Eco-Friendly Desalination using MOF’s could Supply the Lithium needed to Manufacture Batteries required to Mainstream EV’s


A new water purification (desalination) technology could be the key to more electric cars. How?

“Eco-Friendly Mining” of world’s the oceans for the vast amounts of lithium required for EV batteries, could “mainstream” our acceptance (affordability and accessibility) of Electric Vehicles and provide clean water – forecast to be in precious short supply in many parts of the World in the not so distant future.

energy_storage_2013-042216-_11-13-1Humanity is going to need a lot of lithium batteries if electric cars are going to take over, and that presents a problem when there’s only so much lithium available from conventional mines.

A potential solution is being researched that turns the world’s oceans into eco-friendly “Lithium supply mines.”

Scientists have outlined a desalination technique that would use metal-organic frameworks (sponge-like structures with very high surface areas) with sub-nanometer pores to catch lithium ions while purifying ocean water.

The approach mimics the tendency of cell membranes to selectively dehydrate and carry ions, leaving the lithium behind while producing water you can drink.

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While the concept of extracting lithium from our oceans certainly isn’t new, this new technology method would be much more efficient and environmentally friendly.

Instead of tearing up the landscape to find mineral deposits, battery makers would simply have to deploy enough filters.

It could even be used to make the most of water when pollution does take place — recovering lithium from the waste water at shale gas fields.

This method will require more research and development before it’s ready for real-world use.

However, the implications are already clear. If this desalination approach reaches sufficient scale, the world would have much more lithium available for electric vehicles, phones and other battery-based devices. It would also reduce the environmental impact of those devices. storedot-ev-battery-21-889x592 (1)

While some say current lithium mining practices negates some of the eco-friendliness of an EV, this “purification for Lithium” approach could let you drive relatively guilt-free

Reposted from Jonathan Fingas – Engadget

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An Ultra-Thin – Wearable Health Monitor made possible by a ‘Graphene Ink Tattoo’ designed and developed at the University of Texas at Austin


University of Texas at Austin. This is the world’s thinnest wearable Health Monitor, designed and developed by the researchers at the University of Texas at Austin, in the form of a “Graphene-Ink Tattoo”.

Most health monitors in use today are bulky and tend to restrict patients movements. This graphene tattoo will eliminate these restrictions. It picks up electric signal given off by the body and transmits it to a smartphone app.

Watch the Video:

Abstract: Tattoo-like epidermal sensors are an emerging class of truly wearable electronics, owing to their thinness and softness. While most of them are based on thin metal films, a silicon membrane, or nanoparticle-based printable inks, we report sub-micrometer thick, multimodal electronic tattoo sensors that are made of graphene.UT Autin Graphene Ink Tattoo maxresdefault (2)

The graphene electronic tattoo (GET) is designed as filamentary serpentines and fabricated by a cost- and time-effective “wet transfer, dry patterning” method. It has a total thickness of 463 ± 30 nm, an optical transparency of ∼85%, and a stretchability of more than 40%.

The GET can be directly laminated on human skin just like a temporary tattoo and can fully conform to the microscopic morphology of the surface of skin viajust van der Waals forces. The open-mesh structure of the GET makes it breathable and its stiffness negligible. A bare GET is able to stay attached to skin for several hours without fracture or delamination.

Wearable Health Patches 150929112030_1_540x360With liquid bandage coverage, a GET may stay functional on the skin for up to several days. As a dry electrode, GET–skin interface impedance is on par with medically used silver/silver-chloride (Ag/AgCl) gel electrodes, while offering superior comfort, mobility, and reliability. GET has been successfully applied to measure electrocardiogram (ECG), electromyogram (EMG), electroencephalogram (EEG), skin temperature, and skin hydration.

