Print Page | Contact Us | Report Abuse | Sign In | Register
Graphene Updates
Blog Home All Blogs
The latest news and information on all aspects of graphene research, development, application and commercialization.

 

Search all posts for:   

 

Top tags: graphene  2D materials  Sensors  Batteries  nanomaterials  University of Manchester  CVD  First Graphene  electronics  Li-ion batteries  coatings  graphene oxide  graphene production  The Graphene Flagship  Applied Graphene Materials  Carbon Nanotubes  composites  Energy Storage  Graphite  Haydale  Graphene Flagship  Healthcare  3D Printing  Battery  optoelectronics  polymers  Versarien  Adrian Potts  Andre Geim  biosensors 

Grolltex Ships ‘World’s Smallest Graphene Strain Sensor’ to Large European Partner

Posted By Graphene Council, The Graphene Council, Tuesday, May 14, 2019
Grolltex, has shipped the first version of its patented single atom thick strain sensor to a large European sensor maker partner. The company calls this sensor device, ‘the smallest, most sensitive sensor in the world’ as the base sensing material is only one atom thick and the sensor performance is such that it is capable of measuring the contractive strength of individual heart cells called ‘cardiomyocytes’, providing an important parameter on heart cell health.

“Our strain sensor is very versatile because it is small, flexible, robust and with a gauge factor of up to 1300, it is incredibly sensitive. This means it can be used in a wide variety of applications”, said Jeff Draa, Grolltex CEO. “For example, it can be layered into the skins of airplanes to sense micro stress in the fuselage or be used as a wearable blood pressure monitor in a skin patch configuration. The prototype we delivered to our European partner was designed to measure any environmental pressure or strain that a silicon microchip might experience while sitting in its packaging. This can be important information for many defense or autonomous vehicle related device designs”.

Grolltex, short for ‘graphene-rolling-technologies’, is the largest commercial producer of single layer or electronics grade graphene in North America. The company is lately focusing more of its efforts on servicing sensor markets in the life science and biology areas and seeing continually more adoption of graphene as a sensing material for such uses as DNA sequencing and new drug discovery. Monolayer graphene films are today seen as the most promising futuristic sensing materials for their combination of surface to volume ratio (the film is only one atom thick) and its conductivity (the most conductive substance known at room temperature). 

“For advanced sensor makers that operate at the nano-scale, there is no better material to design your device with than single layer graphene”, said Draa. “The applications and devices that our customers are designing with this material are enabling many previously unobtainable measurements and single layer graphene is now available and affordable for industrialization”. Grolltex makes the raw materials for nano-sensing as well as designing specific sensor devices and packaging for many critical, next generation applications. “We are seeing an explosion of activity in the micro-sensing world as sensor makers are picking up on the versatility and measurement performance benefits of this single atom thick material”.

Tags:  Graphene  Grolltex  Jeff Draa  Nanosensors  sensors 

Share |
PermalinkComments (0)
 

NovoCarbon Enters Collaboration Agreement with Versarien Graphene

Posted By Graphene Council, The Graphene Council, Monday, May 13, 2019
Updated: Tuesday, May 14, 2019

Great Lakes Graphite Inc., doing business as NovoCarbon Corporation, announced that the Company and Versarien Graphene have executed a collaboration agreement.

Highlights

  • Versarien will qualify NovoCarbon as a supply chain partner.
  • The Companies will develop a robust graphene supply chain with processing in the USA.
  • The Companies will work to enable a number of applications for a variety of industries.
  • The collaboration between Companies will afford opportunities to create a strong market presence and an improved ability to target significant technology opportunities.


Neill Ricketts, CEO of Versarien plc said, “We are very pleased to have our dedicated facility in Houston up and running. This has enabled us to more efficiently progress a number of new and existing relationships and accelerate our traction in the US. We now have relationships with over 25 companies in North America, encompassing sectors as diverse as automotive, aerospace, consumer goods, oil and gas, sports equipment and specialty plastics."

