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Thomas Skordas: "Graphene is on the way to changing our lives"

Posted By Graphene Council, The Graphene Council, Wednesday, October 2, 2019
Thomas Skordas, Director for Digital Excellence and Science Infrastructure, takes a look at the latest developments in graphene research on the occasion of Graphene Week 2019 – Europe's leading graphene conference, which brings together the latest innovations, leading-edge technology and research on graphene and other layered materials.

Graphene Week was a chance to hear about recent scientific discoveries and technological advances in graphene, one of the key technology areas in Europe today. The great strength of the Graphene Flagship is that it provides a nurturing environment for top scientists, researchers and industry to discover new uses for this fascinating material, which consists of a single layer of carbon atoms.

This year alone, the Flagship has scored some significant achievements. For example, it has used graphene to increase the lifetime of Perovskite solar cells, the most efficient way of converting sunlight to energy in existence, when facing conditions such as heat and moisture. Once they are commercially viable, they could be a game changer for the clean energy transition. Flagship researchers have also built silicon-graphene coin cell batteries, of which a high proportion of the components can be recycled. This patented technology forms the basis of the spin-off Bedimensional, which received a private investment of €18 million in 2018, and test production is expected to start in the coming months.

Graphene has the potential to change our lives, and we are witnessing more and more graphene product launches and spin-offs. The Flagship also regularly presents new demonstrators at events, such as the mobile phone-related technology shown at Mobile World Congress: this video shows what they presented. We are also looking forward to the publication in the next few weeks of a 400-page open-access book, the work of 70 co-authors, with information on how to produce graphene and up to 5000 other layered materials. It will be a “bible” for students and industrial manufacturers interested in the fabrication processes of these materials. We have come a long way: merely fifteen years ago, graphene was isolated for the first time ever, in pioneering experiments using pieces of Scotch tape, but today the methods for synthesising thousands of similar materials are available to anyone in the world.

Tags:  Batteries  Digital Excellence and Science Infrastructure  Graphene  Graphene Flagship  Thomas Skordas 

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Nanochains could increase battery capacity, cut charging time

Posted By Graphene Council, The Graphene Council, Tuesday, September 24, 2019
How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.

Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in today's batteries.

Purdue University scientists and engineers have introduced a potential way that these materials could be restructured into a new electrode design that would allow them to increase a battery's lifespan, make it more stable and shorten its charging time.

The study, appearing as the cover of the September issue of Applied Nano Materials, created a net-like structure, called a "nanochain," of antimony, a metalloid known to enhance lithium ion charge capacity in batteries.

The researchers compared the nanochain electrodes to graphite electrodes, finding that when coin cell batteries with the nanochain electrode were only charged for 30 minutes, they achieved double the lithium-ion capacity for 100 charge-discharge cycles.

Some types of commercial batteries already use carbon-metal composites similar to antimony metal negative electrodes, but the material tends to expand up to three times as it takes in lithium ions, causing it to become a safety hazard as the battery charges.

"You want to accommodate that type of expansion in your smartphone batteries. That way you're not carrying around something unsafe," said Vilas Pol, a Purdue associate professor of chemical engineering.

Through applying chemical compounds -- a reducing agent and a nucleating agent -- Purdue scientists connected the tiny antimony particles into a nanochain shape that would accommodate the required expansion. The particular reducing agent the team used, ammonia-borane, is responsible for creating the empty spaces -- the pores inside the nanochain -- that accommodate expansion and suppress electrode failure.

The team applied ammonia-borane to several different compounds of antimony, finding that only antimony-chloride produced the nanochain structure.

"Our procedure to make the nanoparticles consistently provides the chain structures," said P. V. Ramachandran, a professor of organic chemistry at Purdue.

The nanochain also keeps lithium ion capacity stable for at least 100 charging-discharging cycles. "There's essentially no change from cycle 1 to cycle 100, so we have no reason to think that cycle 102 won't be the same," Pol said.

Henry Hamann, a chemistry graduate student at Purdue, synthesized the antimony nanochain structure and Jassiel Rodriguez, a Purdue chemical engineering postdoctoral candidate, tested the electrochemical battery performance.

The electrode design has the potential to be scalable for larger batteries, the researchers say. The team plans to test the design in pouch cell batteries next.

