Scientists develop Lithium Metal batteries that charge faster, last longer with 10X times more energy by volume than Li-Ion Batteries – BIG potential for Our EV / AV Future


 

October 25, 2018

Rice University scientists are counting on films of carbon nanotubes to make high-powered, fast-charging lithium metal batteries a logical replacement for common lithium-ion batteries.

The Rice lab of chemist James Tour showed thin nanotube films effectively stop dendrites that grow naturally from unprotected lithium metal anodes in batteries. Over time, these tentacle-like dendrites can pierce the battery’s electrolyte core and reach the cathode, causing the battery to fail.

That problem has both dampened the use of lithium metal in commercial applications and encouraged researchers worldwide to solve it.

img_0837-1Rice University graduate student Gladys López-Silva holds a lithium metal anode with a film of carbon nanotubes. Once the film is attached, it becomes infiltrated by lithium ions and turns red. Photo by Jeff Fitlow

Lithium metal charges much faster and holds about 10 times more energy by volume than the lithium-ion electrodes found in just about every electronic device, including cellphones and electric cars.

 

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MIT NEWS: Read More About Lithium Metal Batteries

“One of the ways to slow dendrites in lithium-ion batteries is to limit how fast they charge,” Tour said. “People don’t like that. They want to be able to charge their batteries quickly.”

The Rice team’s answer, detailed in Advanced Materials, is simple, inexpensive and highly effective at stopping dendrite growth, Tour said.

“What we’ve done turns out to be really easy,” he said. “You just coat a lithium metal foil with a multiwalled carbon nanotube film. The lithium dopes the nanotube film, which turns from black to red, and the film in turn diffuses the lithium ions.”

“Physical contact with lithium metal reduces the nanotube film, but balances it by adding lithium ions,” said Rice postdoctoral researcher Rodrigo Salvatierra, co-lead author of the paper with graduate student Gladys López-Silva. “The ions distribute themselves throughout the nanotube film.”

img_0835An illustration shows how lithium metal anodes developed at Rice University are protected from dendrite growth by a film of carbon nanotubes. Courtesy of the Tour Group

When the battery is in use, the film discharges stored ions and the underlying lithium anode refills it, maintaining the film’s ability to stop dendrite growth.

The tangled-nanotube film effectively quenched dendrites over 580 charge/discharge cycles of a test battery with a sulfurized-carbon cathode the lab developed in previous experiments.

The researchers reported the full lithium metal cells retained 99.8 percent of their coulombic efficiency, the measure of how well electrons move within an electrochemical system.

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Rice University scientists have discovered that a film of multiwalled carbon nanotubes quenches the growth of dendrites in lithium metal-based batteries. Courtesy of the Tour Group

Co-authors of the paper are Rice alumni Almaz Jalilov of the King Fahd University of Petroleum and Minerals, Saudi Arabia; Jongwon Yoon, a senior researcher at the Korea Basic Science Institute; and Gang Wu, an instructor, and Ah-Lim Tsai, a professor of hematology, both at the McGovern Medical School at the University of Texas Health Science Center at Houston.

Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The research was supported by the Air Force Office of Scientific Research, the National Institutes of Health, the National Council of Science and Technology, Mexico; the National Council for Scientific and Technological Development, Ministry of Science, Technology and Innovation and Coordination for the Improvement of Higher Education Personnel, Brazil; and Celgard, LLC.

1028_DENDRITE-5-rn-18fsg2wRice University chemist James Tour, left, graduate student Gladys López-Silva and postdoctoral researcher Rodrigo Salvatierra use a film of carbon nanotubes to prevent dendrite growth in lithium metal batteries, which charge faster and hold more power than current lithium-ion batteries. Photo by Jeff Fitlow.

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How nanotechnology research could cure cancer – genetic diseases


Genetic diseases may soon be a thing of the past thanks to nanotechnology, which employs tiny particles to manipulate cells and change our DNA.

Here is how cancer treatment often runs today: a patient develops an aggressive tumor. A surgeon operates to remove the tumor, but a few cancer cells remain, hiding in the body. Chemotherapy is administered, weakening both patient and cancer cells. But the cancer does not die; it comes back and eventually kills the patient.

Now imagine another scenario. After surgery, strands of DNA anchored in tiny gold particles are injected into the affected area. The DNA strands bind to the tumor cells, killing them directly, without the help of chemo. The healthy cells around the tumor cells, which don’t express the tumor gene, are untouched.

Just like that, all the tumor cell stragglers are rendered harmless, corrected on the genetic level. The patient is cured, and without having to endure months of chemotherapy and its brutal side effects: hair loss, nausea and extreme weakness.

The future of medicine won’t focus on treating the symptoms of a disease, according to reseachers: it will focus on curing it at the genetic level.

Nanotechnology, the science of working with particles that are one billionth of a meter, is enabling scientists to change gene expression on the cellular level, potentially curing a host of diseases.

“Nanotechnology medical developments over the coming years will have a wide variety of uses and could potentially save a great number of lives,” says Eleonore Pauwels, senior associate and scholar at the Wilson Center, an interdisciplinary policy research center.

The science of using nanoparticles got its start with a lecture by theoretical physicist Richard Feynman in 1959, but because of the technical challenges, it is only in the past 10 years or so that the technology has really taken off for practical medical applications.

Figuring out how to consistently create the right nanoparticle, get it into the right tissue, ensure it is not degraded and does what it was programmed to do, took some time.

The science of nanotechnology depends on the fact that when things get super small, they function differently. Protein, for example, is a naturally occurring nanoparticle. A single protein molecule is a very different entity than a human being, which is made up of many protein molecules.

Gold, which is used often in medicine, is red when broken down into tiny particles. That microscopic bright red color has been used for centuries to give red stained glass its color.

“Because of their small size, engineered nanomaterials have unique properties that do not exist at the larger scale: increased surface area, charge, reactivity and other physicochemical properties, all of which may affect how nanomaterials interact with biological entities, like cells,” says Sara Brenner, assistant professor of nanobioscience at SUNY Polytechnic Institute.

Scientists are learning to take advantage of those properties to create new treatments. One of the most powerful examples uses DNA, says Chad Mirkin, a professor at Northwestern University and director of the International Institute for Nanotechnology.

DNA is rod shaped and normally would not be able to enter cells, which have developed protection against entry from foreign DNA segments.

But by using nanotechnology, many little snippets of DNA can be attached to a tiny, round synthetic core. The receptors on cells that would block rod shaped DNA do not recognize the tiny spheres of DNA and allow it to enter.

Using that property, a whole new class of treatments for genetic diseases is being developed.

