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Elkem receives Enova financial support for planning the battery materials industrial plant

Posted By Terrance Barkan, Wednesday, October 14, 2020
Elkem has received NOK 10 million in financial support from Enova to fund the initial planning of the potential large-scale battery materials plant in Norway, named Northern Recharge. The project aims to supply the fast-growing battery industry through a competitive production process and make batteries greener with lower CO2 emissions.

“A positive investment decision requires competitive public support mechanisms and supportive government policies. Elkem is also inviting industrial and financial partners to participate. Securing this initial support from Enova is an important step as we progress towards a final investment decision,” says Elkem’s CEO, Michael Koenig.

Enova is owned by the Norwegian Ministry of Climate and Environment, and supports the development of energy and climate technology, among other responsibilities.

“Batteries will undoubtedly play an important role in a future low-emission society. The production of batteries, however, is energy-consuming, so we need to see production processes that are more energy-efficient in the future, such as the innovative synthetic graphite production technology Elkem has developed. We therefore appreciate the opportunity to support their upcoming initial study, in order to increase the probability that this energy-efficient technology can one day be adopted on a full scale," says Enova's Director of Markets, Øyvind Leistad.

Elkem recently selected Herøya, one of the biggest industrial parks in Norway, as the project site. The company will now continue to progress the Northern Recharge project towards a final investment decision in 2021.

“The market for better and greener batteries is growing fast. We believe Elkem and Norway are uniquely positioned to be among the leaders in this industry,” says vice president for Elkem Battery Materials, Stian Madshus.

“Our Northern Recharge project competitively positions us for large-scale and cost-effective material science solutions for the rapidly developing European battery industry. Elkem brings significant industrial processing experience and by utilising efficient and renewable Norwegian hydropower, our product portfolio developments will be uniquely positioned for today’s EV requirements and tomorrow’s next generation advancements for rapid-charging and longer range. We truly appreciate the support from Enova on our journey towards more sustainable and energy efficient battery materials production,” says Madshus.

The project will produce synthetic graphite and composites, which are the leading anode materials in lithium-ion battery cells. Graphite demand is expected to increase more than ten times from today’s level to 2030. In terms of weight, graphite as an anode material typically represents around 10 percent of the total battery weight. Today, most of both battery cell and graphite production takes place in Asia.

Using Elkem's technology and renewable hydropower, the project can potentially reduce CO2 emissions by more than 90 percent compared to conventional production, while potentially reducing energy consumption by around 50 percent.

Elkem is currently constructing an industrial scale pilot plant for battery graphite in Kristiansand, Norway. Commissioning in early 2021, the pilot aims to conclude processing routes and enhance the product qualification process with customers. This project is supported by Innovation Norway.

Elkem also continues to carry out research on silicon-graphite composite materials for improved battery performance. This year, the company is joining the Hydra and 3beLiEVe research projects on next generation lithium-ion batteries, coordinated by SINTEF and the Austrian Institute of Technology, respectively. Both projects have received funding from the European Union's Horizon 2020 research and innovation programme.

Tags:  Battery  Electric Vehicle  Elkem  Energy  Enova  Environment  Graphene  graphite  Michael Koenig  Norwegian Ministry of Climate and Environment  Øyvind Leistad  Stian Madshus 

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Drew Walker Appointed to President of NeoGraf Solutions LLC

Posted By Terrance Barkan, Saturday, October 10, 2020
NeoGraf Solutions LLC, a leading developer and manufacturer of high-performance natural and synthetic graphite sheets and powders, announces the appointment of Drew Walker as President of the company.

Mr. Walker has an extensive history in materials operations management including most recently as President of China Jushi USA Corp., where he launched the world’s largest composite materials business from China to the USA, building a $400M glass fiber materials manufacturing plant.

Prior to that, Mr. Walker served as President and CEO of AGY (Advanced Glass Fiber Yarns) where he took a commodity glass fiber business and built a specialty materials business. His career also included Global Sales Director for South Africa Paper & Pulp (SAPPI), developing new products for a technical papers business all across Asia that enables 100% replication of natural materials with a unique technology that was US-based. 