Tags:  batteries  Battery  Graphene  Henry Hamann  Jassiel Rodriguez  Li-ion  nanomaterials  P. V. Ramachandran  Purdue University  Vilas Pol 

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Graphene IP Portfolio Made Available

Posted By Dexter Johnson, IEEE Spectrum, Tuesday, August 6, 2019
Updated: Thursday, August 1, 2019


Seattle, WA-based Allied Inventors (AI) is a $600M fund that has invested in early-stage technologies to help address industrial challenges. AI manages over 5,000 intellectual property assets in technology areas such as graphene, medical platforms, energy storage, and semiconductors. 

Now AI is looking to monetize its graphene IP portfolio consisting of 87 patents and pending applications through licenses or sale of the patent package. Over 91% of the patent portfolio has been granted in multiple jurisdictions including the US, China, Germany Japan, and India.

AI curated their technology portfolio by partnering with a large network of inventors from well-known universities, research institutions, and companies. In developing its graphene IP portfolio, AI sourced novel technologies relevant to producing quality large scale graphene, detecting graphene defects, and using graphene for a variety of applications.  The resulting IP portfolio consists of patents related to graphene manufacture and graphene applications like batteries, filtration, and nanoparticle composites. 

In one manufacturing process patent (US Patent 8,828,193 and 14/459,860), this technology is an electromagnetic radiation process that can operate at low temperatures and offers a way to rapidly produce graphene from graphite oxide on an industrial scale. Another patent (US Patent 15/313,855) involves the process of and system for converting carbon dioxide into graphene by focusing light beam on it.

In addition to graphene manufacturing patents, the portfolio includes technologies for making graphene-based materials. One of the patents (US Patent 9,944,774) is a simple and cost-effective process for forming graphene wrapped carbon nanotube based polymer composites. These composites can be used for strain sensing applications such as structural health monitoring.

Another patent (US Patent 9,499,410) describes a method for making metal oxide-graphene composites. The technology is based on a solvo-thermal process that can synthesize a variety of metal oxide-graphene composites. It is a simple one-step method for use in applications such as batteries and capacitors. 

“Our carefully-curated graphene portfolio has a wide range of important technologies for the manufacture and application of high quality graphene. This portfolio would be beneficial to companies in the graphene space that are interested in enhancing the value of their technology portfolio,” said Norman Ong, Business Analyst for AI. “While the preference is to monetize the entire IP portfolio, we would be open to exploring different options.” 

Ong invites any organization that is interested in the graphene IP portfolio to visit their website and to contact them directly at info@alliedinventors.com.

 

***

 

DISCLOSURE: The Graphene Council has NO INTEREST in the referenced patents and has no financial gain from the sale or license of any of the above referenced patents. This article is provided for informational purposes only and you are requested to contact the patent owners directly. 

Tags:  batteries  graphene production  Investment  sensors 

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High-safety, flexible and scalable Zn//MnO2 rechargeable planar micro-batteries

Posted By Graphene Council, The Graphene Council, Thursday, July 18, 2019
Updated: Monday, July 15, 2019
Increasing development of micro-scale electronics has stimulated demand of the corresponding micro-scale power sources, especially for micro-batteries (MBs). However, complex manufacturing process and poor flexibility of the traditional stacked batteries have hindered their practical applications.

Planar MBs have recently garnered great attention due to their simple miniaturization, facile serial/parallel integration and capability of working without separator membranes. Furthermore, planar geometry has extremely short ion diffusion pathway, which is attributed to full integration of printed electronics on a single substrate. Also, in order to get rid of the safety issues induced by the flammable organic electrolyte, the aqueous electrolyte, characterized by intrinsic nonflammability, high ionic conductivity, and nontoxicity, is a promising candidate for large-scale wearable and flexible MB applications. As the consequence, various printing techniques have been used for fabricating planar aqueous MBs. "In particular, screen printing can effectively control the precise pattern design with adjustable rheology of the inks, and is very promising for large-scale application." The author said.