By being able to insert DNA into existing cells, scientists can “attack disease at its genetic root and turn off receptors that regulate how a cell functions, stopping a disease pathway in its tracks,” explains Mirkin.

Right now, most of the research into developing therapies using spheres of DNA is focused on disease of the liver, says Mirkin, as anything a person takes in is going to be processed in the liver. Another area of research into nanotech treatments is the skin, as the treatment can be applied topically, making it easy to target one area.

“Potential applications are virtually endless,” explains Brenner. “But some areas of investigation right now for gene therapy are cancer, diabetes, AIDS, cystic fibrosis and heart disease.”

As research into using nanoparticles advances, scientists hope to be able to not just turn off specific signals in cells, but also eventually insert genes to correct for defects and cure more complex diseases.

Called gene therapy, it would involve inserting larger fragments of DNA into cells that have faulty DNA. For example, cystic fibrosis is caused by a defective gene called CFTR. If scientists can figure out a way to get a non-defective copy of the gene into the cells and correct it, they could cure the disease.

“Approximately 4,000 diseases have been found to have a genetic component and are therefore potential targets for gene therapy,” according to Brenner.

While nanotechnology has the potential to revolutionize medicine and how we view treatment of diseases, there are still kinks to work out.

Some of the challenges with nanotechnology include how to get nanoparticles into the right cells and tissues, and how to get them into the cells safely without the nanoparticles degrading.

Nanotechnology is still in its infancy, however. It’s only recently that we were able to produce microscopes that allowed us to see and manipulate nanoparticles. 

Research requires bringing together a number of disciplines like chemistry, biomedical engineering, biology and physics. But pharmaceutical companies have already begun work on creating treatments using nanotech, and many are in various stages of development now. “It’s not a pipe dream,” says Mirkin. Being able to cure genetic diseases of all kinds is on the horizon.

Graphene takes a Step Toward Renewable Fuel – Converting water and carbon dioxide to the renewable energy of the future


graphenetakeJianwu Sun at Linköping University inspecting the growth reactor for growth of cubic silicon carbide. Credit: Thor Balkhed/LiU

Using the energy from the sun and graphene applied to the surface of cubic silicon carbide, researchers at Linköping University, Sweden, are working to develop a method to convert water and carbon dioxide to the renewable energy of the future.

They have now taken an important step toward this goal, reporting a method that makes it possible to produce graphene with several layers in a tightly controlled process. The researchers have also shown that graphene acts as a superconductor in certain conditions. Their results have been published in the scientific journals Carbon and Nano Letters.

Carbon, oxygen and hydrogen are the three elements obtained by taking apart molecules of carbon dioxide and water. The same elements are the building blocks of chemical substances used for fuel, such as ethanol and methane. The conversion of carbon dioxide and water to renewable fuel could provide an alternative to fossil fuels and contribute to reducing carbon dioxide emissions into the atmosphere. Jianwu Sun, senior lecturer at Linköping University, is trying to find a way to do just that.

Researchers at Linköping University have previously developed a world-leading method to produce cubic silicon carbide, which consists of silicon and carbon. The cubic form has the ability to capture energy from the sun and create charge carriers. This is, however, not sufficient. Graphene, one of the thinnest materials ever produced, plays a key role in the project. The material comprises a single  of  atoms bound to each other in a hexagonal lattice. Graphene has a high ability to conduct an electric current, a property that would be useful for solar energy conversion. It also has several unique properties, and possible uses of graphene are being extensively studied all over the world.

jianwu-sun-ifm-liu-tb-dsc2960Read Original Post from Linkoping University

In recent years, the researchers have attempted to improve the process by which graphene grows on a surface in order to control the properties of the graphene. Their recent progress is described in an article in the scientific journal Carbon.

“It is relatively easy to grow one layer of graphene on silicon carbide. But it’s a greater challenge to grow large-area uniform graphene that consists of several layers on top of each other. We have now shown that it is possible to grow uniform graphene that consists of up to four layers in a controlled manner,” says Jianwu Sun of the Department of Physics, Chemistry and Biology at Linköping University.

One of the difficulties posed by multilayer graphene is that the surface becomes uneven when different numbers of layers grow at different locations. The edge when one layer ends has the form of a tiny, nanoscale staircase. Flat layers are desirable, so these steps are a problem, particularly when the steps accumulate in one location, like a wrongly built staircase in which several steps have been united to form one large step. The researchers have now found a way to remove these large, united steps by growing the graphene at a carefully controlled temperature. Furthermore, the researchers have shown that their method makes it possible to control how many layers the graphene will contain. This is the first key step in an ongoing research project whose goal is to make fuel from water and .

In a closely related article in the journal Nano Letters, the researchers describe investigations into the electronic properties of multilayer graphene grown on cubic silicon carbide.

“We discovered that multilayer graphene has extremely promising electrical properties that enable the material to be used as a superconductor, a material that conducts electrical current with zero electrical resistance. This special property arises solely when the graphene layers are arranged in a special way relative to each other,” says Jianwu Sun.

Theoretical calculations had predicted that multilayer  would have superconductive properties, provided that the layers are arranged in a particular way. In the new study, the researchers demonstrate experimentally for the first time that this is the case. Superconducting magnets are extremely powerful magnets used in medical magnetic resonance cameras and in particle accelerators. There are many potential areas of application for superconductors, such as electrical supply lines with zero energy loss, and high-speed trains that float on a magnetic field. Their use is currently limited by the inability to produce superconductors that function at room temperature. Currently available superconductors function only at extremely low temperatures.

 Explore further: Atoms use tunnels to escape graphene cover

More information: Yuchen Shi et al, Elimination of step bunching in the growth of large-area monolayer and multilayer graphene on off-axis 3C SiC (111), Carbon (2018). DOI: 10.1016/j.carbon.2018.08.042

Weimin Wang et al. Flat-Band Electronic Structure and Interlayer Spacing Influence in Rhombohedral Four-Layer Graphene, Nano Letters (2018). DOI: 10.1021/acs.nanolett.8b02530

 

Healing Kidneys with Nanotechnology – ASU Researchers Explore a new horizon for DNA Nanotechnology


healingkidne (1)The illustration shows a diseased kidney on the left and a healthy kidney on the right, after rectangular DNA nanostructures migrated and accumulated in the kidney, acting to alleviate damage due to oxidative stress. Credit: Shireen Dooling

Each year, there are some 13.3 million new cases of acute kidney injury (AKI), a serious affliction. Formerly known as acute renal failure, the ailment produces a rapid buildup of nitrogenous wastes and decreases urine output, usually within hours or days of disease onset. Severe complications often ensue.