Mr. Walker’s responsibilities at NeoGraf include developing and executing the NeoGraf global business strategy by enabling rapid sales growth and operational excellence in key thermal management markets such as electronics, energy, fuel cell, and fire retardant building and construction materials. “It is a privilege to become the President of such a highly regarded global company,” said Walker. “I look forward to executing on growth opportunities over the coming years for NeoGraf, as well as for our partners and customers.”

Mr. Walker considers that his greatest challenge in his new position at NeoGraf will be “rapid growth in a post-COVID world.” However, he comments that “NeoGraf has the strategy, products and technical expertise to capitalize on the next generation of thermal management solutions across the globe.”

Tags:  composite materials  Drew Walker  Graphene  graphite  NeoGraf Solutions 

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Graphite instead of gold: Thin layers for better hydrogen cars

Posted By Terrance Barkan, Thursday, October 1, 2020

Electric cars which can be filled up within five minutes, reach ranges like a diesel and yet drive "cleanly": This is already being achieved by hydrogen fuel cell vehicles today. However, so far they are still rare and expensive. Apart from efficiency problems, this is due, among other things, to one core component: Gold-coated bipolar plates (BiP) in fuel cells are expensive and complex to manufacture.

The Fraunhofer Institute for Material and Beam Technology IWS Dresden, the German automotive group Daimler and the Finnish steel company Outokumpu Nirosta have now developed an economical alternative for rapid mass production.

To this end, scientists at the Fraunhofer IWS have developed a technology that facilitates the continuous production of bipolar plates. Instead of gold, they coat the bipolar plates with a very thin carbon coating. This concept is well suited for mass production and can significantly reduce manufacturing costs. In addition, it contributes to the development of environmentally friendly vehicles.

Fuel cells are promising technological alternatives to battery concepts

„If the automotive industry is talking about alternative drive concepts today, it usually means battery electric driving", explains IWS Director Prof. Christoph Leyens. "Fuel cells, however, could offer an attractive technological solution for application scenarios such as trucks requiring a long range. We therefore work closely together with our industrial partners in order to enable more cost-effective and efficient fuel cells".

"Engineers are idealists, too, and so we are particularly passionate about this project," emphasizes Dr. Teja Roch, scientist at the IWS. "We are delivering a cornerstone for climate-neutral mobility beyond classic combustion engines. However, the project will only work if the new process is profitable in practice. "Our technology offers the potential to significantly reduce the production costs of fuel cells."
A fuel cell - how does it work?

Fuel cells operate like mini power plants: They are supplied with hydrogen and oxygen and use them to generate water, electricity and heat in a chemical reaction. Various designs can be considered. A widely used model is the PEM fuel cell. PEM fuel cells contain stacks consisting of many individual cells, each with a proton exchange membrane (PEM) in the middle. To the right and left of this membrane there are electrodes with catalysts, a gas diffusion layer (GDL) and bipolar plates on both sides. Hydrogen and oxygen flow through these plates into the cell. The plates consist of two stainless steel half plates each, on which special structures for gas flow and heat dissipation are embossed in a forming process and subsequently welded together.

However, since steel surfaces only poorly conduct electricity, bipolar plates are often coated with gold to prevent rust formation. Above all, however, the precious metal ensures that the current can easily flow, meaning that the contact resistance between the gas diffusion layer and the bipolar plate remains low. "However, gold is known to be expensive," says Teja Roch, outlining a problem with this frequently used solution. "In addition, the stainless steel plates for the plates are first formed and welded together and subsequently coated in stacks. This is a rather costly and time-consuming process."

Therefore, IWS researchers and their partners from the automotive and steel industry have explored new paths in the course of the joint project "miniBIP II" funded by the German Federal Ministry of Economics and Technology. Instead of using gold, they have coated the approximately 50 to 100 micrometers (thousandths of a millimeter) thin steel sheets with a graphite-like layer only a few nanometers (millionths of a millimeter) thick. They use physical vapor deposition (PVD) for this process. In this technology, an electric arc in a vacuum chamber first vaporizes the carbon, which is subsequently deposited on the stainless steel in a highly pure, uniform and very thin layer.

