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MSU Fibers 032516 160324104809_1_540x360A microbial protein fiber discovered by a MSU’s Gemma Reguera transports charges at rates high enough to be applied in manmade nanotechnologies.
Credit: Kurt Stepnitz

“This microbial nanowire is made of but a single peptide subunit,” said Gemma Reguera, lead author and MSU microbiologist. “Being made of protein, these organic nanowires are biodegradable and biocompatible. This discovery thus opens many applications in nanoelectronics such as the development of medical sensors and electronic devices that can be interfaced with human tissues.”

Since existing nanotechnologies incorporate exotic metals into their designs, the cost of organic nanowires is much more cost effective as well, she added.

How the nanowires function in nature is comparable to breathing. Bacterial cells, like humans, have to breathe. The process of respiration involves moving electrons out of an organism. Geobacter bacteria use the protein nanowires to bind and breathe metal-containing minerals such as iron oxides and soluble toxic metals such as uranium. The toxins are mineralized on the nanowires’ surface, preventing the metals from permeating the cell.

Reguera’s team purified their protein fibers, which are about 2 nanometers in diameter. Using the same toolset of nanotechnologists, the scientists were able to measure the high velocities at which the proteins were passing electrons.

“They are like power lines at the nanoscale,” Reguera said. “This also is the first study to show the ability of electrons to travel such long distances — more than a 1,000 times what’s been previously proven — along proteins.”

The researchers also identified metal traps on the surface of the protein nanowires that bind uranium with great affinity and could potentially trap other metals. These findings could provide the basis for systems that integrate protein nanowires to mine gold and other precious metals, scrubbers that can be deployed to immobilize uranium at remediation sites and more.

Reguera’s nanowires also can be modified to seek out other materials in which to help them breathe.

“The Geobacter cells are making these protein fibers naturally to breathe certain metals. We can use genetic engineering to tune the electronic and biochemical properties of the nanowires and enable new functionalities. We also can mimic the natural manufacturing process in the lab to mass-produce them in inexpensive and environmentally friendly processes,” Reguera said. “This contrasts dramatically with the manufacturing of humanmade inorganic nanowires, which involve high temperatures, toxic solvents, vacuums and specialized equipment.”

This discovery came from truly listening to bacteria, Reguera said.

“The protein is getting the credit, but we can’t forget to thank the bacteria that invented this,” she said. “It’s always wise to go back and ask bacteria what else they can teach us. In a way, we are eavesdropping on microbial conversations. It’s like listening to our elders, learning from their wisdom and taking it further.”


Story Source:

The above post is reprinted from materials provided by Michigan State University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sanela Lampa-Pastirk, Joshua P. Veazey, Kathleen A. Walsh, Gustavo T. Feliciano, Rebecca J. Steidl, Stuart H. Tessmer, Gemma Reguera. Thermally activated charge transport in microbial protein nanowires. Scientific Reports, 2016; 6: 23517 DOI: 10.1038/srep23517
GNT Thumbnail Alt 3 2015-page-001Advancements in nanotechnology could fundamentally change global approaches to manufacturing, medicine, healthcare, and the environment.

 

In this lecture Dr. Eric Drexler, Senior Visiting Fellow, Oxford Martin School, will look at current advances in the field of advanced nanotechnology, and the impacts and potential applications of their widespread implementation, and Dr. Sonia Trigueros, Co-Director of the Oxford Martin Programme on Nanotechnology, and Oxford Martin Senior Fellow, will consider how targeted nanomedicine could change how we treat disease in the future.

Published on Jan 28, 2016

 

No More nomorewashin
Cotton textile covered with nanostructures invisible to the naked eye. Image magnified 200 times. Credit: RMIT University

A spot of sunshine is all it could take to get your washing done, thanks to pioneering nano research into self-cleaning textiles.

Researchers at RMIT University in Melbourne, Australia, have developed a cheap and efficient new way to grow special —which can degrade organic matter when exposed to light—directly onto .