AKI is responsible for 1.7 million deaths annually. Protecting healthy kidneys from harm and treating those already injured remains a significant challenge for modern medicine.

In new research appearing in the journal Nature Biomedical Engineering, Hao Yan and his colleagues at the University of Wisconsin-Madison and in China describe a new method for treating and preventing AKI. Their technique involves the use of tiny, self-assembling forms measuring just billionths of a meter in diameter.

The triangular, tubular and rectangular shapes are designed and built using a method known as DNA origami. Here, the base pairing properties of DNA’s four nucleotides are used to engineer and fabricate DNA origami nanostructures (DONs), which self-assemble and preferentially accumulate in kidneys.

“The interdisciplinary collaboration between nanomedicine and the in-vivo imaging team led by professor Weibo Cai at the University of Wisconsin-Madison and the DNA nanotechnology team has led to a novel application—applying DNA origami nanostructures to treat ,” Yan says. “This represents a new horizon for DNA nanotechnology research.”

Experiments described in the new study—conducted in mice as well as human embryonic kidney cells—suggest that DONs act as a rapid and active kidney protectant and may also alleviate symptoms of AKI. The distribution of DONs was examined with positron emission tomography (PET). Results showed that the rectangular nanostructures were particularly successful, protecting the kidneys from harm as effectively as the leading drug therapy and alleviating a leading source of AKI known as .

The study is the first to explore the distribution of DNA nanostructures in a living system by means of quantitative imaging with PET and paves the way for a host of new therapeutic approaches for the treatment of AKI as well as other renal diseases.

“This is an excellent example of team science, with multidisciplinary and multinational collaboration,” Cai said. “The four research groups are located in different countries, but they communicate regularly and have synergistic expertise. The three equally-contributing first authors (Dawei Jiang, Zhilei Ge, Hyung-Jun Im) also have very different backgrounds, one in radiolabeling and imaging, one in DNA nanostructures, and the other in clinical nuclear medicine. Together, they drove the project forward.”

Vital organ

Kidneys perform essential roles in body, removing waste and extra water from the blood to form urine. Urine then flows from the kidneys to the bladder through the ureters. Wastes in the blood are produced from the normal breakdown of active muscle and from foods, which the body requires for energy and self-repair.

Acute kidney injury can range considerably in severity. In advanced AKI, kidney transplantation is required as well as supportive therapies including rehydration and dialysis. Contrast-induced AKI, a common form of the illness, is caused by contrast agents sometimes used to improve the clarity of medical imaging. An anti-oxidant drug known as N-acetylcysteine (NAC) is used clinically to protect the kidneys from toxic assault during such procedures, but poor bioavailability of the drug in the kidneys can limit its effectiveness. (Currently, there is no known cure for AKI.)

Nanomedicinethe engineering of atoms or molecules at the nanoscale for biomedical applications—represents a new and exciting avenue of medical exploration and therapy. Recent research in the field has driven advances leading to improved imaging and therapeutics for a range of diseases, including AKI, though the use of nanomaterials within living systems in order to treat  has thus far been limited.

Healing kidneys with nanotechnology
Hao Yan directs the Biodesign Center for Molecular Design and Biomimetics and is the Martin D. Glick Distinguished Professor in the School of Molecular Sciences at ASU. Credit: The Biodesign Institute at Arizona State University

The base-pairing properties of nucleic acids like DNA and RNA enable the design of tiny programmable structures of predictable shape and size, capable of performing a multitude of tasks. Further, these nanoarchitectures are desirable for use in living systems due to their stability, low toxicity, and low immunogenicity.

New designs

The current study marks the first investigation of DNA origami nanostructures within living organisms, using quantitative imaging to track their behavior. The PET imaging used in the study allowed for a quantitative and reliable real-time method to study the circulation of DONs in a living organism and to assess their physiological distribution. Rectangular DONs were identified as the most effective therapeutic to treat AKI in mice, based on the PET analysis.

Yan and his colleagues prepared a series of DONs and used radio labeling to study their behavior in mouse kidney, using PET imaging. The PET scans showed that the DONs had preferentially accumulated in the kidneys of healthy mice as well as those with induced AKI. Of the three shapes used in the experiments, the rectangular DONs provided the greatest benefit in terms of protection and therapy and were comparable in their effect to the drug NAC, considered the gold standard treatment for AKI.

Patients with kidney disease often have accompanying maladies, including a high incidence of cardiovascular disease and malignancy. Acute kidney illness may be induced through the process of oxidative stress, which results from an increase in oxygen-containing waste products known as , that cause damage to lipids, proteins and DNA. This can occur when the delicate balance of free radicals and anti-oxidant defenses becomes destabilized, causing inflammation and accelerating the progression of renal disease. (Foods and supplements rich in antioxidants act to protect cells from the harmful effects of reactive oxygen species.)

Safeguarding kidneys with DNA geometry

The protective and therapeutic effects of the DONs described in the new study are due to the ability of the nanostructures to scavenge reactive oxygen species, thereby insulating vulnerable cells from damage due to oxidative stress. This effect was studied in human embryonic kidney cell lines as well as in living mice. The accumulation of the nanostructures in both healthy and diseased kidneys provided an increased therapeutic effect compared with traditional AKI therapy. (DONs alleviated oxidative stress within 2 hours of incubation with affected kidney cells.)

Improvement in AKI kidney function—comparable with high-dose administration of the drug NAC— was observed following the introduction of nanostructures. Examination of stained tissue samples further confirmed the beneficial effects of the DONs in the kidney.

The authors propose several mechanisms to account for the persistence in the kidneys of properly folded origami nanostructures, including their resistance to digestive enzymes, avoidance of immune surveillance and low protein absorption.

Levels of serum creatinine and blood urea nitrogen (BUN) were used to assess renal function in mice. AKI mice treated with rectangular DONs displayed improved kidney excretory function comparable to mice receiving treatment using the mainline drug NAC.

Further, the team established the safety of rectangular DONs, evaluating their potential to elicit an immune response in mice by examining blood levels of interleukin-6 and tumor necrosis factor alpha. Results showed the DONs were non-immunogenetic and tissue staining of heart, liver, spleen lungs and kidney revealed their low toxicity in primary organs, making them attractive candidates for clinical use in humans.

Based on the effective scavenging of reactive oxygen species by DONs in both human kidney cell culture and living mouse , the study concludes that the approach may indeed provide localized protection for kidneys from AKI and may even offer effective treatment for AKI-damaged kidneys or other renal disorders.

