Platinum-graphene fuel cell catalysts show superior stability over bulk platinum – Georgia Institute of Tecnology


Seung Soon Jang, an associate professor, Faisal Alamgir, an associate professor, and Ji Il Choi, a postdoctoral researcher, all in Georgia Tech’s School of Materials Science and Engineering, examine a piece of platinum-graphene catalyst. Credit: Allison Carter

Films of platinum only two atoms thick supported by graphene could enable fuel cell catalysts with unprecedented catalytic activity and longevity, according to a study published recently by researchers at the Georgia Institute of Technology.

Platinum is one of the most commonly used catalysts for fuel cells because of how effectively it enables the oxidation reduction reaction at the center of the technology. But its high cost has spurred research efforts to find ways to use smaller amounts of it while maintaining the same .

“There’s always going to be an initial cost for producing a fuel cell with , and it’s important to keep that cost as low as possible,” said Faisal Alamgir, an associate professor in Georgia Tech’s School of Materials Science and Engineering. “But the real cost of a fuel cell system is calculated by how long that system lasts, and this is a question of durability.

“Recently there’s been a push to use catalytic systems without , but the problem is that there hasn’t been a system proposed so far that simultaneously matches the catalytic activity and the durability of platinum,” Alamgir said.

The Georgia Tech researchers tried a different strategy. In the study, which was published on September 18 in the journal Advanced Functional Materialsand supported by the National Science Foundation, they describe creating several systems that used atomically-thin  of platinum supported by a layer of graphene—effectively maximizing the total surface area of the platinum available for catalytic reactions and using a much smaller amount of the precious metal.

Most platinum-based catalytic systems use nanoparticles of the metal chemically bonded to a support surface, where surface atoms of the particles do most of the catalytic work, and the catalytic potential of the atoms beneath the surface is never utilized as fully as the surface atoms, if at all.

This graphic shows how the graphene layer in gray provides structure and stability to the two atomic layers of platinum above represented in blue. Credit: Ji Il Choi

Additionally, the researchers showed that the new platinum films that are at least two atoms thick outperformed nanoparticle platinum in the dissociation energy, which is a measure of the energy cost of dislodging a surface platinum atom. That measurement suggests those films could make potentially longer-lasting catalytic systems.

To prepare the atomically-thin films, the researchers used a process called electrochemical atomic layer deposition to grow platinum monolayers on a layer of graphene, creating samples that had one, two or three atomic layers of atoms. The researchers then tested the samples for dissociation energy and compared the results to the energy of a single atom of platinum on graphene as well as the energy from a common configurations of platinum nanoparticles used in catalysts.

“The fundamental question at the heart of this work was whether it was possible that a combination of metallic and  can render the platinum atoms in a platinum-graphene combination more stable than their counterparts in bulk platinum used commonly in catalysts that are supported by metallic bonding,” said Seung Soon Jang, an associate professor in the School of Materials Science and Engineering.

The researchers found that the bond between neighboring platinum atoms in the film essentially combines forces with the bond between the film and the graphene layer to provide reinforcement across the system. That was especially true in the platinum film that was two atoms thick.

“Typically metallic films below a certain thickness are not stable because the bonds between them are not directional, and they tend to roll over each other and conglomerate to form a particle,” Alamgir said. “But that’s not true with graphene, which is stable in a two-dimensional form, even one atom thick, because it has very strong covalent directional bonds between its neighboring . So this new catalytic system could leverage the directional bonding of the graphene to support an atomically-thin film of platinum.”

Future research will involve further testing of how the films behave in a catalytic environment. The researchers found in earlier research on graphene-platinum films that the material behaves similarly in catalytic reactions regardless of which side—graphene or platinum—is the exposed active surface.

“In this configuration, the graphene is not acting as a separate entity from the platinum,” Alamgir said. “They’re working together as one. So we believe that if you’re exposing the  side, you get the same catalytic activity and you could further protect the platinum, potentially further enhancing durability.”

More information: Ji Il Choi et al, Contiguous and Atomically Thin Pt Film with Supra‐Bulk Behavior Through Graphene‐Imposed Epitaxy, Advanced Functional Materials(2019).  DOI: 10.1002/adfm.201902274

Journal information: Advanced Functional Materials

Provided by Georgia Institute of Technology

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Why Asia’s biggest economies are backing hydrogen fuel cell cars


 

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FILE PHOTO: An Air Liquide hydrogen station for hydrogen fuel cell cars is seen in Paris, France, October 13, 2016. REUTERS/Charles Platiau. 

China, Japan and South Korea have set ambitious targets to put millions of hydrogen-powered vehicles on their roads by the end of the next decade at a cost of billions of dollars.

But to date, hydrogen fuel cell vehicles (FCVs) have been upstaged by electric vehicles, which are increasingly becoming a mainstream option due to the success of Tesla Inc’s (TSLA.O) luxury cars as well as sales and production quotas set by China.

Critics argue FCVs may never amount to more than a niche technology. But proponents counter hydrogen is the cleanest energy source for autos available and that with time and more refueling infrastructure, it will gain acceptance.

AMBITIOUS TARGETS

China, far and away the world’s biggest auto market with some 28 million vehicles sold annually, is aiming for more than 1 million FCVs in service by 2030. That compares with just 1,500 or so now, most of which are buses.

fuel-cell-market4Read More: Fuel Cell Market by Type

Japan, a market of more than 5 million vehicles annually, wants to have 800,000 FCVs sold by that time from around 3,400 currently.

South Korea, which has a car market just one third the size of Japan, has set a target of 850,000 vehicles on the road by 2030. But as of end-2018, fewer than 900 have been sold.

