Tag Archives: Lawrence Berkeley National Laboratory

It’s a very ‘carbony’ time: graphene jacket, graphene-skinned airplane, and schwarzite

In August 2018, I been stumbled across several stories about graphene-based products and a new form of carbon.

Graphene jacket

The company producing this jacket has as its goal “… creating bionic clothing that is both bulletproof and intelligent.” Well, ‘bionic‘ means biologically-inspired engineering and ‘intelligent‘ usually means there’s some kind of computing capability in the product. This jacket, which is the first step towards the company’s goal, is not bionic, bulletproof, or intelligent. Nonetheless, it represents a very interesting science experiment in which you, the consumer, are part of step two in the company’s R&D (research and development).

Onto Vollebak’s graphene jacket,

Courtesy: Vollebak

From an August 14, 2018 article by Jesus Diaz for Fast Company,

Graphene is the thinnest possible form of graphite, which you can find in your everyday pencil. It’s purely bi-dimensional, a single layer of carbon atoms that has unbelievable properties that have long threatened to revolutionize everything from aerospace engineering to medicine. …

Despite its immense promise, graphene still hasn’t found much use in consumer products, thanks to the fact that it’s hard to manipulate and manufacture in industrial quantities. The process of developing Vollebak’s jacket, according to the company’s cofounders, brothers Steve and Nick Tidball, took years of intensive research, during which the company worked with the same material scientists who built Michael Phelps’ 2008 Olympic Speedo swimsuit (which was famously banned for shattering records at the event).

The jacket is made out of a two-sided material, which the company invented during the extensive R&D process. The graphene side looks gunmetal gray, while the flipside appears matte black. To create it, the scientists turned raw graphite into something called graphene “nanoplatelets,” which are stacks of graphene that were then blended with polyurethane to create a membrane. That, in turn, is bonded to nylon to form the other side of the material, which Vollebak says alters the properties of the nylon itself. “Adding graphene to the nylon fundamentally changes its mechanical and chemical properties–a nylon fabric that couldn’t naturally conduct heat or energy, for instance, now can,” the company claims.

The company says that it’s reversible so you can enjoy graphene’s properties in different ways as the material interacts with either your skin or the world around you. “As physicists at the Max Planck Institute revealed, graphene challenges the fundamental laws of heat conduction, which means your jacket will not only conduct the heat from your body around itself to equalize your skin temperature and increase it, but the jacket can also theoretically store an unlimited amount of heat, which means it can work like a radiator,” Tidball explains.

He means it literally. You can leave the jacket out in the sun, or on another source of warmth, as it absorbs heat. Then, the company explains on its website, “If you then turn it inside out and wear the graphene next to your skin, it acts like a radiator, retaining its heat and spreading it around your body. The effect can be visibly demonstrated by placing your hand on the fabric, taking it away and then shooting the jacket with a thermal imaging camera. The heat of the handprint stays long after the hand has left.”

There’s a lot more to the article although it does feature some hype and I’m not sure I believe Diaz’s claim (August 14, 2018 article) that ‘graphene-based’ hair dye is perfectly safe ( Note: A link has been removed),

Graphene is the thinnest possible form of graphite, which you can find in your everyday pencil. It’s purely bi-dimensional, a single layer of carbon atoms that has unbelievable properties that will one day revolutionize everything from aerospace engineering to medicine. Its diverse uses are seemingly endless: It can stop a bullet if you add enough layers. It can change the color of your hair with no adverse effects. [emphasis mine] It can turn the walls of your home into a giant fire detector. “It’s so strong and so stretchy that the fibers of a spider web coated in graphene could catch a falling plane,” as Vollebak puts it in its marketing materials.

Not unless things have changed greatly since March 2018. My August 2, 2018 posting featured the graphene-based hair dye announcement from March 2018 and a cautionary note from Dr. Andrew Maynard (scroll down ab out 50% of the way for a longer excerpt of Maynard’s comments),

Northwestern University’s press release proudly announced, “Graphene finds new application as nontoxic, anti-static hair dye.” The announcement spawned headlines like “Enough with the toxic hair dyes. We could use graphene instead,” and “’Miracle material’ graphene used to create the ultimate hair dye.”

From these headlines, you might be forgiven for getting the idea that the safety of graphene-based hair dyes is a done deal. Yet having studied the potential health and environmental impacts of engineered nanomaterials for more years than I care to remember, I find such overly optimistic pronouncements worrying – especially when they’re not backed up by clear evidence.

These studies need to be approached with care, as the precise risks of graphene exposure will depend on how the material is used, how exposure occurs and how much of it is encountered. Yet there’s sufficient evidence to suggest that this substance should be used with caution – especially where there’s a high chance of exposure or that it could be released into the environment.

The full text of Dr. Maynard’s comments about graphene hair dyes and risk can be found here.

Bearing in mind  that graphene-based hair dye is an entirely different class of product from the jacket, I wouldn’t necessarily dismiss risks; I would like to know what kind of risk assessment and safety testing has been done. Due to their understandable enthusiasm, the brothers Tidball have focused all their marketing on the benefits and the opportunity for the consumer to test their product (from graphene jacket product webpage),

While it’s completely invisible and only a single atom thick, graphene is the lightest, strongest, most conductive material ever discovered, and has the same potential to change life on Earth as stone, bronze and iron once did. But it remains difficult to work with, extremely expensive to produce at scale, and lives mostly in pioneering research labs. So following in the footsteps of the scientists who discovered it through their own highly speculative experiments, we’re releasing graphene-coated jackets into the world as experimental prototypes. Our aim is to open up our R&D and accelerate discovery by getting graphene out of the lab and into the field so that we can harness the collective power of early adopters as a test group. No-one yet knows the true limits of what graphene can do, so the first edition of the Graphene Jacket is fully reversible with one side coated in graphene and the other side not. If you’d like to take part in the next stage of this supermaterial’s history, the experiment is now open. You can now buy it, test it and tell us about it. [emphasis mine]

How maverick experiments won the Nobel Prize

While graphene’s existence was first theorised in the 1940s, it wasn’t until 2004 that two maverick scientists, Andre Geim and Konstantin Novoselov, were able to isolate and test it. Through highly speculative and unfunded experimentation known as their ‘Friday night experiments,’ they peeled layer after layer off a shaving of graphite using Scotch tape until they produced a sample of graphene just one atom thick. After similarly leftfield thinking won Geim the 2000 Ig Nobel prize for levitating frogs using magnets, the pair won the Nobel prize in 2010 for the isolation of graphene.

Should you be interested, in beta-testing the jacket, it will cost you $695 (presumably USD); order here. One last thing, Vollebak is based in the UK.

Graphene skinned plane

An August 14, 2018 news item (also published as an August 1, 2018 Haydale press release) by Sue Keighley on Azonano heralds a new technology for airplans,

Haydale, (AIM: HAYD), the global advanced materials group, notes the announcement made yesterday from the University of Central Lancashire (UCLAN) about the recent unveiling of the world’s first graphene skinned plane at the internationally renowned Farnborough air show.

The prepreg material, developed by Haydale, has potential value for fuselage and wing surfaces in larger scale aero and space applications especially for the rapidly expanding drone market and, in the longer term, the commercial aerospace sector. By incorporating functionalised nanoparticles into epoxy resins, the electrical conductivity of fibre-reinforced composites has been significantly improved for lightning-strike protection, thereby achieving substantial weight saving and removing some manufacturing complexities.

Before getting to the photo, here’s a definition for pre-preg from its Wikipedia entry (Note: Links have been removed),

Pre-preg is “pre-impregnated” composite fibers where a thermoset polymer matrix material, such as epoxy, or a thermoplastic resin is already present. The fibers often take the form of a weave and the matrix is used to bond them together and to other components during manufacture.

Haydale has supplied graphene enhanced prepreg material for Juno, a three-metre wide graphene-enhanced composite skinned aircraft, that was revealed as part of the ‘Futures Day’ at Farnborough Air Show 2018. [downloaded from https://www.azonano.com/news.aspx?newsID=36298]

A July 31, 2018 University of Central Lancashire (UCLan) press release provides a tiny bit more (pun intended) detail,

The University of Central Lancashire (UCLan) has unveiled the world’s first graphene skinned plane at an internationally renowned air show.

Juno, a three-and-a-half-metre wide graphene skinned aircraft, was revealed on the North West Aerospace Alliance (NWAA) stand as part of the ‘Futures Day’ at Farnborough Air Show 2018.