Read More Here

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Rice University Expands LIG (laser induced graphene) Research and Applications: Supercapacitor, an Electrocatalyst for Fuel Cells, RFID’s and Biological Sensors


J Tour Graphene on Toast 162948_webIMAGE: THIS IS RICE UNIVERSITY GRADUATE STUDENT YIEU CHYAN, LEFT, AND PROFESSOR JAMES TOUR. view more  CREDIT: JEFF FITLOW/RICE UNIVERSITY

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

laser-induced-graphene-900x420

Laser-Induced graphene supercapacitors may be the future of wearables

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

All-Carbon_Graphene_Supercapacitors_Coming1

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

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Rice alumnus Ruquan Ye is co-lead author of the study. Co-authors are Rice graduate student Yilun Li and postdoctoral fellow Swatantra Pratap Singh and Professor Christopher Arnusch of Ben-Gurion University of the Negev, Israel. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research supported the research.

ANTIBACTERIAL APPLICATIONS OF GRAPHENE OXIDES


Bacterial infections are among the greatest threats to human health. However, due to the increasing spread of multidrug-resistant bacteria, the current antibiotic supply appears to be insufficient, thereby necessitating the exploration of novel antibacterial agents.

Nano-antibacterial agents represent a new strategy for bacterial treatment. Compared with antibiotics, nano-antibacterial agents have two advantages: (1) broad-spectrum bactericidal effects against Gram-positive and Gram-negative bacteria and (2) long-lasting bactericidal effects due to their extraordinary stability.

Significant differences exist in the antibacterial mechanisms between antibiotics and nano-antibacterial agents. Antibiotics can prevent bacterial growth by inhibiting the synthesis of target biomolecules in bacteria, including the cell wall, DNA and proteins.

Nano-antibacterial agents kill bacteria through membrane destruction, oxidative stress response, and interactions with cytosolic molecules (lipids, proteins, DNA, etc.).

Graphene oxide (GO) has antibacterial applications. A review titled “Antibacterial Applications of Graphene Oxides: Structure-Activity Relationships, Molecular Initiating Events and Biosafety,” published in Science Bulletin, primarily discusses the structure-activity relationships (SARs) involved in GO-induced antibacterial action, the molecular initiating events (MIEs), and the biosafety of antibacterial applications.

GO possesses a unique two-dimensional (2-D) honeycombed hydrophobic plane structure and hydrophilic groups, including carboxylic (-COOH) and hydroxyl (-OH) groups on its edge, which determine its excellent antibacterial activity. Among these antibacterial mechanisms, this review summarizes the interactions between GO and the bacterial membrane, especially the significant role of MIEs, including redox reactions with biomolecules, mechanical destruction of membranes, and catalysis of extracellular metabolites.

The review also discusses in detail the physicochemical effect of GO on the bacterial membrane, such as phospholipid peroxidation, insertion, wrapping and the trapping effect, lipid extraction, and free radicals induced by GO.

The full article is available below.

Source: Phys Org

Nanographenes Attracting wide interest from Researchers – ‘Zipping-up’ rings to Make Nanographenes


Graphene Nanorings 162497_webA fast and efficient method for graphene nanoribbon synthesis

INSTITUTE OF TRANSFORMATIVE BIO-MOLECULES (ITBM), NAGOYA UNIVERSITY

Nanographenes are attracting wide interest from many researchers as a powerful candidate for the next generation of carbon materials due to their unique electric properties. Scientists at Nagoya University have now developed a fast way to form nanographenes in a controlled fashion. This simple and powerful method for nanographene synthesis could help generate a range of novel optoelectronic materials, such as organic electroluminescent displays and solar cells.

Nagoya, Japan – A group of chemists of the JST-ERATO Itami Molecular Nanocarbon Project and the Institute of Transformative Bio-Molecules (ITbM) of Nagoya University, and their colleagues have developed a simple and powerful method to synthesize nanographenes. This new approach, recently described in the journal Science, is expected to lead to significant progress in organic synthesis, materials science and catalytic chemistry.

Nanographenes, one-dimensional nanometer-wide strips of graphene, are molecules composed of benzene units. Nanographenes are attracting interest as a powerful candidate for next generation materials, including optoelectronic materials, due to their unique electric characteristics. These properties of nanographenes depend mainly on their width, length and edge structures. Thus, efficient methods to access structurally controlled nanographenes is highly desirable.

