and graphene researchers. Their complementary expertise was crucial to overcoming technical issues with combining diamond and graphene.

img_0118-1
Seeing is believing: Diamond quantum sensor reveals current flows in next-gen materials. An image of the current flow in graphene, obtained using a diamond quantum sensor. The colour reveals where defects lie by showing the current intensity i.e. the number of electrons passing through each second. Credit: University of Melbourne/cqc2t.org

“No one has been able to see what is happening with electric currents in graphene before,” said Nikolai Dontschuk, a graphene researcher at the University of Melbourne School of Physics.

“Building a device that combined graphene with the extremely sensitive nitrogen vacancy colour centre in diamond was challenging, but an important advantage of our approach is that it’s non-invasive and robust – we don’t disrupt the current by sensing it in this way,” he said.

Tetienne explained how the team was able to use diamond to successfully image the current. “Our method is to shine a green laser on the diamond, and see red light arising from the colour centre’s response to an electron’s magnetic field,” he said. “By analysing the intensity of the red light, we determine the magnetic field created by the electric current and are able to image it, and literally see the effect of material imperfections.”
The current-imaging results were published today in the journal Science Advances.

More information: “Quantum imaging of current flow in graphene,” Science Advances (2017). DOI: 10.1126/sciadv.1602429 , advances.sciencemag.org/content/3/4/e1602429

Provided by: Centre for Quantum Computation & Communication Technology

 

Turning Saltwater N2 Clean drinking Water ~ Graphene Could Solve the World’s Water Crisis: Video


Graphene Desal 1-simulationsp

Published on Apr 29, 2017

Turning  saltwater into clean drinking water is an expensive, energy-intensive process, but could the wonder material graphene make it more accessible?
New Discovery Could Unlock Graphene’s Full Potential

Watch the Video:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 




Charge Your Cell Phone in 5 (that’s right .. 5!) Seconds? + New Discovery Could Unlock Graphene’s Full Potential ~ Video


Graphene Supercapacitors 111815 id41889

It’s time for an update on graphene, that super material of the future! Scientists have come up with some new ways of making it that are easier and cheaper than ever before.

“Fascination with this material stems from its remarkable physical properties and the potential applications these properties offer for the future. Although scientists knew one atom thick, two-dimensional crystal graphene existed, no-one had worked out how to extract it from graphite.”

 

More ….

Charge Your Cell Phone In 5 Seconds

Supercapacitors: They’ll enable you to charge your cell phone in 5 seconds, or an electric car in about a minute. They’re cheap, biodegradable, never wear out and as Trace’ll tell you, could be powering your life sooner than you’d think.

 

Still More …

Scientists cook up material 200 times stronger than steel out of soybean oil

Soyben Graphene 8223748-16x9-large“Many production techniques involve the use of intense heat in a vacuum, and expensive ingredients like high-purity metals and explosive compressed gases. Now a team of Australian scientists has detailed how they turned cheap everyday ingredients into graphene under normal air conditions. They said the research, published today in the journal Nature Communications, may open up a new avenue for the low-cost synthesis of the highly sought-after material.” Click on the Link below to read more:

Scientists cook up material 200 times stronger than steel out of soybean oil

 

MIT: Entirely New Approach to Graphene Semiconductors creates a ‘copy machine’ for cheap semiconductor wafers


Graphene Copy Machine 58f786adf3e74This image shows LEDs grown on graphene and then peeled.

 

In 2016, annual global semiconductor sales reached their highest-ever point, at $339 billion worldwide. In that same year, the semiconductor industry spent about $7.2 billion worldwide on wafers that serve as the substrates for microelectronics components, which can be turned into transistors, light-emitting diodes, and other electronic and photonic devices.

A developed by MIT engineers may vastly reduce the overall cost of wafer technology and enable devices made from more exotic, higher-performing than conventional silicon.

The new method, reported today in Nature, uses graphene—single-atom-thin sheets of graphite—as a sort of “copy machine” to transfer intricate crystalline patterns from an underlying to a top layer of identical material.