“We continue to receive a high number of enquiries for the supply of our graphene and other 2D materials from leading US companies and others globally. Versarien is now truly operating on a global basis and I look forward to providing further updates on our activities with our multiple collaboration partners in due course.”


NovoCarbon CEO Paul Ferguson said, “NovoCarbon’s mission is to enhance the ability of companies such as Versarien to serve their customers and markets with consistent, high quality materials.  We are excited to be working with Versarien and their highly capable team.”

Tags:  2D materials  Great Lakes Graphite  Neill Ricketts  NovoCarbon  Patrick Abbott  Paul Ferguson  Versarien 

Share |
PermalinkComments (0)
 

Join the Graphene Flagship Core 3 Project

Posted By Graphene Council, The Graphene Council, Friday, May 10, 2019



The Graphene Flagship is looking for new partners to bring specific industrial and technology transfer competences or capabilities that complement the present consortium in the next core project. 

We are seeking partners with the following expertise:

  • MRAM tools developer to leverage solutions for GRM-spintronic stacks
  • Exposure and risk assessment of GRMs for occupational health
  • Clinical translation of GRM-based therapeutic medical devices for the central nervous system
  • Component manufacturer for GRM-based networking devices and interconnects 
  • Developer of GRM-based laser systems and instrumentation for coherent Raman imaging
  • Manufacturing and modification of GRM-based fibres, yarns and textiles
  • Automotive company with expertise in development of fuel cells for cars
  • Industrial GRM-based supercapacitors manufacturer
  • Manufacturer of GRM-based anticorrosion coatings
  • Developer of GRM-based pressure sensors for health monitoring in automotive applications
  • Manufacturer to deliver a ready-to-reach-the-market sports car with enhanced functionalities based on GRM/Carbon Fibre Reinforced Polymer composites
  • GRM-based composites manufacturer
  • Preparation of large GRM-based multifunctional pipes by filament winding
  • Formulation of low viscosity epoxy resins incorporating GRMs for aerostructures manufactured by infusion technologies


The selected new partners will be incorporated in the scientific and technological Work Packages of the third Core Project under the Horizon 2020 phase of the Graphene Flagship that will run during 1 April 2020 – 31 March 2023.

The addition of new partners to the Graphene Flagship consortium is subject to the approval of the required contract amendment by the Graphene Flagship General Assembly and, at a later stage, the European Commission.

Tags:  Graphene  Graphene Flagship 

Share |
PermalinkComments (0)
 

Call to Action for Graphene Producing Companies

Posted By Terrance Barkan, Thursday, May 9, 2019

The Graphene Council manages the Verified Graphene Producer™ program.

It is the world's most rigorous, independent, third-party inspection program for graphene producing companies and includes; in-person inspection of the production facilities and processes (including quality control measures and health and safety protocols), a random sample of material and a full characterization by a world-class metrology laboratory. 

The Verified Graphene Producer™ program is designed to provide a level of transparency and confidence for graphene consumers that just does not exist anywhere else. 

We encourage all industrial scale, quality producers of graphene materials to consider participating in the Verified Graphene Producer™ program. We see this as an important step in supporting the widespread commercial adoption of graphene materials in all industrial sectors. 

Here is what Neill Ricketts, the CEO of advanced materials company Versarien has to say about the  program:

If you would like more information about  the Verified Graphene Producer™ program, feel free to contact me directly. 

Terrance Barkan CAE, Executive Director, The Graphene Council

tbarkan@thegraphenecouncil.org | Direct +1 202 294 5563

 

This post has not been tagged.

Share |
PermalinkComments (0)
 

Graphene sponge helps lithium sulphur batteries reach new potential

Posted By Graphene Council, The Graphene Council, Friday, May 3, 2019
Updated: Wednesday, May 1, 2019
To meet the demands of an electric future, new battery technologies will be essential. One option is lithium sulphur batteries, which offer a theoretical energy density more than five times that of lithium ion batteries. Researchers at Chalmers University of Technology, Sweden, recently unveiled a promising breakthrough for this type of battery, using a catholyte with the help of a graphene sponge.