The successful proof-of-concept study expands the potential for a new breed of therapeutic programmable nanostructures, engineered to address far-flung medical challenges, from smart drug delivery to precisely targeted organ and tissue repair.

 Explore further: YAP after acute kidney injury

More information: Dawei Jiang et al, DNA origami nanostructures can exhibit preferential renal uptake and alleviate acute kidney injury, Nature Biomedical Engineering (2018). DOI: 10.1038/s41551-018-0317-8

 

One step closer to complex ‘Quantum Teleportation’ – University of Vienna


Quantum-Entanglement4_1024

Novel complex quantum entanglement generated in the laboratory for the first time

For future technologies such as quantum computers and quantum encryption, the experimental mastery of complex quantum systems is inevitable. Scientists from the University of Vienna and the Austrian Academy of Sciences have succeeded in making another leap.

While physicists around the world are trying to increase the number of two-dimensional systems, so-called qubits, researchers around Anton Zeilinger are breaking new ground. They pursue the idea to use more complex quantum systems as qubits and thus can increase the information capacity with the same number of particles.

The developed methods and technologies could in the future enable the teleportation of complex quantum systems. The results of their work “Experimental Greenberger-Horne-Zeilinger Entanglement Beyond QuBits” is published recently in the renowned journal Nature Photonics.

Similar to bits in conventional computers, QuBits are the smallest unit of information in quantum systems. Big companies like Google and IBM are competing with research institutes around the world to produce an increasing number of entangled QuBits. The clear motivation is to develop a functioning quantum computer. A research group at the University of Vienna and the Austrian Academy of Sciences, however, is pursuing a new path to increase the information capacity of complex quantum systems.

quantum-satellite-record-1Quantum Teleportation Explained in the Nutshell

The idea behind it is simple: instead of just increasing the number of particles involved, the complexity of each system is increased. “The special thing about our experiment is that for the first time it entangles three photons beyond the conventional two-dimensional nature,” explains Manuel Erhard, first author of the study. For this purpose, the Viennese physicists use quantum systems which have more than two possible states – in this particular case, the angular momentum of individual light particles. These individual photons now have a higher information capacity than QuBits.

However, the entanglement of these light particles turned out to be difficult on a conceptual level. The researchers overcame this challenge with a ground-breaking idea: a computer algorithm that autonomously searches for an experimental implementation.

Also Read About: Chinese satellite shatters quantum teleportation distance record

With the help of the computer algorithm Melvin an experimental setup to produce this type of entanglement has been uncovered. At first this was still very complex, but at least it worked in principle. After some simplifications, physicists still faced major technological challenges. The team was able to solve these with state-of-the-art laser technology and a specially developed multi-port. “This multi-port is the heart of our experiment and combines the three photons so that they are entangled in three dimensions,” explains Manuel Erhard.

The peculiar property of the three-photon entanglement in three dimensions allows for experimental investigation of new fundamental questions about the behaviour of quantum systems. In addition, the results of this work could also have a significant impact on future technologies, such as quantum teleportation. “I think the methods and technologies that we developed in this publication allow us to teleport a higher proportion of the total quantum information of a single photon, which could be important for quantum communication networks,” Anton Zeilinger points out into the future of possible applications.

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Publication in Nature Photonics: „Experimental Greenberger-Horne-Zeilinger Entanglement Beyond QuBits”, Manuel Erhard, Mehul Malik, Mario Krenn & Anton Zeilinger. https://doi.org/10.1038/s41566-018-0257-6

Hairy nano-cellulose provides green anti-scaling solution – More applications including drug delivery, antimicrobial agents, and fluorescent dyes for medical imaging – McGill University


hairynanotecCredit: McGill University

A new type of cellulose nanoparticle, invented by McGill University researchers, is at the heart of a more effective and less environmentally damaging solution to one of the biggest challenges facing water-based industries: preventing the buildup of scale.

Formed by the accumulation of sparingly soluble minerals, scale can seriously impair the operation of just about any equipment that conducts or stores water – from household appliances to industrial installations. Most of the anti-scaling agents currently in use are high in phosphorus derivatives, environmental pollutants that can have catastrophic consequences for aquatic ecosystems.

In a series of papers published in the Royal Society of Chemistry’s Materials Horizons and the American Chemical Society’s Applied Materials & Interfaces, a team of McGill chemists and chemical engineers describe how they have developed a phosphorus-free anti-scaling solution based on a nanotechnology breakthrough with an unusual name: hairy nanocellulose.

An unlikely candidate

Lead author Amir Sheikhi, now a postdoctoral fellow in the Department of Bioengineering at the University of California, Los Angeles, says despite its green credentials  was not an obvious place to look for a way to fight scale.

“Cellulose is the most abundant biopolymer in the world. It’s renewable and biodegradable. But it’s probably one of the least attractive options for an anti-scaling agent because it’s neutral, it has no charged functional groups,” he says.

While working as a postdoctoral fellow with McGill chemistry professor Ashok Kakkar, Sheikhi developed a number of macromolecular antiscalants that were more effective than products widely used in industry – but all of his discoveries were phosphonate-based. His desire to push his research further and find a phosphorus-free alternative led him to take a closer look at cellulose.

“Nanoengineered hairy cellulose turned out to work even better than the phosphonated molecules,” he says.

The breakthrough came when the research team succeeded in nanoengineering negatively charged carboxyl groups onto cellulose nanoparticles. The result was a particle that was no longer neutral, but instead carried charged functional groups capable of controlling the tendency of positively charged calcium ions to form scale.

Hirsute wonder particle a chance discovery

Previous attempts to functionalize cellulose in this way focused on two earlier forms of nanoparticle – cellulose nanofibrils and . But these efforts produced only a minimal amount of useful product. The difference this time was that the McGill team worked with hairy nanocellulose – a new nanoparticle first discovered in the laboratory of McGill chemistry professor Theo van de Ven.

Van de Ven, who also participated in the anti-scaling research, recalls the moment in 2011 when Han Yang, then a doctoral student in his lab, stumbled upon the new form of nanocellulose.

“He came into my office with a test tube that looked like it had water in it and he said, ‘Sir! My suspension has disappeared!'” van de Ven says with a grin.

“He had a white suspension of kraft fibres and it had turned transparent. When something is transparent, you know immediately it has either dissolved or turned nano. We performed a number of characterizations and we realized he had made a new form of nanocellulose.”

Extreme versatility

The secret to making hairy nanocellulose lies in cutting cellulose nanofibrils – which are made up of an alternating series of crystalline and amorphous regions – at precise locations to produce nanoparticles with amorphous regions sprouting from either end like so many unruly strands of hair.