 

WHY HYDROGEN?

 

Hydrogen’s proponents point to how clean it is as an energy source as water and heat are the only byproducts and how it can be made from a number of sources, including methane, coal, water, even garbage. Resource-poor Japan sees hydrogen as a way to greater energy security.

They also argue that driving ranges and refueling times for FCVs are comparable to gasoline cars, whereas EVs require hours to recharge and provide only a few hundred kilometers of range.

Many backers in China and Japan see FCVs as complementing EVs rather than replacing them. In general, hydrogen is seen as the more efficient choice for heavier vehicles that drive longer distances, hence the current emphasis on city buses.

THE MAIN PLAYERS

Only a handful of automakers have made fuel cell passenger cars commercially available.

Toyota Motor Corp (7203.T) launched the Mirai sedan at the end of 2014, but has sold fewer than 10,000 globally. Hyundai Motor Co (005380.KS) has offered the Nexo crossover since March last year and has sold just under 2,900 worldwide. It had sales of around 900 for its previous FCV model, the Tucson.

Buses are seeing more demand. Both Toyota and Hyundai have offerings and have begun selling fuel cell components to bus makers, particularly in China.

Several Chinese manufacturers have developed their own buses, notably state-owned SAIC Motor (600104.SS), the nation’s biggest automaker, and Geely Auto Group, which also owns the Volvo Cars and Lotus brands.

WHY HAVEN’T FUEL CELL CARS CAUGHT ON YET?

A lack of refueling stations, which are costly to build, is usually cited as the biggest obstacle to widespread adoption of FCVs. At the same time, the main reason cited for the lack of refueling infrastructure is that there are not enough FCVs to make them profitable.

Consumer worries about the risk of explosions are also a big hurdle and residents in Japan and South Korea have protested against the construction of hydrogen stations. This year, a hydrogen tank explosion in South Korea killed two people, which was followed by a blast at a Norway hydrogen station.

Then there’s the cost. Heavy subsidies are needed to bring prices down to levels of gasoline-powered cars. Toyota’s Mirai costs consumers just over 5 million yen ($46,200) after subsidies of 2.25 million yen. That’s still about 50% more than a Camry.

Automakers contend that once sales volumes increase, economies of scale will make subsidies unnecessary.

 

HOW FUEL CELLS WORK

(GRAPHIC: How fuel cell vehicles work: here)

Reuters Graphic

 

Reuters: Reporting by Kevin Buckland in Tokyo; Additional reporting by Yilei Sun in Beijing and Hyunjoo Jin in Seoul; Editing by Edwina Gibbs

 

 

DNA ‘Origami’ takes Flight in Emerging Field of Nano Machines – “(a) … tool may eventually be used to fine tune immunotherapies for individual cancer patients”


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DNA mechanotechnology expands the opportunities for research involving biomedicine and materials sciences, says Khalid Salaita, right, professor of chemistry at Emory University and co-author of the article, along with Aaron Blanchard, left, a graduate student in the Salaita Lab. Credit: Emory University

Just as the steam engine set the stage for the Industrial Revolution, and micro transistors sparked the digital age, nanoscale devices made from DNA are opening up a new era in bio-medical research and materials science.

The journal Science describes the emerging uses of DNA  in a “Perspective” article by Khalid Salaita, a professor of chemistry at Emory University, and Aaron Blanchard, a graduate student in the Wallace H. Coulter Department of Biomedical Engineering, a joint program of Georgia Institute of Technology and Emory.

The article heralds a new field, which Blanchard dubbed “DNA mechanotechnology,” to engineer DNA machines that generate, transmit and sense  at the nanoscale.

“For a long time,” Salaita says, “scientists have been good at making micro devices, hundreds of times smaller than the width of a human hair. It’s been more challenging to make functional nano devices, thousands of times smaller than that. But using DNA as the component parts is making it possible to build extremely elaborate nano devices because the DNA parts self-assemble.”

DNA, or deoxyribonucleic acid, stores and transmits genetic information as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T). The DNA bases have a natural affinity to pair up with each other—A with T and C with G. Synthetic strands of DNA can be combined with natural DNA strands from bacteriophages. By moving around the sequence of letters on the strands, researchers can get the DNA strands to bind together in ways that create different shapes. The stiffness of DNA strands can also easily be adjusted, so they remain straight as a piece of dry spaghetti or bend and coil like boiled spaghetti.

The idea of using DNA as a construction material goes back to the 1980s, when biochemist Nadrian Seeman pioneered DNA nanotechnology. This field uses strands DNA to make functional devices at the nanoscale. The ability to make these precise, three-dimensional structures began as a novelty, nicknamed DNA origami, resulting in objects such as a microscopic map of the world and, more recently, the tiniest-ever game of tic-tac-toe, played on a DNA board.

Work on novelty objects continues to provide new insights into the mechanical properties of DNA. These insights are driving the ability to make DNA machines that generate, transmit and sense mechanical forces.

“If you put together these three main components of mechanical devices, you begin to get hammers and cogs and wheels and you can start building nano machines,” Salaita says. “DNA mechanotechnology expands the opportunities for research involving biomedicine and materials science. It’s like discovering a new continent and opening up fresh territory to explore.”

Potential uses for such devices include drug delivery devices in the form of nano capsules that open up when they reach a target site, nano computers and nano robots working on nanoscale assembly lines.

The use of DNA self-assembly by the genomics industry, for biomedical research and diagnostics, is further propelling DNA mechanotechnology, making DNA synthesis inexpensive and readily available. “Potentially anyone can dream up a nano-machine design and make it a reality,” Salaita says.