The engineers worked out carefully controlled procedures to place single sheets of graphene onto an expensive wafer. They then grew semiconducting material over the graphene layer. They found that graphene is thin enough to appear electrically invisible, allowing the top layer to see through the graphene to the underlying crystalline wafer, imprinting its patterns without being influenced by the graphene.

Graphene is also rather “slippery” and does not tend to stick to other materials easily, enabling the engineers to simply peel the top semiconducting layer from the wafer after its structures have been imprinted.

Jeehwan Kim, the Class of 1947 Career Development Assistant Professor in the departments of Mechanical Engineering and Materials Science and Engineering, says that in conventional semiconductor manufacturing, the wafer, once its crystalline pattern is transferred, is so strongly bonded to the semiconductor that it is almost impossible to separate without damaging both layers.MIT-Slippery-Graphene-1_0

“You end up having to sacrifice the wafer—it becomes part of the device,” Kim says.

With the group’s new technique, Kim says manufacturers can now use graphene as an intermediate layer, allowing them to copy and paste the wafer, separate a copied film from the wafer, and reuse the wafer many times over. In addition to saving on the cost of wafers, Kim says this opens opportunities for exploring more exotic semiconductor materials.

“The industry has been stuck on silicon, and even though we’ve known about better performing semiconductors, we haven’t been able to use them, because of their cost,” Kim says. “This gives the industry freedom in choosing by performance and not cost.”

Kim’s research team discovered this new technique at MIT’s Research Laboratory of Electronics. Kim’s MIT co-authors are first author and graduate student Yunjo Kim; graduate students Samuel Cruz, Babatunde Alawonde, Chris Heidelberger, Yi Song, and Kuan Qiao; postdocs Kyusang Lee, Shinhyun Choi, and Wei Kong; visiting research scholar Chanyeol Choi; Merton C. Flemings-SMA Professor of Materials Science and Engineering Eugene Fitzgerald; professor of electrical engineering and computer science Jing Kong; and assistant professor of mechanical engineering Alexie Kolpak; along with Jared Johnson and Jinwoo Hwang from Ohio State University, and Ibraheem Almansouri of Masdar Institute of Science and Technology.

Graphene Copy II imagesGraphene shift

Since graphene’s discovery in 2004, researchers have been investigating its exceptional electrical properties in hopes of improving the performance and cost of electronic devices. Graphene is an extremely good conductor of electricity, as electrons flow through graphene with virtually no friction. Researchers, therefore, have been intent on finding ways to adapt graphene as a cheap, high-performance semiconducting material.

“People were so hopeful that we might make really fast electronic devices from graphene,” Kim says. “But it turns out it’s really hard to make a good graphene transistor.”

In order for a transistor to work, it must be able to turn a flow of electrons on and off, to generate a pattern of ones and zeros, instructing a device on how to carry out a set of computations. As it happens, it is very hard to stop the flow of electrons through graphene, making it an excellent conductor but a poor semiconductor.

Kim’s group took an entirely new approach to using graphene in semiconductors. Instead of focusing on graphene’s electrical properties, the researchers looked at the material’s mechanical features.

“We’ve had a strong belief in graphene, because it is a very robust, ultrathin, material and forms very strong covalent bonding between its atoms in the horizontal direction,” Kim says. “Interestingly, it has very weak Van der Waals forces, meaning it doesn’t react with anything vertically, which makes graphene’s surface very slippery.”

Copy and peel

The team now reports that graphene, with its ultrathin, Teflon-like properties, can be sandwiched between a wafer and its semiconducting layer, providing a barely perceptible, nonstick surface through which the semiconducting material’s atoms can still rearrange in the pattern of the wafer’s crystals. The material, once imprinted, can simply be peeled off from the graphene surface, allowing manufacturers to reuse the original wafer.

The team found that its technique, which they term “remote epitaxy,” was successful in copying and peeling off layers of semiconductors from the same semiconductor wafers. The researchers had success in applying their technique to exotic wafer and semiconducting materials, including indium phosphide, gallium arsenenide, and gallium phosphide—materials that are 50 to 100 times more expensive than silicon.

Kim says that this new technique makes it possible for manufacturers to reuse wafers—of silicon and higher-performing materials—”conceptually, ad infinitum.”

