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No more playing with fire: Study offers insight into 'safer' rechargeable batteries

Posted By Graphene Council, Friday, August 21, 2020
Lithium-ion batteries (LIBs) are a common type of rechargeable batteries. Their versatile nature and numerous applications in all sorts of electronic devices -- from mobile phones to cars -- makes them seem too good to be true. And perhaps they are: recently, there has been an increase in the number of fire-related incidents associated with LIBs, especially during charging, causing serious concerns over their safety. Scientists now know that these incidents can be due to the use of a broken or unauthorized charger. Often, improper use of these chargers and overcharging can lead to the formation of spiky structures on the negative electrode of the battery, called "lithium (Li) dendrites," which penetrate through the barrier between the negative and positive electrodes and cause a short circuit. Thus, looking at exactly how dendrite formation occurs is crucial to improving the safety of LIBs.

Scientists at Okayama University, led by Associate Professor Kazuma Gotoh, recently took a step in this direction, in a new study published in Journal of Materials Chemistry A. They delved into finding the precise mechanism of dendrite formation in LIBs, in an effort to overcome their limitations and make their practical application easier. Dr Gotoh explains, "We wanted to analyze the formation of metal dendrites in secondary (rechargeable) batteries and contribute to improve the safety of batteries."

Previous studies that tried to understand the process of Li dendrite formation were successful to some extent: they revealed that when the battery is in an overcharged state, dendrite formation occurs in the "overlithiation" phase of the battery cycle. But, these experiments were performed ex situ (outside the actual electrochemical environment), and thus the exact time of onset of dendrite formation was not found. In their new study, Dr Gotoh and his team decided to overcome this limitation. They figured that by applying "operando" methods (which replicate the electrochemical environment) to an analytical technique called "nuclear magnetic resonance" (NMR), they can accurately track the Li atoms in the inner structure of materials, which is not possible when using ex situ methods.

Using this technique, the team had previously succeeded in observing the overcharged states of two types of negative electrodes -- graphite and hard carbon electrodes -- in the overlithiation phase of an LIB. In the new study, they took this to the next level by observing the state of these electrodes during the lithiation and delithiation process (the "charge and discharge" cycle of the battery). Their NMR analysis helped them to track the precise onset time of dendrite formation and Li deposition in the overcharged battery, for both the graphite and hard carbon electrodes. In graphite, they found the Li dendrites form soon after the "fully lithiated" phase of the electrode occurs. In the hard carbon electrode -- in contrast -- they observed that dendrites form only after "quasimetallic" Li clusters occur in the pores of hard carbon. Thus, the scientists deduced that when the battery is overcharged, the quasimetallic Li cluster formation acts as a buffer for the formation of Li dendrites in hard carbon electrodes. They even applied the same analysis to another type of rechargeable battery, called sodium-ion battery (NIB), and found similar results. Dr Gotoh explains, "We found that some carbon materials having inner pores (such as amorphous carbon) have a buffer effect for the deposition of Li and Na dendrites during overcharging of batteries. This knowledge will play an important role in ensuring the safety of LIBs and NIBs."

By revealing the intricacies of the dendrite formation mechanisms in LIBs and NIBs, Dr Gotoh and his team provide useful insight into their safety. In fact, the scientists are optimistic that their findings can be applied to other types of rechargeable batteries in the future. Dr Gotoh concludes, "Our findings can be applied not only to LIBs and NIBs but also to next-generation secondary batteries such as all solid-state batteries. This is an important step in making their practical application easier."

With the findings of this new study, we can hope that we possibly are one step closer to realizing our dream of truly sustainable energy resources.

Tags:  Batteries  Energy Storage  Graphene  Kazuma Gotoh  Li-ion batteries  Okayama University 

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Cuspis Capital Ltd. and GMG enter into Letter of Intent for Go Public Transaction

Posted By Graphene Council, Friday, August 21, 2020
Cuspis Capital Ltd is pleased to announce it has entered into a letter of intent dated August 17, 2020 (the "LOI") with Graphene Manufacturing Group Pty Ltd. ("GMG"), a private company incorporated under the laws of Australia, whereby Cuspis and GMG will complete an arrangement, amalgamation, share exchange, or similar transaction to ultimately form the resulting issuer (the "Resulting Issuer") that will continue on the business of GMG (the "Transaction"), subject to the terms and conditions outlined below. 

Cuspis intends that the Transaction will constitute its Qualifying Transaction, as such term is defined in the policies of the Exchange. Following completion of the Transaction, the Resulting Issuer intends to list as a  Tier 2 Industrial Issuer  on the Exchange.