He gives the example of creating a pair of nano scissors. “You know that you need two rigid rods and that they need to be linked by a pivot mechanism,” he says. “By tinkering with some open-source software, you can create this design and then go onto a computer and place an order to custom synthesize your design. You’ll receive your order in a tube. You simply put the tube contents into a solution, let your device self-assemble, and then use a microscope to see if it works the way you thought that it would.”

Salaita’s lab is one of only about 100 around the world working at the forefront of DNA mechanotechnology. He and Blanchard developed the world’s strongest synthetic DNA-based motor, which was recently reported in Nano Letters.

A key focus of Salaita’s research is mapping and measuring how cells push and pull to learn more about the mechanical forces involved in the human immune system.

Salaita developed the first DNA force gauges for cells, providing the first detailed view of the mechanical forces that one molecule applies to another molecule across the entire surface of a living cell. Mapping such forces may help to diagnose and treat diseases related to cellular mechanics. Cancer cells, for instance, move differently from normal cells, and it is unclear whether that difference is a cause or an effect of the disease.

In 2016, Salaita used these DNA force gauges to provide the first direct evidence for the mechanical forces of T cells, the security guards of the immune system. His lab showed how T cells use a kind of mechanical “handshake” or tug to test whether a cell they encounter is a friend or foe. These mechanical tugs are central to a T cell’s decision for whether to mount an immune response.

“Your blood contains millions of different types of T cells, and each T cell is evolved to detect a certain pathogen or foreign agent,” Salaita explains. “T cells are constantly sampling cells throughout your body using these mechanical tugs. They bind and pull on proteins on a cell’s surface and, if the bond is strong, that’s a signal that the T cell has found a foreign agent.”

Salaita’s lab built on this discovery in a paper recently published in the Proceedings of the National Academy of Sciences (PNAS). Work led by Emory chemistry graduate student Rong Ma refined the sensitivity of the DNA force gauges. Not only can they detect these mechanical tugs at a force so slight that it is nearly one-billionth the weight of a paperclip, they can also capture evidence of tugs as brief as the blink of an eye.

The research provides an unprecedented look at the mechanical forces involved in the immune system. “We showed that, in addition to being evolved to detect certain foreign agents, T cells will also apply very brief mechanical tugs to foreign agents that are a near match,” Salaita says. “The frequency and duration of the tug depends on how closely the foreign agent is matched to the T cell receptor.”

The result provides a tool to predict how strong of an immune response a T cell will mount. “We hope this tool may eventually be used to fine tune immunotherapies for individual cancer patients,” Salaita says. “It could potentially help engineer T  to go after particular .”


Innovative AI Breath Analyzer Diagnoses Diseases by “Smell” – AI System to Detect 17 Diseases from Exhaled Breath with 86% Accuracy


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Re-Posted from Psychology Today: Author Cami Russo

Imagine being able to know if you have Parkinson’s disease, multiple sclerosis, liver failure, Crohn’s diseases, pulmonary hypertension, chronic kidney disease, or any number of cancers based on a simple, non-invasive test of your breath. Breath analyzers to detect alcohol have been around for well over half a century—why not apply the same concept to detect diseases? A global team of scientists from universities in Israel, France, Latvia, China and the United States have developed an artificial intelligence (AI) system to detect 17 diseases from exhaled breath with 86 percent accuracy.

The research team led by Professor Hassam Haick of the Technion-Israel Institute of Technology collected breath samples from 1404 subjects with either no disease (healthy control) or one of 17 different diseases. The disease conditions include lung cancer, colorectal cancer, head and neck cancer, ovarian cancer, bladder cancer, prostate cancer, kidney cancer, gastric cancer, Crohn’s disease, ulcerative colitis, irritable bowel syndrome, idiopathic Parkinson’s, atypical Parkinson ISM, multiple sclerosis, pulmonary hypertension, pre-eclampsia toxemia, and chronic kidney disease.

The concept is relatively simple—identify breath-prints of diseases, and compare it to human exhalation. What makes it complicated is the execution of the concept. For example, how to identify the breathprint of a disease? Is it unique like a fingerprint? To answer these questions requires a deeper look at the molecular composition of breath.

When we exhale, nitrogen, oxygen, carbon dioxide, argon, and water vapor are released. Human breath also contains volatile organic compounds (VOCs)–organic chemicals that are emitted as gases, and have a high vapor pressure at normal temperature. American biochemist Linus Pauling, one of the founders of modern quantum chemistry and molecular biology, and recipient of the 1954 Nobel Prize in Chemistry, and the 1962 Nobel Peace Prize, studied 250 human breath volatiles using a gas-liquid chromatogram in 1971. Pauling is widely regarded as a pioneer in modern breath analysis. Exhaled breath contains approximately over 3,500 components mostly comprised of VOCs in small quantities according to a 2011 study published in “Annals of Allergy, Asthma & Immunology.”

VOCs are the common factor in the smelling process for both breath analyzers and humans. When we inhale, the nose draws in odor molecules that typically contain volatile (easy to evaporate) chemicals. Once the odor molecules contact the olfactory epithelium tissue that lines the nasal cavity, it binds with the olfactory receptors and sends an electrical impulse to a spherical structure called the glomerulus in the olfactory bulb of the brain.

There are approximately 2,000 glomeruli near the surface of the olfactory bulb. Smell is the brain’s interpretation of the odorant patterns released from the glomerulus. The human nose can detect a trillion smells. In Haick’s researcher team, nanotechnology and machine learning replaces the biological brain in the smelling process.