An exotic future

The group’s graphene-based peel-off technique may also advance the field of flexible electronics. In general, wafers are very rigid, making the devices they are fused to similarly inflexible. Kim says now, semiconductor devices such as LEDs and solar cells can be made to bend and twist. In fact, the group demonstrated this possibility by fabricating a flexible LED display, patterned in the MIT logo, using their technique.

“Let’s say you want to install solar cells on your car, which is not completely flat—the body has curves,” Kim says. “Can you coat your semiconductor on top of it? It’s impossible now, because it sticks to the thick wafer. Now, we can peel off, bend, and you can do conformal coating on cars, and even clothing.”

Going forward, the researchers plan to design a reusable “mother wafer” with regions made from different exotic materials. Using as an intermediary, they hope to create multifunctional, high-performance devices. They are also investigating mixing and matching various semiconductors and stacking them up as a multimaterial structure.

“Now, exotic materials can be popular to use,” Kim says. “You don’t have to worry about the cost of the wafer. Let us give you the copy machine. You can grow your semiconductor device, peel it off, and reuse the .”

Explore further: Researchers ‘iron out’ graphene’s wrinkles

More information: Remote epitaxy through graphene enables two-dimensional material-based layer transfer, Natur

Non-flammable graphene membrane developed for safe mass production – Applications in Fuel Cells, Solar Cells, Super Capacitors & Sensors


NF grapheneThis visualization shows layers of graphene used for membranes. Credit: University of Manchester

” … this makes it possible to mass-produce graphene and to improve a host of products, from fuel cells to solar cells to supercapacitors and sensors.”

University of Arkansas researchers have discovered a simple and scalable method for turning graphene oxide into a non-flammable and paper-like graphene membrane that can be used in large-scale production.

“Due to their and excellent charge and heat conductivities, graphene-based materials have generated enormous excitement,” said Ryan Tian, associate professor of in the J. William Fulbright College of Arts and Sciences. “But high flammability jeopardizes the material’s promise for large-scale manufacturing and wide applications.”

Graphene’s extremely high flammability has been an obstacle to further development and commercialization. However, this makes it possible to mass-produce graphene and to improve a host of products, from fuel cells to solar cells to supercapacitors and sensors. Tian has a provisional patent for this new discovery.

Using metal ions with three or more positive charges, researchers in Tian’s laboratory bonded graphene-oxide flakes into a transparent membrane. This new form of carbon-polymer sheet is flexible, nontoxic and mechanically strong, in addition to being non-flammable.

Further testing of the material suggested that crosslinking, or bonding, using transition metals and rare-earth metals, caused the to possess new semiconducting, magnetic and optical properties.

For the past decade, scientists have focused on graphene, a two-dimensional material that is a single atom in thickness, because it is one of the strongest, lightest and most conductive materials known. For these reasons, graphene and similar two-dimensional materials hold great potential to substitute for traditional semiconductors. Graphene oxide is a common intermediate for graphene and graphene-derived materials made from graphite, which is a crystalline form of carbon.

The researchers’ findings were published in The Journal of Physical Chemistry C.

Explore further: New study shows nickel graphene can be tuned for optimal fracture strength

More information: Hulusi Turgut et al. Multivalent Cation Cross-Linking Suppresses Highly Energetic Graphene Oxide’s Flammability, The Journal of Physical Chemistry C (2017). DOI: 10.1021/acs.jpcc.6b13043

 

Graphene in 2017: The Story So Far ~ An Update


Graphene 2017 ImageForArticle_4454(1)

In October 2004, University of Manchester’s Andre Geim, along with his colleague Kostya Novoselov, discovered published their discovery that when a block of graphite is broken down to just 10 or 100 layers thick, a material known as graphene emerges1.

With substantial material properties involving its superior strength as well as both heat and electricity conductibility, while remaining such a thin material, graphene has become one of the most studied materials to date.

While graphene is most often employed in disciplines such as bioengineering, composite materials, energy technology and nanotechnology, its ability to be interjected with other elements allows for its applications to be limitless.directa-plus-colmar-graphene-ski-jacket

One of the most pressing challenges that the graphene industry faces is a lack of pure production of the material. A recent research report conducted by the Centre for Advanced 2 D Materials (CA2DM) at the National University of Singapore has found that most graphene production companies generate a material that is comprised of a graphene content of only 2-10%2.