The University’s aerospace engineering team has worked in partnership with the Sheffield Advanced Manufacturing Research Centre (AMRC), the University of Manchester’s National Graphene Institute (NGI), Haydale Graphene Industries (Haydale) and a range of other businesses to develop the unmanned aerial vehicle (UAV), which also includes graphene batteries and 3D printed parts.

Billy Beggs, UCLan’s Engineering Innovation Manager, said: “The industry reaction to Juno at Farnborough was superb with many positive comments about the work we’re doing. Having Juno at one the world’s biggest air shows demonstrates the great strides we’re making in leading a programme to accelerate the uptake of graphene and other nano-materials into industry.

“The programme supports the objectives of the UK Industrial Strategy and the University’s Engineering Innovation Centre (EIC) to increase industry relevant research and applications linked to key local specialisms. Given that Lancashire represents the fourth largest aerospace cluster in the world, there is perhaps no better place to be developing next generation technologies for the UK aerospace industry.”

Previous graphene developments at UCLan have included the world’s first flight of a graphene skinned wing and the launch of a specially designed graphene-enhanced capsule into near space using high altitude balloons.

UCLan engineering students have been involved in the hands-on project, helping build Juno on the Preston Campus.

Haydale supplied much of the material and all the graphene used in the aircraft. Ray Gibbs, Chief Executive Officer, said: “We are delighted to be part of the project team. Juno has highlighted the capability and benefit of using graphene to meet key issues faced by the market, such as reducing weight to increase range and payload, defeating lightning strike and protecting aircraft skins against ice build-up.”

David Bailey Chief Executive of the North West Aerospace Alliance added: “The North West aerospace cluster contributes over £7 billion to the UK economy, accounting for one quarter of the UK aerospace turnover. It is essential that the sector continues to develop next generation technologies so that it can help the UK retain its competitive advantage. It has been a pleasure to support the Engineering Innovation Centre team at the University in developing the world’s first full graphene skinned aircraft.”

The Juno project team represents the latest phase in a long-term strategic partnership between the University and a range of organisations. The partnership is expected to go from strength to strength following the opening of the £32m EIC facility in February 2019.

The next step is to fly Juno and conduct further tests over the next two months.

Next item, a new carbon material.

Schwarzite

I love watching this gif of a schwarzite,

The three-dimensional cage structure of a schwarzite that was formed inside the pores of a zeolite. (Graphics by Yongjin Lee and Efrem Braun)

An August 13, 2018 news item on Nanowerk announces the new carbon structure,

The discovery of buckyballs [also known as fullerenes, C60, or buckminsterfullerenes] surprised and delighted chemists in the 1980s, nanotubes jazzed physicists in the 1990s, and graphene charged up materials scientists in the 2000s, but one nanoscale carbon structure – a negatively curved surface called a schwarzite – has eluded everyone. Until now.

University of California, Berkeley [UC Berkeley], chemists have proved that three carbon structures recently created by scientists in South Korea and Japan are in fact the long-sought schwarzites, which researchers predict will have unique electrical and storage properties like those now being discovered in buckminsterfullerenes (buckyballs or fullerenes for short), nanotubes and graphene.

An August 13, 2018 UC Berkeley news release by Robert Sanders, which originated the news item, describes how the Berkeley scientists and the members of their international  collaboration from Germany, Switzerland, Russia, and Italy, have contributed to the current state of schwarzite research,

The new structures were built inside the pores of zeolites, crystalline forms of silicon dioxide – sand – more commonly used as water softeners in laundry detergents and to catalytically crack petroleum into gasoline. Called zeolite-templated carbons (ZTC), the structures were being investigated for possible interesting properties, though the creators were unaware of their identity as schwarzites, which theoretical chemists have worked on for decades.

Based on this theoretical work, chemists predict that schwarzites will have unique electronic, magnetic and optical properties that would make them useful as supercapacitors, battery electrodes and catalysts, and with large internal spaces ideal for gas storage and separation.

UC Berkeley postdoctoral fellow Efrem Braun and his colleagues identified these ZTC materials as schwarzites based of their negative curvature, and developed a way to predict which zeolites can be used to make schwarzites and which can’t.

“We now have the recipe for how to make these structures, which is important because, if we can make them, we can explore their behavior, which we are working hard to do now,” said Berend Smit, an adjunct professor of chemical and biomolecular engineering at UC Berkeley and an expert on porous materials such as zeolites and metal-organic frameworks.

Smit, the paper’s corresponding author, Braun and their colleagues in Switzerland, China, Germany, Italy and Russia will report their discovery this week in the journal Proceedings of the National Academy of Sciences. Smit is also a faculty scientist at Lawrence Berkeley National Laboratory.

Playing with carbon

Diamond and graphite are well-known three-dimensional crystalline arrangements of pure carbon, but carbon atoms can also form two-dimensional “crystals” — hexagonal arrangements patterned like chicken wire. Graphene is one such arrangement: a flat sheet of carbon atoms that is not only the strongest material on Earth, but also has a high electrical conductivity that makes it a promising component of electronic devices.

schwarzite carbon cage

The cage structure of a schwarzite that was formed inside the pores of a zeolite. The zeolite is subsequently dissolved to release the new material. (Graphics by Yongjin Lee and Efrem Braun)

Graphene sheets can be wadded up to form soccer ball-shaped fullerenes – spherical carbon cages that can store molecules and are being used today to deliver drugs and genes into the body. Rolling graphene into a cylinder yields fullerenes called nanotubes, which are being explored today as highly conductive wires in electronics and storage vessels for gases like hydrogen and carbon dioxide. All of these are submicroscopic, 10,000 times smaller than the width of a human hair.

To date, however, only positively curved fullerenes and graphene, which has zero curvature, have been synthesized, feats rewarded by Nobel Prizes in 1996 and 2010, respectively.

In the 1880s, German physicist Hermann Schwarz investigated negatively curved structures that resemble soap-bubble surfaces, and when theoretical work on carbon cage molecules ramped up in the 1990s, Schwarz’s name became attached to the hypothetical negatively curved carbon sheets.

“The experimental validation of schwarzites thus completes the triumvirate of possible curvatures to graphene; positively curved, flat, and now negatively curved,” Braun added.

Minimize me

Like soap bubbles on wire frames, schwarzites are topologically minimal surfaces. When made inside a zeolite, a vapor of carbon-containing molecules is injected, allowing the carbon to assemble into a two-dimensional graphene-like sheet lining the walls of the pores in the zeolite. The surface is stretched tautly to minimize its area, which makes all the surfaces curve negatively, like a saddle. The zeolite is then dissolved, leaving behind the schwarzite.

soap bubble schwarzite structure

A computer-rendered negatively curved soap bubble that exhibits the geometry of a carbon schwarzite. (Felix Knöppel image)

“These negatively-curved carbons have been very hard to synthesize on their own, but it turns out that you can grow the carbon film catalytically at the surface of a zeolite,” Braun said. “But the schwarzites synthesized to date have been made by choosing zeolite templates through trial and error. We provide very simple instructions you can follow to rationally make schwarzites and we show that, by choosing the right zeolite, you can tune schwarzites to optimize the properties you want.”

Researchers should be able to pack unusually large amounts of electrical charge into schwarzites, which would make them better capacitors than conventional ones used today in electronics. Their large interior volume would also allow storage of atoms and molecules, which is also being explored with fullerenes and nanotubes. And their large surface area, equivalent to the surface areas of the zeolites they’re grown in, could make them as versatile as zeolites for catalyzing reactions in the petroleum and natural gas industries.

Braun modeled ZTC structures computationally using the known structures of zeolites, and worked with topological mathematician Senja Barthel of the École Polytechnique Fédérale de Lausanne in Sion, Switzerland, to determine which of the minimal surfaces the structures resembled.

The team determined that, of the approximately 200 zeolites created to date, only 15 can be used as a template to make schwarzites, and only three of them have been used to date to produce schwarzite ZTCs. Over a million zeolite structures have been predicted, however, so there could be many more possible schwarzite carbon structures made using the zeolite-templating method.

Other co-authors of the paper are Yongjin Lee, Seyed Mohamad Moosavi and Barthel of the École Polytechnique Fédérale de Lausanne, Rocio Mercado of UC Berkeley, Igor Baburin of the Technische Universität Dresden in Germany and Davide Proserpio of the Università degli Studi di Milano in Italy and Samara State Technical University in Russia.