Tags:  Cuspis Capital  Graphene  Graphene Manufacturing Group 

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Oak Ridge National Laboratory, the University of Kentucky, and Penn State University Receive $10M to Develop Coal-Derived Carbon Products

Posted By Graphene Council, Friday, August 21, 2020
Two U.S. Department of Energy (DOE) National Laboratories, the National Energy Technology Laboratory (NETL) and Oak Ridge National Laboratory (ORNL), are working with the University of Kentucky and the Pennsylvania State University to further the research and development of coal-derived carbon fibers.

This research, valued at $10 million, will investigate all aspects of coal-derived carbon fiber production—from computational chemistry and pitch processing to the final spinning and heat treatment process of the fibers. The aim is to produce fibers with superior properties at a lower cost than currently available.

Through this effort, ORNL researchers will work to understand the chemistry and processing conditions required to produce different grades of coal-derived carbon fiber. NETL, ORNL, and the university teams will work closely to diversify U.S. coal use in domestic manufacturing, while making coal and coal-based products more attractive for export.

Because of competition from low-priced natural gas and incentivized renewable energy, the market for coal in the electric power generation sector is decreasing. However, coal-to-products opportunities can develop new markets for coal, which have the potential to offset this decrease.

For example, the market for carbon fibers is estimated to see an annual growth rate of 12 percent through 2024, driven largely by increased use in aerospace and defense applications and in light-weighting of vehicle structures. Additional market growth is also possible in other high-volume applications, such as thermal insulation for buildings and materials for construction and infrastructure.

“NETL’s demonstration of coal-based graphene to reinforce concrete and engineered plastics, along with other examples from the Advanced Coal Processing Program, shows that coal has a major role in the future, beyond electricity generation,” said NETL’s Technology Manager Joseph Stoffa. “We welcome the contributions of ORNL in this endeavor and look forward to the projects these Congressional appropriations will fund.”

The $10 million that ORNL’s Carbon Fiber Technology Facility will receive comes as a part of $30 million in fiscal year 2020 Congressional appropriations to support DOE’s Advanced Coal Processing Program. This program supports the development of technologies that can utilize coal for purposes outside the traditional thermal and metallurgical markets.

Of the $10 million funding, $4.5 million will support University of Kentucky research to determine how coal tar pitch, the carbon fiber precursor, can be tailored and optimized for the specific type of desired fiber. Additionally, $80,000 will go to the Pennsylvania State University for material characterization.

Tags:  carbon fiber  Energy  Graphene  Joseph Stoffa  National Energy Technology Laboratory  Oak Ridge National Laboratory  Pennsylvania State University  University of Kentucky 

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First Graphene Announces Study Shows Concrete is Enhanced with Graphene

Posted By Graphene Council, Thursday, August 20, 2020
First Graphene today released a technical update on the application of its proprietary PureGRAPH® graphene as an additive in cement grouts and concrete.

The study shows that graphene admixtures increase strength, reduce materials usage (reducing carbon footprint) and potentially increase longevity of products. This analysis is noteworthy since cement is estimated to amount to 6% of all CO2 emissions from human activity.

Cement is the most manufactured and traded product globally after water, which is causing enormous climate change challenges to reduce its carbon footprint. In 2015, the total mass of cement produced was 4.6 billion tonnes. This is equivalent to about 626 kg per capita, a value higher than the amount of human food consumption.

With population growth, increased urbanisation and improved living standards of the global population, the demand for concrete products continues to grow at an accelerating rate.

First Graphene Managing Director, Craig McGuckin says:
“The initial work demonstrates a low dosage of PureGRAPH® generates an increase in compressive and tensile strengths, when compared to the base product,”. Mr. McGuckin further stated “While there is a considerable amount of further work to be done, this is very encouraging for enhancing the performance of concrete both new and recycled, but equally the sustainability benefits for the environment.”

Tags:  Concrete  Craig McGuckin  First Graphene  Graphene 

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A key to cheaper renewable fuels: keeping iron from rusting

Posted By Graphene Council, Thursday, August 20, 2020
Washington State University researchers have made a key first step in economically converting plant materials to fuels: keeping iron from rusting.

The researchers have determined how to keep iron from rusting in important chemical reactions that are needed to convert plant materials to fuels, meaning that the cheap and readily available element could be used for cost-effective biofuels conversion. Led by Yong Wang, Voiland Distinguished Professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, and Shuai Wang from the State Key Laboratory for Physical Chemistry of Solid Surfaces at Xiamen University, the researchers report on their work on the cover of the July issue of ACS Catalysis.