The ideal synthesis of nanographenes would be a ‘LEGO’-like assembly of benzene units to define the exact number and shape of the molecule. However, this direct approach is currently not possible. The team developed an alternative method that is simple and controls the nanographene structure as it forms in three key steps.

First, simple benzene derivatives are assembled linearly, through a cross-coupling reaction. Then, these benzene chains are connected to each other by a palladium catalyst that leads to a molecule with three benzene rings bound together in a flat, triangle-like shape. This process repeats all the way up the chain, effectively zipping up the rings together.

The innovation the team developed was a new way to achieve the middle step that forms the three-ring triangle-like unit that forms the core for further reactions to generate the nanographene molecule. A classic technique to connect benzene units uses aryl halides as reaction reagents. Aryl halides are aromatic compounds in which one or more hydrogen atoms bonded to an aromatic ring are replaced by halogen atoms such as fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). This allows benzene to connect at a single point through a process called dimerization, which was discovered by Fritz Ullmann and Jean Bielecki in 1901. However, the Ullmann reaction does not generate nanographenes when using the compound phenylene as the starting material.

The team discovered that using a palladium catalyst enabled connections between benzene units at two points, providing the triangle-like structure of three benzene rings. A triphenylene moiety is formed in the center of each group of rings.

“This discovery was quite accidental,” says Designated Associate Professor Kei Murakami, a chemist at Nagoya University and one of the leaders of this study. “We think that this reaction is the key of this new approach for nanographene synthesis.”

The team then utilized a process called the Scholl reaction to repeat this process and successfully synthesize a nanographene molecule. The reaction proceeds in a similar manner to benzene rings being zipped up, with the triphenylene moiety acting as the core.

“One of the most difficult parts of this research was obtaining scientific evidence to prove the structures of the triphenylene derivative and nanographene molecules,” says Yoshito Koga, a graduate student who mainly conducted the experiments. “Since no one in our group has ever handled triphenylenes and nanographenes before, I was conducting the research through a ‘trial and error’ manner. I was extremely excited when I first saw the mass spectrometry signal of the desired molecule to reveal the mass of the molecule through MALDI (Matrix Assisted Laser Desorption/Ionization), which indicated that we had actually succeeded in making nanographene in a controlled fashion.”

The team had already succeeded in synthesizing various triphenylene derivatives, such as molecules including 10 benzene rings, naphthalene (a fused pair of benzene rings), nitrogen atoms, and sulfur atoms. These unprecedented triphenylene derivatives could potentially be used in solar cells.

“The approach for creating functional molecules from simple benzene units will be applicable to the synthesis of not only nanographene, but also to various other nanocarbon materials,” says Murakami.

“Nanographenes are bound to be useful as future materials,” says Professor Kenichiro Itami, director of the JST-ERATO Itami Molecular Nanocarbon Project. “We hope that our discovery will lead to the acceleration of applied research and advance the field of nanographene science.”

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This article “Synthesis of partially and fully fused polyaromatics by annulative chlorophenylene dimerization” by Yoshito Koga, Takeshi Kaneda, Yutaro Saito, Kei Murakami and Kenichiro Itami is published online in Science. DOI: 10.1126/science.aap9801

JST-ERATO Itami Molecular Nanocarbon Project

The JST-ERATO Itami Molecular Nanocarbon Project was launched at Nagoya University in April 2014. This is a 5-year project that seeks to open the new field of nanocarbon science. This project entails the design and synthesis of as-yet largely unexplored nanocarbons as structurally well-defined molecules, and the development of novel, highly functional materials based on these nanocarbons. Researchers combine chemical and physical methods to achieve the controlled synthesis of well-defined uniquely structured nanocarbon materials, and conduct interdisciplinary research encompassing the control of molecular arrangement and orientation, structural and functional analysis, and applications in devices and biology. The goal of this project is to design, synthesize, utilize, and understand nanocarbons as molecules.