Canadian based company Elcora Advanced Materials Corporation has become one of the leading graphene producers in the world, while also maintaining products comprised of 55% graphene content. As its unique designed processing technology not only works towards achieving the purest form of graphene possible, Elcora ensures the cost effective production of graphene from natural graphite in a green and efficient manner.

Learn more about Elcora Advanced Materials

By minimizing the need for using harsh chemicals, while also eliminating the environmentally damaging byproducts or waste that often follow graphene production, Elcora is one of the most environmentally safe graphene plants available today3.

After acquiring control of the Ragedera graphite mine located in Colombo, Sri Lanka, Elcora Advanced Material has been able to successfully produce an estimated 18,000 tonnes of high quality graphite per year.

 

With production bases located in both South Wales and Seoul, Korea, Haydale Graphene Industries is one of the numerous companies working towards enhancing the carbon fiber composites for specific aerospace and automotive needs. In doing so, research conducted by both Haydale and scientists from the School of Engineering at Cardiff University have investigated how the addition of graphene nanoplaatelets (GP) and carbon nanotubes (CNT) into the composites can allow for reinforcing benefits of the technology.

These benefits include an increased resistance and tolerance to damage of the vehicle, while also showing a 13% increase in the compression strength following impact performance studies. By positively influencing composites such as aircraft wings and automobile parts, Haydale has improved these important properties that are required for maintaining such high performance structures4.

Learn more about Haydale

In addition to achieving such impressive material improvements, the techniques employed during this process were performed in a much more cost effective, green and efficient manner. The process employed in the development of this composite involved treating the surface of the nanomaterials with Haydale’s low temperature and low energy HDPlas ® plasma process4.

This plasma functionalization process not only produces high integrity materials, but also avoids the typical waste production associated with functionalization processes while simultaneously promoting homogenous dispersion and chemical bonding. Haydale researchers are hopeful that this newly developed material can allow for lighter and stronger wings to be implemented into aircraft deisgns that can simultaneously reduce the amount of carbon dioxide emissions released by these aircrafts.

Rahul Nair from the University of Manchester in the United Kingdom has recently developed a method involving the use of graphene oxide in order to effectively desalinate water. Considered to be the oxidized form of graphene, graphene oxide membranes have recently emerged as an excellent membrane material that is capable of separating multiple different types of molecules and ions present in an aqueous solution5.

The sieving potential of graphene oxide membranes has been successful in removing small nanoparticles, organic molecules and large salts from solution; however, their ability to filter out common salts has not been documented until now. Previous attempts at employing graphene oxide membranes in the filtration of smaller salts in water have caused the membranes to expand and prevent the flow of water from entering the pores of the membrane.Graphene Mem 050815 3-anewapproach

By placing walls composed of a substance known as epoxy resin that is typically used in glues and coatings on either side of the graphene oxide membrane, the team of researchers led by Dr. Nair was able to successfully prevent the swelling of the membranes upon its immersion in water6.

With a uniform pore size within the membrane of only 0.9 nm in width, this highly selective graphene oxide membrane has several advantages as compared to its bulk counterpart, graphene7. As a much more inexpensive option coupled with a long operational lifetime, graphene oxide membranes have a spectacular separation potential that could have a significant impact in a wide variety of energy reduction and environmental conservation industries around the world.

Outside of its potential for water purification purposes, researchers believe that this technology could also provide a useful addition in the dehydration and purification of biofuels. In most biofuel processes, water is formed as a byproduct, and its presence in the biofuel can affect the final product in a detrimental way. Therefore, the hope is that the application of graphene oxide membranes in this industrial process could have an advantageous use.

Request more information about Graphene

Similarly, graphene oxide membranes have a well-documented gas separation ability that prevents any vapor molecules from passing through the membrane. In one of the first studies illustrating this property, researchers measured the loss of weight within a containing initially filled with alcohol before and after it was sealed with a graphene oxide membrane8.