Here’s a link to and a citation for the paper,

Generating carbon schwarzites via zeolite-templating by Efrem Braun, Yongjin Lee, Seyed Mohamad Moosavi, Senja Barthel, Rocio Mercado, Igor A. Baburin, Davide M. Proserpio, and Berend Smit. PNAS August 14, 2018. 201805062; published ahead of print August 14, 2018. https://doi.org/10.1073/pnas.1805062115

This paper appears to be open access.

3D printed all liquid electronics

Even after watching the video, I still don’t quite believe it. A March 28, 2018 news item on ScienceDaily announces the work,

Scientists from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab [or LBNL]) have developed a way to print 3-D structures composed entirely of liquids. Using a modified 3-D printer, they injected threads of water into silicone oil — sculpting tubes made of one liquid within another liquid.

They envision their all-liquid material could be used to construct liquid electronics that power flexible, stretchable devices. The scientists also foresee chemically tuning the tubes and flowing molecules through them, leading to new ways to separate molecules or precisely deliver nanoscale building blocks to under-construction compounds.

A March 28, 2018 Berkeley Lab March 26, 2018 news release (also on EurekAlert), which originated the news item, describe the work in more detail,

The researchers have printed threads of water between 10 microns and 1 millimeter in diameter, and in a variety of spiraling and branching shapes up to several meters in length. What’s more, the material can conform to its surroundings and repeatedly change shape.

“It’s a new class of material that can reconfigure itself, and it has the potential to be customized into liquid reaction vessels for many uses, from chemical synthesis to ion transport to catalysis,” said Tom Russell, a visiting faculty scientist in Berkeley Lab’s Materials Sciences Division. He developed the material with Joe Forth, a postdoctoral researcher in the Materials Sciences Division, as well as other scientists from Berkeley Lab and several other institutions. They report their research March 24 [2018] in the journal Advanced Materials.

The material owes its origins to two advances: learning how to create liquid tubes inside another liquid, and then automating the process.

For the first step, the scientists developed a way to sheathe tubes of water in a special nanoparticle-derived surfactant that locks the water in place. The surfactant, essentially soap, prevents the tubes from breaking up into droplets. Their surfactant is so good at its job, the scientists call it a nanoparticle supersoap.

The supersoap was achieved by dispersing gold nanoparticles into water and polymer ligands into oil. The gold nanoparticles and polymer ligands want to attach to each other, but they also want to remain in their respective water and oil mediums. The ligands were developed with help from Brett Helms at the Molecular Foundry, a DOE Office of Science User Facility located at Berkeley Lab.

In practice, soon after the water is injected into the oil, dozens of ligands in the oil attach to individual nanoparticles in the water, forming a nanoparticle supersoap. These supersoaps jam together and vitrify, like glass, which stabilizes the interface between oil and water and locks the liquid structures in position.

This stability means we can stretch water into a tube, and it remains a tube. Or we can shape water into an ellipsoid, and it remains an ellipsoid,” said Russell. “We’ve used these nanoparticle supersoaps to print tubes of water that last for several months.”

Next came automation. Forth modified an off-the-shelf 3-D printer by removing the components designed to print plastic and replacing them with a syringe pump and needle that extrudes liquid. He then programmed the printer to insert the needle into the oil substrate and inject water in a predetermined pattern.

“We can squeeze liquid from a needle, and place threads of water anywhere we want in three dimensions,” said Forth. “We can also ping the material with an external force, which momentarily breaks the supersoap’s stability and changes the shape of the water threads. The structures are endlessly reconfigurable.”

This image illustrates how the water is printed,

These schematics show the printing of water in oil using a nanoparticle supersoap. Gold nanoparticles in the water combine with polymer ligands in the oil to form an elastic film (nanoparticle supersoap) at the interface, locking the structure in place. (Credit: Berkeley Lab)

Here’s a link to and a citation for the paper,

Reconfigurable Printed Liquids by Joe Forth, Xubo Liu, Jaffar Hasnain, Anju Toor, Karol Miszta, Shaowei Shi, Phillip L. Geissler, Todd Emrick, Brett A. Helms, Thomas P. Russell. Advanced Materials https://doi.org/10.1002/adma.201707603 First published: 24 March 2018

This paper is behind a paywall.

Largest database of elemental crystal surfaces and shapes in the world

A Sept. 13, 2016 news item on Nanowerk describes the database,

Nanoengineers at the University of California San Diego [UCSD], in collaboration with the Materials Project at Lawrence Berkeley National Laboratory (Berkeley Lab), have created the world’s largest database of elemental crystal surfaces and shapes to date. Dubbed Crystalium, this new open-source database can help researchers design new materials for technologies in which surfaces and interfaces play an important role, such as fuel cells, catalytic converters in cars, computer microchips, nanomaterials and solid-state batteries.

rystalium is a new open-source database with the largest collection of elemental crystal surfaces and shapes to date. Image courtesy of the Materials Virtual Lab at UC San Diego

Crystalium is a new open-source database with the largest collection of elemental crystal surfaces and shapes to date. Image courtesy of the Materials Virtual Lab at UC San Diego

A Sept. 13, 2016 UCSD news release reveals more about the goals for the database and the database itself (Note: Links have been removed),

“This work is an important starting point for studying the material surfaces and interfaces, where many novel properties can be found. We’ve developed a new resource that can be used to better understand surface science and find better materials for surface-driven technologies,” said Shyue Ping Ong, a nanoengineering professor at UC San Diego and senior author of the study.

For example, fuel cell performance is partly influenced by the reaction of molecules such as hydrogen and oxygen on the surfaces of metal catalysts. Also, interfaces between the electrodes and electrolyte in a rechargeable lithium-ion battery host a variety of chemical reactions that can limit the battery’s performance. The work in this study is useful for these applications, said Ong, who is also part of a larger effort by the UC San Diego Sustainable Power and Energy Center to design better battery materials.

“Researchers can use this database to figure out which elements or materials are more likely to be viable catalysts for processes like ammonia production or making hydrogen gas from water,” said Richard Tran, a nanoengineering PhD student in Ong’s Materials Virtual Lab and the study’s first author. Tran did this work while he was an undergraduate at UC San Diego.

The work, published Sept. 13 [2016] in the journal Scientific Data, provides the surface energies and equilibrium crystal shapes of more than 100 polymorphs of 72 elements in the periodic table. Surface energy describes the stability of a surface; it is a measure of the excess energy of atoms on the surface relative to those in the bulk material. Knowing surface energies is useful for designing materials that perform their functions primarily on their surfaces, like catalysts and nanoparticles.

The surface energies of some elements in their crystal form have been measured experimentally, but this is not a trivial task. It involves melting the crystal, measuring the resulting liquid’s surface tension at the melting temperature, then extrapolating that value back to room temperature. This process also requires that the sample have a clean surface, which is challenging because other atoms and molecules (like oxygen and water) can easily adsorb to the surface and modify the surface energy.

Surface energies obtained by this method are averaged values that lack the facet-specific resolution that is necessary for design, Ong said. “This is one of the areas where the ’virtual laboratory’ can create the most value—by allowing us to precisely control the models and conditions in a way that is extremely difficult to do in experiments.”

Also, the surface energy is not just a single number for each crystal because it depends on the crystal’s orientation. “A crystal is a regular arrangement of atoms. When you cut a crystal in different places and at different angles, you expose different facets with unique arrangements of atoms,” explained Ong, who teaches the course NANO106 – Crystallography of Materials at UC San Diego.

To carry out this ambitious project, Ong and his team developed highly sophisticated automated workflows to calculate surface energies from first principles. These workflows are built on the popular open-source Python Materials Genomics library and FireWorks workflow codes of the Materials Project, which were co-authored by Ong.

“The techniques for calculating surface energies have been known for decades. The major accomplishment is the codification of how to generate surface models and run these complex calculations in a robust and efficient manner,” Tran said. The surface model generation software code developed by the team has already been extended by others to study substrates and interfaces. Powerful supercomputers at the San Diego Supercomputer Center and the National Energy Research Scientific Computing Center at the Lawrence Berkeley National Lab were used for the calculations.

Ong’s team worked with researchers from the Berkeley Lab’s Materials Project to develop and construct Crystalium’s website. Co-founded and directed by Berkeley Lab scientist Kristin Persson, the Materials Project is a Google-like database of material properties calculated by supercomputers.