“By breaking the nanofibrils up the way we do, you get all these cellulose chains sticking out which are accessible to chemicals,” van de Ven explains. “That’s why our nanocellulose can be functionalized to a far greater extent than other kinds.”

Given the chemical versatility of hairy nanocellulose, the research team sees strong potential for applications beyond anti-scaling, including drug delivery, antimicrobial agents, and fluorescent dyes for medical imaging.

“We can link just about any molecule you can think of to hairy ,” van de Ven says.

 Explore further: Ready-to-use recipe for turning plant waste into gasoline

More information: Amir Sheikhi et al. Overcoming Interfacial Scaling Using Engineered Nanocelluloses: A QCM-D Study, ACS Applied Materials & Interfaces (2018). DOI: 10.1021/acsami.8b07435

Amir Sheikhi et al. Nanoengineering colloidal and polymeric celluloses for threshold scale inhibition: towards universal biomass-based crystal modification, Materials Horizons (2018). DOI: 10.1039/C7MH00823F

 

What’s Next: Beyond the lithium-ion battery


PWENERGYNov18Provoost_IMEC-635x357Drive for innovation: Electric vehicles are a major target for R&D on novel battery materials. (Image courtesy: imec)
31 Oct 2018
Note to Readers: This article first appeared in the 2018 Physics World Focus on Energy Technologies Engineering a sustainable, electrified future means developing battery materials with properties that surpass those found in current technologies.

The batteries we depend on for our mobile phones and computers are based on a technology that is more than a quarter-century old. Rechargeable lithium-ion (Li-ion) batteries were first introduced in 1991, and their appearance heralded a revolution in consumer electronics. From then on, we could pack enough energy in a small volume to start engineering a whole panoply of portable electronic devices – devices that have given us much more flexibility and comfort in our lives and jobs.

In recent years, Li-ion batteries have also become a staple solution in efforts to solve the interlinked conundrums of climate change and renewable energy. Increasingly, they are being used to power electric vehicles and as the principal components of home-based devices that store energy generated from renewable sources, helping to balance an increasingly diverse and smart electrical grid. The technology has improved too: over the past two and a half decades, battery experts have succeeded in making Li-ion batteries 5–10% more efficient each year, just by further optimizing the existing architecture.

Ultimately, though, getting from where we are now to a truly carbon-free economy will require better-performing batteries than today’s (or even tomorrow’s) Li-ion technology can deliver. In electric vehicles, for example, a key consideration is for batteries to be as small and lightweight as possible.

 

Achieving that goal calls for energy densities that are much higher than the 300 Wh/kg and 800 Wh/L which are seen as the practical limits for today’s Li-ion technology.

Another issue holding back the adoption of electric vehicles is cost, which is currently still around 300–200 $/kWh, although that is widely projected to go below 100 $/kWh by 2025 or even earlier. The time required to recharge a battery pack – still in the range of a few hours – will also have to come down, and as batteries move into economically critical applications such as grid storage and grid balancing, very long lifetimes (a decade or more) will become a key consideration too.

There is still some room left to improve existing Li-ion technology, but not enough to meet future requirements. Instead, the process of battery innovation needs a step change: materials-science breakthroughs, new electrode chemistries and architectures that have much higher energy densities, new electrolytes that can deliver the necessary high conductivity – all in a battery that remains safe and is long-lasting as well as economical and sustainable to produce.

Lithium magic

To appreciate why this is such a challenge, it helps to understand the basic architecture of existing batteries. Rechargeable Li-ion batteries are made up of one or more cells, each of which is a small chemical factory essentially consisting of two electrodes with an electrolyte in between. When the electrodes are connected (for example with a wire via a lamp), an electrochemical process begins. In the anode, electrons and lithium ions are separated, and the electrons buzz through the wire and light up the lamp. Meanwhile, the positively-charged lithium ions move through the electrolyte to the cathode. There, electrons and Li-ions combine again, but in a lower energy state than before.

The beauty of rechargeable batteries is that these processes can be reversed, returning lithium ions to the anode and restoring the energy states and the original difference in electrical potential between the electrodes. Lithium ions are well suited for this task. Lithium is not only the lightest metal in the periodic table, but also the most reactive and will most easily part with its electrons. It has been chosen as the basis for rechargeable batteries precisely because it can do the most work with the least mass and the fewest chemical complications. More specifically, in batteries using lithium, it is possible to make the electric potential difference between anodes and cathodes higher than is possible with other materials.

To date, therefore, the main challenge for battery scientists has been to find chemical compositions of electrodes and electrolyte that will let the lithium ions do their magic in the best possible way: electrodes that can pack in as many lithium ions as possible while setting up as high an electrical potential difference as possible; and an electrolyte that lets lithium ions flow as quickly as possible back and forth between the anode and cathode.

Seeking a solid electrolyte

The electrolyte in most batteries is a liquid. This allows the electrolyte not only to fill the space between the electrodes but also to soak them, completely filling all voids and spaces and providing as much contact as possible between the electrodes and the electrolyte. To complete the picture, a porous membrane is added between the electrodes. This inhibits electrical contact between the electrodes and prevents finger like outgrowths of lithium from touching and short-circuiting the battery.
For all the advantages of liquid electrolytes, though, scientists have long sought to develop solid alternatives. A solid electrolyte material would eliminate several issues at the same time. Most importantly, it would replace the membrane, allowing the electrodes to be placed much closer together without touching, thereby, making the battery more compact and boosting its energy density. A solid electrolyte would also make batteries stronger, potentially meaning that the amount of protective and structural casing could be cut without compromising on safety.

Unfortunately, the solid electrolytes proposed so far have generally fallen short in one way or another. In particular, they lack the necessary conductivity (expressed in milli-Siemens per centimetre, or mS/cm). Unsurprisingly, ions tend not to move as freely through a solid as they do through a liquid. That reduces both the speed at which a battery can charge and, conversely, the quantity of power it can release in a given time.

Scientists at imec – one of Europe’s premier nanotechnology R&D centres, and a partner in the EnergyVille consortium for sustainable energy and intelligent energy systems research – recently came up with a potential solution. The new material is a nanoporous oxide mix filled with ionic compounds and other additives, with the pores giving it a surface area of about 500 m2/mL – “comparable to an Olympic swimming pool folded into a shot glass,” says Philippe Vereecken, imec’s head of battery research. Because ions move faster along the pores’ surface than in the middle of a lithium salt electrolyte, he explains, this large surface area amplifies the ionic conductivity of the nanoengineered solid. The result is a material with a conductivity of 10 mS/cm at room temperature – equivalent to today’s liquid electrolytes.