In a new article published in Beijing-based National Science Review, Zhong-Shuai Wu at Dalian Institute of Chemical Physics, Chinese Academy of Sciences, constructed aqueous rechargeable planar Zn//MnO2 batteries by an applicable and cost-effective screen printing strategy. "The planar Zn//MnO2 micro-batteries, free of separators, were manufactured by directly printing the zinc ink as the anode and γ-MnO2 ink as the cathode, high-quality graphene ink as metal-free current collectors, working in environmentally benign neutral aqueous electrolytes of 2 M ZnSO4 and 0.5 M MnSO4." The author stated. Diverse shapes of Zn//MnO2 MBs were fabricated onto different substrates, implying the potential for widespread applications.

The planar separator-free Zn//MnO2 MBs, tested in neutral aqueous electrolyte, deliver high volumetric capacity of 19.3 mAh/cm3 (corresponding to 393 mAh/g), at 7.5 mA/cm3, and notable volumetric energy density of 17.3 mWh/cm3, outperforming lithium thin-film batteries (<=10 mWh/cm3). Moreover, The Zn//MnO2 planar MBs present long-term cyclability, holding high capacity retention of 83.9% after 1300 times at 5 C, superior to stacked Zn//MnO2 MBs reported. Also, Zn//MnO2 planar MBs exhibit exceptional flexibility without observable capacity decay under serious deformation, and remarkable serial and parallel integration of constructing bipolar cells with high voltage and capacity output.

This satisfactory result will open numerous intriguing opportunities in various applications of intelligent, printed and miniaturized electronics. Also, this work will inspire scientists working in nanotechnology, chemistry, material science and energy storage, and may have significant impact on both future technological development of planar micro-scale energy-storage devices and research of graphene based materials.

Tags:  Batteries  Dalian Institute of Chemical Physics  Energy Storage  Graphene  Zhong-Shuai Wu 

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Leading Graphene Innovator Sees Graphene Market at a Tipping Point

Posted By Dexter Johnson, IEEE Spectrum, Wednesday, July 17, 2019

The Global Graphene Group (G3) has a 17-year relationship with graphene since Dr. Bor Jang, cofounder of Nanotek Instruments, Inc., discovered graphene in 2002.

Today, the G3 organization currently consists of three groupings of companies. First, there is Nanotek Instruments that holds the over three hundred patents the company has filed since its inception in 1997.

Another of the three branches involves graphene production and this branch includes Angstron Materials Group and Taiwan Graphene Company. Angstron Materials is involved in producing graphene intermediates and thermal interface materials. Taiwan Graphene Company produces graphene oxide and graphene powder.

The third branch of the corporate structure of G3 involves the company’s energy storage interests. This includes two companies: Honeycomb Battery Company and Angstron Energy Company. Angstron Energy produces both a high-energy silicon anode and a graphene-enabled cathode. Honeycomb Battery is focused on producing lithium-sulfur batteries, non-flammable electrolytes and next-generation lithium battery technologies.

G3 recently became a member of The Graphene Council and we took the opportunity to talk to the company’s representatives, including Dr. Jang. Here is our discussion.

Q: The Global Graphene Group (G3) has an interesting pedigree, being a holding company for Angstron Materials, Nanotek Instruments and Honeycomb Battery. Could you provide a bit of background of how the company came to be and how the various companies that make it up create an overall strategy for the commercialization of graphene?

A: In order to properly answer this question, we would like to tell a brief story about a 17-year relationship with graphene.

Dr. Bor Jang founded Nanotek Instruments Inc. in 1997 and over the past two decades, researchers at Nanotek have developed a broad array of nanomaterials and energy storage and conversion technologies.

A significant accomplishment of Nanotek researchers is the fact that Dr. Jang’s research team discovered/invented graphene in 2002, two years before Drs. A. Geim and K. Novoselov published their first paper on graphene in 2004 [Science 306, 666–669 (October 2004)]. Drs. Geim and Novoselov won the 2010 Nobel Physics Prize for their work on graphene.