Following the membrane sealing, researchers found that no noticeable variation in the weight of or the pressure within the container was detected. As a result of this remarkable gas separation property, researchers are hopeful the use of graphene oxide membranes can be applied to the controlling of greenhouse gas emissions, as well as the purification of hydrogen-related clean energy gases, in future real world applications.

The University of Cambridge has recently developed a highly conductive ink known as ‘Graphene – IPA Ink.” Composed of powdered graphite dissolved in alcohol, this ink has the potential to be used in inkjet printers that print electrical circuits onto paper.

By forcing the ink through a micrometer-scale capillary at an extremely high pressure, the resulting product is a smooth and conductive material9. Researchers are hopeful that devices such as Radio Frequency Identification (RFID) antennas, passports, electronic tags, and similar everyday items can be printed at a much cheaper rate with the application of electronic circuits printed using this graphene ink.Graphene defectsarepe

While graphene may appear to be a single product, it has developed into several different types of applications in its short 13-year live span since its first entrance into the scientific world. Its wide range of uses allow for this material to have a promising future, in which its varying and impressive properties of transparency, strength and conductivity can improve almost every industry of the world.

The world of two-dimensional materials, like graphene, have allowed for researchers to manipulate different geometries and combinations of these compounds to create wonderful new products of the future. As research and development projects continue to work on graphene and its numerous applied products, new two-dimensional materials continue to be discovered each day in continuance of this revolutionary pathway that has set by graphene.

References

  1. “This Month in Physics History.” American Physical Society. 22 Oct. 2014. Web. https://www.aps.org/publications/apsnews/200910/physicshistory.cfm.
  2. “Graphene R&D.” Elcora Advanced Materials. Web. https://www.elcoracorp.com/graphene-rd/.
  3. Ecclestone, Christopher. “Analyst on How Elcora Has Positioned Themselves as a Leader in the Graphite Space.” InvestorIntel. 06 Apr. 2017. Web. https://investorintel.com/sectors/technology-metals/technology-metals-intel/elcora-pulling-ahead-leadership-graphite-space/.
  4. “Carbon Fibre Composites.” Haydale. 11 Nov. 2014. Web. http://www.haydale.com/news/graphene-toughened-composites-a-milestone-for-next-generation-aerospace-structures/.
  5. An, Di, Ling Yang, Ting-Jie Wang, and Boyang Liu. “Separation Performance of Graphene Oxide Membrane in Aqueous Solution.” Industrial & Engineering Chemistry Research 55.17 (2016): 4803-810. Web.
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  10. Image Credit: Shutterstock.com/OliveTree

 

Link to Original Article from AzNano

MIT: “Ironing out” graphene’s wrinkles to make ‘Pristine Graphene’ ~ Promising Successor to Silicon (at the ‘Speed of Light’)


MIT-Wrinkle Single-Domain_0.jpg

Researchers at MIT have found a way to make graphene with fewer wrinkles, and to iron out the wrinkles that do appear. They found each wafer exhibited uniform performance, meaning that electrons flowed freely across each wafer, at similar speeds, even across previously wrinkled regions.

New technique produces highly conductive graphene wafers.

” … electrons can blitz through graphene at velocities approaching the speed of light, far faster than they can travel through silicon and other semiconducting materials.

” … Graphene, therefore, has been touted as a promising successor to silicon, with the potential to enable faster, more efficient electronic and photonic devices.”

” … pristine graphene — a single, perfectly flat, ultrathin sheet of carbon atoms, precisely aligned and linked together like chickenwire — is extremely difficult.”

” … which can derail an electron’s bullet-train journey, significantly limiting graphene’s electrical performance.”

From an electron’s point of view, graphene must be a hair-raising thrill ride. For years, scientists have observed that electrons can blitz through graphene at velocities approaching the speed of light, far faster than they can travel through silicon and other semiconducting materials.

Graphene, therefore, has been touted as a promising successor to silicon, with the potential to enable faster, more efficient electronic and photonic devices.