The researchers' novel idea is a porous, sponge-like aerogel, made of reduced graphene oxide, that acts as a free-standing electrode in the battery cell and allows for better and higher utilisation of sulphur.

A traditional battery consists of four parts. First, there are two supporting electrodes coated with an active substance, which are known as an anode and a cathode. In between them is an electrolyte, generally a liquid, allowing ions to be transferred back and forth. The fourth component is a separator, which acts as a physical barrier, preventing contact between the two electrodes whilst still allowing the transfer of ions.

The researchers previously experimented with combining the cathode and electrolyte into one liquid, a so-called 'catholyte'. The concept can help save weight in the battery, as well as offer faster charging and better power capabilities. Now, with the development of the graphene aerogel, the concept has proved viable, offering some very promising results.

Taking a standard coin cell battery case, the researchers first insert a thin layer of the porous graphene aerogel.

"You take the aerogel, which is a long thin cylinder, and then you slice it - almost like a salami. You take that slice, and compress it, to fit into the battery," says Carmen Cavallo of the Department of Physics at Chalmers, and lead researcher on the study. Then, a sulphur-rich solution - the catholyte - is added to the battery. The highly porous aerogel acts as the support, soaking up the solution like a sponge.

"The porous structure of the graphene aerogel is key. It soaks up a high amount of the catholyte, giving you high enough sulphur loading to make the catholyte concept worthwhile. This kind of semi-liquid catholyte is really essential here. It allows the sulphur to cycle back and forth without any losses. It is not lost through dissolution - because it is already dissolved into the catholyte solution," says Carmen Cavallo.

Some of the catholyte solution is applied to the separator as well, in order for it to fulfil its electrolyte role. This also maximises the sulphur content of the battery.

Most batteries currently in use, in everything from mobile phones to electric cars, are lithium-ion batteries. But this type of battery is nearing its limits, so new chemistries are becoming essential for applications with higher power requirements. Lithium sulphur batteries offer several advantages, including much higher energy density. The best lithium ion batteries currently on the market operate at about 300 watt-hours per kg, with a theoretical maximum of around 350. Lithium sulphur batteries meanwhile, have a theoretical energy density of around 1000-1500 watt-hours per kg.

"Furthermore, sulphur is cheap, highly abundant, and much more environmentally friendly. Lithium sulphur batteries also have the advantage of not needing to contain any environmentally harmful fluorine, as is commonly found in lithium ion batteries," says Aleksandar Matic, Professor at Chalmers Department of Physics, who leads the research group behind the paper.

The problem with lithium sulphur batteries so far has been their instability, and consequent low cycle life. Current versions degenerate fast and have a limited life span with an impractically low number of cycles. But in testing of their new prototype, the Chalmers researchers demonstrated an 85% capacity retention after 350 cycles.

The new design avoids the two main problems with degradation of lithium sulphur batteries - one, that the sulphur dissolves into the electrolyte and is lost, and two, a 'shuttling effect', whereby sulphur molecules migrate from the cathode to the anode. In this design, these undesirable issues can be drastically reduced.

Tags:  Aleksandar Matic  Battery  Carmen Cavallo  Chalmers University of Technology  Graphene  Li-ion Batteries  Lithium 

Share |
PermalinkComments (0)
 

Decoupled graphene thanks to potassium bromide

Posted By Graphene Council, The Graphene Council, Friday, May 3, 2019
Updated: Wednesday, May 1, 2019

The use of potassium bromide in the production of graphene on a copper surface can lead to better results. When potassium bromide molecules arrange themselves between graphene and copper, it results in electronic decoupling. This alters the electrical properties of the graphene produced, bringing them closer to pure graphene, as reported by physicists from the universities of Basel, Modena and Munich in the journal ACS Nano.

Graphene consists of a layer of carbon atoms just one atom in thickness in a honeycomb pattern and is the subject of intensive worldwide research. Thanks to its high level of flexibility, combined with excellent stability and electrical conductivity, graphene has numerous promising applications – particularly in electronic components.