“The Materials Project was designed to be an open and accessible tool for scientists and engineers to accelerate materials innovation,” Persson said. “In five years, it has attracted more than 20,000 users working on everything from batteries to photovoltaics to thermoelectrics, and it’s extremely gratifying to see scientists like Ong providing lots of high quality computed data of high interest and making it freely available and easily accessible to the public.”

The researchers pointed out that their database is the most extensive collection of calculated surface energies for elemental crystalline solids to date. Compared to previous compilations, Crystalium contains surface energies for far more elements, including both metals and non-metals, and for more facets in each crystal. The elements that have been excluded from their calculations are gases and radioactive elements. Notably, Ong and his team have validated their calculated surface energies with those from experiments, and the values are in excellent agreement.

Moving forward, the team will work on expanding the scope of the database beyond single elements to multi-element compounds like alloys, which are made of two or more different metals, and binary oxides, which are made of oxygen and one other element. Efforts are also underway to study the effect of common adsorbates, such as hydrogen, on surface energies, which is key to understanding the stability of surfaces in aqueous media.

“As we continue to build this database, we hope that the research community will see it as a useful resource for the rational design of target surface or interfacial properties,” said Ong,

Here’s a link to and a citation for the paper,

Surface energies of elemental crystals by Richard Tran, Zihan Xu, Balachandran Radhakrishnan, Donald Winston, Wenhao Sun, Kristin A. Persson, & Shyue Ping Ong.  Scientific Data 3, Article number: 160080 (2016)  doi:10.1038/sdata.2016.80 Published online: 13 September 2016

This paper is open access.

Here, too, is a link to Crystalium.

Lawrence Berkeley National Laboratory (US) and five of its nanoscience projects

An Aug 3, 2016 Lawrence Berkeley National Laboratory news release (also on Azonano as an Aug. 5, 2016 news item) features a selection of their nanoscience projects (Note: Links, embedded images, and embedded videos have been removed),

1. A DIY paint-on coating for energy efficient windows

This “cool” DIY retrofit tech could improve the energy efficiency of windows and save money. Researchers are developing a polymer-based heat-reflective coating that makes use of the unusual molecular architecture of a polymer.

It has the potential to be painted on windows at one-tenth the cost of current retrofit approaches. Window films on the market today reflect infrared solar energy back to the sky while allowing visible light to pass through, but a professional contractor is needed to install them. A low-cost option could significantly expand adoption and result in potential annual energy savings equivalent to taking 5 million cars off the road.

2. Nanowires that move data at light speed

Researchers have found a new way to produce nanoscale wires that can serve as tiny, tunable lasers. The excellent performance of these tiny lasers is promising for the field of optoelectronics, which is focused on combining electronics and light to transmit data, among other applications. Miniaturizing lasers to the nanoscale could further revolutionize computing, bringing light-speed data transmission to desktop, and ultimately, handheld computing devices.

3. Nano sponges that fight climate change

Scientists are developing nano sponges that could capture carbon from power plants before it enters the atmosphere. Initial tests show the hybrid membrane, composed of nano-sized cages (called metal-organic frameworks) and a polymer, is eight times more carbon dioxide permeable than membranes composed only of the polymer.

Boosting carbon dioxide permeability is a big goal in efforts to develop carbon capture materials that are energy efficient and cost competitive. Watch this video for more on this technology.

4. Custom-made chemical factories

Scientists have recently reengineered a building block of a nanocompartment that occurs naturally in bacteria, greatly expanding the potential of nanocompartments to serve as custom-made chemical factories. Researchers hope to tailor this new use to produce high-value chemical products, such as medicines, on demand

The sturdy nanocompartments are formed by hundreds of copies of just three different types of proteins. Their natural counterparts, known as bacterial microcompartments, encase a wide variety of enzymes that carry out highly specialized chemistry in bacteria.

5. Nanotubes that assemble themselves

Researchers have discovered a family of nature-inspired polymers that, when placed in water, spontaneously assemble into hollow crystalline nanotubes. What’s more, the nanotubes can be tuned to all have the same diameter of between five and ten nanometers.

Controlling the diameter of nanotubes, and the chemical groups exposed in their interior, enables scientists to control what goes through. Nanotubes have the potential to be incredibly useful, from delivering cancer-fighting drugs inside cells to desalinating seawater.

It’s nice to see projects grouped together like that as it gives you a bigger picture of what’s taking place at the lab than you’re likely to get reading news releases about individual projects and breakthroughs.

Berkeley Lab has also got an introductory video which does one of the best jobs I’ve seen of conveying the concept of the nanoscale,

H/t to Aug. 10, 2016 news item on Nanowerk for the Berkeley Lab’s ‘nano penny’ video.

Self-healing diamond-like carbon from the Argonne Lab (US)

Argonne researchers, from left, Subramanian Sankaranarayanan, Badri Narayanan, Ali Erdemir, Giovanni Ramirez and Osman Levent Eryilmaz show off metal engine parts that have been treated with a diamond-like carbon coating similar to one developed and explored by the team. The catalytic coating interacts with engine oil to create a self-healing diamond-like film that could have profound implications for the efficiency and durability of future engines. (photo by Wes Agresta)

Argonne researchers, from left, Subramanian Sankaranarayanan, Badri Narayanan, Ali Erdemir, Giovanni Ramirez and Osman Levent Eryilmaz show off metal engine parts that have been treated with a diamond-like carbon coating similar to one developed and explored by the team. The catalytic coating interacts with engine oil to create a self-healing diamond-like film that could have profound implications for the efficiency and durability of future engines. (photo by Wes Agresta)

An Aug. 5, 2016 news item on ScienceDaily makes the announcement,

Fans of Superman surely recall how the Man of Steel used immense heat and pressure generated by his bare hands to form a diamond out of a lump of coal.

The tribologists — scientists who study friction, wear, and lubrication — and computational materials scientists at the U.S. Department of Energy’s (DOE’s) Argonne National Laboratory will probably never be mistaken for superheroes. However, they recently applied the same principles and discovered a revolutionary diamond-like film of their own that is generated by the heat and pressure of an automotive engine.

An Aug. 5, 2016 Argonne National Laboratory news release (also on EurekAlert) by Greg Cunningham, which originated the news item, explains further,

The discovery of this ultra-durable, self-lubricating tribofilm – a film that forms between moving surfaces — was first reported yesterday in the journal Nature. It could have profound implications for the efficiency and durability of future engines and other moving metal parts that can be made to develop self-healing, diamond-like carbon (DLC) tribofilms.

“This is a very unique discovery, and one that was a little unexpected,” said Ali Erdemir, the Argonne Distinguished Fellow who leads the team. “We have developed many types of diamond-like carbon coatings of our own, but we’ve never found one that generates itself by breaking down the molecules of the lubricating oil and can actually regenerate the tribofilm as it is worn away.”

The phenomenon was first discovered several years ago by Erdemir and his colleague Osman Levent Eryilmaz in the Tribology and Thermal-Mechanics Department in Argonne’s Center for Transportation Research. But it took theoretical insight enhanced by the massive computing resources available at Argonne to fully understand what was happening at the molecular level in the experiments. The theoretical understanding was provided by lead theoretical researcher Subramanian Sankaranarayanan and postdoctoral researcher Badri Narayanan from the Center for Nanoscale Materials (CNM), while the computing power was provided by the Argonne Leadership Computing Facility (ALCF) and the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory. CNM, ALCF and NERSC are all DOE Office of Science User Facilities.

The original discovery occurred when Erdemir and Eryilmaz decided to see what would happen when a small steel ring was coated with a catalytically active nanocoating – tiny molecules of metals that promote chemical reactions to break down other materials – then subjected to high pressure and heat using a base oil without the complex additives of modern lubricants. When they looked at the ring after the endurance test, they didn’t see the expected rust and surface damage, but an intact ring with an odd blackish deposit on the contact area.

“This test creates extreme contact pressure and temperatures, which are supposed to cause the ring to wear and eventually seize,” said Eryilmaz. “But this ring didn’t significantly wear and this blackish deposit was visible. We said, ‘This material is strange. Maybe this is what is causing this unusual effect.'”

Looking at the deposit using high-powered optical and laser Raman microscopes, the experimentalists realized the deposit was a tribofilm of diamond-like carbon, similar to several other DLCs developed at Argonne in the past. But it worked even better. Tests revealed the DLC tribofilm reduced friction by 25 to 40 percent and that wear was reduced to unmeasurable values.

