#Putting batteries on stage spotlights performance at the nanoscale Used in everything from electric vehicles to laptop computers,
the lithium battery is ubiquitous, but it is understood not well at the atomic scale. To see what happens on the nanoscale,
scientists at DOE's Joint Center for Energy storage Research (JCESR) designed and implemented a small device, known as an operando electrochemical stage.
Using this stage inside a state-of-the-art aberration-corrected transmission electron microscope they can take nanoscale-resolution pictures of lithium ions as they are deposited on or dissolve off of an electrode while the battery runs("Observation and Quantification of Nanoscale Processes in Lithium batteries
by Operando Electrochemical (S) TEM"."Lithium deposited on the platinum anode at the beginning (top), during (middle) and end (bottom) of the second cycle.
Residual dead lithium can be seen on and around the anode. With the new stage, scientists can directly image changes as they occur.
The new images allow precise measurements and descriptions of what happens inside the battery. This information is vital to control performance-and safety-limiting processes.
Now, scientists can rapidly visualize and test new pairings of electrodes and electrolytes (see Battery 101).
The new stage will help quickly sort through options for longer lasting, safer batteries. Methodsmoving beyond the current industry-standard lithium-ion battery has been difficult.
In lithium-air and other designs, interactions at the electrode-electrolyte interfaces affect the battery's performance and safety.
To understand the reactions, scientists at the Pacific Northwest National Laboratory, as part of JCESR, created an operando electrochemical stage.
Using it in an aberration-corrected scanning transmission electron microscope, scientists can now chemically image the interface between the platinum anode and the electrolyte during the battery operation.
The imaging method highlights solid lithium metal uniquely identifying it from the components that make up the protective solid electrolyte interphase layer.
Using these images and standard electrochemical data, scientists can quantify, at the nanoscale, the amount of lithium that ends up irreversibly deposited after each charge/discharge cycle.
This means they can view dendrites--the microscopic thorns that cause batteries to fail--as they form.
The technique also shows the growth of the solid electrolyte interphase layer, which wraps around and protects the anode.
The layer is formed as a result of the electrolyte breaking down. In their studies, the team found that extended battery cycling leads to lithium growing beneath the layer--the genesis of the dendrites that have implications for battery safety and performance.
What's Next? This new imaging tool opens up possibilities to rapidly visualize and test electrode/electrolyte pairings for new battery systems.
These systems could allow electric cars to travel great distances between charges. Also, one day, such systems could store energy from wind and solar stations, making the intermittent energy available when needed d
#Squid-inspired'invisibility stickers'could help you evade detection in the dark (w/video) Squid are the ultimate camouflage artists,
blending almost flawlessly with their backgrounds so that unsuspecting prey can't detect them. Using a protein that's key to this process,
scientists have designed"invisibility stickers"that could one day help soldiers disguise themselves, even when sought by enemies with tough-to-fool infrared cameras.
The researchers will present their work today at the 249th National Meeting & Exposition of the American Chemical Society (ACS.
ACS, the world's largest scientific society, is holding the meeting here through Thursday. It features nearly 11,000 presentations on a wide range of science topics."
"Soldiers wear uniforms with the familiar green and brown camouflage patterns to blend into foliage during the day,
but under low light and at night, they're still vulnerable to infrared detection, "explains Alon Gorodetsky,
Ph d."We've developed stickers for use as a thin, flexible layer of camo with the potential to take on a pattern that will better match the soldiers'infrared reflectance to their background and hide them from active infrared visualization."
"To work toward this effect, Gorodetsky of the University of California at Irvine (UCI) turned to squid skin for inspiration.
Squid skin features unusual cells known as iridocytes, which contain layers or platelets composed of a protein called reflectin.
The animal uses a biochemical cascade to change the thickness of the layers and their spacing.