Molecules for decoupling

Mono-Layer Graphene is often produced via a chemical reaction on metallic surfaces in a process known as chemical vapor deposition. The graphene layer and the underlying metal are then electrically coupled, which diminishes some of the special electrical properties of graphene. For use in electronics, the graphene has to be transferred onto insulating substrates in a multistep process, during which there is a risk of damage and contamination.

In order to obtain defect-free, pure graphene, it is therefore preferable to decouple the graphene electrically from the metallic substrate and to develop a method that allows easier transfer without damage. The group led by Professor Ernst Meyer from the Department of Physics and the Swiss Nanoscience Institute (SNI) of the University of Basel is investigating ways of incorporating molecules between the graphene layer and the substrate after the chemical deposition process, which leads to this type of decoupling.

Altering electrical properties

In a study carried out by SNI doctoral student Mathias Schulzendorf, scientists have shown that potassium bromide is ideally suited to this. Potassium bromide is a soluble hydrogen bromide salt. Unlike the chemically similar compound sodium chloride, potassium bromide molecules arrange themselves between the graphene layer and the copper substrate. This was demonstrated by researchers in a variety of scanning probe microscopy studies.

Calculations performed by colleagues at the University of Modena and Reggio Emilia (Italy) explain this phenomenon: It is more energetically advantageous for the system if potassium bromide molecules arrange themselves between the graphene and copper than if they are deposited on the graphene – as happens with sodium chloride.

The researchers have shown that the intermediate layer of potassium bromide alters the electrical properties of graphene – until they correspond to those expected for free graphene. “Our work has demonstrated that the graphene and the underlying metal can be decoupled using potassium bromide, bringing us a key step closer to producing clean and defect-free graphene,” says project supervisor Dr. Thilo Glatzel, who is a member of Meyer’s team.

Tags:  Ernst Meyer  Graphene  Thilo Glatzel  Universities of Basel. Swiss Nanoscience Institute 

Share |
PermalinkComments (0)
 

New graphene-based material developed for medical implants

Posted By Graphene Council, The Graphene Council, Thursday, May 2, 2019
Updated: Wednesday, May 1, 2019
A group of scientists have developed a new material for biomedical applications by combining a graphene-based nanomaterial with Hydroxyapatite (HAp), a commonly used bioceramic in implants.

In recent years, biometallic implants have become popular as a means to repair, restructure or replace damaged or diseased parts in orthopaedic and dental procedures. Metal parts also find use in devices such as pacemakers.

However, metallic implants face several limitations and are not a permanent solution. They react with body fluids and corrode, release wear and tear debris resulting in toxins and inflammation. They also have high thermal expansion and low compressive strength causing pain and are dense and may cause reactions.

On the other hand, bioceramics do not have these limitations. HAp specifically is osteoconductive, with a bone-like porous structure offering the required scaffold for tissue re-growth. However, it is brittle and lacks the mechanical strength of metals. The problem is overcome by combining it with nanoparticles of materials such as Zirconia.

In the new research, scientists have combined HAp with graphene nanoplatelets. “Previously reported studies have focused on only structural properties of such composites without throwing light on their biological properties. We have found that combining HAp with graphene nanomaterial enhances mechanical strength, provides better in-vivo imaging and biocompatibility without changing its basic bone-like properties,” explained Dr Gautam Chandkiram, the principal investigator at University of Lucknow, while speaking to India Science Wire.

Purification of the base ceramic material is a significant primary challenge in fabricating composites. According to scientists, in the current study, highly efficient biocompatible Hydroxyapatite was successfully prepared via a microwave irradiation technique and the consequent composites was synthesised using a simple solid-state reaction method.

The process involved mixing different concentrations of graphene nanoplatelet powders and drying, crushing, sieving and ball-milling the resulting slurry. The fine composite powder was further cold-compressed and sintered at 1200 degrees Celsius to achieve the desired density.

The scientists found that the composite had adequate interfacial area between the nanoparticles, with the graphene nanoplatelets well distributed into the hydroxyapatite matrix, while exhibiting high fracture resistance. Further, structural characterization, mechanical and load bearing tests showed that the 2D nature of graphene improves the load transfer efficiency significantly.