There is no doubt that Drs. Geim and Novoselov have made highly significant contributions to graphene science and, as such, well-deserve this Nobel Prize. However, it is important for Graphene Council’s members and associates to recognize that Nanotek researchers had submitted three (3) US patent applications and delivered a lecture on graphene before October 2004 when that milestone paper was published. This fact is evidenced in the following:

  • B. Z. Jang and W. C. Huang, “Nano-scaled Graphene Plates,” US Patent Application No. 10/274,473 (submitted on 10/21/2002); now U.S. Pat. No. 7,071,258 (issued 07/04/2006).
  • B. Z. Jang, et al. “Process for Producing Nano-scaled Graphene Plates,” U.S. Patent Application No. 10/858,814 (06/03/2004).
  • Bor Z. Jang, “Nanocomposite compositions for hydrogen storage and methods for supplying hydrogen to fuel cells,” US Pat. Appl. No. 10/910,521 (08/03/2004); now US Pat. No. 7,186,474 (03/06/2007).
  • W. Schwalm, M. Schwalm, and B. Z. Jang, “Local Density of States for Nanoscale Graphene Fragments,” Am. Phy. Soc. Paper No. C1.157, 03/2004, Montreal, Canada.

(In March 2004, Dr. Jang and his colleagues (Drs. W. Schwalm, M. Schwalm, and J. Wagner) presented a paper at the American Physical Society’s Annual Meeting in Montreal, Canada that discussed the density of state function and related electronic properties of graphene.)

Contrary to the common misconception in the graphene space that the liquid phase exfoliation method was developed in 2008 by a Dublin College team (Hernandez, Y. et al. “High-yield production of graphene by liquid-phase exfoliation of graphite,” Nature Nanotechnology, 3, 563–568 (2008)), Dr. Zhamu/Dr. Jang’s research team at Nanotek developed this method and filed a patent application in 2007.

This provides an effective way of producing pristine graphene directly from graphite without chemical intercalation or oxidation [A. Zhamu, et al., “Method of Producing Exfoliated Graphite, Flexible Graphite, and Nano-Scaled Graphene Plates,” US Patent Application No. 11/800,728 (05/08/2007); now US Patent No. 7,824,651 (11/02/2010)].

Between 2002 and 2007, the Nanotek teams also developed other important graphene production processes, including chemical oxidation, supercritical fluid exfoliation, and electrochemical exfoliation.

Supported by significant IP on several different graphene production processes and graphene applications in composites, thermal management, supercapacitor, and batteries, etc., Drs. Zhamu and Jang decided to co-found Angstron Materials, Inc. in 2007 to begin to scale-up of selected graphene production processes and certain graphene application products.

Subsequently, after many years of development, prototyping, and mass production efforts and establishment of a vast IP portfolio, we found the timing was right for us to establish several business units for more effective commercialization of vastly different products for different industries.

Taiwan Graphene Company (TGC) was founded in 2015 as a leading producer of single-layer graphene oxide, graphene-based nano-intermediates and non-energy-focused application products. Angstron Energy Company (AEC) was founded in 2015 as producer of lithium battery anode and cathode materials. Honeycomb Battery Company (HBC) was also founded in 2015 as a developer and producer of next-generation safe and long-lasting lithium metal batteries, including quasi-solid state battery, lithium-sulfur battery, and lithium-air battery. Angstron Materials was assigned as a research and development company for development of new processes and products. Nanotek remains as the IP-holding company. As suggested by our investors, we also decided to position all five organizations under one umbrella – Global Graphene Group (G3).

Q: How are you marketing graphene at this point, i.e. are you selling graphene raw materials, master batches, etc.? Or are you developing products that incorporate graphene, specifically for Li-ion batteries? Are there other applications you’re pursuing in addition to energy storage?

A: Our Taiwan Graphene Co. (TGC) is selling graphene in powder and dispersion forms, masterbatches for composites, thermal management products, etc. Angstron Energy Co. (AEC) is selling graphene-enabled Si anode materials and graphene-enhanced cathode materials for the lithium-ion battery industry. Honeycomb Battery Company (HBC) is poised to commercialize lithium metal protection technology, non-flammable electrolytes, graphene-enabled sulfur and selenium cathodes, and graphene-enhanced current collectors for next-generation lithium batteries.

Q: What production methods do you use to make your graphene? How has this production avenue determined the applications for your material?

A: We use a combination of improved chemical oxidation process, liquid phase exfoliation, and other proprietary processes, which G3 invented. We have found that different applications require the use of different graphene types produced by different processes.

Q: What have you discovered to be the biggest challenges for your commercialization of graphene and how have you overcome them?

A: We see the greatest challenge to commercialization that it takes time to qualify the application of graphene into various products. We have relationships with several large OEMs in different markets working with our graphene. It just takes time to go through the qualification process.