The work paves the way towards nano-enhanced textiles that can spontaneously clean themselves of stains and grime simply by being put under a light bulb or worn out in the sun.

Dr Rajesh Ramanathan said the process developed by the team had a variety of applications for catalysis-based industries such as agrochemicals, pharmaceuticals and natural products, and could be easily scaled up to industrial levels.

“The advantage of textiles is they already have a 3D structure so they are great at absorbing light, which in turn speeds up the process of degrading organic matter,” he said.

“There’s more work to do to before we can start throwing out our washing machines, but this advance lays a strong foundation for the future development of fully self-cleaning textiles.”

The researchers from the Ian Potter NanoBioSensing Facility and NanoBiotechnology Research Lab at RMIT worked with copper and silver-based nanostructures, which are known for their ability to absorb visible light.

No more washing: Nano-enhanced textiles clean themselves with light
The red color indicates the presence of silver nanoparticles — the total coverage on the image shows the nanostructures grown by the RMIT team are present throughout the textile. Image magnified 200 times. Credit: RMIT University

When the nanostructures are exposed to light, they receive an energy boost that creates ““. These “hot electrons” release a burst of energy that enables the nanostructures to degrade organic matter.

The challenge for researchers has been to bring the concept out of the lab by working out how to build these nanostructures on an industrial scale and permanently attach them to textiles.

The RMIT team’s novel approach was to grow the nanostructures directly onto the textiles by dipping them into a few solutions, resulting in the development of stable nanostructures within 30 minutes.

No more washing: Nano-enhanced textiles clean themselves with light
Close-up of the nanostructures grown on cotton textiles by RMIT University researchers. Image magnified 150,000 times. Credit: RMIT University

When exposed to , it took less than six minutes for some of the nano-enhanced textiles to spontaneously clean themselves.

“Our next step will be to test our nano-enhanced textiles with organic compounds that could be more relevant to consumers, to see how quickly they can handle common stains like tomato sauce or wine,” Ramanathan said.

The research is published on March 23, 2016 in the high-impact journal Advanced Materials Interfaces.

Explore further: Silver in the washing machine: Nanocoatings release almost no nanoparticles

More information: Samuel R. Anderson et al. Robust Nanostructured Silver and Copper Fabrics with Localized Surface Plasmon Resonance Property for Effective Visible Light Induced Reductive Catalysis, Advanced Materials Interfaces (2016). DOI: 10.1002/admi.201500632

Drop of Water 160322080534_1_540x360
Drop of water. “Hydrogen production through an electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells,” says Professor Yao.
Credit: © Deyan Georgiev / Fotolia

Groundbreaking research at Griffith University is leading the way in clean energy, with the use of carbon as a way to deliver energy using hydrogen.

Professor Xiangdong Yao and his team from Griffith’s Queensland Micro- and Nanotechnology Centre have successfully managed to use the element to produce hydrogen from water as a replacement for the much more costly platinum.

“Hydrogen production through an electrochemical process is at the heart of key renewable energy technologies including water splitting and hydrogen fuel cells,” says Professor Yao.

“Despite tremendous efforts, exploring cheap, efficient and durable electrocatalysts for hydrogen evolution still remains a great challenge.

“Platinum is the most active and stable electrocatalyst for this purpose, however its low abundance and consequent high cost severely limits its large-scale commercial applications.

“We have now developed this carbon-based catalyst, which only contains a very small amount of nickel and can completely replace the platinum for efficient and cost-effective hydrogen production from water.

“In our research, we synthesize a nickel-carbon-based catalyst, from carbonization of metal-organic frameworks, to replace currently best-known platinum-based materials for electrocatalytic hydrogen evolution.

“This nickel-carbon-based catalyst can be activated to obtain isolated nickel atoms on the graphitic carbon support when applying electrochemical potential, exhibiting highly efficient hydrogen evolution performance and impressive durability.”