Further experiments, led by postdoctoral researcher Giovanni Ramirez, revealed that multiple types of catalytic coatings can yield DLC tribofilms. The experiments showed the coatings interact with the oil molecules to create the DLC film, which adheres to the metal surfaces. When the tribofilm is worn away, the catalyst in the coating is re-exposed to the oil, causing the catalysis to restart and develop new layers of tribofilm. The process is self-regulating, keeping the film at consistent thickness. The scientists realized the film was developing spontaneously between the sliding surfaces and was replenishing itself, but they needed to understand why and how.

To provide the theoretical understanding of what the tribology team was seeing in its experiments, they turned to Sankaranarayanan and Narayanan, who used the immense computing power of ALCF’s 10-petaflop supercomputer, Mira. They ran large-scale simulations to understand what was happening at the atomic level, and determined that the catalyst metals in the nanocomposite coatings were stripping hydrogen atoms from the hydrocarbon chains of the lubricating oil, then breaking the chains down into smaller segments. The smaller chains joined together under pressure to create the highly durable DLC tribofilm.

“This is an example of catalysis under extreme conditions created by friction. It is opening up a new field where you are merging catalysis and tribology, which has never been done before,” said Sankaranarayanan. “This new field of tribocatalysis has the potential to change the way we look at lubrication.”

The theorists explored the origins of the catalytic activity to understand how catalysis operates under the extreme heat and pressure in an engine. By gaining this understanding, they were able to predict which catalysts would work, and which would create the most advantageous tribofilms.

“Interestingly, we found several metals or composites that we didn’t think would be catalytically active, but under these circumstances, they performed quite well,” said Narayanan. “This opens up new pathways for scientists to use extreme conditions to enhance catalytic activity.”

The implications of the new tribofilm for efficiency and reliability of engines are huge. Manufacturers already use many different types of coatings — some developed at Argonne — for metal parts in engines and other applications. The problem is those coatings are expensive and difficult to apply, and once they are in use, they only last until the coating wears through. The new catalyst allows the tribofilm to be continually renewed during operation.

Additionally, because the tribofilm develops in the presence of base oil, it could allow manufacturers to reduce, or possibly eliminate, some of the modern anti-friction and anti-wear additives in oil. These additives can decrease the efficiency of vehicle catalytic converters and can be harmful to the environment because of their heavy metal content.

Here’s a link to and a citation for the paper,

Carbon-based tribofilms from lubricating oils by Ali Erdemir, Giovanni Ramirez, Osman L. Eryilmaz, Badri Narayanan, Yifeng Liao, Ganesh Kamath, & Subramanian K. R. S. Sankaranarayanan. Nature 536, 67–71 (04 August 2016) doi:10.1038/nature18948 Published online 03 August 2016

This paper is behind a paywall.

Pushing efficiency of perovskite-based solar cells to 31%

This atomic force microscopy image of the grainy surface of a perovskite solar cell reveals a new path to much greater efficiency. Individual grains are outlined in black, low-performing facets are red, and high-performing facets are green. A big jump in efficiency could possibly be obtained if the material can be grown so that more high-performing facets develop. (Credit: Berkeley Lab)

This atomic force microscopy image of the grainy surface of a perovskite solar cell reveals a new path to much greater efficiency. Individual grains are outlined in black, low-performing facets are red, and high-performing facets are green. A big jump in efficiency could possibly be obtained if the material can be grown so that more high-performing facets develop. (Credit: Berkeley Lab)

It’s always fascinating to observe a trend (or a craze) in science, an endeavour that outsiders (like me) tend to think of as impervious to such vagaries. Perovskite seems to be making its way past the trend/craze phase and moving into a more meaningful phase. From a July 4, 2016 news item on Nanowerk,

Scientists from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered a possible secret to dramatically boosting the efficiency of perovskite solar cells hidden in the nanoscale peaks and valleys of the crystalline material.

Solar cells made from compounds that have the crystal structure of the mineral perovskite have captured scientists’ imaginations. They’re inexpensive and easy to fabricate, like organic solar cells. Even more intriguing, the efficiency at which perovskite solar cells convert photons to electricity has increased more rapidly than any other material to date, starting at three percent in 2009 — when researchers first began exploring the material’s photovoltaic capabilities — to 22 percent today. This is in the ballpark of the efficiency of silicon solar cells.

Now, as reported online July 4, 2016 in the journal Nature Energy (“Facet-dependent photovoltaic efficiency variations in single grains of hybrid halide perovskite”), a team of scientists from the Molecular Foundry and the Joint Center for Artificial Photosynthesis, both at Berkeley Lab, found a surprising characteristic of a perovskite solar cell that could be exploited for even higher efficiencies, possibly up to 31 percent.

A July 4, 2016 Berkeley Lab news release (also on EurekAlert), which originated the news item, details the research,

Using photoconductive atomic force microscopy, the scientists mapped two properties on the active layer of the solar cell that relate to its photovoltaic efficiency. The maps revealed a bumpy surface composed of grains about 200 nanometers in length, and each grain has multi-angled facets like the faces of a gemstone.

Unexpectedly, the scientists discovered a huge difference in energy conversion efficiency between facets on individual grains. They found poorly performing facets adjacent to highly efficient facets, with some facets approaching the material’s theoretical energy conversion limit of 31 percent.

The scientists say these top-performing facets could hold the secret to highly efficient solar cells, although more research is needed.

“If the material can be synthesized so that only very efficient facets develop, then we could see a big jump in the efficiency of perovskite solar cells, possibly approaching 31 percent,” says Sibel Leblebici, a postdoctoral researcher at the Molecular Foundry.

Leblebici works in the lab of Alexander Weber-Bargioni, who is a corresponding author of the paper that describes this research. Ian Sharp, also a corresponding author, is a Berkeley Lab scientist at the Joint Center for Artificial Photosynthesis. Other Berkeley Lab scientists who contributed include Linn Leppert, Francesca Toma, and Jeff Neaton, the director of the Molecular Foundry.

A team effort

The research started when Leblebici was searching for a new project. “I thought perovskites are the most exciting thing in solar right now, and I really wanted to see how they work at the nanoscale, which has not been widely studied,” she says.

She didn’t have to go far to find the material. For the past two years, scientists at the nearby Joint Center for Artificial Photosynthesis have been making thin films of perovskite-based compounds, and studying their ability to convert sunlight and CO2 into useful chemicals such as fuel. Switching gears, they created pervoskite solar cells composed of methylammonium lead iodide. They also analyzed the cells’ performance at the macroscale.

The scientists also made a second set of half cells that didn’t have an electrode layer. They packed eight of these cells on a thin film measuring one square centimeter. These films were analyzed at the Molecular Foundry, where researchers mapped the cells’ surface topography at a resolution of ten nanometers. They also mapped two properties that relate to the cells’ photovoltaic efficiency: photocurrent generation and open circuit voltage.

This was performed using a state-of-the-art atomic force microscopy technique, developed in collaboration with Park Systems, which utilizes a conductive tip to scan the material’s surface. The method also eliminates friction between the tip and the sample. This is important because the material is so rough and soft that friction can damage the tip and sample, and cause artifacts in the photocurrent.

Surprise discovery could lead to better solar cells

The resulting maps revealed an order of magnitude difference in photocurrent generation, and a 0.6-volt difference in open circuit voltage, between facets on the same grain. In addition, facets with high photocurrent generation had high open circuit voltage, and facets with low photocurrent generation had low open circuit voltage.

“This was a big surprise. It shows, for the first time, that perovskite solar cells exhibit facet-dependent photovoltaic efficiency,” says Weber-Bargioni.

Adds Toma, “These results open the door to exploring new ways to control the development of the material’s facets to dramatically increase efficiency.”

In practice, the facets behave like billions of tiny solar cells, all connected in parallel. As the scientists discovered, some cells operate extremely well and others very poorly. In this scenario, the current flows towards the bad cells, lowering the overall performance of the material. But if the material can be optimized so that only highly efficient facets interface with the electrode, the losses incurred by the poor facets would be eliminated.

“This means, at the macroscale, the material could possibly approach its theoretical energy conversion limit of 31 percent,” says Sharp.

A theoretical model that describes the experimental results predicts these facets should also impact the emission of light when used as an LED. …

The Molecular Foundry is a DOE Office of Science User Facility located at Berkeley Lab. The Joint Center for Artificial Photosynthesis is a DOE Energy Innovation Hub led by the California Institute of Technology in partnership with Berkeley Lab.