Q: What direction do you see for the company in the future? Do you see the company moving further up the value chain to the point where all your graphene production is used internally?

A: The future is to grow. We’re targeting to reach $600m+ in annual sales within the next five years between the combination of products in our value chain and graphene raw materials.

Q: What do you think we can expect in the commercialization of graphene over the next 5 to 10 years?

A: Several major applications (so-called killer applications) of graphene are expected to emerge soon. We will see exponential growth as customers integrate graphene into their products to a point where large expansions of graphene manufacturing are necessary. The challenge will be keeping up with the demand.

Tags:  batteries  discovery  graphene  Nobel Prize 

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Flexible, transparent monolayer graphene device for power generation and storage

Posted By Graphene Council, The Graphene Council, Wednesday, May 15, 2019
Updated: Tuesday, May 14, 2019
Researchers at Daegu Gyeongbuk Institute of Science and Technology developed single-layer graphene based multifunctional transparent devices that are expected to be used as electronics and skin-attachable devices with power generation and self-charging capability (ACS Applied Materials & Interfaces, "Single-Layer Graphene-Based Transparent and Flexible Multifunctional Electronics for Self-Charging Power and Touch-Sensing Systems").

Senior Researcher Changsoon Choi's team actively used single-layered graphene film as electrodes in order to develop transparent devices. Due to its excellent electrical conductivity and light and thin characteristics, single-layered graphene film is perfect for electronics that require batteries.

By using high-molecule nano-mat that contains semisolid electrolyte, the research team succeeded in increasing transparency (maximum of 77.4%) to see landscape and letters clearly.

Furthermore, the research team designed structure for electronic devices to be self-charging and storing by inserting energy storage panel inside the upper layer of power devices and energy conversion panel inside the lower panel. They even succeeded in manufacturing electronics with touch-sensing systems by adding a touch sensor right below the energy storage panel of the upper layer.

Senior Researcher Changsoon Choi in the Smart Textile Research Group, the co-author of this paper, said that "We decided to start this research because we were amazed by transparent smartphones appearing in movies. While there are still long ways to go for commercialization due to high production costs, we will do our best to advance this technology further as we made this success in the transparent energy storage field that has not had any visible research performances."

Tags:  Batteries  Changsoon Choi  Daegu Gyeongbuk Institute of Science and Technolog  Graphene  nanomaterials 

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New Technique Produces Longer-lasting Lithium Batteries

Posted By Graphene Council, The Graphene Council, Monday, April 29, 2019
Updated: Friday, April 26, 2019
The grand challenge to improve energy storage and increase battery life, while ensuring safe operation, is becoming evermore critical as we become increasingly reliant on this energy source for everything from portable devices to electric vehicles. A Columbia Engineering team led by Yuan Yang, assistant professor of materials science and engineering, announced that they have developed a new method for safely prolonging battery life by inserting a nano-coating of boron nitride (BN) to stabilize solid electrolytes in lithium metal batteries. Their findings are outlined in a new study published by Joule.

While conventional lithium ion (Li-ion) batteries are currently widely used in daily life, they have low energy density, resulting in shorter battery life, and, because of the highly flammable liquid electrolyte inside them, they can short out and even catch fire. Energy density could be improved by using lithium metal to replace the graphite anode used in Li-ion batteries: lithium metal’s theoretical capacity for the amount of charge it can deliver is almost 10 times higher than that of graphite. But during lithium plating, dendrites often form and, if they penetrate the membrane separator in the middle of the battery, they can create short-circuits, raising concerns about battery safety.

“We decided to focus on solid, ceramic electrolytes. They show great promise in improving both safety and energy density, as compared with conventional, flammable electrolytes in Li-ion batteries,” says Yang. “We are particularly interested in rechargeable solid-state lithium batteries because they are promising candidates for next-generation energy storage.”

Most solid electrolytes are ceramic, and therefore non-flammable, eliminating safety concerns. In addition, solid ceramic electrolytes have a high mechanical strength that can actually suppress lithium dendrite growth, making lithium metal a coating option for battery anodes. However, most solid electrolytes are unstable against Li—they can be easily corroded by lithium metal and cannot be used in batteries.