Proponents of a hydrogen economy advocate hydrogen as a potential fuel for motive power including cars and boats and on-board auxiliary power, stationary power generation (e.g., for the energy needs of buildings), and as an energy storage medium (e.g., for interconversion from excess electric power generated off-peak).

Professor Yao says that this work may enable new opportunities for designing and tuning properties of electrocatalysts at atomic scale for large-scale water electrolysis.


Story Source:

The above post is reprinted from materials provided by Griffith University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lili Fan, Peng Fei Liu, Xuecheng Yan, Lin Gu, Zhen Zhong Yang, Hua Gui Yang, Shilun Qiu, Xiangdong Yao.Atomically isolated nickel species anchored on graphitized carbon for efficient hydrogen evolution electrocatalysis. Nature Communications, 2016; 7: 10667 DOI: 10.1038/ncomms10667

Deposit Naon parts printingnanoPrinting has come a long way since the days of Johannes Gutenberg. Now, researchers have developed a new method that uses plasma to print nanomaterials onto a 3-D object or flexible surface, such as paper or cloth. The technique could make it easier and cheaper to build devices like wearable chemical and biological sensors, flexible memory devices and batteries, and integrated circuits.

One of the most common methods to deposit nanomaterials—such as a layer of nanoparticles or nanotubes—onto a surface is with an inkjet printer similar to an ordinary printer found in an office. Although they use well-established technology and are relatively cheap, have limitations. They can’t print on textiles or other flexible materials, let alone 3-D objects. They also must print liquid ink, and not all materials are easily made into a liquid.

Some nanomaterials can be printed using aerosol printing techniques. But the material must be heated several hundreds of degrees to consolidate into a thin and smooth film. The extra step is impossible for printing on cloth or other materials that can burn, and means higher cost for the materials that can take the heat.

Deposit Naon parts printingnano
The nozzle firing a jet of carbon nanotubes with helium plasma off and on. When the plasma is off, the density of carbon nanotubes is small. The plasma focuses the nanotubes onto the substrate with high density and good adhesion. Credit: …more

The plasma method skips this heating step and works at temperatures not much warmer than 40 degrees Celsius. “You can use it to deposit things on paper, plastic, cotton, or any kind of textile,” said Meyya Meyyappan of NASA Ames Research Center. “It’s ideal for soft substrates.” It also doesn’t require the printing material to be liquid.

The researchers, from NASA Ames and Stanford Linear Accelerator Center, describe their work in the American Institute of Physics journal Applied Physics Letters.

They demonstrated their technique by printing a layer of carbon nanotubes on paper. They mixed the nanotubes into a plasma of helium ions, which they then blasted through a nozzle and onto paper. The plasma focuses the nanoparticles onto the paper surface, forming a consolidated layer without any need for additional heating.

The team printed two simple chemical and . The presence of certain molecules can change the electrical resistance of the carbon nanotubes. By measuring this change, the device can identify and determine the concentration of the molecule. The researchers made a chemical sensor that detects ammonia gas and a biological sensor that detects dopamine, a molecule linked to disorders like Parkinson’s disease and epilepsy.

But these were just simple proofs-of-principle, Meyyappan said. “There’s a wide range of biosensing applications.” For example, you can make sensors that monitor health biomarkers like cholesterol, or food-borne pathogens like E. coli and Salmonella.

Because the method uses a simple nozzle, it’s versatile and can be easily scaled up. For example, a system could have many nozzles like a showerhead, allowing it to print on large areas. Or, the nozzle could act like a hose, free to spray nanomaterials on the surfaces of 3-D objects.

“It can do things inkjet printing cannot do,” Meyyappan said. “But anything inkjet printing can do, it can be pretty competitive.”

The method is ready for commercialization, Meyyappan said, and should be relatively inexpensive and straightforward to develop. Right now, the researchers are designing the technique to print other kinds of materials such as copper. They can then print materials used for batteries onto thin sheets of metal such as aluminum. The sheet can then be rolled into tiny batteries for cellphones or other devices.