Researchers also examined cell viability of the composite by observing metabolic activity in specific cells using a procedure known as MTT assay. They used gut tissues of Drosophila larvae and primary osteoblast cells of a rat. “The overall cell viability studies demonstrated that there is no cytotoxic effect of the composites on any cell type,” explained Dr. Gautam.

Biomaterials also find use in drug delivery and bioimaging diagnosis. “Our research on the composite found that it displays a better fluorescence behaviour as compared to pure hydroxyapatite, indicating it has a great potential in bone engineering and bioimaging bio-imaging applications as well,” he added.

Tags:  2D Materials  Gautam Chandkiram  Graphene  Medical  nanomaterials  University of Lucknow 

Share |
PermalinkComments (0)
 

Thomas Swan Advanced Materials announce exciting Graphene collaboration with Graphene Composites Ltd pioneering advanced protection against knife and gun-crime

Posted By Graphene Council, The Graphene Council, Wednesday, May 1, 2019
Thomas Swan is proud to collaborate with nano-materials technology manufacturer Graphene Composites Ltd to provide the graphene solution in their GC Shield™ armour products. The product is the result of a lengthy development collaboration between the companies together with the Centre for Process Innovation (CPI) using GNP-M grade graphene from Thomas Swan in the final application - an endorsement of the company’s ability to manufacture graphene in volume.

The GC Shield™ comes in a range of armour products providing lightweight, mobile protection to individuals and groups, plus effective protection for installation in large spaces. From a lightweight, flexible shield that is both bullet and stab-proof and can fit into a schoolbag, the GC Shield™ Plus has been successfully tested to stop multiple 7.62 x 51mm NATO M80 sniper bullets and AR-15 assault rifle M193 bullets fired at close range. The GC Shield™ Curtain can be deployed quickly, effectively and safely to provide protection in large spaces (e.g. school cafeterias, open plan areas, entrance halls).

Michael Edwards, head of the Advanced Materials Division at Thomas Swan said “It is always great to see an end-application that transfers into production demonstrating real-life applications for graphene – something that has been evasive in our market to date. As always there is a learning curve to be developed with a willing partner for a go-to market product, but we are always delighted to reach that point”.

Thomas Swan has a patented process to produce Multiple Layer (MLG) and Graphene Nanoplatelets (GNP) in volume at our facility in Consett, UK. Using our patented process of HighShear Liquid Phase Exfoliation licensed from Professor Jonathan Coleman’s work at Trinity College Dublin, we have further enhanced the process using our expertise at Thomas Swan, scaling-up to a 20T per year GNP capacity available today. We have the distinct advantage of being an established global player in the chemicals and materials business.

With manufacturing in the UK, a subsidiary company in the USA together with QA, logistics, regulatory and safety management, we are a leader in the field of 2D materials. Sandy Chen, CEO and founder of Graphene Composites said “Thomas Swan’s expertise in graphene manufacturing has been crucial to our success in developing our revolutionary armour products. Not only has the high quality and consistent manufacture made this possible but as a company, their willingness to collaborate closely with our Technical Team in our development processes has led to innovative and agile product design and development. This has enabled us to get our products market-ready much more quickly”.

Tags:  2D materials  Graphene  Graphene Composites  Jonathan Coleman  Michael Edwards  nanomaterials  Sandy Chen  Thomas Swan 

Share |
PermalinkComments (0)
 

Future Surrey research stars backed with grants totaling £1 million by EPSRC

Posted By Graphene Council, The Graphene Council, Tuesday, April 30, 2019
Updated: Friday, April 26, 2019

Surrey University has recently seen four successful New Investigator Award applications - including projects that look at new techniques to better understand the movements of plastics in our oceans, an investigation into the next generation of dental materials, a project looking to develop a game-changing carbon capture material and security protocols for future communications networks.