Haick’s team of scientists developed a system, aptly called “NaNose,” that uses nanotechnology-based sensors trained to detect volatile organic compounds associated with select diseases in the study. NaNose has two layers. One is an inorganic nanolayer with nanotubes and gold nanoparticles for electrical conductivity. The other is an organic sensing layer with carbon that controls the electrical resistance of the inorganic layer based on the incoming VOCs. The electrical resistance changes depending on the VOCs.

Artificial intelligence (AI) is used to analyze the data. Specifically, deep learning is used to identify patterns in the data in order to match incoming signals with the chemical signature of specific diseases. The AI system was then trained on more than 8,000 patients in clinics with promising results—the system detected gastric cancer with 92-94 percent accuracy in a blinded test. The researchers discovered that “each disease has its own unique breathprint.”

Efforts are underway to miniaturize and commercialize the innovative technology developed by Haick’s team in a project called “SniffPhone.”  In November 2018, the European Commission’s Horizon 2020 awarded the SniffPhone the “2018 Innovation Award” for the “Most Innovative Project.”

The market opportunity for medical breath analyzers is expected to grow. By 2024, the breath analyzer market is projected to increase to USD 11.3 billion globally according to figures published in Jun 2018 by Grand View Research—alcohol detection has a majority of the revenue share. Currently breath analyzers are used to detect alcohol, drugs, and to diagnose asthma and gastroenteric conditions. Clinical applications are projected to increase due to the introduction of “introduction of advanced technologies to detect nitric oxide and carbon monoxide in breath,” Grand View Research states. According to the study, the medical application segment is expected to grow due to ability of breath analyzers to detect volatile organic compounds (VOCs) that may help in “early diagnosis of conditions including cardiopulmonary diseases and lung and breast cancer,” and act as “biomarkers to assess disease progressions.”

By applying cross-disciplinary innovative technologies from the fields of artificial intelligence, nanotechnology, and molecular chemistry, diagnosing a wide variety of diseases may be as simple and non-invasive as a breath analysis using a handheld device in the not-so-distant future.

 

One-atom switch supercharges fluorescent dyes – Rice University


Rice lab discovers simple technique to make biocompatible ‘turn-on’ dyes

It only took the replacement of one atom for Rice University scientists to give new powers to biocompatible fluorescent molecules.

The Rice lab of chemist Han Xiao reported in the Journal of the American Chemical Society it has developed a single-atom switch to turn fluorescent dyes used in biological imaging on and off at will. The technique will enable high-resolution imaging and dynamic tracking of biological processes in living cells, tissues and animals.

The Rice lab developed a minimally modified probe that can be triggered by a broad range of visible light. The patented process could replace existing photoactivatable fluorophores that may only be activated with ultraviolet light or require toxic chemicals to turn on the fluorescence, characteristics that limit their usefulness.

The researchers took advantage of a phenomenon known as photo-induced electron transfer (PET), which was already known to quench fluorescent signals.

Rice University chemist Han Xiao and his colleagues have discovered a simple method to turn fluorescent tags on and off with visible light by switching one atom. (Credit: Jeff Fitlow/Rice University)

Rice University chemist Han Xiao and his colleagues have discovered a simple method to turn fluorescent tags on and off with visible light by switching one atom. Photo by Jeff Fitlow

They put fluorophores in cages of thiocarbonyl, the moeity responsible for quenching. With one-step organic synthesis, they replaced an oxygen atom in the cage with one of sulfur. That enabled them to induce the PET effect to quench fluorescence.

Triggering the complex again with visible light near the fluorescent molecule’s preferred absorbance oxidized the cage in turn. That knocked out the sulfur and replaced it with an oxygen atom, restoring fluorescence.

“All it takes to make these is a little chemistry and one step,” said Xiao, who joined Rice in 2017 with funding from the Cancer Prevention and Research Institute of Texas  (CPRIT). “We demonstrated in the paper that it works the same for a range of fluorescent dyes. Basically, one reaction solves a lot of problems.”

Researchers worldwide use fluorescent molecules to tag and track cells or elements within cells. Activating the tags with low-powered visible light rather than ultraviolet is much less damaging to the cells being studied, Xiao said, and makes the long exposures of living cells required by super-resolution imaging possible.

Super-resolution experiments by Theodore Wensel, the Robert A. Welch Chair in Chemistry at Baylor College of Medicine, and his team confirmed their abilities, he said.

“We feel this will be a really good probe for living-cell imaging,” Xiao said. “People also use photoactivatable dye to track the dynamics of proteins, to see where and how far and how fast they travel. Our work was to provide a simple, general way to generate this dye.”

At top, a sequence shows the design of thio-caged dyes designed at Rice University to be triggered by visible light. At bottom, confocal and super-resolution imaging of a lipid droplet in living adipocytes incubated with BODIPY (green), SNile Red (red) and Hoechst 33342 (blue), followed by photoactivation using a 561 nm laser. Scale bar: 10 µm. Scale bar for super-resolution image of lipid droplet labeled with SNile Red, bottom right: 1 µm. Courtesy of the Xiao Lab

At top, a sequence shows the design of thio-caged dyes designed at Rice University to be triggered by visible light. At bottom, confocal and super-resolution imaging of a lipid droplet in living adipocytes incubated with BODIPY (green), SNile Red (red) and Hoechst 33342 (blue), followed by photoactivation using a 561-nanometer laser. Scale bar: 10 µm. Scale bar for super-resolution image of lipid droplet labeled with SNile Red, bottom right: 1 µm. Courtesy of the Xiao Lab

The researchers found their technique worked on a wide range of common fluorescent tags and could even be mixed for multicolor imaging of targeted molecules in a single cell.