Coating costs reduced by half

Even in the pre-series stage, this carbon layer achieves a contact resistance similar to the gold coating. In other words, if the engineers further improve their process up to mass production, the coating will conduct electricity at least as well as the precious metal, possibly even better - at half the cost of coating. Fraunhofer IWS scientists are convinced that this will contribute to a new generation of more efficient fuel cells with higher electrical yield.

In addition, the innovative Fraunhofer technology also promises a higher production speed. The carbon layer is so extremely thin that the coating process itself takes only a few seconds. In addition, stack producers will in future be able to coat entire sheet metal rolls "non-stop" before forming. After all, the Fraunhofer coating is so durable that it can withstand the forming and welding process. "This enables a continuous manufacturing process and thus a much higher production throughput than ever before," explains Dr. Roch.

Fuel cell vehicles with the range of a diesel

Such improved and lower-cost fuel cells are particularly important for mobile use. They are particularly suitable for environmentally friendly cars, buses and long-range trucks that need to be refueled quickly. The "miniBIP II" project thus contributes to the Federal Government's recently reaffirmed strategy of making Germany a pioneer of future hydrogen technologies. Some market analysts such as IDTechEx and McKinsey expect that by 2030 several million vehicles with fuel cell technology will already be on the road worldwide. The Fraunhofer-Gesellschaft has taken up this challenge. In a joint initiative, the involved institutes are providing their "expertise to support the hydrogen age". Fraunhofer IWS participates in this network as well. Further information can be found online here: https://www.fraunhofer.de/en/research/current-research/hydrogen.html

Tags:  Automotive  Christoph Leyens  Daimler  Fraunhofer IWS  Fuel Cells  Graphene  Graphite  Outokumpu Nirosta  Teja Roch 

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ZEN Graphene Solutions Develops Graphene-Based Ink with 99% Virucidal Activity against COVID-19

Posted By Graphene Council, Wednesday, September 23, 2020
ZEN Graphene Solutions is pleased to report that after 5 months of optimization, it has developed a novel graphene-based virucidal ink with 99% effectiveness against COVID-19.
Highlights:

• ZEN’s Virucidal ink is 99% effective against the COVID-19 virus
• ZEN’s Virucidal ink was still 99% effective a minimum of 35 days after application to N95 mask material
• ZEN is now developing plans to expedite commercialization of this product, pending regulatory approval.
• ZEN has filed a provisional patent for this graphene-based virucidal product
• ZEN invites PPE companies to reach out for potential partnerships to bring this new technology to market: Antiviralink@ZENGraphene.com
• ZEN is beginning antibacterial and antifungal tests utilizing its proprietary ink formulation

The company has received results from the latest round of testing of its proprietary, virucidal graphene-based ink formulation at Western University’s ImPaKT facility Biosafety Level 3 laboratory. Two graphene-based ink samples at different concentrations were applied to N95 mask filtration media and then exposed to the SARS-CoV-2 virus that causes COVID-19 and tested for antiviral properties in accordance with ISO 18184:2019. Very significant virucidal activity was recorded and reported, achieving 99% inactivation of the virus for both samples in 3 separate tests each and verified through a second round of testing. Of significance, the antiviral effect of the second round of testing was on material that was prepared 35 days earlier demonstrating the ongoing virucidal activity of ZEN’s proprietary ink. For those interested in seeing the report, please contact the company directly.

The research and development of this antiviral ink formulation was conducted entirely by ZEN’s research team at its Guelph, Ontario facility using a graphene product that was produced from its Albany PureTM Graphite.

ZEN is now developing plans to bring this novel virucidal ink to commercial production including working with regulatory authorities and government agencies to fast track this product to Canadian and global markets to help the fight against the Coronavirus pandemic. ZEN is expanding the testing of this graphene-based ink formulation to include pathogenic bacteria and fungi and will report on these tests as soon as the results are available.