Researchers have been trying to find more efficient ways to create fuels and chemicals from renewable plant-based resources, such as from algae, crop waste, or forest residuals. But, these bio-based fuels tend to be more expensive with less energy density than fossil fuels. One big hurdle in using plant-based feedstocks for fuel is that oxygen has to be removed from them before they can be used.

“You want to use the cheapest catalyst to remove the oxygen,” said Jean-Sabin McEwen, a co-author on the paper and associate professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering.  “Iron is a good choice because it’s super abundant.”

Iron-based catalysts show great promise for being able to remove oxygen, but because the plant materials also contain oxygen, the iron oxidizes, or rusts, during the reaction, and then the reaction stops working. The trick is to get the iron to remove the oxygen from the plants without taking up so much oxygen that the reaction stops.

In their work, the researchers anchored their iron catalyst with a carbon structure that was modified to incorporate nitrogen. The structure modifies the properties of the iron, so that it interacts less with oxygen while it continues to do the required work of removing oxygen from the plant material. The researchers used the nitrogen as a sort of control dial to tune the iron’s interaction with oxygen.

In another recently published paper in Chemical Science led by Yong Wang and Junming Sun, a research assistant professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering, the researchers discovered a durable iron-based catalyst with a thin carbon graphene layer around it. The graphene layer protected the iron while cesium ions allowed the researchers to tailor its electronic properties for the desired reaction.

“We dialed down the oxygen reaction,” Sun said. “By protecting iron and tuning its properties, these works provide the scientific basis for using earth abundant and cost-effective iron as catalysts for biomass conversion.”

The researchers are now working to better understand the chemistry of the reactions, so they can further increase the reactivity of the iron catalysts. They also will need to try their catalysts with real feedstocks instead of the model compounds used for the study. The feedstocks collected from farm fields will be more complicated in their compositions with a lot of impurities, and the researchers would also have to integrate their catalyst into a series of steps that are used in the conversion process.

“We are trying to make the conversion as economically as possible,” Wang said.  “The key is trying to find robust catalysts based on low-cost, earth abundant elements. This is a first step in that direction.”

Tags:  biofuels  Graphene  Jean-Sabin McEwen  Junming Sun  Washington State University 

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A new two-dimensional carbon allotrope -- semiconducting diamane film synthesized

Posted By Graphene Council, Thursday, August 20, 2020
Atomically thin diamond, also called diamane, is a two-dimensional carbon allotrope and has attracted considerable scientific interest due to its potential physical properties. However, previous studies suggest that atomically thin diamond films are not achievable in a pristine state because diamonds possess a three-dimensional crystalline structure and would lack chemical stability when thinned down to the thickness of diamond's unit cell due to the dangling sp3 bonds. Chemical functionalization of the surface carbons with specific chemical groups was considered necessary to stabilize the two-dimensional structure, such as surface hydrogenation or fluorination, and various substrates have also been used in these synthesizing attempts. But all of these attempts change the composition of diamond films, that is to say, the successful synthesis of a pristine diamane has up until now not been achieved.

Regulating the phase transition process of carbon materials under high pressure and high temperature is always a straightforward method for achieving diamondization. Here, a team of scientists led by Drs. Feng Ke and Bin Chen from HPSTAR (the Center for High Pressure Science and Technology Advanced Research) used this direct approach, diamondization of mechanically exfoliated few-layer graphene via compression, to synthesize the long-sought-after diamane film. The study is published in Nano Letters.

The diamondization process is usually accompanied by an opening of an energy gap and a dramatic resistance increase due to the sp2-sp3 rehybridization between carbon atoms. "The in-situ electrical transport measurements of few-layer graphene are difficult to carry out under high pressure," said Feng Ke. "However, using our recently developed photolithography-based microwiring technique to prepare film electrodes on a diamond surface for resistance measurements, we are able to study the pressure-induced sp2-sp3 diamondization transition of mechanically exfoliated graphene with layer thickness ranging from 12- to bilayer at room temperature."

Their studies demonstrate that pristine h-diamane could be synthesized by compressing trilayer and thicker graphene to above 20 GPa at room temperature, which once synthesized could be preserved to about 1.0 GPa upon decompression. "The optical absorption reveals that h-diamane has an energy gap of 2.8 ± 0.3 eV, and further band structure calculations confirm an indirect band gap of 2.7-2.9 eV," explained the co-frist-author Lingkong Zhang, a PhD student at HPSTAR. "Compared to gapless graphene, semiconducting h-diamane offers exciting possibilities for carbon-based electronic devices."