Explore further: Ink with tin nanoparticles could print future circuit boards

More information: “Plasma jet printing for flexible substrates,” R. Gandhiraman, E. Singh, D. Diaz-Cartagena, D. Nordlund, J. Koehne and M. Meyyappan,Applied Physics Letters , March 22, 2016. DOI: 10.1063/1.4943792

GH Gas 031716 global-climate-changeHybrid materials developed at Berkeley Lab could lead to cheaper ways to reduce power plant greenhouse gas emissions

In this animation, exhaust from a power plant contacts a hybrid membrane recently developed at Berkeley Lab. The membrane’s carbon dioxide highways (yellow) enable the rapid flow of carbon dioxide (red and white molecules) while maintaining selectivity over nitrogen (blue molecules). The membrane is eight times more carbon dioxide permeable than a polymer-only membrane. (Credit: Berkeley Lab)

A new, highly permeable carbon capture membrane developed by scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) could lead to more efficient ways of separating carbon dioxide from power plant exhaust, preventing the greenhouse gas from entering the atmosphere and contributing to climate change.

The researchers focused on a hybrid membrane that is part polymer and part metal-organic framework, which is a porous three-dimensional crystal with a large internal surface area that can absorb enormous quantities of molecules.

In a first, the scientists engineered the membrane so that carbon dioxide molecules can travel through it via two distinct channels. Molecules can travel through the polymer component of the membrane, like they do in conventional gas-separation membranes. Or molecules can flow through “carbon dioxide highways” created by adjacent metal-organic frameworks.

Initial tests show this two-route approach makes the hybrid membrane 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.

The research is the cover article of the March issue of the journalEnergy & Environmental Science.

“In our membrane, some CO2 molecules get an express ride through the highways formed by metal-organic frameworks, while others take the polymer pathway. This new approach will enable the design of higher performing gas separation membranes,” says Norman Su, a graduate student in the Chemical and Biomolecular Engineering Department at UC Berkeley and a user at the Molecular Foundry.

He conducted the research with Jeff Urban, Facility Director of the Inorganic Nanostructures Facility at the Molecular Foundry, and a team of scientists that included staff at the Advanced Light Source.

Capturing carbon emissions from electric power plants and other sources is a hot research topic because there’s a lot of room for improvement. The conventional way of separating carbon dioxide from flue gas is amine adsorption, which isn’t economical at scale because it adds significant capital cost and reduces the electrical output of power plants.

Scientists are exploring polymer membranes as a more energy efficient alternative to amine adsorption. These membranes are relatively inexpensive and easy to work with, but current commercial membranes have low carbon dioxide permeability. To overcome this, scientists have developed hybrid membranes that are part polymer and part metal-organic framework. These hybrids harness the carbon dioxide selectivity of metal-organic frameworks while maintaining the processability of polymers.

But, until now, scientists have not been able to engineer hybrid membranes with enough metal-organic frameworks to form continuous channels through the membrane. This means that, somewhere in a carbon dioxide molecule’s journey through the membrane, the molecule must contact the polymer. This constrains the molecule’s transport to the polymer.

In this latest research, Berkeley Lab scientists have developed a hybrid membrane in which metal-organic frameworks account for 50 percent of its weight, which is about 20 percent more than other hybrid membranes. Previously, the mechanical stability of a hybrid membrane limited the amount of metal-organic frameworks that could be packed in it.

“But we got our membrane to 50 weight percent without compromising its structural integrity,” says Su.

And 50 weight percent appears to be the magic number. At that threshold, there are so many metal organic frameworks in the membrane that they form a continuous network of highways through the membrane. When that happens, the hybrid membrane switches from having a single channel to transport carbon dioxide, in which the molecules must go through the polymer, to two channels, in which the molecules can either move through the polymer or through the metal-organic framework highways.

“This is the first hybrid polymer-MOF membrane to have these dual transport pathways, and it could be a big step toward more competitive carbon capture processes,” says Su.