Rice postdoctoral researcher Juan Tang is lead author of the paper. Co-authors are Rice graduate students Kuan-Lin Wu and Jingqi Pei; postdoctoral fellow Michael Robichaux of Baylor; and graduate student Nhung Nguyen and Yubin Zhou, an assistant professor at the Center for Translational Cancer Research at Texas A&M University. Xiao is the Norman Hackerman-Welch Young Investigator and an assistant professor of chemistry, biosciences, and bioengineering.

CPRIT, the Robert A. Welch Foundation, a Hamill Innovation Award, a John S. Dunn Foundation Collaborative Research Award and the National Institutes of Health supported the research.

Stretchy Plastic Electrolytes could Enable NEW lithium-ion Battery Design – Replaces Expensive metals and traditional liquid Electrolyte with Lower Cost transition metal fluorides and a Solid Polymer Electrolyte


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A lithium-ion battery is shown using a promising new cathode and electrolyte system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte. Credit: Allison Carter

The growing popularity of lithium-ion batteries in recent years has put a strain on the world’s supply of cobalt and nickel—two metals integral to current battery designs—and sent prices surging.

In a bid to develop alternative designs for lithium-based batteries with less reliance on those , researchers at the Georgia Institute of Technology have developed a promising new  and  system that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a .

“Electrodes made from transition metal fluorides have long shown stability problems and rapid failure, leading to significant skepticism about their ability to be used in next generation batteries,” said Gleb Yushin, a professor in Georgia Tech’s School of Materials Science and Engineering. “But we’ve shown that when used with a solid polymer electrolyte, the metal fluorides show remarkable stability—even at —which could eventually lead to safer, lighter and cheaper lithium-ion batteries.”

In a typical lithium-ion battery, energy is released during the transfer of lithium ions between two electrodes—an anode and a cathode, with a cathode typically comprising lithium and transition metals such as cobalt, nickel and manganese. The ions flow between the electrodes through a liquid electrolyte.

For the study, which was published Sept. 9 in the journal Nature Materials and sponsored by the Army Research Office, the research team fabricated a new type of cathode from iron fluoride active material and a solid polymer electrolyte nanocomposite. Iron fluorides have more than double the lithium capacity of traditional cobalt- or nickel-based cathodes. In addition, iron is 300 times cheaper than cobalt and 150 times cheaper than nickel.

To produce such a cathode, the researchers developed a process to infiltrate a solid polymer electrolyte into the prefabricated iron fluoride electrode. They then hot pressed the entire structure to increase density and reduce any voids.

Stretchy plastic electrolytes could enable new lithium-ion battery design

Gleb Yushin, a professor in Georgia Tech’s School of Materials Science and Engineering and Kostiantyn Turcheniuk, research scientist in Yushin’s lab, inspect a battery using a new cathode design that replaces expensive metals and traditional liquid electrolyte with lower cost transition metal fluorides and a solid polymer electrolyte. Credit: Allison Carter

Two central features of the polymer-based electrolyte are its ability to flex and accommodate the swelling of the iron fluoride while cycling and its ability to form a very stable and flexible interphase with iron fluoride. Traditionally, that swelling and massive side reactions have been key problems with using iron fluoride in previous battery designs.

“Cathodes made from iron fluoride have enormous potential because of their high capacity, low material costs and very broad availability of ,” Yushin said. “But the volume changes during cycling as well as parasitic side reactions with liquid electrolytes and other degradation issues have limited their use previously. Using a solid electrolyte with elastic properties solves many of these problems.”

The researchers then tested several variations of the new solid-state batteries to analyze their performance over more than 300 cycles of charging and discharging at elevated temperature of 122 degrees Fahrenheit, noting that they outperformed previous designs using metal  even when these were kept cool at room temperatures.

The researchers found that the key to the enhanced battery performance was the solid polymer electrolyte. In previous attempts to use metal fluorides, it was believed that metallic ions migrated to the surface of the cathode and eventually dissolved into the liquid electrolyte, causing a capacity loss, particularly at elevated temperatures. In addition,  fluorides catalyzed massive decomposition of liquid electrolytes when cells were operating above 100 degrees Fahrenheit. However, at the connection between the solid electrolyte and the cathode, such dissolving doesn’t take place and the solid electrolyte remains remarkably stable, preventing such degradations, the researchers wrote.

“The polymer electrolyte we used was very common, but many other solid electrolytes and other battery or electrode architectures—such as core-shell particle morphologies—should be able to similarly dramatically mitigate or even fully prevent parasitic side reactions and attain stable performance characteristics,” said Kostiantyn Turcheniuk, research scientist in Yushin’s lab and a co-author of the manuscript.

In the future, the researchers aim to develop new and improved solid electrolytes to enable fast charging and also to combine solid and liquid electrolytes in new designs that are fully compatible with conventional cell manufacturing technologies employed in large battery factories.


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Study: New solvent-free, single lithium-ion conducting covalent organic framework

New route to Carbon-Neutral Fuels (CNF) from carbon dioxide discovered – Stanford University and Technical University of Denmark (DTU)


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Artistic representation of a nickel-based electrode as a broken down fuel pump and of a cerium-based electrode as a new, productive pump. Credit: Cube3D

If the idea of flying on battery-powered commercial jets makes you nervous, you can relax a little. Researchers have discovered a practical starting point for converting carbon dioxide into sustainable liquid fuels, including fuels for heavier modes of transportation that may prove very difficult to electrify, like airplanes, ships and freight trains.