CEO Dr. Francis Dube commented, “These recent results have dramatically exceeded our expectations with our ink achieving 99% virucidal activity against the SARS-CoV-2 virus 35 days after production of the samples. I am very proud of our Research and Development team for their exceptional work in developing this novel formulation. We are excited about the role our ink can play in the fight against this global pandemic and are moving quickly to mobilize our resources to bring this product to market.”

Tags:  Francis Dube  Graphene  Graphite  Healthcare  ZEN Graphene Solutions 

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Talga Boosts European Natural Graphite Resources

Posted By Graphene Council, Saturday, September 19, 2020
Talga Resources is pleased to announce significant increases in the Company’s natural graphite mineral resources within its wholly-owned Vittangi Graphite Project in northern Sweden.

Talga has completed a review of its four JORC (2012) compliant graphite mineral resources within Vittangi to standardise parameters for increased accuracy in upcoming feasibility studies and enable better mine planning, permitting and reporting.

The review also identified significant new Exploration Targets to be tested along strike and at depth from current resources, providing potential for future additional resource growth. Highlights  of results of the review include:

• Updated Nunasvaara South Mineral Resource Estimate defines 15% increase in total natural graphite resources at Vittangi

• Vittangi graphite mineral resource now stands at 19.5 million tonnes at 24.0% graphite (based on a revised 10% cut-off grade across the project)

• Vittangi remains the world’s highest grade natural graphite resource1, set to play a significant role in battery anode production for the booming electric vehicle market

• Talga’s total graphite resource inventory in Sweden increases to 55.3 million tonnes at 17.5% graphite, representing the largest source of natural graphite defined in Europe2

• Additional growth Exploration Targets totalling 26–46 million tonnes at 20–30% graphite defined within Vittangi and set to be drill-tested for potential further increases in scale

Note that the potential quantity and grade of the Exploration Target is conceptual in nature, there has been insufficient exploration to estimate a Mineral Resource and it is uncertain if further exploration will result in the estimation of a Mineral Resource.

Commenting on the resource upgrade, Talga Managing Director Mark Thompson said: “We are pleased to continue defining and growing these globally significant and strategically important European graphite deposits.“

“The European Commission recently published an updated list of Critical Raw Materials necessary for the energy transition to a more sustainable society. Natural graphite features on this list of materials vital to European development as it forms nearly half the volume of active materials in electric vehicle batteries, where it is used as the anode.”

“With projected anode demand set to reach 3.2 million tonnes by 20303 the potential of Talga’s Swedish integrated natural graphite anode production facility is significant for the European electric vehicle supply chain and the ‘green’ economy.

Tags:  Batteries  Graphene  Graphite  Mark Thompson  Talga Resources 

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WHAT HAPPENS BETWEEN THE SHEETS? ‘FLOATING’ GRAPHENE ON A BED OF CALCIUM ATOMS

Posted By Graphene Council, Saturday, September 19, 2020
Adding calcium to graphene creates an extremely-promising superconductor, but where does the calcium go?

Adding calcium to a composite graphene-substrate structure creates a high transition-temperature (Tc) superconductor.

In a new study, an Australian-led team has for the first time confirmed what actually happens to those calcium atoms: surprising everyone, the calcium goes underneath both the upper graphene sheet and a lower ‘buffer’ sheet, ‘floating’ the graphene on a bed of calcium atoms.

Superconducting calcium-injected graphene holds great promise for energy-efficient electronics and transparent electronics.

STUDYING CALCIUM-DOPED GRAPHENE: THROWING OFF THE DUVET

Graphene’s properties can be fine-tuned by injection of another material (a process known as ‘intercalation’) either underneath the graphene, or between two graphene sheets.

This injection of foreign atoms or molecules alters the electronic properties of the graphene by either increasing its conductance, decreasing interactions with the substrate, or both.