Using this new electrolyte material, imec’s engineers have built a cell prototype using standard available electrodes: LFP (LiFePO4) for the cathode and LTO (Li4Ti5O12) for the anode. While charging, the new cell reached 80% of its capacity in one hour, which is already comparable to a similar cell made with a liquid electrolyte. Vereecken adds that the team hopes for even better results with future devices. “Computations show that the new material might even be engineered to sustain conductivities of up to 100 mS/cm,” he says.

Meanwhile, back at the electrode

Electrodes are conventionally made from sintered and compressed powders. Combining these with a solid electrolyte would normally entail mixing the electrode as a powder with the electrolyte also in powder form, and then compressing the result for a maximum contact. But even then, there will always remain pores and voids that are not filled and the contact surface will be much smaller than is possible with a liquid electrolyte that fully soaks the electrode.

Lithium-sulphur is a promising material that could store more energy than today’s technology allows

Lith Sulfur Batts c5cs00410a-f2_hi-res

Imec’s new nano-composite material avoids this problem because it is actually applied as a liquid, via wet chemical coating, and only afterwards converted into a solid. That way it can impregnate dense powder electrodes, filling all cavities and making maximum contact just as a liquid electrolyte would. Another benefit is that even as a solid, the material remains somewhat elastic, which is essential as some electrodes expand and contract during battery charging and discharging. A final advantage is that because the solid material can be applied via a wet precursor, it is compatible with current Li-ion battery fabrication processes – something that Vereecken says is “quite important for the battery manufacturers” because otherwise more “disruptive” fabrication processes would have to be put in place.

To arrive at the energy densities required to give electric vehicles a long driving range, though, still more changes are needed. One possibility is to make the particles in the electrode powders smaller, so that they can be packed more densely. This would produce a larger contact surface with the electrolyte per volume, improving the energy density and charging rate of the cell. There is a catch, though: while a larger contact surface results in more ions being created and changing sides within the battery, it also gives more way for unwanted reactions that will degrade the battery’s materials and shorten its lifetime. “To improve the stability,” says Vereecken, “imec’s experts work on a solution where they coat all particles with an ultrathin buffer layer.” The challenge, he says, is to make these layers both chemically inert and highly conductive.

Introducing new materials

By combining solid electrolytes with thicker electrodes made from smaller particles, it may be possible to produce batteries with energy densities that exceed the current maximum of around 800 Wh/L. These batteries could also charge in 30 minutes or less. But to extend the energy density even further, to 1000 Wh/L and beyond, a worldwide effort is on to look for new and better electrode materials. Anodes, for example, are currently made from carbon in the form of graphite. That carbon could be replaced by silicon, which can hold up to ten times as many lithium ions per gram of electrode. The drawback is that when the battery is charged, a silicon anode will expand to more than three times its normal size as it fills with lithium ions. This may break up the electrode, and possibly even the battery casing.

A better alternative may be to replace carbon with pure lithium metal. A lithium anode will also store up to ten times as much lithium ions per gram of electrode as graphite, but without the swelling seen in silicon anodes. Lithium anodes were, in fact, used in the early days of Li-ion batteries, but as the metal is very reactive, especially in combination with liquid electrolytes, the idea was dropped in favour of more stable alternatives. Vereecken, however, believes that progress in solid electrolytes means it is “high time to revisit lithium metal as a material for the anode”, especially since it is possible to add protective functional coatings to nanoparticles.

Disruptive innovations are on the horizon for cathodes as well. Lithium-sulphur, for example, is a promising material that could store more energy than today’s technology allows. Indeed, the “ideal” lithium battery might well feature a lithium-air (lithium peroxide) cathode in combination with a pure lithium anode. But whereas the material composition of these batteries sounds simple, the path to realizing them will not be so easy, and there is still some way to go before any of these developments will be integrated into commercial batteries. Once that happens, though, huge payoffs are possible. The most obvious would be electrical cars that drive farther and charge faster, but better lithium batteries could also be the breakthrough needed to make renewable power ubiquitous – and thus finally let us off the fossil-fuel hook.

Genesis Nanotechnology, Inc. is pleased to present Tenka Energy, Inc. Building Ultra-Thin Energy Dense SuperCaps and NexGen Nano-Enabled Pouch & Cylindrical Batteries – Energy Storage Made Small and POWERFUL! YouTube Video

 

 

Update EV News: Volvo buys a stake in electric charging firm FreeWire Technologies


Volvo and MOBI

Oct. 24, 2018

Volvo Cars has acquired a stake in electric car charging company FreeWire Technologies via the Volvo Cars Tech Fund, deepening the company’s commitment to a fully electric future. (See Industry Announcement Below)

While Volvo Cars’s electrification strategy does not envision direct ownership of charging or service stations, the investment in FreeWire reinforces its overall commitment to supporting a widespread transition to electric mobility together with other partners.

FWire mobisLeafsFreeWire is a San Francisco-based company that has been a pioneer in flexible fast-charging technology for electric cars. It specialises in both stationary and mobile fast charging technology, allowing electric car charging to be deployed quickly and widely. (Check Out FWT’s website – Featuring ‘MOBI’)  FreeWire Technologies – Electrification Beyond the Grid

Installing traditional fixed fast-charging stations is usually a cost- and labour intensive process that requires a lot of electrical upgrades to support the connection between charging stations and the main electrical grid. FreeWire’s charging stations remove that complication and use low-voltage power, allowing operators to simply use existing power outlets. This means drivers can enjoy all the benefits of fast charging without operators needing to go through the hassle of establishing a high-voltage connection to the grid.

Volvo Cars has one of the auto industry’s most ambitious electrification strategies. Every new Volvo car launched from 2019 will be electrified, and by 2025 the company aims for fully electric cars to make up 50 per cent of its overall global sales.

“Volvo Cars’ future is electric, as reflected by our industry-leading commitment to electrify our entire product range,” said Zaki Fasihuddin, CEO of the Volvo Cars Tech Fund. “To support wider consumer adoption of electric cars, society needs to make charging an electric car as simple as filling up your tank. Our investment in FreeWire is a firm endorsement of the company’s ambitions in this area.”

“FreeWire’s fast charging technology holds great promise to simplify the experience for customers of electrified Volvos,” said Atif Rafiq, chief digital officer at Volvo Cars. “With this move, we aim to make the future of sustainable, electric cars more practical and convenient.”