This in turn affects how the cells reflect light and thus, the skin's coloration. Gorodetsky's group coaxed bacteria to produce reflectin
and then coated a hard substrate with the protein. To induce structural--and light-reflecting--changes just like those of iridocytes
the film needed some kind of trigger. An initial search revealed that acetic acid vapors could cause the film to swell
But these conditions won't work for soldiers in the field.""What we were doing was the equivalent of bathing the film in acetic acid vapors--essentially exposing it to concentrated vinegar,
"Now Gorodetsky has fabricated reflectin films on conformable polymer substrates, effectively sticky tape one might find in any household.
a mechanical trigger that might more realistically be used in military operations. Although the technology isn't ready for field use just yet,
he envisions soldiers or security personnel could one day carry in their packs a roll of invisibility stickers that they could cover their uniforms with as needed."
They also could have uses outside the military--for example in clothing that can selectively trap
or release body heat to keep people comfortable in different environments. Moreover, in collaboration with Francesco Tombola, Ph d,
. and Lisa Flanagan, Ph d.,from the UCI School of medicine, Gorodetsky's lab has shown that reflectin supports cell growth.
has been demonstrated recently by a research group at the University of Alabama in Huntsville (UAH). Vibrant optical colors are generated from ultra-thin single layer silicon films deposited on a thin aluminum film surface with a low cost manufacturing process.
The thickness of the silicon films ranges from 20 to 200 nanometers for creating different colors.
For reference, 100 nanometers is about 1/1000 of the thickness of a single sheet of paper.
One nanometer is about two atomic layers of silicon. The silicon color coating process can be applied on almost any material surface.
Doctoral student Seyed Sadreddin Mirshafieyan and Dr. Junpeng Guo in Dr. Guos lab with a disc showing a rainbow of optical colors created with ultra-thin layers of silicon.
and has been used widely in electronics industry, but also most importantly, silicon is an indirect bandgap semiconductor material with both high index of refraction and low optical absorption in the visible spectrum.
The combination of high index of refraction and low absorption enables strong optical wave interference inside ultra-thin silicon films
a physical process that results in colors, says Dr. Junpeng Guo, professor of electrical engineering and optics,
who has published the result with his graduate student, Seyed Sadreddin Mirshafieyan, in a recent issue of Optics Express("Silicon colors:
Currently, colors on computer and iphone screens come from dye materials pre-placed on the pixels.
The demonstrated silicon colors can sustain high temperatures and harsh environment. The reason these colors are so vibrant,
while his student holds a collection of color samples. And the colors are very durable.
The new technology may hold promise for many applications such as for jewelry, automotive interior trim, aviation, signage, colored keypads, electronics and wearable displays s
#Medical nanoparticles for the local treatment of lung cancer Nanoparticles can function as carriers for medicines to combat lung cancer:
Working in a joint project at the NIM (Nanosystems Initiative Munich) Excellence Cluster, scientists from the Helmholtz Zentrum Mnchen (HMGU) and the Ludwig-Maximilians-Universitt (LMU) in Munich have developed nanocarriers that site-selectively release medicines/drugs at the tumor site in human and mouse lungs.
In the journal, ACS Nano("Protease-Mediated Release of Chemotherapeutics from Mesoporous Silica Nanoparticles to ex Vivo Human and Mouse Lung Tumors"),the scientists reported that this approach led to a significant increase
in the effectiveness of current cancer medicines in lung tumour tissue. Tumor tissue in the lung.
Image: Sabine van Rijt, CPC/ilbd, Helmholtz Zentrum Mnchen) Nanoparticles are extremely small particles that can be modified for a variety of uses in the medical field.
For example, nanoparticles can be engineered to be able to transport medicines specifically to the disease site while not interfering with healthy body parts.
Selective drug transport verified in human tissue for the first time The Munich scientists have developed nanocarriers that only release the carried drugs in lung tumour areas.
The team headed by Silke Meiners, Oliver Eickelberg and Sabine van Rijt from the Comprehensive Pneumology Center (HMGU
working with colleagues from the Chemistry department (LMU) headed by Thomas Bein, were able to show nanoparticles'selective drug release to human lung tumour tissue for the first time.