About WPI-ITbM

The Institute of Transformative Bio-Molecules (ITbM) at Nagoya University in Japan is committed to advance the integration of synthetic chemistry, plant/animal biology and theoretical science, all of which are traditionally strong fields in the university. ITbM is one of the research centers of the Japanese MEXT (Ministry of Education, Culture, Sports, Science and Technology) program, the World Premier International Research Center Initiative (WPI). The aim of ITbM is to develop transformative bio-molecules, innovative functional molecules capable of bringing about fundamental change to biological science and technology. Research at ITbM is carried out in a “Mix Lab” style, where international young researchers from various fields work together side-by-side in the same lab, enabling interdisciplinary interaction. Through these endeavors, ITbM will create “transformative bio-molecules” that will dramatically change the way of research in chemistry, biology and other related fields to solve urgent problems, such as environmental issues, food production and medical technology that have a significant impact on the society.

About JST-ERATO

ERATO (The Exploratory Research for Advanced Technology), one of the Strategic Basic Research Programs, aims to form a headstream of science and technology, and ultimately contribute to science, technology, and innovation that will change society and the economy in the future. In ERATO, a Research Director, a principal investigator of ERATO research project, establishes a new research base in Japan and recruits young researchers to implement his or her challenging research project within a limited time frame.

SWEDISH START-UP ENABLES FULL-SCALE IMPLEMENTATION OF GRAPHENE


A breakthrough at Uppsala University has solved the practical implementation issues of the world’s strongest material graphene.

Up until now a major challenge has been agglomeration under upscaling that has effectively prevented utilization of the fantastic properties of graphene in real-life applications.

The novel hybrid ionic graphene material named Aros Graphene® solves this and is expected to revolutionize the way we design electronics, energy storage and mechanical systems. The highly anticipated revolution of graphene just came one step closer.

Graphene is a two-dimensional carbon material that is only one atom thick and it is the strongest and thinnest material ever known. It is also extremely conductive for heat and electricity as well as ultra-light and transparent. It was first isolated in 2004 and was rewarded with the Nobel prize in 2010.

Graphene is predicted to revolutionize the energy sector and electronics and we could even build lightweight aircraft of graphene composites in the future.

But until now there has been one major challenge with graphene. More than 10 years after the first isolation of graphene we can still use it in very limited applications. Graphene’s properties dramatically degrades under upscaling.

Researchers all over the world have been struggling with this challenge and recently a breakthrough was made at the Ångström Laboratory, Uppsala University in Sweden.

A major challenge of working with graphene was the agglomeration under upscaling. We had fantastic properties at the nano-scale and less encouraging properties at macro-scale. The challenges have driven me to intensively think about solutions to bring such a wonder-material to industrial products while keeping its amazing properties, says Dr. Mamoun Taher.

Dr. Mamoun Taher is a material scientist of Syrian origin, who came to Sweden in 2010 for his masters and PhD studies. Since 2015 he has been doing research at the Ångström Laboratory at Uppsala University and has also been working on graphene related projects with ABB, one of the largest engineering companies in the world.

Aros Graphene® is a hybrid ionic graphene material that is easy and eco-friendly to manufacture and can be applied as an additive into a matrix, a coating or even by 3D printing.

With Aros Graphene® we can finally realize the full potential of graphene and we have already shown that in preliminary tests with potential customers. The first commercial applications will be available in 2019.

The most remarkable discovery was, however, not that we had produced a new material but the striking properties we found that this novel material possessed.

It turns out that Aros Graphene® has the electrical and thermal properties of graphene not only in two dimensions but in 3D, and furthermore the surface has extremely low friction and high wear resistance.

This novel material is expected to pave the way for new sustainable products in a number of industrial applications, says Björn Lindh, entrepreneur, previously in Disruptive Materials with the famous material Upsalite®, and now co-founder of Graphmatech, which will commercialize Aros Graphene®.

Graphmatech has been accepted both to the EU-sponsored incubator program InnoEnergy and ABB’s Innovation and Growth hub SynerLeap and got initial funding from Vinnova. The next step is to prove Aros Graphene® in different customer applications.