In addition to fabricating the hybrid membrane at the Molecular Foundry, the scientists analyzed the material at beamline 12.2.2 of the Advanced Light Source.

The research was supported by the Department of Energy’s Office of Science, Berkeley Lab’s Laboratory-Directed Research and Development Program, and the Department of Defense.

The Advanced Light Source and the Molecular Foundry are DOE Office of Science User Facilities located at Berkeley Lab.

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Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.

DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov

Updated:

Advanced Nano Scale Storage 111245_web

OAK RIDGE, Tenn., March 16, 2016 — Researchers at theDepartment of Energy’s Oak Ridge National Laboratory have combined advanced in-situ microscopy and theoretical calculations to uncover important clues to the properties of a promising next-generation energy storage material for supercapacitors and batteries.

ORNL’s Fluid Interface Reactions, Structures and Transport (FIRST) research team, using scanning probe microscopy made available through the Center for Nanophase Materials Sciences (CNMS) user program, have observed for the first time at the nanoscale and in a liquid environment how ions move and diffuse between layers of a two-dimensional electrode during electrochemical cycling. This migration is critical to understanding how energy is stored in the material, called MXene, and what drives its exceptional energy storage properties.

“We have developed a technique for liquid environments that allows us to track how ions enter the interlayer spaces. There is very little information on how this actually happens,” said Nina Balke, one of a team of researchers working with Drexel University’s Yury Gogotsi in the FIRST Center, a DOE Office of Science Energy Frontier Research Center.

“The energy storage properties have been characterized on a microscopic scale, but no one knows what happens in the active material on the nanoscale in terms of ion insertion and how this affects stresses and strains in the material,” Balke said.

The so-called MXene material — which acts as a two-dimensional electrode that could be fabricated with the flexibility of a sheet of paper — is based on MAX-phase ceramics, which have been studied for decades. Chemical removal of the “A” layer leaves two-dimensional flakes composed of transition metal layers — the “M” — sandwiching carbon or nitrogen layers (the “X”) in the resulting MXene, which physically resembles graphite.

These MXenes, which have exhibited very high capacitance, or ability to store electrical charge, have only recently been explored as an energy storage medium for advanced batteries.

“The interaction and charge transfer of the ion and the MXene layers is very important for its performance as an energy storage medium. The adsorption processes drive interesting phenomena that govern the mechanisms we observed through scanning probe microscopy,” said FIRST researcher Jeremy Come.

The researchers explored how the ions enter the material, how they move once inside the materials and how they interact with the active material. For example, if cations, which are positively charged, are introduced into the negatively charged MXene material, the material contracts, becoming stiffer.

That observation laid the groundwork for the scanning probe microscopy-based nanoscale characterization. The researchers measured the local changes in stiffness when ions enter the material. There is a direct correlation with the diffusion pattern of ions and the stiffness of the material.

Come noted that the ions are inserted into the electrode in a solution.

“Therefore, we need to work in liquid environment to drive the ions within the MXene material. Then we can measure the mechanical properties in-situ at different stages of charge storage, which gives us direct insight about where the ions are stored,” he said.

Until this study the technique had not been done in a liquid environment.

The processes behind ion insertion and the ionic interactions in the electrode material had been out of reach at the nanoscale until the CNMS scanning probe microscopy group’s studies. The experiments underscore the need for in-situ analysis to understand the nanoscale elastic changes in the 2D material in both dry and wet environments and the effect of ion storage on the energy storage material over time.

The researchers’ next steps are to improve the ionic diffusion paths in the material and explore different materials from the MXene family. Ultimately, the team hopes to understand the process’s fundamental mechanism and mechanical properties, which would allow tuning the energy storage as well as improving the material’s performance and lifetime.

ORNL’s FIRST research team also provided additional calculations and simulations based on density functional theory that support the experimental findings. The work was recently published in the Journal Advanced Energy Materials.

###

The research team in addition to Balke and Come and Drexel’s Gogotsi included Michael Naguib, Stephen Jesse, Sergei V. Kalinin, Paul R.C. Kent and Yu Xie, all of ORNL.