Tumour specific proteins were used to release drugs from the nanocarriers Tumour tissue in the lung contains high concentrations of certain proteases,
which are enzymes that break down and cut specific proteins. The scientists took advantage of this by modifying the nanocarriers with a protective layer that only these proteases can break down,
a process that then releases the drug. Protease concentrations in the healthy lung tissue are too low to cleave this protective layer
and so the medicines stay protected in the nanocarrier.""Using these nanocarriers we can very selectively release a drug such as a chemotherapeutic agent specifically at the lung tumour,"reports research group leader Meiners."
"We observed that the drug's effectiveness in the tumour tissue was 10 to 25 times greater compared to
when the drugs were used on their own. At the same time, this approach also makes it possible to decrease the total dose of medicines
and consequently to reduce undesirable effects.""Further studies will now be directed to examine the safety of the nanocarriers in vivo
and verify the clinical efficacy in an advanced lung tumour mouse model l
#Artificial hand able to respond sensitively thanks to muscles made from smart metal wires Engineers at Saarland University have taken a leaf out of natures book by equipping an artificial hand with muscles made from shape-memory wire.
The new technology enables the fabrication of flexible and lightweight robot hands for industrial applications and novel prosthetic devices.
The muscle fibres are composed of bundles of ultrafine nickel-titanium alloy wires that are able to tense and flex.
The research group led by Professor Stefan Seelecke will be showcasing their prototype artificial hand and how it makes use of shape-memory metal muscles at HANNOVER MESSE the worlds largest industrial fair from April 13th to April 17th.
and Innovation Stand in Hall 2, Stand B 46, are looking for development partners. Filomena Simone, an engineer in the research team led by Professor Stefan Seelecke,
is working on the prototype of the artificial hand. The hand is the perfect tool. Developed over millions of years,
The research team led by Professor Stefan Seelecke from Saarland University and the Center for Mechatronics and Automation Technology (Zema) is using a new technology based on the shape memory properties of nickel-titanium alloy.
The engineers have provided the artificial hand with muscles that are made up from very fine wires
Shape-memory alloy (SMA) wires offer significant advantages over other techniques, says Stefan Seelecke. Up until now, artificial hands,
As a result they are dependent on other devices and equipment, such as electric motors or pneumatics they tend to be heavy, relatively inflexible, at times loud,
when it conducts electricity, the material transforms its lattice structure causing it to contract like a muscle,
but have the tensile strength of a thick wire. The bundle can rapidly contract and relax while exerting a high tensile force,
A semiconductor chip controls the relative motions of the SMA wires allowing precise movements to be carried out.
And the system does need not sensors. The material from which wires are made has sensor properties.
The controller unit is able to interpret electric resistance measurement data so that it knows the exact position of the wires at any one time,
says Seelecke. This enables the hand and the fingers to be moved with high precision. The research team will be exhibiting their system prototypes at HANNOVER MESSE 2015
and exploiting the sensor properties of SMA wire e
#Switchable adhesion principle enables damage-free handling of sensitive devices even in vacuum Components with highly sensitive surfaces are used in automotive, semiconductor and display technologies as well as for complex optical lens systems.
During the production, these parts often have to be handled many times by pick -and-place processes.
The researchers from the INM will be presenting their results from 13 to 17 april 2015 in Hall 2 at the stand B46 of the Hannover Messe in the context of the leading trade fair for R & D and Technology Transfer.
Furthermore the development group works on the gripping of objects with curved surfaces without leaving residues.
Additionally, the scientists also focus on developing other triggers for switching the adhesion like light, magnetic field, electric field or changes in temperature.
Chemists, physicists, biologists, materials scientists and engineers team up to focus on these essential questions: Which material properties are new,
New materials for energy application, new concepts for medical surfaces, new surface materials for tribological applications and nano safety and nano bio.
Nanocomposite Technology, Interface Materials, and Bio Interfaces s
#Squeeze to remove heat: Elastocaloric materials enable more efficient, 'green'cooling Move over, vapor compression cooling technology.
Emerging"elastocaloric"refrigeration is potentially much more efficient and, unlike vapor compression, relies on environmentally-friendly refrigerants.