But manufacturing pristine graphene — a single, perfectly flat, ultrathin sheet of carbon atoms, precisely aligned and linked together like chickenwire — is extremely difficult. Conventional fabrication processes often generate wrinkles, which can derail an electron’s bullet-train journey, significantly limiting graphene’s electrical performance.

Now engineers at MIT have found a way to make graphene with fewer wrinkles, and to iron out the wrinkles that do appear. After fabricating and then flattening out the graphene, the researchers tested its electrical conductivity. They found each wafer exhibited uniform performance, meaning that electrons flowed freely across each wafer, at similar speeds, even across previously wrinkled regions.

In a paper published today in the Proceedings of the National Academy of Sciences, the researchers report that their techniques successfully produce wafer-scale, “single-domain” graphene — single layers of graphene that are uniform in both atomic arrangement and electronic performance.

“For graphene to play as a main semiconductor material for industry, it has to be single-domain, so that if you make millions of devices on it, the performance of the devices is the same in any location,” says Jeehwan Kim, the Class of 1947 Career Development Assistant Professor in the departments of Mechanical Engineering and Materials Science and Engineering at MIT. “Now we can really produce single-domain graphene at wafer scale.”graphene wonder material images

Kim’s co-authors include Sanghoon Bae, Samuel Cruz, and Yunjo grapehene electronics imagesKim from MIT, along with researchers from IBM, the University of California at Los Angeles, and Kyungpook National University in South Korea.

A patchwork of wrinkles

The most common way to make graphene involves chemical vapor deposition, or CVD, a process in which carbon atoms are deposited onto a crystalline substrate such as copper foil. Once the copper foil is evenly coated with a single layer of carbon atoms, scientists submerge the entire thing in acid to etch away the copper. What remains is a single sheet of graphene, which researchers then pull out from the acid.

The CVD process can produce relatively large, macroscropic wrinkles in graphene, due to the roughness of the underlying copper itself and the process of pulling the graphene out from the acid. The alignment of carbon atoms is not uniform across the graphene, creating a “polycrystalline” state in which graphene resembles an uneven, patchwork terrain, preventing electrons from flowing at uniform rates.

In 2013, while working at IBM, Kim and his colleagues developed a method to fabricate wafers of single-crystalline graphene, in which the orientation of carbon atoms is exactly the same throughout a wafer.

Rather than using CVD, his team produced single-crystalline graphene from a silicon carbide wafer with an atomically smooth surface, albeit with tiny, step-like wrinkles on the order of several nanometers. They then used a thin sheet of nickel to peel off the topmost graphene from the silicon carbide wafer, in a process called layer-resolved graphene transfer.

Ironing charges

In their new paper, Kim and his colleagues discovered that the layer-resolved graphene transfer irons out the steps and tiny wrinkles in silicon carbide-fabricated graphene. Before transferring the layer of graphene onto a silicon wafer, the team oxidized the silicon, creating a layer of silicon dioxide that naturally exhibits electrostatic charges. When the researchers then deposited the graphene, the silicon dioxide effectively pulled graphene’s carbon atoms down onto the wafer, flattening out its steps and wrinkles.

Kim says this ironing method would not work on CVD-fabricated graphene, as the wrinkles generated through CVD are much larger, on the order of several microns.

“The CVD process creates wrinkles that are too high to be ironed out,” Kim notes. “For silicon carbide graphene, the wrinkles are just a few nanometers high, short enough to be flattened out.”

To test whether the flattened, single-crystalline graphene wafers were single-domain, the researchers fabricated tiny transistors on multiple sites on each wafer, including across previously wrinkled regions.

“We measured electron mobility throughout the wafers, and their performance was comparable,” Kim says. “What’s more, this mobility in ironed graphene is two times faster. So now we really have single-domain graphene, and its electrical quality is much higher [than graphene-attached silicon carbide].”

Kim says that while there are still challenges to adapting graphene for use in electronics, the group’s results give researchers a blueprint for how to reliably manufacture pristine, single-domain, wrinkle-free graphene at wafer scale.

“If you want to make any electronic device using graphene, you need to work with single-domain graphene,” Kim says. “There’s still a long way to go to make an operational transistor out of graphene. But we can now show the community guidelines for how you can make single-crystalline, single-domain graphene.”