Predicting the fate of our plastics

Dr Thomas Bond, Lecturer from Surrey’s Department of Civil and Environmental Engineering, was granted over £260,000 to develop his research that will better predict the location of plastic litter in the environment. It is not known where 99 percent of the ocean’s plastic litter is, making it difficult to deal with this catastrophic environmental problem. Dr Bond will be looking at how different commonly used plastics behave and he will be using several experimental tests to develop methods that predict the fate of plastics polluting our waters.

Dr Bond said: “The amount of plastic litter in the environment is growing rapidly. Its presence poses a severe threat to marine and freshwater life. However, at the heart of our knowledge of plastic litter lies a black hole. I hope this project will give us a clearer picture of what happens to plastic waste in the environment. We will also investigate whether promoting sustainable types of plastics may obviate the problem of plastic litter in the environment.”

Next generation of dental material

Dr Tan Sui, Lecturer in Materials Engineering from the Department of Mechanical Engineering Sciences, was given just over £250,000 to investigate the next generation of dental materials that could be key to improving oral restorative surgeries. Together with the Universities of Bristol and Birmingham, the National Physical Laboratory and the Agency for Science, Technology and Research, Dr Sui will look to create a material that acts and performs like natural dental materials, with improved longevity.

Dr Tan Sui said: “Thanks to the advances of science and medicine we are all living longer but, unfortunately, our teeth are not faring so well. We hope this project will give us a deep understanding of novel dental materials, especially zirconia-based composites, with bioinspired functionally graded and textured microstructures -- and of how through refinement they may be durable enough to become the optimal dental restorative products.”

Carbon capture

Dr Marco Sacchi, Royal Society University Research Fellow, was awarded £230,000 to develop a computational research project that will reduce the cost and increase the efficiency of materials for carbon capture. In his project, Dr Sacchi will use Graphene, a newly discovered “miracle” material that has promising physical and thermal properties. The project will see Dr Sacchi join forces with a multidisciplinary team of chemists, nanotechnologists and physicists in industry and academia to test Graphene’s scientific boundaries and whether it can be used to entrap and treat greenhouse gases.

Dr Sacchi said: “Climate change is the biggest challenge that faces our planet today. It is an incredibly complex problem that requires teamwork from across the scientific spectrum to find sustainable solutions. We believe that by combining theoretical modelling with experimental validation, material testing and applied catalysis we will be able test the boundaries of Graphene and maximise its societal impact.”

Cybersecurity

Dr Ioana Boureanu, Lecturer in the Department of Computer Science and Surrey Centre for Cyber Security, was awarded just under £300,000 for the Automatic Verification of Complex Privacy Requirements in Unbounded-Size Secure Systems (AutoPaSS) project. AutoPaSS will develop formal methods and software-tools needed to analyse security and, especially, privacy in modern communications systems. AutoPaSS is in collaboration with industrial partners Thales and Vector GB Ltd.

Dr Boureanu said: “Today's devices execute concurrently in numerous and hyper-connected ways. So, we need reliable system-analysis techniques that capture not only cybersecurity properties but also modern connectivity. Importantly, this becomes an even bigger challenge if one needs to faithfully analyse rich privacy properties, such as anonymity and users’ untraceability. AutoPaSS will address this gap in the formal verification of 2020s' secure systems such as those driven by Internet of Things and connected, smart cars.”

Professor David Sampson, Vice-Provost, Research and Innovation, said: “These fantastic projects show that the University of Surrey is generating a wealth of bold, novel and innovative research ideas that have the potential to change everyday lives and the health of the planet. I want to congratulate our up-and-coming academics on their first steps into leading a research project. As a University, we are committed to supporting them and we wish them every success in these first steps towards an independent research career.”

Tags:  David Sampson  Engineering and Physical Sciences Research Council  Graphene  Ioana Boureanu  Marco Sacchi  Plastics  Tan Sui  Thomas Bond  University of Surrey 

Share |
PermalinkComments (0)
 

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 

Share |
PermalinkComments (0)
 
Page 8 of 24
 |<   <<   <  3  |  4  |  5  |  6  |  7  |  8  |  9  |  10  |  11  |  12  |  13  >   >>   >|