In elastocaloric materials a change in mechanical stress can create a change in temperature. In the Journal of Applied Physics("Elastocaloric effect of Ni-Ti wire for application in a cooling device"),a team of researchers from Technical University of Denmark report that the elastocaloric effect opens the door to alternative forms
of solid-state refrigeration that are direct replacements for vapor compression technology. The elastocaloric effect is one of many flavors of"caloric effects"
a phenomenon in which a sudden change of an external field can alter thermodynamic properties of a solid material such as temperature or entropy, a measure of the material's disorder.
The Danish team specializes in caloric effects and is always on the lookout for new ways to build more efficient coolers.
which involves applying a change in magnetic field to materials, they decided to also explore the potential of elastocaloric cooling.
lead author and a postdoctoral researcher at the Technical University of Denmark. In terms of basic underlying concepts, the elastocaloric effect is associated with the"martensitic phase transformation,
or by applying an external stress. This is responsible for the temperature-induced"shape memory effect "and stress-induced"superelasticity."
"So, how exactly does the elastocaloric cooling cycle work?""When an elastocaloric (superelastic) material in the austenitic phase is stressed axially,
"After the stress is removed, the crystal structure reverts back to its austenitic phase, which causes the material to cool down
and further absorb heat from its surroundings. The team's work is the first demonstration that shows elastocaloric materials such as a nickel-titanium (Ni-Ti) alloy can be loaded cyclically
and unloaded with a reproducible elastocaloric effect over a wide temperature range.""This is an important step toward the use of elastocaloric materials in cooling devices such as household refrigerators and air conditioners,
or even heat pumps, for which the required temperature between the heat source and its heat sink is approximately 30 Kelvin or more,
Tuek and colleagues also stabilized the Ni-Ti alloy to ensure a reproducible effect, which is crucial for practical applications,
and created a uniform elastocaloric effect for the alloy. While heat pumps, air conditioners and refrigerators are most likely to benefit from elastocaloric technology,
"elastocaloric cooling can be viewed as a direct substitute for vapor compression technology--one that's more efficient
"The team's future work will focus on ways to load the material to increase its resistance to fatigue,
#Nanotechnology makes possible a robotic germ (Nanowerk News) As nanotechnology makes possible a world of machines too tiny to see,
the new nanobot engineered at the University of Illinois at Chicago is a far cry from Robocop.
UIC researchers created an electromechanical device--a humidity sensor--on a bacterial spore. They call it NERD, for Nano-Electro-Robotic Device.
--and then attached two electrodes on either side of the spore,"said Vikas Berry, UIC associate professor of chemical engineering and principal investigator on the study."
As it shrinks, the quantum dots come closer together, increasing their conductivity, as measured by the electrodes."
"We get a very clean response--a very sharp change the moment we change humidity,
than a sensor made with the most advanced man-made water-absorbing polymers. There was also better sensitivity in extreme low-pressure, low-humidity situations."
Currently available sensors increase in sensitivity as humidity rises, Berry said. NERD's sensitivity is actually higher at low humidity."
"Here we have a biological entity. We've made the sensor on the surface of these spores, with the spore a very active complement to this device.
The biological complement is actually working towards responding to stimuli and providing information
#Desalination with nanoporous graphene membrane Less than 1 percent of Earth's water is drinkable. Removing salt and other minerals from our biggest available source of water--seawater--may help satisfy a growing global population thirsty for fresh water for drinking, farming, transportation, heating, cooling and industry.
But desalination is an energy-intensive process, which concerns those wanting to expand its application.
Now, a team of experimentalists led by the Department of energy's Oak ridge National Laboratory has demonstrated an energy-efficient desalination technology that uses a porous membrane made of strong, slim graphene--a carbon honeycomb one atom thick.
The results are published in the March 23 advance online issue of Nature Nanotechnology("Water Desalination Using Nanoporous Single-layer graphene"."
""Our work is a proof of principle that demonstrates how you can desalinate saltwater using freestanding,
porous graphene,"said Shannon Mark Mahurin of ORNL's Chemical sciences Division, who co-led the study with Ivan Vlassiouk in ORNL's Energy and Transportation Science Division."