Additional information, pictures and data about Aros Graphene®, Graphmatech can be found at www.graphmatech.com

Stanford University: Lithium/graphene “foil” makes for a great battery electrode – 2X current Energy Density


Graphene handles the issues that come with an electrode’s lithium moving elsewhere.

Lithium ion batteries, as the name implies, work by shuffling lithium atoms between a battery’s two electrodes. So, increasing a battery’s capacity is largely about finding ways to put more lithium into those electrodes. These efforts, however, have run into significant problems.

If lithium is a large fraction of your electrode material, then moving it out can cause the electrode to shrink. Moving it back in can lead to lithium deposits in the wrong places, shorting out the battery.

Now, a research team from Stanford has figured out how to wrap lots of lithium in graphene. The resulting structure holds a place open for lithium when it leaves, allowing it to flow back to where it started.

Tests of the resulting material, which they call a lithium-graphene foil, show it could enable batteries with close to twice the energy density of existing lithium batteries.

Lithium behaving badly

One obvious solution to increasing the amount of lithium in an electrode is simply to use lithium metal itself. But that’s not the easiest thing to do. Lithium metal is less reactive than the other members of its column of the periodic table (I’m looking at you, sodium and potassium), but it still reacts with air, water, and many electrolyte materials.

In addition, when lithium leaves the electrode and returns, there’s no way to control where it re-forms metal. After a few charge/discharge cycles, the lithium electrode starts to form sharp spikes that can ultimately grow large enough to short out the battery.

To have better control over how lithium behaves at the electrode, the Stanford group has looked into the use of some lithium-rich alloys. Lithium, for example, forms a complex with silicon where there are typically over four lithium atoms for each atom of silicon. When the lithium leaves the electrode, the silicon stays behind, providing a structure to incorporate the lithium when it returns on the other half of the charge/discharge cycle.

While this solves the problems with lithium metal, it creates a new one: volume changes. The silicon left behind when the lithium runs to the other electrode simply doesn’t take up as much volume as it does when the same electrode is filled with the lithium-silicon mix.

As a result, the electrode expands and contracts dramatically during a charge-discharge cycle, putting the battery under physical stress. (Mind you, a lithium metal electrode disappears entirely, possibly causing an even larger mechanical stress.)

And that would seem to leave us stuck. Limiting the expansion/contraction of the electrode material would seem to require limiting the amount of lithium that moves into and out of it. Which would, of course, mean limiting the energy density of the battery.

Between the sheets

In the new work, the researchers take their earlier lithium-silicon work and combine it with graphene. Graphene is a single-atom-thick sheet of carbon atoms linked together, and it has a number of properties that make it good for batteries. It conducts electricity well, making it easy to shift charges to and from the lithium when the battery charges and discharges. It’s also extremely thin, which means that packing a lot of graphene molecules into the electrode doesn’t take up much space. And critically for this work, graphene is mechanically tough.

To make their electrode material, the team made nanoparticles of the lithium-silicon material. These were then mixed in with graphene sheets in an eight-to-one ratio. A small amount of a plastic precursor was added, and the whole mixture was spread across a plastic block. Once spread, the polymer precursor created a thin film of polymer on top of the graphene-nanoparticle mix. This could be peeled off, and then the graphene-nanoparticle mix could be peeled off the block as a sheet.

The resulting material, which they call a foil, contains large clusters of the nanoparticles typically surrounded by three to five layers of graphene. Depending on how thick you make the foil, there can be several layers of nanoparticle clusters, each separated by graphene.

The graphene sheets make the material pretty robust, as you can fold and unfold it and then still use it as a battery electrode. They also help keep the air from reacting with the lithium inside. Even after two weeks of being exposed to the air, the foil retained about 95 percent of its capacity as an electrode. Lower the fraction of graphene used in the starting mix and air becomes a problem, with the electrode losing nearly half of its capacity in the same two weeks.