“Lithium metal is indispensable for enhancing energy density and so it’s critical that we be able to use it as the anode for solid electrolytes,” says Qian Cheng, the paper’s lead author and a postdoctoral research scientist in the department of applied physics and applied mathematics who works in Yang's group. “To adapt these unstable solid electrolytes for real-life applications, we needed to develop a chemically and mechanically stable interface to protect these solid electrolytes against the lithium anode. It is essential that the interface not only be highly electronically insulating, but also ionically conducting in order to transport lithium ions. Plus, this interface has to be super-thin to avoid lowering the energy density of batteries.”

To address these challenges, the team worked with colleagues at Brookhaven National Lab and the City University of New York. They deposited 5~10 nm boron nitride (BN) nano-film as a protective layer to isolate the electrical contact between lithium metal and the ionic conductor (the solid electrolyte), along with a trace quantity of polymer or liquid electrolyte to infiltrate the electrode/electrolyte interface. They selected BN as a protective layer because it is chemically and mechanically stable with lithium metal, providing a high degree of electronic insulation. They designed the BN layer to have intrinsic defects, through which lithium ions can pass through, allowing it to serve as an excellent separator. In addition, BN can be readily prepared by chemical vapor deposition to form large-scale (~dm level), atomically thin scale (~nm level), and continuous films.

“While earlier studies used polymeric protection layers as thick as 200 µm, our BN protective film, at only 5~10 nm thick, is record-thin—at the limit of such protection layers—without lowering the energy density of batteries,” Cheng says. “It’s the perfect material to function as a barrier that prevents the invasion of lithium metal to solid electrolyte. Like a bullet-proof vest, we’ve developed a lithium-metal-proof ‘vest’ for unstable solid electrolytes and, with that innovation, achieved long-cycling lifetime lithium metal batteries.”

The researchers are now extending their method to a broad range of unstable solid electrolytes and further optimizing the interface. They expect to fabricate solid-state batteries with high performance and long-cycle lifetimes.
 

Tags:  Batteries  Boron Nitride  Columbia Engineering  Graphene  Li-Ion batteries  Qian Cheng  Yuan Yang 

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Graphene and the Nuclear Decommissioning Authority in the UK

Posted By Graphene Council, The Graphene Council, Friday, April 5, 2019
Updated: Friday, April 5, 2019

Emerging technologies such as graphene are being investigated by the Nuclear Decommissioning Authority (NDA) in the UK for their potential to improve decommissioning of nuclear sites.

The Challenge

To identify how graphene, an emerging technology, could improve delivery of NDA’s mission.

The Solution

Review the properties of graphene including the latest developments and areas for potential deployment.

Technology Review : Graphene – a form of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice with unique chemical and physical properties.

Expected Benefits: Raising awareness of new emerging technology across the NDA Group and supply chain.

The NDA published a report on its findings and research over the period of 2016 - 2018: "Graphene and its use in nuclear decommissioning", produced in collaboration with NSG Environmental, the University of Manchester and the National Physical Laboratory

Highlights:

Graphene’s chemical and physical properties are unique:

- one of the thinnest but also strongest materials

- conducts heat better than all other materials

- conducts electricity

- is optically transparent but so dense that it is impermeable to gases

Developments in graphene-based technology have been rapid in a number of areas, including advanced electronics, water filtration and high-strength materials. NDA identified graphene as an emerging technology that could be useful to improve delivery of its mission.

NDA carried out a technology review to compare the properties and potential uses of graphene against the challenges facing the UK in decommissioning its earliest nuclear sites. The opportunities identified included:

  • Advanced materials: Graphene-doped materials could help to immobilise nuclear wastes.
  • Composites incorporating graphene could be used in the construction of stronger buildings or containers for storing nuclear materials.
  • Cleaning up liquid wastes: Graphene-based materials could absorb or filter radioactive elements, helping to clean up spills or existing radioactive wastes.
  • Sensors: Graphene in sensors could improve the detection of radiation or monitor for the signs of corrosion in containers.
  • Batteries: Graphene could produce smaller, longer-lasting batteries that would enable robots to operate for longer in contaminated facilities.

NDA also assessed the potential limitations in graphene’s use to provide a balanced assessment.