"It's a huge advance, "said Vlassiouk, pointing out a wealth of water travels through the porous graphene membrane."
"The flux through the current graphene membranes was at least an order of magnitude higher than that through state-of-the-art reverse osmosis polymeric membranes."
"Current methods for purifying water include distillation and reverse osmosis. Distillation, or heating a mixture to extract volatile components that condense,
requires a significant amount of energy. Reverse osmosis, a more energy-efficient process that nonetheless requires a fair amount of energy,
is the basis for the ORNL technology. Making pores in the graphene is key. Without these holes, water cannot travel from one side of the membrane to the other.
The water molecules are simply too big to fit through graphene's fine mesh. But poke holes in the mesh that are just the right size
or passage of a fluid through a semipermeable membrane into a solution in which the solvent is concentrated more."
Today reverse-osmosis filters are typically polymers. A filter is thin and resides on a support.
"That all serves to reduce the amount of energy that it takes to drive the process."
A porous graphene membrane could be more permeable than a polymer membrane, so separated water would drive faster through the membrane under the same conditions, the scientists reasoned."
The researchers transferred the graphene membrane to a silicon nitride support with a micrometer-sized hole.
Then the team exposed the graphene to an oxygen plasma that knocked carbon atoms out of the graphene's nanoscale chicken wire lattice to create pores.
The longer the graphene membrane was exposed to the plasma, the bigger the pores that formed,
The silicon nitride chip held the graphene membrane in place while water flowed through it from one chamber to the other.
To figure out the best pore size for desalination, the researchers relied on the Center for Nanophase Materials sciences (CNMS),
a DOE Office of Science User Facility at ORNL. There, aberration-corrected scanning transmission electron microscopy (STEM) imaging, led by Raymond Unocic,
allowed for atom-resolution imaging of graphene, which the scientists used to correlate the porosity of the graphene membrane with transport properties.
They determined the optimum pore size for effective desalination was 0. 5 to 1 nanometers,
They also found the optimal density of pores for desalination was one pore for every 100 square nanometers."
So far, the oxygen plasma approach worked the best, "he added. He worries more about gremlins that plague today's reverse osmosis membranes--growths on membrane surfaces that clog them (called"biofouling)
"and ensuring the mechanical stability of a membrane under pressure e
#Rapid and efficient DNA chip technology for testing 14 major types of food borne pathogens Conventional methods for testing foodborne pathogens is based on the cultivation of pathogens,
a process that is complicated and time consuming. So there is demand for alternative methods to test for foodborne pathogens that are simpler, quick and applicable to a wide range of potential applications.
Now Toshiba Ltd and Kawasaki City Institute for Public health have collaborated in the development of a rapid and efficient automatic abbreviated DNA detection technology that can test for 14 major types of food
borne pathogens. The so called DNA chip card employs electrochemical DNA chips and overcomes the complicated procedures associated with genetic testing of conventional methods.
The DNA chip card is expected to find applications in hygiene management in food manufacture, pharmaceuticals, and cosmetics.
The so-called automatic abbreviated DNA detection technology DNA chip card was developed by Toshiba Ltd and in a collaboration with Kawasaki City Institute for Public health, used to simultaneously detect 14 different types of foodborne pathogens in less than 90 minutes.
The detection sensitivity depends on the target pathogen and has a range of 1e+01? 05 cfu/ml.
Notably, such tests would usually take 4-5 days using conventional methods based on pathogen cultivation.
Furthermore, in contrast to conventional DNA protocols that require high levels of skill and expertise,
the DNA chip card only requires the operator to inject nucleic acid, thereby making the procedure easier to use and without specialized operating skills.
Examples of pathogens associated with food poisoning that were tested with the DNA chip card d
#Chemists make new silicon-based nanomaterials In a paper published in the journal Nano Letters("A Silicon-Based Two-dimensional Chalcogenide:
Growth of Si2te3 Nanoribbons and Nanoplates"),the researchers describe methods for making nanoribbons and nanoplates from a compound called silicon telluride.