And it worked pretty well as an electrode. When the lithium left, the nanoparticles did shrink, but the graphene sheets held the structure together and kept it from shrinking. And it retained 98 percent of its original capacity even after 400 charge-discharge cycles. Perhaps most importantly, when paired with a vanadium oxide cathode, the energy density was just over 500 Watt-hours per kilogram. Current lithium-ion batteries top out at about half that.

Normally, work like this can take a while to get out of an academic lab and have a company start looking into it. In this case, however, the head of the research group Yi Cui already has a startup company with batteries on the market. So, this could take somewhat less time for a thorough commercial evaluation. The biggest sticking point may be the cost of the graphene. A quick search suggests that graphene is still thousands of dollars per kilogram, although it has come down, and lots of people are looking for ways to make it even less expensive.

If they succeed, then the rest of the components of this electrode are pretty cheap. And the process for making it seems pretty simple.

Nature Nanotechnology, 2017. DOI: 10.1038/NNANO.2017.129  (About DOIs).

Graphene girders extend the life of lithium-ion batteries


Nanoscale reinforcement with graphene girders boosts performance of silicon anodes, Warwick team discovers

When you want to make a structure stronger, put a girder across it. It’s a simple principle that every civil engineer knows well. But a team at Warwick Manufacturing Group has found that it applies just as well on very small scales as in megastructures. Melanie Loveridge and colleagues are studying methods for improving lithium-ion batteries, and have found that minute girders could provide an answer to a problem that has been plaguing the field.

Ever since their first introduction in the early 1990s, the anode of lithium batteries has been made of graphite. It has long been apparent that silicon would be a better material, as it can hold ten times more charge per gramme than carbon. But the mechanics of lithium ion batteries, where lithium ions are absorbed into the anode, create problems.

When silicon is lithiated, it expands. But it is an inelastic material, and repeated expansion and contraction — as happens during charge-discharge cycles — can lead to cracking and crumbling, which makes the capacity of the battery fade over time. Graphene has been tried as a reinforcing material for nanostructured silicon, but this has led to other problems.

Loveridge’s team is looking at a material known as FLG (few-layer graphene). As the name implies, this is composed of a few connected layers of single-atom-thick graphene sheets, which can be manipulated together.

In a paper in Nature Scientific Reports, the WMG team describes how FLG can improve the performance of anodes containing micron-sized particles of silicon. The team started with a mixture of 60 per cent micro-silicon, 16 per cent FLG, 14 per cent sodium/polyacrylic acid and 10 per cent carbon additives, and put these anodes through 100 charge-discharge cycles.

“The flakes of FLG were mixed throughout the anode and acted like a set of strong, but relatively elastic, girders. These flakes of FLG increased the resilience and tensile properties of the material greatly reducing the damage caused by the physical expansion of the silicon during lithiation. The graphene enhances the long range electrical conductivity of the anode and maintains a low resistance in a structurally stable composite,” Loveridge said.

Moreover, she added, the graphene girders keep the silicon particles apart. In their absence, the particles tend to ‘weld’ together, restricting lithium diffusion through the anode and reducing the surface area available for lithiation.

“The presence of FLG in the mixture tested by the WMG University of Warwick led researchers to hypothesise that this phenomenon is highly effective in mitigating electrochemical silicon fusion,” Loveridge stated.

The team is now working on scaling up their graphene girders discovery to produce pouch cells based on their reinforced anodes, as part of a two-year graphene flagship project along with Varta Micro-innovations, Cambridge University, CIC, Lithops and IIT (Italian Institute of Technology).

Source

Graphene Research and the World’s 5 Biggest Problems: From Clean Water and Healthcare to Energy and Infastructure – Solutions based in Graphene may Hold the Key


In September 2015, world leaders gathered at a historic UN summit to adopt the Sustainable Development Goals (SDGs). These are 17 ambitious targets and indicators that help guide and coordinate governments and international organizations to alleviate global problems. For example, SDG 3 is to “ensure healthy lives and promote well-being for all at all ages.” Others include access to clean water, reducing the effects of climate change, and affordable healthcare.