Here’s a link to and a citation for the paper,

Facet-dependent photovoltaic efficiency variations in single grains of hybrid halide perovskite by Sibel Y. Leblebici, Linn Leppert, Yanbo Li, Sebastian E. Reyes-Lillo, Sebastian Wickenburg, Ed Wong, Jiye Lee, Mauro Melli, Dominik Ziegler, Daniel K. Angell, D. Frank Ogletree, Paul D. Ashby, Francesca M. Toma, Jeffrey B. Neaton, Ian D. Sharp, & Alexander Weber-Bargioni. Nature Energy 1, Article number: 16093 (2016  doi:10.1038/nenergy.2016.93 Published online: 04 July 2016

This paper is behind a paywall.

Dexter Johnson’s July 6, 2016 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website} presents his take on the impact that this new finding may have,

The rise of the crystal perovskite as a potential replacement for silicon in photovoltaics has been impressive over the last decade, with its conversion efficiency improving from 3.8 to 22.1 percent over that time period. Nonetheless, there has been a vague sense that this rise is beginning to peter out of late, largely because when a solar cell made from perovskite gets larger than 1 square centimeter the best conversion efficiency had been around 15.6 percent. …

X-rays reveal memristor workings

A June 14, 2016 news item on ScienceDaily focuses on memristors. (It’s been about two months since my last memristor posting on April 22, 2016 regarding electronic synapses and neural networks). This piece announces new insight into how memristors function at the atomic scale,

In experiments at two Department of Energy national labs — SLAC National Accelerator Laboratory and Lawrence Berkeley National Laboratory — scientists at Hewlett Packard Enterprise (HPE) [also referred to as HP Labs or Hewlett Packard Laboratories] have experimentally confirmed critical aspects of how a new type of microelectronic device, the memristor, works at an atomic scale.

This result is an important step in designing these solid-state devices for use in future computer memories that operate much faster, last longer and use less energy than today’s flash memory. …

“We need information like this to be able to design memristors that will succeed commercially,” said Suhas Kumar, an HPE scientist and first author on the group’s technical paper.

A June 13, 2016 SLAC news release, which originated the news item, offers a brief history according to HPE and provides details about the latest work,

The memristor was proposed theoretically [by Dr. Leon Chua] in 1971 as the fourth basic electrical device element alongside the resistor, capacitor and inductor. At its heart is a tiny piece of a transition metal oxide sandwiched between two electrodes. Applying a positive or negative voltage pulse dramatically increases or decreases the memristor’s electrical resistance. This behavior makes it suitable for use as a “non-volatile” computer memory that, like flash memory, can retain its state without being refreshed with additional power.

Over the past decade, an HPE group led by senior fellow R. Stanley Williams has explored memristor designs, materials and behavior in detail. Since 2009 they have used intense synchrotron X-rays to reveal the movements of atoms in memristors during switching. Despite advances in understanding the nature of this switching, critical details that would be important in designing commercially successful circuits  remained controversial. For example, the forces that move the atoms, resulting in dramatic resistance changes during switching, remain under debate.

In recent years, the group examined memristors made with oxides of titanium, tantalum and vanadium. Initial experiments revealed that switching in the tantalum oxide devices could be controlled most easily, so it was chosen for further exploration at two DOE Office of Science User Facilities – SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) and Berkeley Lab’s Advanced Light Source (ALS).

At ALS, the HPE researchers mapped the positions of oxygen atoms before and after switching. For this, they used a scanning transmission X-ray microscope and an apparatus they built to precisely control the position of their sample and the timing and intensity of the 500-electronvolt ALS X-rays, which were tuned to see oxygen.

The experiments revealed that even weak voltage pulses create a thin conductive path through the memristor. During the pulse the path heats up, which creates a force that pushes oxygen atoms away from the path, making it even more conductive. Reversing the voltage pulse resets the memristor by sucking some of oxygen atoms back into the conducting path, thereby increasing the device’s resistance. The memristor’s resistance changes between 10-fold and 1 million-fold, depending on operating parameters like the voltage-pulse amplitude. This resistance change is dramatic enough to exploit commercially.

To be sure of their conclusion, the researchers also needed to understand if the tantalum atoms were moving along with the oxygen during switching. Imaging tantalum required higher-energy, 10,000-electronvolt X-rays, which they obtained at SSRL’s Beam Line 6-2. In a single session there, they determined that the tantalum remained stationary.

“That sealed the deal, convincing us that our hypothesis was correct,” said HPE scientist Catherine Graves, who had worked at SSRL as a Stanford graduate student. She added that discussions with SLAC experts were critical in guiding the HPE team toward the X-ray techniques that would allow them to see the tantalum accurately.

Kumar said the most promising aspect of the tantalum oxide results was that the scientists saw no degradation in switching over more than a billion voltage pulses of a magnitude suitable for commercial use. He added that this knowledge helped his group build memristors that lasted nearly a billion switching cycles, about a thousand-fold improvement.

“This is much longer endurance than is possible with today’s flash memory devices,” Kumar said. “In addition, we also used much higher voltage pulses to accelerate and observe memristor failures, which is also important in understanding how these devices work. Failures occurred when oxygen atoms were forced so far away that they did not return to their initial positions.”

Beyond memory chips, Kumar says memristors’ rapid switching speed and small size could make them suitable for use in logic circuits. Additional memristor characteristics may also be beneficial in the emerging class of brain-inspired neuromorphic computing circuits.

“Transistors are big and bulky compared to memristors,” he said. “Memristors are also much better suited for creating the neuron-like voltage spikes that characterize neuromorphic circuits.”

The researchers have provided an animation illustrating how memristors can fail,

This animation shows how millions of high-voltage switching cycles can cause memristors to fail. The high-voltage switching eventually creates regions that are permanently rich (blue pits) or deficient (red peaks) in oxygen and cannot be switched back. Switching at lower voltages that would be suitable for commercial devices did not show this performance degradation. These observations allowed the researchers to develop materials processing and operating conditions that improved the memristors’ endurance by nearly a thousand times. (Suhas Kumar) Courtesy: SLAC

This animation shows how millions of high-voltage switching cycles can cause memristors to fail. The high-voltage switching eventually creates regions that are permanently rich (blue pits) or deficient (red peaks) in oxygen and cannot be switched back. Switching at lower voltages that would be suitable for commercial devices did not show this performance degradation. These observations allowed the researchers to develop materials processing and operating conditions that improved the memristors’ endurance by nearly a thousand times. (Suhas Kumar) Courtesy: SLAC

Here’s a link to and a citation for the paper,

Direct Observation of Localized Radial Oxygen Migration in Functioning Tantalum Oxide Memristors by Suhas Kumar, Catherine E. Graves, John Paul Strachan, Emmanuelle Merced Grafals, Arthur L. David Kilcoyne3, Tolek Tyliszczak, Johanna Nelson Weker, Yoshio Nishi, and R. Stanley Williams. Advanced Materials, First published: 2 February 2016; Print: Volume 28, Issue 14 April 13, 2016 Pages 2772–2776 DOI: 10.1002/adma.201505435

This paper is behind a paywall.

Some of the ‘memristor story’ is contested and you can find a brief overview of the discussion in this Wikipedia memristor entry in the section on ‘definition and criticism’. There is also a history of the memristor which dates back to the 19th century featured in my May 22, 2012 posting.

A treasure trove of molecule and battery data released to the public

Scientists working on The Materials Project have taken the notion of open science to their hearts and opened up access to their data according to a June 9, 2016 news item on Nanowerk,

The Materials Project, a Google-like database of material properties aimed at accelerating innovation, has released an enormous trove of data to the public, giving scientists working on fuel cells, photovoltaics, thermoelectrics, and a host of other advanced materials a powerful tool to explore new research avenues. But it has become a particularly important resource for researchers working on batteries. Co-founded and directed by Lawrence Berkeley National Laboratory (Berkeley Lab) scientist Kristin Persson, the Materials Project uses supercomputers to calculate the properties of materials based on first-principles quantum-mechanical frameworks. It was launched in 2011 by the U.S. Department of Energy’s (DOE) Office of Science.

A June 8, 2016 Berkeley Lab news release, which originated the news item, provides more explanation about The Materials Project,

The idea behind the Materials Project is that it can save researchers time by predicting material properties without needing to synthesize the materials first in the lab. It can also suggest new candidate materials that experimentalists had not previously dreamed up. With a user-friendly web interface, users can look up the calculated properties, such as voltage, capacity, band gap, and density, for tens of thousands of materials.