The issues identified included:
- cost
- scale-up
- environmental concerns
- lack of standardization
- knowledge regarding radiation tolerance

The report was shared with technical experts across the NDA group, published online and summarised in the Nuclear Institute’s journal: Nuclear Futures. As the technology moves on from early-stage research, NDA and its businesses are continuing to monitor developments, such as the recently opened Graphene Engineering and Innovation Centre (GEIC), with the aim of supporting graphene-based technologies and accelerating their uptake within the nuclear decommissioning sector.

NDA is progressing further projects investigating the potential of other emerging technologies. Engagement continues with academia and industry to identify innovations that could improve delivery of the mission.

Tags:  Andre Geim  Batteries  Graphene  Graphite  Konstantin Novoselov  Sensors  University of Manchester 

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Expanding the Use of Silicon in Batteries, By Preventing Electrodes From Expanding

Posted By Graphene Council, The Graphene Council, Tuesday, March 26, 2019
The latest lithium-ion batteries on the market are likely to extend the charge-to-charge life of phones and electric cars by as much as 40 percent. This leap forward, which comes after more than a decade of incremental improvements, is happening because developers replaced the battery’s graphite anode with one made from silicon. Research from Drexel University and Trinity College in Ireland now suggests that an even greater improvement could be in line if the silicon is fortified with a special type of material called MXene.

This adjustment could extend the life of Li-ion batteries as much as five times, the group recently reported in Nature Communications. It’s possible because of the two-dimensional MXene material’s ability to prevent the silicon anode from expanding to its breaking point during charging — a problem that’s prevented its use for some time.

Silicon anodes are projected to replace graphite anodes in Li-ion batteries with a huge impact on the amount of energy stored,” said Yury Gogotsi, PhD, Distinguished University and Bach Professor in Drexel’s College of Engineering and director of the A.J. Drexel Nanomaterials Institute in the Department of Materials Science and Engineering, who was a co-author of the research. “We’ve discovered adding MXene materials to the silicon anodes can stabilize them enough to actually be used in batteries.”

In batteries, charge is held in electrodes — the cathode and anode — and delivered to our devices as ions travel from anode to cathode. The ions return to the anode when the battery is recharged. Battery life has steadily been increased by finding ways to improve the electrodes’ ability to send and receive more ions. Substituting silicon for graphite as the primary material in the Li-ion anode would improve its capacity for taking in ions because each silicon atom can accept up to four lithium ions, while in graphite anodes, six carbon atoms take in just one lithium. But as it charges, silicon also expands — as much as 300 percent — which can cause it to break and the battery to malfunction.

Most solutions to this problem have involved adding carbon materials and polymer binders to create a framework to contain the silicon. The process for doing it, according to Gogotsi, is complex and carbon contributes little to charge storage by the battery.

By contrast, the Drexel and Trinity group’s method mixes silicon powder into a MXene solution to create a hybrid silicon-MXene anode. MXene nanosheets distribute randomly and form a continuous network while wrapping around the silicon particles, thus acting as conductive additive and binder at the same time. It’s the MXene framework that also imposes order on ions as they arrive and prevents the anode from expanding.

“MXenes are the key to helping silicon reach its potential in batteries,” Gogotsi said. “Because MXenes are two-dimensional materials, there is more room for the ions in the anode and they can move more quickly into it — thus improving both capacity and conductivity of the electrode. They also have excellent mechanical strength, so silicon-MXene anodes are also quite durable up to 450 microns thickness.”

MXenes, which were first discovered at Drexel in 2011, are made by chemically etching a layered ceramic material called a MAX phase, to remove a set of chemically-related layers, leaving a stack of two-dimensional flakes. Researchers have produced more than 30 types of MXene to date, each with a slightly different set of properties. The group selected two of them to make the silicon-MXene anodes tested for the paper: titanium carbide and titanium carbonitride. They also tested battery anodes made from graphene-wrapped silicon nanoparticles.

All three anode samples showed higher lithium-ion capacity than current graphite or silicon-carbon anodes used in Li-ion batteries and superior conductivity — on the order of 100 to 1,000 times higher than conventional silicon anodes, when MXene is added.

“The continuous network of MXene nanosheets not only provides sufficient electrical conductivity and free space for accommodating the volume change but also well resolves the mechanical instability of Si,” they write.  “Therefore, the combination of viscous MXene ink and high-capacity Si demonstrated here offers a powerful technique to construct advanced nanostructures with exceptional performance.”