The XRD measurements have shown that the few-layer graphene to h-diamane transition is a gradual structural transition, which helps to understand the continuous resistance increase and absorbance decrease in trilayer and thicker graphene with pressure above the transition pressure. Theoretical calculations indicate that a (−2110)-oriented h-diamane is energetically stable and has a lower enthalpy than its few-layer graphene precursor above the transition pressure.

"Like the discovery of graphene, carbon nanotubes, fullerenes, and other novel carbon allotropes, the realization of a pristine diamane represents another exciting achievement in materials science," added Dr. Bin Chen, "Thermal treatment at high pressure may be helpful to preserve a pristine h-diamane to ambient pressure, as suggested from the high-temperature and high-pressure method to synthesize a pressure quenchable h-diamond. The challenges still remain to achieve the preservation and industrial applications of diamane."

Tags:  2D Materials  Bin Chen  carbon nanotubes  Feng Ke  Graphene  HPSTAR 

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Combining graphene and nitrides for high-power, high-frequency electronics

Posted By Graphene Council, Thursday, August 20, 2020
Researchers at Graphene Flagship partners CNR-IMM, Italy, CNRS-CRHEA, France, and STMicroelectronics, Poland, in collaboration with Graphene Flagship Associate Member TopGaN, Poland, collaborated on the Partnering Project GraNitE to produce graphene-enabled hot electron transistor (HET) devices. Thanks to nitride semiconductors, they achieved devices with current densities a million times higher than previous prototypes.

Nitride semiconductors are in the spotlight for their potential to be incorporated into HETs to improve their properties and performance. HETs are a type of vertical transistor that can operate at frequencies in the terahertz (THz) range, making them very valuable for applications in communications, medical diagnostics and security. Graphene is promising for applications in HETs, owing to its thinness and high conductivity. They are typically made from nitrides of gallium, aluminium or indium, or alloys of these metals. Aluminium and gallium nitrides are key ingredients in high-electron mobility transistors (HEMTs) – one of the technological foundations of 5G communications.

Gallium-based technologies do have their limitations, however, and GraNitE seeks to take advantage of graphene and layered materials to overcome them. The GraNitE team incorporated graphene as an active ingredient into high-powered aluminium-gallium nitride (AlGaN) and gallium nitride (GaN) based nitride transistors to better dissipate heat, by taking advantage of graphene's high thermal conductivity. The devices also operate at higher frequency thanks to the incorporation of high-quality graphene.

The team devised two approaches. Their first was to deposit graphene onto the surface of the nitride semiconductor using chemical vapour deposition (CVD). This resulted in highly homogeneous, nanocrystalline graphene films,1 ­­which could lead to uptake by industry. The second was to grow monolayer graphene using CVD on a copper surface, then to transfer and integrate it into thin layers of AlGaN and GaN. This method resulted in a graphene/AlGaN junction with excellent rectifying properties, ideal for applications in switches, with an injection mechanism tuneable by modifying the AlGaN composition and thickness.2

Graphene Flagship partnering project GraNitE used their graphene nitride junction as a key building block to fabricate prototype HET devices. Their devices had a low voltage threshold and an electric current density six orders of magnitude higher than those in previous silicon tests,2 representing an important advance in the development of hybrid graphene/nitride semiconductors, and paving the way for future exploitation of this technology.

"The integration of graphene and nitride semiconductors is one of the most viable approaches to harness the unique properties of these materials for industrial applications," says Filippo Giannazzo, GraNitE Project Leader and Senior Scientist at Graphene Flagship partner CNR-IMM, Italy.

Tags:  chemical vapour deposition  CNR-IMM  Filippo Giannazzo  Graphene  Graphene Flagship  semiconductors  transistor 

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BE Resources Announces Letter of Intent to Acquire Bio Graphene Solutions Inc.

Posted By Graphene Council, Thursday, August 20, 2020
BE Resources Inc. announces that has signed a non-binding letter of intent dated August 17, 2020 (the "LOI") with Bio Graphene Solutions Inc.  a private company incorporated under the Canada Business Corporations Act (the "CBCA"), which sets forth the general terms and conditions of a proposed reverse takeover transaction (the "Acquisition"). In addition and in connection with the Proposed Transaction, the parties have agreed that as a condition of closing, BGS or the Company will complete a private placement of common shares for a minimum raise of C$600,000 at a price of at least $0.15 in accordance with subsection 4.2(h) of Policy 5.4 of the TSX Venture Exchange (the "Exchange") (the "Proposed Private Placement").

The Acquisition will, pursuant to the policies of the Exchange, constitute a 'reverse takeover' of the Company. The corporation resulting from the Proposed Transaction (the "Resulting Issuer") will carry on the business of BGS as currently constituted. This is an arms-length transaction.