Two sets of data were released last month: nearly 1,500 compounds investigated for multivalent intercalation electrodes and more than 21,000 organic molecules relevant for liquid electrolytes as well as a host of other research applications. Batteries with multivalent cathodes (which have multiple electrons per mobile ion available for charge transfer) are promising candidates for reducing cost and achieving higher energy density than that available with current lithium-ion technology.

The sheer volume and scope of the data is unprecedented, said Persson, who is also a professor in UC Berkeley’s Department of Materials Science and Engineering. “As far as the multivalent cathodes, there’s nothing similar in the world that exists,” she said. “To give you an idea, experimentalists are usually able to focus on one of these materials at a time. Using calculations, we’ve added data on 1,500 different compositions.”

While other research groups have made their data publicly available, what makes the Materials Project so useful are the online tools to search all that data. The recent release includes two new web apps—the Molecules Explorer and the Redox Flow Battery Dashboard—plus an add-on to the Battery Explorer web app enabling researchers to work with other ions in addition to lithium.

“Not only do we give the data freely, we also give algorithms and software to interpret or search over the data,” Persson said.

The Redox Flow Battery app gives scientific parameters as well as techno-economic ones, so battery designers can quickly rule out a molecule that might work well but be prohibitively expensive. The Molecules Explorer app will be useful to researchers far beyond the battery community.

“For multivalent batteries it’s so hard to get good experimental data,” Persson said. “The calculations provide rich and robust benchmarks to assess whether the experiments are actually measuring a valid intercalation process or a side reaction, which is particularly difficult for multivalent energy technology because there are so many problems with testing these batteries.”

Here’s a screen capture from the Battery Explorer app,

The Materials Project’s Battery Explorer app now allows researchers to work with other ions in addition to lithium.

The Materials Project’s Battery Explorer app now allows researchers to work with other ions in addition to lithium. Courtesy: The Materials Project

The news release goes on to describe a new discovery made possible by The Materials Project (Note: A link has been removed),

Together with Persson, Berkeley Lab scientist Gerbrand Ceder, postdoctoral associate Miao Liu, and MIT graduate student Ziqin Rong, the Materials Project team investigated some of the more promising materials in detail for high multivalent ion mobility, which is the most difficult property to achieve in these cathodes. This led the team to materials known as thiospinels. One of these thiospinels has double the capacity of the currently known multivalent cathodes and was recently synthesized and tested in the lab by JCESR researcher Linda Nazar of the University of Waterloo, Canada.

“These materials may not work well the first time you make them,” Persson said. “You have to be persistent; for example you may have to make the material very phase pure or smaller than a particular particle size and you have to test them under very controlled conditions. There are people who have actually tried this material before and discarded it because they thought it didn’t work particularly well. The power of the computations and the design metrics we have uncovered with their help is that it gives us the confidence to keep trying.”

The researchers were able to double the energy capacity of what had previously been achieved for this kind of multivalent battery. The study has been published in the journal Energy & Environmental Science in an article titled, “A High Capacity Thiospinel Cathode for Mg Batteries.”

“The new multivalent battery works really well,” Persson said. “It’s a significant advance and an excellent proof-of-concept for computational predictions as a valuable new tool for battery research.”

Here’s a link to and a citation for the paper,

A high capacity thiospinel cathode for Mg batteries by Xiaoqi Sun, Patrick Bonnick, Victor Duffort, Miao Liu, Ziqin Rong, Kristin A. Persson, Gerbrand Ceder and  Linda F. Nazar. Energy Environ. Sci., 2016, Advance Article DOI: 10.1039/C6EE00724D First published online 24 May 2016

This paper seems to be behind a paywall.

Getting back to the news release, there’s more about The Materials Project in relationship to its membership,

The Materials Project has attracted more than 20,000 users since launching five years ago. Every day about 20 new users register and 300 to 400 people log in to do research.

One of those users is Dane Morgan, a professor of engineering at the University of Wisconsin-Madison who develops new materials for a wide range of applications, including highly active catalysts for fuel cells, stable low-work function electron emitter cathodes for high-powered microwave devices, and efficient, inexpensive, and environmentally safe solar materials.

“The Materials Project has enabled some of the most exciting research in my group,” said Morgan, who also serves on the Materials Project’s advisory board. “By providing easy access to a huge database, as well as tools to process that data for thermodynamic predictions, the Materials Project has enabled my group to rapidly take on materials design projects that would have been prohibitive just a few years ago.”

More materials are being calculated and added to the database every day. In two years, Persson expects another trove of data to be released to the public.

“This is the way to reach a significant part of the research community, to reach students while they’re still learning material science,” she said. “It’s a teaching tool. It’s a science tool. It’s unprecedented.”

Supercomputing clusters at the National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility hosted at Berkeley Lab, provide the infrastructure for the Materials Project.

Funding for the Materials Project is provided by the Office of Science (US Department of Energy], including support through JCESR [Joint Center for Energy Storage Research].

Happy researching!

Nature-inspired nanotubes from the Lawrence Berkeley National* Laboratory

A March 29, 2016 news item on Nanotechnology Now  announces a new technique for nature-inspired self-assembling polymer nanotubes,

When it comes to the various nanowidgets scientists are developing, nanotubes are especially intriguing. That’s because hollow tubes that have diameters of only a few billionths of a meter have the potential to be incredibly useful, from delivering cancer-fighting drugs inside cells to desalinating seawater.

But building nanostructures is difficult. And creating a large quantity of nanostructures with the same trait, such as millions of nanotubes with identical diameters, is even more difficult. This kind of precision manufacturing is needed to create the nanotechnologies of tomorrow.

Help could be on the way. As reported online the week of March 28 [2016] in the journal Proceedings of the National Academy of Sciences [PNAS], researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have discovered a family of nature-inspired polymers that, when placed in water, spontaneously assemble into hollow crystalline nanotubes. What’s more, the nanotubes can be tuned to all have the same diameter of between five and ten nanometers, depending on the length of the polymer chain.

A March 28, 2016 Berkeley Lab news release (also on EurekAlert), which originated the news item, provides more detail,

The polymers have two chemically distinct blocks that are the same size and shape. The scientists learned these blocks act like molecular tiles that form rings, which stack together to form nanotubes up to 100 nanometers long, all with the same diameter.

“This points to a new way we can use synthetic polymers to create complex nanostructures in a very precise way,” says Ron Zuckermann, who directs the Biological Nanostructures Facility in Berkeley Lab’s Molecular Foundry, where much of this research was conducted.

Several other Berkeley Lab scientists contributed to this research, including Nitash Balsara of the Materials Sciences Division and Ken Downing of the Molecular Biophysics and Integrated Bioimaging Division.

“Creating uniform structures in high yield is a goal in nanotechnology,” adds Zuckermann. “For example, if you can control the diameter of nanotubes, and the chemical groups exposed in their interior, then you can control what goes through—which could lead to new filtration and desalination technologies, to name a few examples.”

The research is the latest in the effort to build nanostructures that approach the complexity and function of nature’s proteins, but are made of durable materials. In this work, the Berkeley Lab scientists studied a polymer that is a member of the peptoid family. Peptoids are rugged synthetic polymers that mimic peptides, which nature uses to form proteins. They can be tuned at the atomic scale to carry out specific functions.

For the past several years, the scientists have studied a particular type of peptoid, called a diblock copolypeptoid, because it binds with lithium ions and could be used as a battery electrolyte. Along the way, they serendipitously found the compounds form nanotubes in water. How exactly these nanotubes form has yet to be determined, but this latest research sheds light on their structure, and hints at a new design principle that could be used to build nanotubes and other complex nanostructures.

Diblock copolypeptoids are composed of two peptoid blocks, one that’s hydrophobic one that’s hydrophilic. The scientists discovered both blocks crystallize when they meet in water, and form rings consisting of two to three individual peptoids. The rings then form hollow nanotubes.

Cryo-electron microscopy imaging of 50 of the nanotubes showed the diameter of each tube is highly uniform along its length, as well as from tube to tube. This analysis also revealed a striped pattern across the width of the nanotubes, which indicates the rings stack together to form tubes, and rules out other packing arrangements. In addition, the peptoids are thought to arrange themselves in a brick-like pattern, with hydrophobic blocks lining up with other hydrophobic blocks, and the same for hydrophilic blocks.