Injecting calcium into graphite creates a composite material (calcium-intercalated graphite, CaC6) with a relatively ‘high’ superconducting transition temperature (Tc). In this case, the calcium atoms ultimately reside between graphene sheets.

Injecting calcium into graphene on a silicon-carbide substrate also creates a high-Tc superconductor, and we always thought we knew where the calcium went in this case too…

Graphene on silicon-carbide has two layers of carbon atoms: one graphene layer on top of another ‘buffer layer’: a carbon layer (graphene-like in structure) that forms between the graphene and the silicon-carbide substrate during synthesis, and is non-conducting due to being partially bonded to the substrate surface.

“Imagine the silicon carbide is like a mattress with a fitted sheet (the buffer layer bonded to it) and a flat sheet (the graphene),” explains lead author Jimmy Kotsakidis.

Conventional wisdom held that calcium should inject between the two carbon layers (between two sheets), similar to injection between the graphene layers in graphite. Surprisingly, the Monash University-led team found that when injected, the calcium atoms’ final destination location instead lies between buffer layer and the underlying silicon-carbide substrate (between the fitted sheet and the mattress!).

“It was quite a surprise to us when we realised that the calcium was bonding to the silicon surface of the substrate, it really went against what we thought would happen”, explains Kotsakidis.

Upon injection, the calcium breaks the bonds between the buffer layer and substrate surface, thus, causing the buffer layer to ‘float’ above the substrate, creating a new, quasi-freestanding bilayer graphene structure (Ca-QFSBLG).

This result was unanticipated, with extensive previous studies not considering calcium intercalation underneath the buffer layer. The study thus resolves long-standing confusion and controversy regarding the position of the intercalated calcium.

X-ray photoelectron spectroscopy (XPS) measurements at the Australian Synchrotron were able to pinpoint the location of the calcium near to the silicon carbide surface

Results were also supported by low-energy electron diffraction (LEED), and scanning tunnelling microscopy (STM) measurements, and by modelling using density functional theory (DFT).

AND MAGNESIUM TOO…
With this information at hand, the Australian team also decided to investigate if magnesium–which is notoriously difficult to inject into the graphite structure –could be inserted (intercalated) into graphene on a silicon-carbide substrate.

To the researchers’ surprise, magnesium behaved remarkably similarly to calcium, and also injected between the graphene and substrate, again ‘floating’ the graphene.

Both magnesium- and calcium-intercalated graphene n-type doped the graphene, and resulted in a low workfunction graphene, an attractive aspect when using graphene as a conducting electrical contact for other materials.

But unlike calcium, magnesium-intercalated graphene remained stable in ambient atmosphere for at least 6 hours, overcoming a major technical hurdle for alkali and alkaline earth intercalated graphene.

“The fact that Mg-QFSBLG is a low workfunction material and n-type dopes the graphene while remaining quite stable in ambient atmosphere is a huge step in the right direction for implementing these novel intercalated materials in technological applications,” explains co-author Prof Michael Fuhrer.

“Magnesium-intercalated graphene could be a stepping stone towards discovery of other similarly stable intercalants.”

Tags:  Electronics  Graphene  Graphite  Jimmy Kotsakidis  Monash University  superconductor 

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Graphene additives show a new way to control the structure of organic crystals

Posted By Graphene Council, Wednesday, September 2, 2020
A team of researchers at The University of Manchester has demonstrated that the surface properties of graphene can be used to control the structure of organic crystals obtained from solution.

Organic crystal structures can be found in a large number of products, such as food, explosives, colour pigments and pharmaceuticals. However, organic crystals can come in different structures, called polymorphs: each of these forms has very different physical and chemical properties, despite having the same chemical composition.

To make a comparison, diamond and graphite are polymorphs because they are composed both by carbon atoms, but they have very different properties because the atoms are bonded to form different structures. The same concept can be extended to organic molecules, when interacting between each other to form crystals.