The FIRST Center is an Energy Frontier Research Center supported by the DOE Office of Science (Basic Energy Sciences). The Center for Nanophase Materials Sciences and the National Energy Research Scientific Computing Center are DOE Office of Science User Facilities.

UT-Battelle manages ORNL for the DOE’s Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov/.

Image:https://www.ornl.gov/sites/default/files/news/images/JCome_MXene.jpg

Image cutline: When a negative bias is applied to a two-dimensional MXene electrode, Li+ ions from the electrolyte migrate in the material via specific channels to the reaction sites, where the electron transfer occurs. Scanning probe microscopy at Oak Ridge National Laboratory has provided the first nanoscale, liquid environment analysis of this energy storage material.

NOTE TO EDITORS: You may read other press releases from Oak Ridge National Laboratory or learn more about the lab athttp://www.ornl.gov/news. Additional information about ORNL is available at the sites below:
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Nanosys-Green-QD-on-blue-BLU1-660x495
Published on Mar 12, 2016
Jason looks at how Quantum Dot technology has progressed, initially as a research topic and then as a commercial product. He defines what commercial success looks like and outlines future market opportunities for the further success of Quantum Dots. Topics include: Quantum Dot business models, architectures and long term roadmap, regulatory environment and future market opportunities.

Nanosys CEO Jason Hartlove: Video

 

GNT Thumbnail Alt 3 2015-page-001

 

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newfuelcelld 031516A powdery mixture of graphene-wrapped magnesium nanocrystals, produced at Berkeley Lab, is stable in air. The mixture’s energy properties show promise for use in hydrogen fuel cells. Credit: Eun Seon Cho/Berkeley Lab

Hydrogen is the lightest and most plentiful element on Earth and in our universe. So it shouldn’t be a big surprise that scientists are pursuing hydrogen as a clean, carbon-free, virtually limitless energy source for cars and for a range of other uses, from portable generators to telecommunications towers—with water as the only byproduct of combustion.

While there remain scientific challenges to making -based energy sources more competitive with current automotive propulsion systems and other energy technologies, researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a new materials recipe for a battery-like cell—which surrounds hydrogen-absorbing magnesium nanocrystals with atomically thin graphene sheets—to push its performance forward in key areas.

The graphene shields the nanocrystals from oxygen and moisture and contaminants, while tiny, natural holes allow the smaller hydrogen molecules to pass through. This filtering process overcomes common problems degrading the performance of metal hydrides for .

These graphene-encapsulated magnesium crystals act as “sponges” for hydrogen, offering a very compact and safe way to take in and store hydrogen. The nanocrystals also permit faster fueling, and reduce the overall “tank” size.

“Among metal hydride-based materials for hydrogen storage for vehicle applications, our materials have good performance in terms of capacity, reversibility, kinetics and stability,” said Eun Seon Cho, a postdoctoral researcher at Berkeley Lab and lead author of a study related to the new fuel cell formula, published recently in Nature Communications.

New fuel cell design powered by graphene-wrapped nanocrystals
Thin sheets of graphene oxide (red sheets) have natural, atomic-scale defects that allow hydrogen gas molecules to pass through while blocking larger molecules such as oxygen (O2) and water (H2O). Berkeley Lab researchers encapsulated …more

In a hydrogen fuel cell-powered vehicle using these materials, known as a “metal hydride” (hydrogen bound with a metal) fuel cell, hydrogen gas pumped into a vehicle would be chemically absorbed by the magnesium nanocrystaline powder and rendered safe at low pressures.

Jeff Urban, a Berkeley Lab staff scientist and co-author, said, “This work suggests the possibility of practical hydrogen storage and use in the future. I believe that these materials represent a generally applicable approach to stabilizing reactive materials while still harnessing their unique activity—concepts that could have wide-ranging applications for batteries, catalysis, and energetic materials.”