“Images of the tubes captured by electron microscopy were essential for establishing the presence of this unusual structure,” says Balsara. “The formation of tubular structures with a hydrophobic core is common for synthetic polymers dispersed in water, so we were quite surprised to see the formation of hollow tubes without a hydrophobic core.”

X-ray scattering analyses conducted at beamline 7.3.3 of the Advanced Light Source revealed even more about the nanotubes’ structure. For example, it showed that one of the peptoid blocks, which is usually amorphous, is actually crystalline.

Remarkably, the nanotubes assemble themselves without the usual nano-construction aids, such as electrostatic interactions or hydrogen bond networks.

“You wouldn’t expect something as intricate as this could be created without these crutches,” says Zuckermann. “But it turns out the chemical interactions that hold the nanotubes together are very simple. What’s special here is that the two peptoid blocks are chemically distinct, yet almost exactly the same size, which allows the chains to pack together in a very regular way. These insights could help us design useful nanotubes and other structures that are rugged and tunable—and which have uniform structures.”

This cryo-electron microscopy image shows the self-assembling nanotubes have the same diameter. The circles are head-on views of nanotubes. The dark-striped features likely result from crystallized peptoid blocks. (Credit: Berkeley Lab)

This cryo-electron microscopy image shows the self-assembling nanotubes have the same diameter. The circles are head-on views of nanotubes. The dark-striped features likely result from crystallized peptoid blocks. (Credit: Berkeley Lab)

Here’s a link to and a citation for the paper,

Self-assembly of crystalline nanotubes from monodisperse amphiphilic diblock copolypeptoid tiles by Jing Sun, Xi Jiang, Reidar Lund, Kenneth H. Downing, Nitash P. Balsara, and Ronald N. Zuckermann. PNAS 2016 ; published ahead of print March 28, 2016, doi: 10.1073/pnas.1517169113

This paper is behind a paywall.

*’Lawrence Berkeley Laboratory’ changed to ‘Lawrence Berkeley National Laboratory’ on April 3, 2016.

Weaving at the nanoscale

A Jan. 21, 2016 news item on ScienceDaily announces a brand new technique,

For the first time, scientists have been able to weave a material at molecular level. The research is led by University of California Berkeley, in cooperation with Stockholm University. …

A Jan. 21, 2016 Stockholm University press release, which originated the news item, provides more information,

Weaving is a well-known way of making fabric, but has until now never been used at the molecular level. Scientists have now been able to weave organic threads into a three-dimensional material, using copper as a template. The new material is a COF, covalent organic framework, and is named COF-505. The copper ions can be removed and added without changing the underlying structure, and at the same time the elasticity can be reversibly changed.

– It almost looks like a molecular version of the Vikings chain-armour. The material is very flexible, says Peter Oleynikov, researcher at the Department of Materials and Environmental Chemistry at Stockholm University.

COF’s are like MOF’s porous three-dimensional crystals with a very large internal surface that can adsorb and store enormous quantities of molecules. A potential application is capture and storage of carbon dioxide, or using COF’s as a catalyst to make useful molecules from carbon dioxide.

Complex structure determined in Stockholm

The research is led by Professor Omar Yaghi at University of California Berkeley. At Stockholm University Professor Osamu Terasaki, PhD Student Yanhang Ma and Researcher Peter Oleynikov have contributed to determine the structure of COF-505 at atomic level from a nano-crystal, using electron crystallography methods.

– It is a difficult, complicated structure and it was very demanding to resolve. We’ve spent lot of time and efforts on the structure solution. Now we know exactly where the copper is and we can also replace the metal. This opens up many possibilities to make other materials, says Yanhang Ma, PhD Student at the Department of Materials and Environmental Chemistry at Stockholm University.

Another of the collaborating institutions, US Department of Energy Lawrence Berkeley National Laboratory issued a Jan. 21, 2016 news release on EurekAlert, providing a different perspective and some additional details,

There are many different ways to make nanomaterials but weaving, the oldest and most enduring method of making fabrics, has not been one of them – until now. An international collaboration led by scientists at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, has woven the first three-dimensional covalent organic frameworks (COFs) from helical organic threads. The woven COFs display significant advantages in structural flexibility, resiliency and reversibility over previous COFs – materials that are highly prized for their potential to capture and store carbon dioxide then convert it into valuable chemical products.

“Weaving in chemistry has been long sought after and is unknown in biology,” Yaghi says [Omar Yaghi, chemist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and UC Berkeley’s Chemistry Department and is the co-director of the Kavli Energy NanoScience Institute {Kavli-ENSI}]. “However, we have found a way of weaving organic threads that enables us to design and make complex two- and three-dimensional organic extended structures.”

COFs and their cousin materials, metal organic frameworks (MOFs), are porous three-dimensional crystals with extraordinarily large internal surface areas that can absorb and store enormous quantities of targeted molecules. Invented by Yaghi, COFs and MOFs consist of molecules (organics for COFs and metal-organics for MOFs) that are stitched into large and extended netlike frameworks whose structures are held together by strong chemical bonds. Such frameworks show great promise for, among other applications, carbon sequestration.

Through another technique developed by Yaghi, called “reticular chemistry,” these frameworks can also be embedded with catalysts to carry out desired functions: for example, reducing carbon dioxide into carbon monoxide, which serves as a primary building block for a wide range of chemical products including fuels, pharmaceuticals and plastics.

In this latest study, Yaghi and his collaborators used a copper(I) complex as a template for bringing threads of the organic compound “phenanthroline” into a woven pattern to produce an immine-based framework they dubbed COF-505. Through X-ray and electron diffraction characterizations, the researchers discovered that the copper(I) ions can be reversibly removed or restored to COF-505 without changing its woven structure. Demetalation of the COF resulted in a tenfold increase in its elasticity and remetalation restored the COF to its original stiffness.

“That our system can switch between two states of elasticity reversibly by a simple operation, the first such demonstration in an extended chemical structure, means that cycling between these states can be done repeatedly without degrading or altering the structure,” Yaghi says. “Based on these results, it is easy to imagine the creation of molecular cloths that combine unusual resiliency, strength, flexibility and chemical variability in one material.”

Yaghi says that MOFs can also be woven as can all structures based on netlike frameworks. In addition, these woven structures can also be made as nanoparticles or polymers, which means they can be fabricated into thin films and electronic devices.

“Our weaving technique allows long threads of covalently linked molecules to cross at regular intervals,” Yaghi says. “These crossings serve as points of registry, so that the threads have many degrees of freedom to move away from and back to such points without collapsing the overall structure, a boon to making materials with exceptional mechanical properties and dynamics.”

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This research was primarily supported by BASF (Germany) and King Abdulaziz City for Science and Technology (KACST).

It’s unusual that neither Stockholm University not the Lawrence Berkeley National Laboratory list all of the institutions involved. To get a sense of this international collaboration’s size, I’m going to list them,

  • 1Department of Chemistry, University of California, Berkeley, Materials Sciences Division, Lawrence Berkeley National Laboratory, and Kavli Energy NanoSciences Institute, Berkeley, CA 94720, USA.
  • 2Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden.
  • 3Department of New Architectures in Materials Chemistry, Materials Science Institute of Madrid, Consejo Superior de Investigaciones Científicas, Madrid 28049, Spain.
  • 4Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565, Japan.
  • 5NSF Nanoscale Science and Engineering Center (NSEC), University of California at Berkeley, 3112 Etcheverry Hall, Berkeley, CA 94720, USA.
  • 6Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
  • 7King Abdulaziz City of Science and Technology, Post Office Box 6086, Riyadh 11442, Saudi Arabia.
  • 8Material Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
  • 9School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.

Given that some of the money came from a German company, I’m surprised not one German institution was involved.

Here’s a link to and citation for the paper,

Weaving of organic threads into a crystalline covalent organic framework by Yuzhong Liu, Yanhang Ma, Yingbo Zhao, Xixi Sun, Felipe Gándara, Hiroyasu Furukawa, Zheng Liu, Hanyu Zhu, Chenhui Zhu, Kazutomo Suenaga, Peter Oleynikov, Ahmad S. Alshammari, Xiang Zhang, Osamu Terasaki, Omar M. Yaghi. Science  22 Jan 2016: Vol. 351, Issue 6271, pp. 365-369 DOI: 10.1126/science.aad4011

This paper is behind a paywall.