If you think these goals might be difficult to meet, you’re right. Reports show progress is lacking in many of the 17 categories, implying they may not be met by the target date of 2030. However, paired with progress in social and political arenas, advances in science and technology could be a key accelerant to progress too.

Just one example? Graphene, a futuristic material with a growing set of potential applications.

Graphene is comprised of tightly-knit carbon atoms arranged into a sheet only one atom thick. This makes it the thinnest substance ever made, yet it is 200 times stronger than steel, flexible, stretchable, self-healing, transparent, more conductive than copper, and even superconductive. A square meter of graphene weighing a mere 0.0077 grams can support four kilograms. It is a truly remarkable material—but this isn’t news to science and tech geeks.

Headlines touting graphene as the next wonder material have been a regular occurrence in the last decade, and the trip from promise to practicality has felt a bit lengthy.

But that’s not unexpected; it can take time for new materials to go mainstream. Meanwhile, the years researching graphene have yielded a long list of reasons to keep at it.

Since first isolated in 2004 at the University of Manchester—work that led to a Nobel Prize in 2010— researchers all over the world have been developing radical ways to use and, importantly, make graphene. Indeed, one of the primary factors holding back widespread adoption has been how to produce graphene at scale on the cheap, limiting it to the lab and a handful of commercial applications. Fortunately, there have been advances toward mass production.

Last year, for example, a team from Kansas State University used explosions to synthesize large quantities of graphene. Their method is simple: Fill a chamber with acetylene or ethylene gas and oxygen. Use a vehicle spark plug to create a contained detonation. Collect the graphene that forms afterward. Acetylene and ethylene are composed of carbon and hydrogen, and when the hydrogen is consumed in the explosion, the carbon is free to bond with itself, forming graphene. This method is efficient because all it takes is a single spark.

Whether this technique will usher in the graphene revolution, as some have claimed, remains to be seen. What’s more certain is there will be no shortage of problems solved when said revolution arrives. Here’s a look at the ways today’s research suggests graphene may help the UN meet its ambitious development goals.

Clean Water

SDG 6 is to “ensure availability and sustainable management of water and sanitation for all.” As of now, the UN estimates that “water scarcity affects more than 40 percent of the global population and is projected to rise.”

Graphene-based filters could very well be the solution. Jiro Abraham from the University of Manchester helped develop scalable graphene oxide sieves to filter seawater. He claims, “The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes.”

Furthermore, researchers from Monash University and the University of Kentucky have developed graphene filters that can filter out anything larger than one nanometer. They say their filters “could be used to filter chemicals, viruses, or bacteria from a range of liquids. It could be used to purify water, dairy products or wine, or in the production of pharmaceuticals.”

Carbon Emissions

SDG 13 focuses on taking “urgent action to combat climate change and its impacts.”

Of course, one of the main culprits behind climate change is the excessive amount of carbon dioxide being emitted into the atmosphere. Graphene membranes have been developed that can capture these emissions.

Researchers at the University of South Carolina and Hanyang University in South Korea independently developed graphene-based filters that can be used to separate unwanted gases from industrial, commercial, and residential emissions. Henry Foley at the University of Missouri has claimed these discoveries are “something of a holy grail.”

With these, the world might be able to stem the rise of CO2 in the atmosphere, especially now that we have crossed the important 400 parts per million threshold.

Healthcare

Many around the world do not have access to adequate healthcare, but graphene may have an impact here as well.

First of all, graphene’s high mechanical strength makes it a perfect material for replacing body parts like bones, and because of its conductivity it can replace body parts that require electrical current, like organs and nerves. In fact, researchers at the Michigan Technological University are working on using 3D printers to print graphene-based nerves, and this team is developing biocompatible materials using graphene to conduct electricity.

Graphene can also be used to make biomedical sensors for detecting diseases, viruses, and other toxins. Because every atom of graphene is exposed, due to it being only one atom thick, sensors can be far more sensitive. Graphene oxide sensors, for example, could detect toxins at levels 10 times less than today’s sensors. These sensors could be placed on or under the skin and provide doctors and researchers with vast amounts of information.