 

Carbon-neutral re-use of CO2 has emerged as an alternative to burying the greenhouse gas underground. In a new study published today in Nature Energy, researchers from Stanford University and the Technical University of Denmark (DTU) show how electricity and an Earth-abundant catalyst can convert CO2 into energy-rich carbon monoxide (CO) better than conventional methods.

The catalyst—cerium oxide—is much more resistant to breaking down. Stripping oxygen from CO2 to make CO gas is the first step in turning CO2 into nearly any liquid fuel and other products, like synthetic gas and plastics. The addition of hydrogen to CO can produce fuels like synthetic diesel and the equivalent of jet fuel. The team envisions using renewable power to make the CO and for subsequent conversions, which would result in  products.

“We showed we can use electricity to reduce CO2 into CO with 100 percent selectivity and without producing the undesired byproduct of solid carbon,” said William Chueh, an associate professor of materials science and engineering at Stanford, one of three senior authors of the paper.

Chueh, aware of DTU’s research in this area, invited Christopher Graves, associate professor in DTU’s Energy Conversion & Storage Department, and Theis Skafte, a DTU doctoral candidate at the time, to come to Stanford and work on the technology together.

“We had been working on high-temperature CO2 electrolysis for years, but the collaboration with Stanford was the key to this breakthrough,” said Skafte, lead author of the study, who is now a postdoctoral researcher at DTU. “We achieved something we couldn’t have separately—both fundamental understanding and practical demonstration of a more robust material.”

Barriers to conversion

One advantage sustainable liquid fuels could have over the electrification of transportation is that they could use the existing gasoline and diesel infrastructure, like engines, pipelines and gas stations. Additionally, the barriers to electrifying airplanes and ships—long distance travel and the high weight of batteries—would not be problems for energy-dense, carbon-neutral fuels.

New route to carbon-neutral fuels from carbon dioxide discovered by Stanford-DTU team
From left: Christopher Graves, Michal Bajdich and Michael Machala in front of the pulsed laser deposition machine that Machala used to fabricate the electrodes. Credit: Mark Golden

Although plants reduce CO2 to carbon-rich sugars naturally, an artificial electrochemical route to CO has yet to be widely commercialized. Among the problems: Devices use too much electricity, convert a low percentage of CO2 molecules, or produce pure carbon that destroys the device. Researchers in the new study first examined how different devices succeeded and failed in CO2 electrolysis.

With insights gained, the researchers built two cells for CO2 conversion testing: one with cerium oxide and the other with conventional nickel-based catalysts. The ceria electrode remained stable, while carbon deposits damaged the nickel electrode, significantly shortening the catalyst’s lifetime.

“This remarkable capability of ceria has major implications for the practical lifetime of CO2 electrolyzer devices,” said DTU’s Graves, a senior author of the study and visiting scholar at Stanford at the time. “Replacing the current nickel electrode with our new ceria electrode in the next generation electrolyzer would improve device lifetime.”

Road to commercialization

Eliminating early cell death could significantly lower the cost of commercial CO production. The suppression of carbon buildup also allows the new type of device to convert more of the CO2 to CO, which is limited to well below 50 percent CO product concentration in today’s cells. This could also reduce .

“The carbon-suppression mechanism on ceria is based on trapping the carbon in stable oxidized form. We were able to explain this behavior with computational models of CO2 reduction at elevated temperature, which was then confirmed with X-ray photoelectron spectroscopy of the cell in operation,” said Michal Bajdich, a senior author of the paper and an associate staff scientist at the SUNCAT Center for Interface Science & Catalysis, a partnership between the SLAC National Accelerator Laboratory and Stanford’s School of Engineering.

The high cost of capturing CO2 has been a barrier to sequestering it underground on a large scale, and that high cost could be a barrier to using CO2 to make more sustainable fuels and chemicals. However, the market value of those products combined with payments for avoiding the carbon emissions could help technologies that use CO2 overcome the cost hurdle more quickly.

The researchers hope that their initial work on revealing the mechanisms in CO2 electrolysis devices by spectroscopy and modeling will help others in tuning the surface properties of ceria and other oxides to further improve CO2 electrolysis.


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Plastics, fuels and chemical feedstocks from CO2? They’re working on it

Nanoparticles used to Transport Anti-Cancer Agent to Cells – University of Cambridge


Cancer transport 14-nanoparticle
Cells with MOFs carrying siRNA. Credit: University of Cambridge

Scientists from the University of Cambridge have developed a platform that uses nanoparticles known as metal-organic frameworks to deliver a promising anti-cancer agent to cells.

Research led by Dr. David Fairen-Jimenez, from the Cambridge Department of Chemical Engineering and Biotechnology, indicates  (MOFs) could present a viable platform for delivering a potent anti-cancer agent, known as siRNA, to .

Small interfering ribonucleic acid (siRNA), has the potential to inhibit overexpressed cancer-causing genes, and has become an increasing focus for scientists on the hunt for new cancer treatments.

Fairen-Jimenez’s group used computational simulations to find a MOF with the perfect pore size to carry an siRNA molecule, and that would breakdown once inside a cell, releasing the siRNA to its target. Their results were published today in Cell Press journal, Chem.

Some cancers can occur when  inside cells cause over-production of particular proteins. One way to tackle this is to block the gene expression pathway, limiting the production of these proteins.