Pursuant to the terms of the LOI, it is intended that the Company and BGS will enter into a business combination by way of a share exchange, merger, amalgamation, arrangement, or other similar form of transaction. The final structure of the business combination is subject to receipt by the parties of tax, corporate, and securities law advice and will be agreed to and superseded by a definitive agreement (the "Definitive Agreement") between the Company and BGS with such agreement to include representations, warranties, conditions and covenants typical for a transaction of this nature.

It is proposed by BGS that the Company delist from the Exchange and apply to list on the Canadian Securities Exchange (“CSE”) with listing to be effective from closing.

The Acquisition is subject to, among other details, mutual due diligence, approval of the Exchange to delist, and approval of the new listing by the CSE as applicable, and standard closing conditions, including the conditions described herein.

The name of the Corporation will be changed in due course to a name containing “Bio-Graphene” or such other name as may be agreed.

Tags:  BE Resources  Bio Graphene Solutions  Graphene 

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Henriksen lands CAREER grant to chase electron effects

Posted By Graphene Council, Thursday, August 20, 2020
Erik Henriksen, assistant professor of physics in Arts & Sciences at Washington University in St. Louis, has been awarded a prestigious Faculty Early Career Development (CAREER) Award by the National Science Foundation. His grant, expected to total $850,000 over the next five years, is for research that explores many-particle interactions in graphene and other single-atom-thick materials.

The behavior of electrons determines the fundamental properties of any material — such as its ability to conduct electricity, or its reflectivity. But these electron interactions are mostly impossible to directly perceive.

“The odd reason that no one has been able to investigate this is that spectroscopic techniques are blind to correlated motion of electrons in most materials,” Henriksen said. “In graphene, amusingly enough, spectroscopy does work and can directly observe the appearance of such many-particle effects.”

Henriksen painstakingly built a unique facility at Washington University that allows him to shine infrared light through graphene under the influence of a strong magnetic field, at extremely low temperatures — revealing the fundamental ways in which electrons jostle with each other as part of a larger system.

“We want to perform spectroscopy of the fractional quantum Hall effect, a remarkable many-particle correlated electron effect discovered in the 1980s,” he said. Henriksen’s graduate adviser Horst L. Stormer was awarded the 1998 Nobel Prize in physics for his role in that discovery. “This effect is characterized by strange features such as apparent fractional electron charges and electrons that bind to magnetic field lines.”

Henriksen also will use funds from his CAREER grant to place atomically small slivers of materials between two mirrors, trapping the light such that it bounces back and forth through the slivers thousands of times.

“Ultimately, this creates novel particles that are a quantum mixture of light and matter: a new form of stuff that doesn’t normally exist,” Henriksen said. “With graphene and our low-temp facility, we can do this in a new regime no one has looked at before.

“Hopefully, this means we’ll find new behaviors,” he said. “Or, at the very least, we can enhance the correlated effects.”

Henriksen plays a key role in the university’s Center for Quantum Sensors. To that end, he also is working to develop novel graphene-based infrared sensors and light emitters operating in the so-called ‘terahertz gap,’ a part of the infrared spectrum that is historically bereft of convenient sources and detectors.

In a forthcoming paper at Physical Review X, a scientific journal of the American Physical Society, Henriksen directly observed many-particle effects and how they show up as unusual gaps in the electronic structure of graphene.

“Many materials can be understood as if the electrons inside were unaware of or unaffected by each other,” Henriksen said. “It’s weird but true. But when you find a material where this is not the case, things get very interesting!”

Tags:  Erik Henriksen  Graphene  quantum materials  Sensors  Washington University 

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Update re. Innovate UK Loan Agreement

Posted By Graphene Council, Tuesday, August 18, 2020
Versarien plc is pleased to provide an update in relation to the £5 million loan facility ("the Loan"), which was awarded by Innovate UK Loans Limited, a wholly owned subsidiary of UK Research and Innovation, on 1 July 2020, to support Versarien's G SCALE project.

As announced on 1 July 2020, the Loan was to become available for drawdown in eight quarterly tranches, following the completion of normal commercial security arrangements. The Company can confirm that the relevant security documentation was successfully completed and it has now received £1.96 million, being the first instalment of the Loan. As agreed, the Company can drawdown the remaining instalments every three months over the next 21-month period.  

Neill Ricketts, CEO of Versarien, commented: "We are delighted to have now completed the initial process with Innovate UK Loans. With the quarterly instalments underway we can now move forward with our plans to scale up our G SCALE related collaborations and look forward to providing updates on the project's progress in due course."

Tags:  Graphene  Innovate UK  Neill Ricketts  Versarien 

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