The research, conducted at Berkeley Lab’s Molecular Foundry and Advanced Light Source, is part of a National Lab Consortium, dubbed HyMARC (Hydrogen Materials—Advanced Research Consortium) that seeks safer and more cost-effective hydrogen storage, and Urban is Berkeley Lab’s lead scientist for that effort.

The U.S. market share for all electric-drive vehicles in 2015, including full-electric, hybrids and plug-in hybrid vehicles, was 2.87 percent, which amounts to about 500,000 electric-drive vehicles out of total vehicle sales of about 17.4 million, according to statistics reported by the Electric Drive Transportation Association, a trade association promoting electric-drive vehicles.

Hydrogen-fuel-cell vehicles haven’t yet made major in-roads in vehicle sales, though several major auto manufacturers including Toyota, Honda, and General Motors, have invested in developing hydrogen fuel-cell vehicles. Indeed, Toyota released a small-production model called the Mirai, which uses compressed-hydrogen tanks, last year in the U.S.

A potential advantage for hydrogen-fuel-cell vehicles, in addition to their reduced environmental impact over standard-fuel vehicles, is the high specific energy of hydrogen, which means that can potentially take up less weight than other battery systems and fuel sources while yielding more electrical energy.

A measure of the energy storage capacity per weight of hydrogen fuel cells, known as the “gravimetric energy density,” is roughly three times that of gasoline. Urban noted that this important property, if effectively used, could extend the total vehicle range of hydrogen-based transportation, and extend the time between refueling for many other applications, too.

More R&D is needed to realize higher-capacity hydrogen storage for long-range vehicle applications that exceed the performance of existing electric-vehicle batteries, Cho said, and other applications may be better suited for hydrogen fuel cells in the short term, such as stationary power sources, forklifts and airport vehicles, portable power sources like laptop battery chargers, portable lighting, water and sewage pumps and emergency services equipment.

Cho said that a roadblock to metal hydride storage has been a relatively slow rate in taking in (absorption) and giving out (desorption) hydrogen during the cycling of the units. In fuel cells, separate chemical reactions involving hydrogen and oxygen produce a flow of electrons that are channeled as electric current, creating water as a byproduct.

The tiny size of the graphene-encapsulated nanocrystals created at Berkeley Lab, which measure only about 3-4 nanometers, or billionths of a meter across, is a key in the new fuel cell materials’ fast capture and release of hydrogen, Cho said, as they have more surface area available for reactions than the same material would at larger sizes.

Another key is protecting the magnesium from exposure to air, which would render it unusable for the fuel cell, she added.

Working at The Molecular Foundry, researchers found a simple, scalable and cost-effective “one pan” technique to mix up the graphene sheets and magnesium oxide nanocrystals in the same batch. They later studied the coated nanocrystals’ structure using X-rays at Berkeley Lab’s Advanced Light Source. The X-ray studies showed how pumped into the fuel cell mixture reacted with the magnesium nanocrystals to form a more stable molecule called magnesium hydride while locking out oxygen from reaching the magnesium.

“It is stable in air, which is important,” Cho said.

Next steps in the research will focus on using different types of catalysts—which can improve the speed and efficiency of chemical reactions—to further improve the fuel cell’s conversion of electrical current, and in studying whether different types of material can also improve the fuel cell’s overall capacity, Cho said.

Explore further: Hydrogen released to fuel cell more quickly when stored in metal nanoparticles

More information: Eun Seon Cho et al. Graphene oxide/metal nanocrystal multilaminates as the atomic limit for safe and selective hydrogen storage, Nature Communications (2016). DOI: 10.1038/ncomms10804

Measurements of electrical properties of a plastic tape (yellow), taken using a specially designed microwave cavity (the white cylinder at center) and accompanying electrical circuit, change quickly and consistently in response to changes in the tape’s thickness. The setup is inspired by high-volume roll-to-roll manufacturing devices used to mass-produce nanomaterials. The changes in the tape’s thickness spell NIST in Morse code.
Credit: NIST/Nathan Orloff

Manufacturers may soon have a speedy and nondestructive way to test a wide array of materials under real-world conditions, thanks to an advance that researchers at the National Institute of Standards and Technology (NIST) have made in roll-to-roll measurements. Roll-to-roll measurements are typically optical measurements for roll-to-roll manufacturing, any method that uses conveyor belts for continuous processing of items, from tires to nanotechnology components.