Understanding and reacting to how materials work on a molecular level is key because the wrong polymorph can cause a food to have a bad taste, or a drug to be less effective. There are several examples of drugs removed from the market because of polymorphism-related problems. As such, production of a specific polymorph is currently a fundamental problem for both research and industry and it does involve substantial scientific and economic challenges.

New research from The University of Manchester has now demonstrated that adding graphene to an evaporating solution containing organic molecules can substantially improve the selectivity towards a certain crystalline form. This opens up new applications of graphene in the field of crystal engineering, which have been completely unexplored so far.

Professor Cinzia Casiraghi, who led the team, said: “Ultimately, we have shown that advanced materials, such as graphene and the tools of nanotechnology enable us to study crystallisation of organic molecules from a solution in a radically new way. We are now excited to move towards molecules that are commonly used for pharmaceuticals and food to further investigate the potential of graphene in the field of crystal engineering."

In the report, published in ACS Nano, the team has shown that by tuning the surface properties of graphene, it is possible to change the type of polymorphs produced. Glycine, the simplest amino acid, has been used as reference molecule, while different types of graphene have been used either as additive or as templates.

Matthew Boyes, and Adriana Alieva, PhD students at The University of Manchester, both contributed to this work: “This is a pioneering work on the use of graphene as an additive in crystallisation experiments. We have used different types of graphene with varying oxygen content and looked at their effects on the crystal outcome of glycine. We have observed that by carefully tuning the oxygen content of graphene, it is possible to induce preferential crystallisation.” said Adriana.

Computer modelling, performed by Professor Melle Franco at the University of Aveiro, Portugal, supports the experimental results and attributes the polymorph selectivity to the presence of hydroxyl groups allowing for hydrogen bonding interactions with the glycine molecules, thereby favouring one polymorph over the other, once additional layers of the polymorph are added during crystal growth.

This work has been financially supported by the European Commission in the framework of the European Research Council (ERC Consolidator), which supports the most innovative research ideas in Europe, by placing emphasis on the quality of the idea rather than the research area, and it is a joint collaboration between the Department of Chemistry and the Department of Chemical Engineering, with Dr Thomas Vetter.

Tags:  ACS Nano  Adriana Alieva  Cinzia Casiraghi  European Research Council  Graphene  graphite  Healthcare  Matthew Boyes  Melle Franco  Thomas Vetter  University of Aveiro  University of Manchester 

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Manchester-led research offers advance in superconductors with a ‘twist’

Posted By Graphene Council, Friday, August 14, 2020
An international research team led by The University of Manchester has revealed a nanomaterial that mirrors the “magic angle” effect originally found in a complex man-made structure known as twisted bilayer graphene – a key area of study in physics in recent years.

The new research shows that the special topology of rhombohedral graphite effectively provides an inbuilt “twist” and therefore offers an alternative medium to study potentially game-changing effects like superconductivity. “It is an interesting alternative to highly popular studies of magic-angle graphene” said graphene pioneer Professor Sir Andre Geim, a co-author of the study.

The team, led by Artem Mishchenko, Professor of Condensed Matter Physics at The University of Manchester published its findings today in the journal Nature.

“Rhombohedral graphite can help to better understand materials in which strong electronic correlations are important - such as heavy-fermion compounds and high-temperature superconductors”, said Professor Mishchenko. 

A previous step-forward in two-dimensional materials research was the curious behaviour that stacking one sheet of graphene atop one another and twisting it to a ‘magic angle’ changed the bilayer’s properties, turning it into a superconductor.

Professor Mishchenko and his colleagues have now observed the emergence of strong electron-electron interactions in a weakly stable rhombohedral form of graphite - the form in which graphene layers stack slightly differently compared to stable hexagonal form.

Interactions in twisted bilayer graphene are exceptionally sensitive to the twist angle. Tiny deviations of about 0.1 degree from the exact magic angle strongly supress interactions. It is extremely difficult to make devices with the required accuracy and, especially, find sufficiently uniform ones to study the exciting physics involved. The newly published findings on rhombohedral graphite has now opened an alternative route to accurately making superconductor devices.