“We’re thrilled to partner with Volvo Cars to develop new markets and business models around our EV fast charging and ultra-fast charging technology,” said Arcady Sosinov, CEO of FreeWire. “Having a car maker with both the legacy and future vision of Volvo is going to give us access to technology, testing, and new strategies that will really accelerate the growth of the company.”

The Volvo Cars Tech Fund was launched earlier this year and aims to invest in high-potential technology start-ups around the globe. It focuses its investments on strategic technology trends transforming the auto industry, such as artificial intelligence, electrification, autonomous drive and digital mobility services.

Earlier this year, the Volvo Cars Tech Fund announced its first investment in Luminar Technologies, a leading start-up in the development of advanced sensor technology for use in autonomous vehicles, with whom Volvo Cars collaborates on the development and testing of its LiDAR sensing technology on Volvo cars.

Companies benefit from participation by the Volvo Cars Tech Fund as they may gain the ability to validate technologies, accelerate market introduction, as well as potentially access Volvo Cars’ global network and unique position in the Chinese car market.

 

 Volvo Car Group in 2017

For the 2017 financial year, Volvo Car Group recorded an operating profit of 14,061 MSEK (11,014 MSEK in 2016). Revenue over the period amounted to 210,912 MSEK (180,902 MSEK). For the full year 2017, global sales reached a record 571,577 cars, an increase of 7.0 per cent versus 2016. The results underline the comprehensive transformation of Volvo Cars’ finances and operations in recent years, positioning the company for its next growth phase.

About Volvo Car Group

Volvo has been in operation since 1927. Today, Volvo Cars is one of the most well-known and respected car brands in the world with sales of 571,577 cars in 2017 in about 100 countries. Volvo Cars has been under the ownership of the Zhejiang Geely Holding (Geely Holding) of China since 2010. It formed part of the Swedish Volvo Group until 1999, when the company was bought by Ford Motor Company of the US. In 2010, Volvo Cars was acquired by Geely Holding.

In 2017, Volvo Cars employed on average approximately 38,000 (30,400) full-time employees. Volvo Cars head office, product development, marketing and administration functions are mainly located in Gothenburg, Sweden. Volvo Cars head office for China is located in Shanghai. The company’s main car production plants are located in Gothenburg (Sweden), Ghent (Belgium), Chengdu, Daqing (China) and Charleston (USA), while engines are manufactured in Skövde (Sweden) and Zhangjiakou (China) and body components in Olofström (Sweden).

About Volvo Cars Tech Fund Volvo download

Volvo Cars Tech Fund is a new venture fund under the Volvo Cars umbrella, and is dedicated to advancing Volvo’s mission of ecology, safety, and technology across its vehicles. The fund was established in 2018, and is based out of Volvo Cars R&D Tech Center in Mountain View, California. Read more here.

 

 

Industry Announcement

Volvo is the latest business to take an interest in FreeWire.  Swedish luxury vehicles company Volvo Cars has bought a stake in FreeWire Technologies, a California-based electric car charging business. 

The acquisition has been made through the Volvo Cars Tech Fund, which was launched earlier this year. In an announcement Wednesday, Volvo described FreeWire as a “pioneer in flexible fast charging technology for electric cars.”Volvo becomes the latest major business to take an interest in FreeWire. In January 2018, BP Ventures announced it was investing $5 million in the business. 

From 2019, every new car that Volvo launches is set to be electrified. The business wants fully-electric cars to account for 50 percent of overall global sales by the year 2025.

“To support wider consumer adoption of electric cars, society needs to make charging an electric car as simple as filling up your tank,” Zaki Fasihuddin, the Volvo Cars Tech Fund CEO, said in a statement. “Our investment in FreeWire is a firm endorsement of the company’s ambitions in this area.”

In 2017, there were more than 3 million electric and plug-in hybrid cars on the planet’s roads, according to the International Energy Agency’s (IEA) Global Electric Vehicles Outlook. This represents an increase of 54 percent compared to 2016.

Almost 580,000 electric cars were sold in China last year, according to the IEA, while around 280,000 were sold in the U.S.

In terms of charging infrastructure, the IEA says that, globally, there were an estimated 3 million private chargers at homes and workplaces in 2017. The number of “publicly accessible” chargers amounted to roughly 430,000.

Will Drexel’s Discovery Enable a Lithium-Sulfur ‘Battery (R)evolution’?


Lithium-sulfur batteries could be the energy storage devices of the future, if they can get past a chemical phenomenon that reduces their endurance. Drexel researchers have reported a method for making a sulfur cathode that could preserve the batteries’ exceptional performance. (Image from Drexel News)

Drexel’s College of Engineering reports that researchers and the industry are looking at Li-S batteries to eventually replace Li-ion batteries because a new chemistry that theoretically allows more energy to be packed into a single battery.

img_0808This improved capacity, on the order of 5-10 times that of Li-ion batteries, equates to a longer run time for batteries between charges.

However, the problem is that Li-S batteries have trouble maintaining their superiority beyond just a few recharge cycles. But a solution to that problem may have been found with new research.

The new approach, reported by in a recent edition of the American Chemical Society journal Applied Materials and Interfaces, shows that it can hold polysulfides in place, maintaining the battery’s impressive stamina, while reducing the overall weight and the time required to produce them.

“We have created freestanding porous titanium monoxide nanofiber mat as a cathode host material in lithium-sulfur batteries,” said Vibha Kalra, PhD, an associate professor in the College of Engineering who led the research.

img_0810

“This is a significant development because we have found that our titanium monoxide-sulfur cathode is both highly conductive and able to bind polysulfides via strong chemical interactions, which means it can augment the battery’s specific capacity while preserving its impressive performance through hundreds of cycles.

We can also demonstrate the complete elimination of binders and current collector on the cathode side that account for 30-50 percent of the electrode weight — and our method takes just seconds to create the sulfur cathode, when the current standard can take nearly half a day.”

img_0811

Please find the full report here: LINK
TiO Phase Stabilized into Free-Standing Nanofibers as Strong Polysulfide Immobilizer in Li-S Batteries: Evidence for Lewis Acid-Base Interactions
Arvinder Singh and Vibha Kalra

ACS Appl. Mater. Interfaces, Just Accepted Manuscript

DOI: 10.1021/acsami.8b11029

We report the stabilization of titanium monoxide (TiO) nanoparticles in nanofibers through electrospinning and carbothermal processes and their unique bi-functionality – high conductivity and ability to bind polysulfides – in Li-S batteries. The developed 3-D TiO/CNF architecture with the inherent inter-fiber macropores of nanofiber mats provides a much higher surface area (~427 m2 g-1) and overcomes the challenges associated with the use of highly dense powdered Ti-based suboxides/monoxide materials, thereby allowing for high active sulfur loading among other benefits.