The materials are pure, p-type semiconductors (positive charge carriers) that could be used in a variety of electronic and optical devices.
Their layered structure can take up lithium and magnesium, meaning it could also be used to make electrodes in those types of batteries.
Chemists from Brown University have come up with a way to make new nanomaterials from a silicon-based compound.
The materials can be made in a variety of morphologies and could be used in semiconductor devices, optics or batteries.
Image: Koski lab/Brown University)" Silicon-based compounds are the backbone of modern electronics processing,
"said Kristie Koski, assistant professor of chemistry at Brown, who led the work.""Silicon telluride is in that family of compounds,
and we've shown a totally new method for using it to make layered, two-dimensional nanomaterials."
"Koski and her team synthesized the new materials through vapor deposition in a tube furnace.
When heated in the tube, silicon and tellurium vaporize and react to make a precursor compound that is deposited on a substrate by an argon carrier gas.
The silicon telluride then grows from the precursor compound. Different structures can be made by varying the furnace temperature
and using different treatments of the substrate. By tweaking the process, the researchers made nanoribbons that are about 50 to 1, 000 nanometers in width and about 10 microns long.
They also made nanoplates flat on the substrate and standing upright.""We see the standing plates a lot,
to change the material from a p-type semiconductor (one with positive charge carriers) to an n-type (one with negative charge carriers).
The materials are not particularly stable out in the environment, Koski says, but that's easily remedied."
"We think this is a good candidate for bringing the properties of 2-D materials into the realm of electronics,
#New study shows bacteria can use magnetic nanoparticles to create a'natural battery'(Nanowerk News) New research shows bacteria can use tiny magnetic particles to effectively create a'natural battery.'
'According to work published in journal Science on 27 march("Redox cycling of Fe (II) and Fe (III) in magnetite by Fe-metabolizing bacteria),
"the bacteria can load electrons onto and discharge electrons from microscopic particles of magnetite. This discovery holds out the potential of using this mechanism to help clean up environmental pollution,
and other bioengineering applications. The European Association of Geochemistry is highlighting this work as especially interesting.
According to study leader Dr James Byrne (Tübingen:""The geochemistry is interesting in itself, but there are also potentially useful implications
which may derive form this work. The flow of electrons is critical to the existence of all life
and the fact that magnetite can be considered to be redox active opens up the possibility of bacteria being able to exist
or survive in environments where other redox active compounds are in short supply in comparison to magnetite.
In our study we only looked at iron metabolizing bacteria, but we speculate that it might be possible for other non-iron metabolizing organisms to use magnetite as a battery as well
-or if they can be made to use it, through genetic engineering. But this is something that we do not know yet"Researchers from the University of Tübingen, the University of Manchester,
and Pacific Northwest National Laboratory, USA, incubated the soil and water dwelling purple bacteria Rhodopseudomonas palustris with magnetite and controlled the amount of light the cultures were exposed to.
Using magnetic, chemical and mineralogical analytical methods, the team showed that in light conditions which replicated the daytime,
phototrophic iron-oxidizing bacteria removed electrons from the magnetite, thereby discharging it. During the nighttime conditions, the iron-reducing bacteria took over
and were able to dump electrons back onto the magnetite and recharge it for the following cycle.
This oxidation reduction mechanism was repeated over several cycles meaning that the battery was used over repeated day-night cycles.
Whilst this work has been on iron-metabolizing bacteria, it is thought that in the environment the potential for magnetite to act as a battery could extend to many other types of bacteria
which do normally not require iron to grow, e g. fermenters. Co-author, Andreas Kappler (Tübingen), who is also secretary of the European Association of Geochemistry,
said:""This may have some interesting geochemical applications. There has been considerable recent work on using magnetite to clean up toxic metals.
For example, magnetite can reduce the toxic form of chromium, chromium VI, to the less toxic chromium (III),
which can then be incorporated into a magnetite crystal. The fact that this magnetite may then be exposed to these reducing bacteria could potentially enhance its remediation capacity.
But we are still at an early stage of understanding the bioengineering implications of this discovery"e
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