Graphite, a carbon material made up of stacked graphene layers, has two stable forms: hexagonal and rhombohedral. The former is more stable, and has thus been extensively studied, while the latter is less so.

To better understand the new result, it is important to note that the graphene layers are stacked in different ways in these two forms of graphite. Hexagonal graphite (the form of carbon found in pencil lead) is composed of graphene layers orderly stacked on top of each other. The metastable rhombohedral form has a slightly different stacking order, and this slight difference leads to a drastic change in its electronic spectrum.

Rhombohedral graphite can help to better understand materials in which strong electronic correlations are important - such as heavy-fermion compounds and high-temperature superconductors, Professor Artem Mishchenko.

Previous theoretical studies have pointed to the existence of all kinds of many-body physics in the surface states of rhombohedral graphite – including high-temperature magnetic ordering and superconductivity. These predictions could not be verified, however, since electron transport measurements on the material were completely lacking until now.

The Manchester team has been studying hexagonal graphite films for several years and have developed advanced technologies to produce high-quality samples. One of their techniques involves encapsulating the films with an atomically-flat insulator, hexagonal boron nitride (hBN), which serves to preserve the high electronic quality in the resulting hBN/hexagonal graphite/hBN heterostructures. In their new experiments on rhombohedral graphite, the researchers modified their technology to preserve the fragile stacking order of this less stable form of graphite.

The researchers imaged their samples, which contained up to 50 layers of graphene, using Raman spectroscopy to confirm that the stacking order in the material remained intact and that it was of high quality. They then measured electronic transport properties of their samples in the traditional way - by recording the resistance of the material as they changed the temperature and the strength of a magnetic field applied to it.

The energy gap can also be opened in the surface states of rhombohedral graphite by applying an electric field explains Professor Mishchenko: “The surface-state gap opening, which was predicted theoretically, is also an independent confirmation of the rhombohedral nature of the samples, since such a phenomenon is forbidden in hexagonal graphite.”

In rhombohedral graphite thinner than 4nm, a band gap is present even without applying an external electric field. The researchers say they are as yet unsure of the exact nature of this spontaneous gap opening (which occurs at the “charge neutrality”– the point at which densities of electrons and holes are balanced), but the research team are busy working on answering this question.

Further investigation of rhombohedral graphite could shed more light on the origin of many-body phenomena in strongly correlated materials such as heavy-fermion compounds and high-temperature superconductors.

Tags:  Andre Geim  Artem Mishchenko  Graphene  Graphite  superconductor  The University of Manchester 

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Anode Material for Safe Batteries with a Long Cycle Life

Posted By Graphene Council, Monday, August 10, 2020
The demand for electric vehicles is increasing, accompanied by a growing need for smart grids that ensure a sustainable energy supply. These and other mobile and stationary technologies require suitable batteries. Storing as much energy as possible in the smallest possible space with the lowest possible weight – lithium-ion batteries (LIB) still meet this requirement best. The research aims at improving the energy density, power density, safety, and cycle life of these batteries. The electrode material is of major importance here. Anodes of lithium-ion batteries consist of a current collector and an active material applied to it that stores energy in the form of chemical bonds. In most cases, graphite is used as the active material. 

However, negative electrodes made of graphite have a low charging rate. Moreover, they are associated with safety issues. Among the alternative active materials, lithium titanate oxide (LTO) has already been commercialized. Negative electrodes with LTO present a higher charging rate and are considered to be safer than those made of graphite. The drawback is that lithium-ion batteries with lithium titanate oxide tend to have a lower energy density.

The team around Professor Helmut Ehrenberg, head of the Institute for Applied Materials – Energy Storage Systems (IAM-ESS) of KIT, now investigated another highly promising anode material: lithium lanthanum titanate with a perovskite crystal structure (LLTO). According to the study, which was carried out in collaboration with scientists from Jilin University in Changchun (China) and other research institutes in China and Singapore, LLTO anodes have a lower electrode potential compared to commercialized LTO anodes, which allows for a higher cell voltage and a higher capacity. “Cell voltage and storage capacity ultimately determine the energy density of a battery,” explains Ehrenberg. “In the future, LLTO anodes might be used to build particularly safe high-performance cells with a long cycle life.” 