Chinese scientists have even created a sensor that can detect a single cancerous cell. Further, scientists at the University of Manchester report graphene oxide can hunt and neutralize cancer stem cells.

Infrastructure

SDG 9 is to “build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation.” Graphene-enhanced composites and other building materials could bring us closer to meeting this goal.

Recent research shows that the more graphene is added, the better the composite becomes. This means graphene can be added to building materials like concrete, aluminum, etc., which will allow for stronger and lighter materials.

Resins are also getting better thanks to the addition of graphene. Research by Graphene Flagship, the EU’s billion-euro project to further graphene research, and their partner Avanzare suggests “graphene enhances the functionality of the resin, combining graphene’s electrical conductivity and mechanical strength with excellent corrosion resistance.” Some uses for this are making pipes and storage tanks corrosion-resistant, and making stronger adhesives.

Energy

SDG 7 is to “ensure access to affordable, reliable, sustainable and modern energy for all.” Because of its light weight, conductivity, and tensile strength, graphene may make sustainable energy cheaper and more efficient.

For example, graphene composites can be used to create more versatile solar panels. Researchers at MIT say, “The ability to use graphene…is making possible truly flexible, low-cost, transparent solar cells that can turn virtually any surface into a source of electric power.”

We’ll also be able to build bigger and lighter wind turbines thanks to graphene composites.

Further, graphene is already being used to enhance traditional lithium-ion batteries, which are the batteries commonly found in consumer electronics. Research is also being done into graphene aerogels for energy storage and supercapacitors. All of these will be essential for large-scale storage of renewable energy.

Over the next decade, graphene is likely to find more and more uses out in the real world, not only helping the UN and member states meet the SDGs, but enhancing everything from touch screens to MRI machines and from transistors to unknown uses as a superconductor.

New research is being published and new patents being filed regularly, so keep an eye out for this amazing material.

Manchester University: Photon-friendly graphene membranes mimic photosynthesis to produce hydrogen


Graphene membranes that mimic photosynthesis to produce hydrogen by harvesting solar energy could be developed following the discovery of a new effect.

Researchers at Manchester University have discovered that the rate at which graphene conducts protons increases 10 fold when it is illuminated with sunlight.

Dubbed the “photo-proton” effect, the finding could lead to graphene membranes being used to produce hydrogen from artificial photosynthesis, as well as for light-induced water splitting, photo-catalysis and in photodetectors.

Graphene – a one atom-thick sheet of carbon – is already known to be an extremely good conductor of electrons, and can absorb light of all wavelengths.

But it has also recently been found to be permeable to thermal protons, the nuclei of hydrogen atoms.

To discover how light affects the behaviour of these protons, the researchers fabricated graphene membranes and decorated them on one side with platinum nanoparticles.

When they illuminated the membrane with sunlight, they found the proton conductivity increased by 10 times, according to Dr Marcelo Lozada-Hidalgo, who led the research alongside Prof Sir Andre Geim.

“This is a new effect, it can only be found in graphene, there are no other materials that can use light to produce an enhancement in proton transport,” said Lozada-Hidalgo. “Scientifically this is a new physical phenomenon, which is quite remarkable.”

What’s more, when the researchers measured the photoresponsivity of the membrane using electrical measurements and mass spectrometry, they discovered that around 5,000 hydrogen molecules were being formed in response to every light particle. Existing photovoltaic devices need thousands of photons to produce a single hydrogen molecule.

“To put this in context, people have been developing silicon photodiodes for the best part of 50 years, while we did not expect this material to be responsive to light in the first place, and found that it outperforms pretty much everything that is out there,” said Lozada-Hidalgo.

The researchers have published their findings in Nature Nanotechnology. They now plan to investigate the addition of catalysts to the membrane, to enable it to split water molecules. This would allow it to act as a complete artificial leaf, said Lozada-Hidalgo.

“The goal of this project is to make an artificial leaf, to split water molecules and then use the protons to generate hydrogen,” he said. “What we’re missing is the bit to break the water in the first place, and for that we need another catalyst.”