The developed TiO/CNF-S cathodes exhibit high initial discharge capacities of ~1080 mAh g-1, ~975 mAh g-1, and ~791 mAh g-1 at 0.1C, 0.2C, and 0.5C rates, respectively with long term cycling. Furthermore, free-standing TiO/CNF-S cathodes developed with rapid sulfur melt infiltration (~5 sec) eradicate the need of inactive elements viz. binders, additional current collectors (Al-foil) and additives. Using postmortem XPS and Raman analysis, this study is the first to reveal the presence of strong Lewis acid-base interaction between TiO (3d2) and Sx2- through coordinate covalent Ti-S bond formation.

Our results highlight the importance of developing Ti-suboxides/monoxide based nanofibrous conducting polar host materials for next-generation Li-S batteries.

“Reprinted with permission from (DOI: 10.1021/acsami.8b11029). Copyright (2018) American Chemical Society.”

 

 

MIT: Mass producing cell-sized robots that could monitor conditions inside oil/gas pipelines or search out disease while floating through the bloodstream


This photo shows circles on a graphene sheet where the sheet is draped over an array of round posts, creating stresses that will cause these discs to separate from the sheet. The gray bar across the sheet is liquid being used to lift the discs from the surface. Credit: Felice Frankel

Tiny robots no bigger than a cell could be mass-produced using a new method developed by researchers at MIT. The microscopic devices, which the team calls “syncells” (short for synthetic cells), might eventually be used to monitor conditions inside an oil or gas pipeline, or to search out disease while floating through the bloodstream.

The key to making such tiny devices in large quantities lies in a method the team developed for controlling the natural fracturing process of atomically-thin, brittle , directing the fracture lines so that they produce miniscule pockets of a predictable size and shape. Embedded inside these pockets are electronic circuits and materials that can collect, record, and output data.

The novel process, called “auto-perforation,” is described in a paper published today in the journal Nature Materials, by MIT Professor Michael Strano, postdoc Pingwei Liu, graduate student Albert Liu, and eight others at MIT.

The system uses a two-dimensional form of carbon called graphene, which forms the outer structure of the tiny syncells. One layer of the material is laid down on a surface, then tiny dots of a polymer material, containing the electronics for the devices, are deposited by a sophisticated laboratory version of an inkjet printer. Then, a second layer of graphene is laid on top.

Controlled fracturing

People think of graphene, an ultrathin but extremely strong material, as being “floppy,” but it is actually brittle, Strano explains. But rather than considering that brittleness a problem, the team figured out that it could be used to their advantage.

“We discovered that you can use the brittleness,” says Strano, who is the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “It’s counterintuitive. Before this work, if you told me you could fracture a material to control its shape at the nanoscale, I would have been incredulous.”

But the new system does just that. It controls the fracturing process so that rather than generating random shards of material, like the remains of a broken window, it produces pieces of uniform shape and size. “What we discovered is that you can impose a strain field to cause the fracture to be guided, and you can use that for controlled fabrication,” Strano says.

When the top layer of graphene is placed over the array of polymer dots, which form round pillar shapes, the places where the graphene drapes over the round edges of the pillars form lines of high strain in the material.

As Albert Liu describes it, “imagine a tablecloth falling slowly down onto the surface of a circular table. One can very easily visualize the developing circular strain toward the table edges, and that’s very much analogous to what happens when a flat sheet of graphene folds around these printed polymer pillars.”

As a result, the fractures are concentrated right along those boundaries, Strano says. “And then something pretty amazing happens: The graphene will completely fracture, but the fracture will be guided around the periphery of the pillar.” The result is a neat, round piece of graphene that looks as if it had been cleanly cut out by a microscopic hole punch.

Because there are two layers of graphene, above and below the polymer pillars, the two resulting disks adhere at their edges to form something like a tiny pita bread pocket, with the polymer sealed inside. “And the advantage here is that this is essentially a single step,” in contrast to many complex clean-room steps needed by other processes to try to make microscopic robotic devices, Strano says.

The researchers have also shown that other two-dimensional materials in addition to graphene, such as molybdenum disulfide and hexagonal boronitride, work just as well.

Cell-like robots

Ranging in size from that of a human red blood cell, about 10 micrometers across, up to about 10 times that size, these tiny objects “start to look and behave like a living biological cell. In fact, under a microscope, you could probably convince most people that it is a cell,” Strano says. mit_logo

This work follows up on earlier research by Strano and his students on developing syncells that could gather information about the chemistry or other properties of their surroundings using sensors on their surface, and store the information for later retrieval, for example injecting a swarm of such particles in one end of a pipeline and retrieving them at the other to gain data about conditions inside it.

While the new syncells do not yet have as many capabilities as the earlier ones, those were assembled individually, whereas this work demonstrates a way of easily mass-producing such devices.

Apart from the syncells’ potential uses for industrial or biomedical monitoring, the way the tiny devices are made is itself an innovation with great potential, according to Albert Liu. “This general procedure of using controlled fracture as a production method can be extended across many length scales,” he says. “[It could potentially be used with] essentially any 2-D materials of choice, in principle allowing future researchers to tailor these atomically thin surfaces into any desired shape or form for applications in other disciplines.”

This is, Albert Liu says, “one of the only ways available right now to produce stand-alone integrated microelectronics on a large scale” that can function as independent, free-floating devices. Depending on the nature of the electronics inside, the devices could be provided with capabilities for movement, detection of various chemicals or other parameters, and memory storage.

There are a wide range of potential new applications for such cell-sized robotic devices, says Strano, who details many such possible uses in a book he co-authored with Shawn Walsh, an expert at Army Research Laboratories, on the subject, called “Robotic Systems and Autonomous Platforms,” which is being published this month by Elsevier Press.

As a demonstration, the team “wrote” the letters M, I, and T into a memory array within a syncell, which stores the information as varying levels of electrical conductivity. This information can then be “read” using an electrical probe, showing that the material can function as a form of electronic memory into which data can be written, read, and erased at will.

It can also retain the data without the need for power, allowing information to be collected at a later time. The researchers have demonstrated that the particles are stable over a period of months even when floating around in water, which is a harsh solvent for electronics, according to Strano.

“I think it opens up a whole new toolkit for micro- and nanofabrication,” he says.

More information: 
Pingwei Liu et al, Autoperforation of 2D materials for generating two-terminal memristive Janus particles, Nature Materials(2018).  DOI: 10.1038/s41563-018-0197-z

Provided by: Massachusetts Institute of Technology