In order for new materials such as carbon nanotubes and graphene to play an increasingly important role in electronic devices, high-tech composites and other applications, manufacturers will need quality-control tests to ensure that products have desired characteristics, and lack flaws. Current test procedures often require cutting, scratching or otherwise touching a product, which slows the manufacturing process and can damage or even destroy the sample being tested.

To add to existing testing non-contact methods, NIST physicists Nathan Orloff, Christian Long and Jan Obrzut measured properties of films by passing them through a specially designed metal box known as a microwave cavity. Electromagnetic waves build up inside the cavity at a specific “resonance” frequency determined by the box’s size and shape, similar to how a guitar string vibrates at a specific pitch depending on its length and tension. When an object is placed inside the cavity, the resonance frequency changes in a way that depends on the object’s size, electrical resistance and dielectric constant, a measure of an object’s ability to store energy in an electric field. The frequency change is reminiscent of how shortening or tightening a guitar string makes it resonate at a higher pitch, says Orloff.

The researchers also built an electrical circuit to measure these changes. They first tested their device by running a strip of plastic tape known as polyimide through the cavity, using a roll-to-roll setup resembling high-volume roll-to-roll manufacturing devices used to mass-produce nanomaterials. As the tape’s thickness increased and decreased–the researchers made the changes in tape thickness spell “NIST” in Morse code–the cavity’s resonant frequency changed in tandem. So did another parameter called the “quality factor,” which is the ratio of the energy stored in the cavity to the energy lost per frequency cycle. Because polyimide’s electrical properties are well known, a manufacturer could use the cavity measurements to monitor whether tape is coming off the production line at a consistent thickness–and even feeding back information from the measurements to control the thickness.

Alternatively, a manufacturer could use the new method to monitor the electrical properties of a less well-characterized material of known dimensions. Orloff and Long demonstrated this by passing 12- and 15-centimeter-long films of carbon nanotubes deposited on sheets of plastic through the cavity and measuring the films’ electrical resistance. The entire process took “less than a second,” says Orloff. He added that with industry-standard equipment, the measurements could be taken at speeds beyond 10 meters per second, more than enough for many present-day manufacturing operations.

The new method has several advantages for a thin-film manufacturer, says Orloff. One, “You can measure the entire thing, not just a small sample,” he said. Such real-time measurements could be used to tune the manufacturing process without shutting it down, or to discard a faulty batch of product before it gets out the factory door. “This method could significantly boost prospects of not making a faulty batch in the first place,” Long noted.

And because the method is nondestructive, Orloff added, “If a batch passes the test, manufacturers can sell it.”

Films of carbon nanotubes and graphene are just starting to be manufactured in bulk for potential applications such as composite airplane materials, smartphone screens and wearable electronic devices.

Orloff, Long and Obrzut submitted a patent application for this technique in December 2015.

A producer of such materials has already expressed interest in the new method, said Orloff. “They’re really excited about it.” He added that the method is not specific to nanomanufacturing, and with a properly designed cavity, could also help with quality control of many other kinds of products, including tires, pharmaceuticals and even beer.


Story Source:

The above post is reprinted from materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Nathan D. Orloff, Christian J. Long, Jan Obrzut, Laurent Maillaud, Francesca Mirri, Thomas P. Kole, Robert D. McMichael, Matteo Pasquali, Stephan J. Stranick, J. Alexander Liddle. Noncontact conductivity and dielectric measurement for high throughput roll-to-roll nanomanufacturing. Scientific Reports, 2015; 5: 17019 DOI: 10.1038/srep17019

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