Chuanfang Zhang, PhD, a post-doctoral researcher at Trinity and lead author of the study, also notes that the production of the MXene anodes, by slurry-casting, is easily scalable for mass production of anodes of any size, which means they could make their way into batteries that power just about any of our devices.

“Considering that more than 30 MXenes are already reported, with more predicted to exist, there is certainly much room for further improving the electrochemical performance of battery electrodes by utilizing other materials from the large MXene family,” he said.

Tags:  Batteries  Battery  Chuanfang Zhang  Drexel University  Graphene  Li-ion batteries  Trinity College in Ireland  Yury Gogotsi 

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THE SECRET LIFE OF BATTERIES

Posted By Graphene Council, The Graphene Council, Friday, February 22, 2019
Updated: Friday, February 22, 2019

Koffi Pierre Yao, a new assistant professor of mechanical engineering at the University of Delaware, is uncovering novel insights about what happens inside the batteries that power our smartphones, laptops, and electric vehicles. He plans to use this knowledge to develop faster-charging batteries that make electric vehicles the go-to automobiles for drivers.

Several of today’s electric vehicles, such as the Tesla Model 3 and Nissan Leaf, run on lithium-ion batteries. But it takes inconveniently too long to recharge those vehicles when you can fill up your gas tank in the time it takes to pick up gas-station coffee. In a lithium-ion battery, positively charged lithium ions move through the electrode to deliver energy.

Scientists all over the world do time-consuming research on lithium-ion batteries in an attempt to optimize these power units. “Usually people will make an electrode, test it, make another one, test it, and so on, and it’s kind of a serial process,” said Yao.

Instead, Yao uses physical probes to look inside batteries while they work and develop a direct physical understanding of how lithium ions flow within batteries. When a battery is charging, the lithium flows unevenly in a way that’s difficult to measure. Yao started working on this while he was a postdoctoral associate at Argonne National Laboratory (ANL), a position he held from 2016 until 2018, when he joined UD’s faculty.

In a new paper published in Energy & Environmental Science, a journal published by the Royal Society of Chemistry, Yao describes how he and his colleagues at ANL used X-rays to get a micron-scale movie of how lithium distributes within the electrode while lithium-ion batteries are running.

“We put an industrial-grade battery under an X-ray beam and mapped the distribution of the lithium within the electrodes,” he said.



Yao and his colleagues knew that the lithium did not distribute homogeneously. Imagine a group of people running through a small doorway. It takes time for people to spread out into the interior of the room; therefore, there will be crowding at the entry point. That’s similar to how lithium moves through the electrode. Still, Yao and his colleagues were surprised at the extent to which lithium scattered inhomogeneously.

The goal is to use this knowledge to reduce testing time and speed up the research and development (R&D) process for these batteries.

In another new paper published in Advanced Energy Materials, Yao describes how he and his colleagues used X-rays to quantify the activity in a silicon-graphite electrode. Cell phone batteries typically contain graphite, but silicon offers some potential benefits over graphite.

“We’re interested in silicon because it can increase the capacity of the electrode by a factor of 10 compared to graphite,” he said. However, silicon is less stable than graphite and degrades faster, so a blend of the two may prove to be a viable solution. “Some of the lithium goes into the graphite, and some goes into the silicon,” he said.

Yao and his colleagues sought to discover exactly where the lithium ions traveled within this blended electrode.

“It’s something people haven’t previously been able to do in the literature,” Yao said. “We provide a clear picture of which of silicon and graphite plays host to lithium at any point in time. Now we can go forward and manipulate this pattern to stabilize the cycling.” This knowledge can help Yao in his quest to design novel particles to make faster-charging and higher energy batteries.

At UD, Yao plans to expand upon his research on batteries with his colleagues at the Center for Fuel Cells and Batteries and more. Yao received his master’s and doctoral degrees in mechanical engineering from the Massachusetts Institute of Technology (MIT) and his bachelor’s degree in mechanical engineering at UD. As an undergraduate at UD, he was mentored by Ajay Prasad, Engineering Alumni Distinguished Professor and Chair of Engineering, who introduced him to electric cars and electrochemistry, and the science behind them.

Tags:  Batteries  Graphene  Koffi Pierre Yao  Li-ion Batteries  Lithium  University of Delaware 

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