SiRNA molecules can do just that—binding to specific gene messenger molecules and destroying them before they can tell the cell to produce a particular protein. This process is known as ‘gene knockdown’. Scientists have begun to focus more on siRNAs as potential cancer therapies in the last decade, as they offer a versatile solution to disease treatment—all you need to know is the sequence of the gene you want to inhibit and you can make the corresponding siRNA that will break it down. Instead of designing, synthesising and testing new drugs—an incredibly costly and lengthy process—you can make a few simple changes to the siRNA molecule and treat an entirely different disease.

One of the problems with using siRNAs to treat disease is that the molecules are very unstable and are often broken down by the cell’s natural defence mechanisms before they can reach their targets. SiRNA molecules can be modified to make them more stable, but this compromises their ability to knock down the target genes. It’s also difficult to get the molecules into cells—they need to be transported by another vehicle acting as a delivery agent.

Nanoparticles used to transport anti-cancer agent to cells
Crystalline metal-organic framework. Credit: David Fairen-Jimenez

The Cambridge researchers have used a special nanoparticle to protect and deliver siRNA to cells, where they show its ability to inhibit a specific target gene.

Fairen-Jimenez leads research into advanced materials, with a particular focus on MOFs: self-assembling 3-D compounds made of metallic and organic building blocks connected together.

There are thousands of different types of MOFs that researchers can make—there are currently more than 84,000 MOF structures in the Cambridge Structural Database with 1000 new structures published each month—and their properties can be tuned for specific purposes. By changing different components of the MOF structure, researchers can create MOFs with different pore sizes, stabilities and toxicities, enabling them to design structures that can carry molecules such as siRNAs into cells without harmful side effects.

“With traditional cancer therapy if you’re designing new drugs to treat the system, these can have different behaviours, geometries, sizes, and so you’d need a MOF that is optimal for each of these individual drugs,” says Fairen-Jimenez. “But for siRNA, once you develop one MOF that is useful, you can in principle use this for a range of different siRNA sequences, treating different diseases.”

“People that have done this before have used MOFs that don’t have a porosity that’s big enough to encapsulate the siRNA, so a lot of it is likely just stuck on the outside,” says Michelle Teplensky, former Ph.D. student in Fairen-Jimenez’s group, who carried out the research. “We used a MOF that could encapsulate the siRNA and when it’s encapsulated you offer more protection. The MOF we chose is made of a zirconium based metal node and we’ve done a lot of studies that show zirconium is quite inert and it doesn’t cause any toxicity issues.”

Using a biodegradable MOF for siRNA delivery is important to avoid unwanted build-up of the structures once they’ve done their job. The MOF that Teplensky and team selected breaks down into harmless components that are easily recycled by the cell without harmful side effects. The large pore size also means the team can load a significant amount of siRNA into a single MOF molecule, keeping the dosage needed to knock down the genes very low.

“One of the benefits of using a MOF with such large pores is that we can get a much more localised, higher dose than other systems would require,” says Teplensky. “SiRNA is very powerful, you don’t need a huge amount of it to get good functionality. The dose needed is less than 5% of the porosity of the MOF.”Structure-and-mechanism-of-siRNA-A-Structure-of-siRNA-B-Action-of-RNAi

MOFs or other vehicles to carry small molecules into cells is that they are often stopped by the cells on the way to their target. This process is known as endosomal entrapment and is essentially a defence mechanism against unwanted components entering the cell. Fairen-Jimenez’s team added extra components to their MOF to stop them being trapped on their way into the cell, and with this, could ensure the siRNA reached its target.

The team used their system to knock down a gene that produces fluorescent proteins in the cell, so they were able to use microscopy imaging methods to measure how the fluorescence emitted by the proteins compared between cells not treated with the MOF and those that were. The group made use of in-house expertise, collaborating with super-resolution microscopy specialists Professors Clemens Kaminski and Gabi Kaminski-Schierle, who also lead research in the Department of Chemical Engineering and Biotechnology.

Using the MOF platform, the team were consistently able to prevent gene expression by 27%, a level that shows promise for using the technique to knock down cancer genes.

Fairen-Jimenez believes they will be able to increase the efficacy of the system and the next steps will be to apply the platform to genes involved in causing so-called hard-to-treat cancers.

“One of the questions we get asked a lot is ‘why do you want to use a metal-organic framework for healthcare?’, because there are metals involved that might sound harmful to the body,” says Fairen-Jimenez. “But we focus on difficult diseases such as hard-to-treat cancers for which there has been no improvement in treatment in the last 20 years. We need to have something that can offer a solution; just extra years of life will be very welcome.”

The versatility of the system will enable the team to use the same adapted MOF to deliver different siRNA sequences and target different . Because of its large pore size, the MOF also has the potential to deliver multiple drugs at once, opening up the option of combination therapy.


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Renewable to Clean Energy – Floating wind-to-hydrogen plan to heat millions of UK homes


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Project aiming to deploy 4GW, £12bn ‘green hydrogen’ array in the North Sea is backed by UK government

Floating offshore wind turbines far out in the North Sea will convert seawater to ‘green’ hydrogen that will be pumped ashore and used to heat millions of homes, under an ambitious plan just awarded UK government funding.

Deployment of a 4GW floating wind farm in the early 2030s at an estimated cost of £12bn ($14.8bn) could be the first step in the eventual replacement of natural gas by hydrogen in the UK energy system, claimed Kevin Kinsella, director of the Dolphyn project for consultancy ERM.

ERM – which is working on Dolphyn with the Tractebel unit of French energy giant Engie and offshore specialist ODE – plans to integrate hydrogen production technology into a 10MW floating wind turbine platform, enabling each unit to import seawater, convert it to hydrogen and export the gas via a pipeline.