The study contributes to the work of the research platform for electrochemical storage, CELEST (Center for Electrochemical Energy Storage Ulm & Karlsruhe), one of the largest battery research platforms worldwide, which also includes the POLiS excellence cluster.

Besides energy density, power density, safety and cycle life, the charging rate is another determining factor for the suitability of a battery for demanding applications. In principle, the maximum discharge current and the minimum charging time depend on the ion and electron transport both within the solid body and at the interfaces between the electrode and electrolyte materials. To improve the charging rate, it is common practice to reduce the particle size of the electrode material from micro to nano scale. The study, which was published in the Nature Communications journal by KIT researchers and their cooperation partners, shows that even particles of a few micrometers in size in LLTOs with a perovskite structure feature a higher power density and a better charging rate than LTO nanoparticles. The research team attributes this to the so-called pseudocapacitance of LLTO: Not only are individual electrons attached to this anode material, but also charged ions, which are bound by weak forces and can reversibly transfer charges to the anode. “Thanks to the larger particles, LLTO basically enables simpler and more cost-effective electrode manufacturing processes,” explains Ehrenberg.

Tags:  Battery  Graphene  Graphite  Helmut Ehrenberg  Karlsruhe Institute of Technology  Li-ion Batteries 

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Independent University Research Confirms and Quantifies Ease of Conversion of ZEN Graphene’s Albany PureTM Graphite to Graphene

Posted By Graphene Council, Monday, August 10, 2020
ZEN Graphene Solutions is pleased to announce that a recent peer reviewed research article clearly demonstrates that ZEN’s Albany Graphite exfoliates more easily than other commercially available flake graphite test samples. Significantly, this article provides quantitative data that ZEN’s Albany PureTM Graphite has the highest exfoliation rate constant of the materials tested, indicating that it exfoliates more easily than the other materials.

This study was recently published in the peer reviewed journal, Carbon and utilizes an interfacial trapping exfoliation process which is spontaneous and driven by the spreading of graphene at a liquid-liquid interface between two immiscible fluids (e.g. oil and water) and thus lowering the free energy of the system. The article reported “the time to reach full emulsion for the Albany PureTM material was much shorter than for other graphite reference material (Figure 1). The paper also concluded that “the source of the graphite plays a role in the exfoliation in addition to the flake size”. This advantage will likely translate into a more efficient and economic exfoliation process as the company advances towards commercialization.  Additional testing was also conducted to compare the purified East Pipe and West Pipe material and confirmed very similar exfoliation rates for the two pipes as shown in Figure 2 below.

Francis Dubé, ZEN CEO commented, “We have known for a long time that our material exfoliated into graphene faster and better than flake graphite but quantifying it so clearly was a significant confirmation. I want to thank Prof. Douglas Adamson at UConn for his excellent research!”

These results provide additional third-party confirmation that Albany PureTM Graphite exfoliates more easily than other commercially available graphite material and supports the results that were published by Dr. Yoshihiko Arao, Assistant Professor in the Department of Chemical Engineering at Tokyo Tech and reported in an October 16, 2018 news release. In this article, it was reported that the particle size was linked to the ease of producing graphene from graphite through exfoliation – the smaller the feed graphite particle, the easier to exfoliate. The researchers further concluded that, due to the size of its flakes, the exfoliation productivity of graphite derived from ZEN’s Albany PureTM Graphite performed up to 1500% better than the researchers’ reference flake graphite materials. Interestingly, in the UConn study, the ZEN samples had a slightly larger flake size than the other graphite samples, yet still showed faster exfoliation. The company surmises that the turbostratic nature along with the slightly larger d-spacing between the layers were the reason why Albany PureTM Graphite performed better in this study.

Tags:  Francis Dubé  Graphene  Graphite  ZEN Graphene Solutions 

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