“If you had 30 of those in the North Sea you could replace the natural gas requirement for the whole country.”

Deployment of hundreds of the floating platforms would be able to tap into the excellent wind resources far out in the North Sea, way beyond the depths accessible to fixed-bottom foundations, Kinsella told Recharge, estimating that a 4GW floating wind farm could produce enough hydrogen to heat 1.5 million homes.

“If you had 30 of those in the North Sea you could totally replace the natural gas requirement for the whole country, and be totally self-sufficient with hydrogen,” said Kinsella.

ERM in August received £427,000 under a UK government support plan for promising hydrogen technologies. That will be used to develop a prototype unit for deployment off Scotland using a 2MW turbine from MHI Vestas and the WindFloat platform, designed by floating wind specialist Principle Power and already successfully tested off Portugal, Kinsella added.

It plans to have the 2MW prototype ready for a final investment decision by 2021, at which point ERM hopes a major energy player – “an Engie or a BP or a Total” – will back the project to take it forward to deployment by 2023, with a full-scale 10MW version in the water in 2026.

Will floating wind power help Big Oil crack its ‘Kinder Egg’?

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The Dolphyn team is integrating into the floating turbine platform the systems needed for water intake, desalination and conversion of water to hydrogen via proton exchange membrane (PEM) technology.

The gas will then be exported under pressure via a flexible riser, before joining the output of other turbines to be pumped to shore via a trunkline. Kinsella said the project team is talking to a “major oil company” about repurposing an existing pipeline for hydrogen export.

The floating wind-to-hydrogen turbines would be completely independent of the power grid – a major contributor to cost reduction Kinsella, said. “Once you get a long way offshore it’s the electrical infrastructure that dominates the costs.” They will be equipped with an on-board energy storage unit to make them self-sufficient, with the ability to restart the turbine from a standstill.

Generating ‘green hydrogen’ – completely produced via renewables – competitively at scale is one of the big challenges before it can assume a key role in the energy transition. Pilot green hydrogen projects currently operate at five to ten-times the cost of ‘grey’ hydrogen, which is produced using fossil fuels but is by far the cheapest existing option.

However, research group BloombergNEF recently projected an 80% fall in the cost of green hydrogen by 2030, opening the way for its widespread use as a carbon-free fuel.

ERM’s projections suggest a full-scale floating wind farm deployed in 2032 – by which time 15MW turbines may be used – could produce hydrogen at £1.15/kg ($1.41/kg). “This is comparable with the projected wholesale UK price of natural gas,” Kinsella claimed.

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Decarbonising heat and transport, as well as power supplies, are major challenges facing the UK as it seeks to become emissions ‘net-zero’ by 2050.

A 2018 report from the UK Committee on Climate Change said hydrogen could largely replace natural gas for heating into the 2030s, but questioned whether renewable generation could compete on cost with hydrogen produced using gas itself then subjected to carbon capture and storage.

Automated Electric Shuttle Makes its Debut on NREL Campus


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The EasyMile automated electric shuttle took its inaugural ride around the NREL campus this week.

NREL’s intelligent campus ventures accelerated this week with the introduction of an automated electric vehicle in its employee shuttle fleet.

Designed to cover short distances and predefined routes, the fully electric EasyMile EZ10 shuttle took its inaugural ride on Monday, transporting staff and visitors around NREL’s South Table Mountain campus after a dedication ceremony marking its first day of operation.

Attending the dedication were NREL Director Martin Keller, Associate Laboratory Directors Johney Green and Julie Baker, and shuttle partners Jeff Womack of MV Transportation and Sharad Agarwal of EasyMile. The event drew local press from The Denver Post, CBS4, and the Golden Transcript, who interviewed Green as well as Kevin Walkowicz, manager of NREL’s Advanced Vehicles and Fueling Infrastructure Group, and Jeffrey Gonder, manager of NREL’s Mobility, Behavior, and Advanced Powertrains Group.

The automated vehicle serves as one of two circulator shuttles primarily transporting staff to and from the parking garage during peak hours. For the first year, onboard vehicle stewards from MV Transportation, the lab’s shuttle service subcontractor, will monitor vehicle operations to ensure safety.

The shuttle can carry up to 12 passengers and is designed to travel along a pre-programmed route. It is equipped with a full range of sensors and an intelligent vehicle system to detect obstacles and avoid collisions. Real-time data processing allows the driverless vehicle system to decide how to behave as it progresses safely along the road.

In-Use Operations Data to Inform Research Efforts

NREL will collect and analyze vehicle and charging system operational data to help researchers better understand associated energy use, charging and energy storage needs, and autonomous systems operation and control.

“The results of our data analysis effort will help inform the design and optimization of intelligent energy management systems onboard these types of vehicles—such as managed wireless charging or predictive route-based propulsion system control,” said Walkowicz.

NREL will also explore ways in which these systems can enable intelligent load management for the entire campus in scenarios with a high concentration of energy coming from renewables or behind-the-meter energy storage.

“It will also feed into NREL’s mobility modeling and energy impacts analyses of connected and automated vehicles, in particular related to automated mobility districts—campus-sized implementations of connected and automated vehicle technologies geared to realize the benefits of a fully electric automated mobility service within a confined region or district,” said Gonder.

Ultimately, this research effort will provide insight into a variety of areas important to the connected, intelligent, and automated vehicle space including grid integration, intelligent charge management, energy use, urban mobility, and human interactions with automated transportation systems.

Learn more about NREL’s transportation research and its on-campus sustainability efforts.