New Nanomaterial helps Store Solar Energy (as Hydrogen) Efficiently and Inexpensively


Perovskite New Solar Material pic3

Efficient storage technologies are necessary if solar and wind energy is to help satisfy increased energy demands.

One important approach is storage in the form of hydrogen extracted from water using solar or wind energy. This process takes place in a so-called electrolyser. Thanks to a new material developed by researchers at the Paul Scherrer Institute PSI and Empa, these devices are likely to become cheaper and more efficient in the future. The material in question works as a catalyst accelerating the splitting of water molecules: the first step in the production of hydrogen. Researchers also showed that this new material can be reliably produced in large quantities and demonstrated its performance capability within a technical electrolysis cell – the main component of an electrolyser. The results of their research have been published in the current edition of the scientific journal Nature Materials.

Perovskite New Material Researchers pic1

The scientists Emiliana Fabbri and Thomas Schmidt in a lab at PSI where they conducted experiments to study the performance of the newly developed catalyst for electrolysers. (Photo: Paul Scherrer Institute/Mahir Dzambegovic.)

Since solar and wind energy is not always available, it will only contribute significantly to meeting energy demands once a reliable storage method has been developed. One promising approach to this problem is storage in the form of hydrogen. This process requires an electrolyser, which uses electricity generated by solar or wind energy to split water into hydrogen and oxygen. Hydrogen serves as an energy carrier. It can be stored in tanks and later transformed back into electrical energy with the help of fuel cells. This process can be carried out locally, in places where energy is needed such as domestic residences or fuel cell vehicles, enabling mobility without the emission of CO2.

Inexpensive and efficient

Researchers at the Paul Scherrer Institute PSI have now developed a new material that functions as a catalyst within an electrolyser and thus accelerates the splitting of water molecules: the first step in the production of hydrogen. “There are currently two types of electrolysers on the market: one is efficient but expensive because its catalysts contain noble metals such as iridium. The others are cheaper but less efficient”, explains Emiliana Fabbri, researcher at the Paul Scherrer Institute. “We wanted to develop an efficient but less expensive catalyst that worked without using noble metals.”

Exploring this procedure, researchers were able to use a material that had already been developed: an intricate compound of the elements barium, strontium, cobalt, iron and oxygen – a so-called perovskite. But they were the first to develop a technique enabling its production in the form of miniscule nanoparticles. This is the form required for it to function efficiently since a catalyst requires a large surface area on which many reactive centres are able to accelerate the electrochemical reaction. Once individual catalyst particles have been made as small as possible, their respective surfaces combine to create a much larger overall surface area.

Researchers used a so-called flame-spray device to produce this nanopowder: a device operated by Empa that sends the material’s constituent parts through a flame where they merge and quickly solidify into small particles once they leave the flame. “We had to find a way of operating the device that reliably guaranteed the solidifying of the atoms of the various elements in the right structure,” emphasizes Fabbri. “We were also able to vary the oxygen content where necessary, enabling the production of different material variants.”

Successful Field Tests

Researchers were able to show that these procedures work not only in the laboratory but also in practice. The production method delivers large quantities of the catalyst powder and can be made readily available for industrial use. “We were eager to test the catalyst in field conditions. Of course, we have test facilities at PSI capable of examining the material but its value ultimately depends upon its suitability for industrial electrolysis cells that are used in commercial electrolysers,” says Fabbri. Researchers tested the catalyst in cooperation with an electrolyser manufacturer in the US and were able to show that the device worked more reliably with the new PSI-produced perovskite than with a conventional iridium-oxide catalyst.

Examining in Milliseconds

Researchers were also able to carry out precise experiments that provided accurate information on what happens in the new material when it is active. This involved studying the material with X-rays at PSI’s Swiss Light Source SLS. This facility provides researchers with a unique measuring station capable of analysing the condition of a material over successive timespans of just 200 milliseconds. “This enables us to monitor changes in the catalyst during the catalytic reaction: we can observe changes in the electronic properties or the arrangement of atoms,” says Fabbri. At other facilities, each individual measurement takes about 15 minutes, providing only an averaged image at best.” These measurements also showed how the structures of particle surfaces change when active – parts of the material become amorphous which means that the atoms in individual areas are no longer uniformly arranged. Unexpectedly, this makes the material a better catalyst.

Use in the ESI Platform

Working on the development of technological solutions for Switzerland’s energy future is an essential aspect of the research carried out at PSI. To this end, PSI makes its ESI (Energy System Integration) experimental platform available to research and industry, enabling promising solutions to be tested in a variety of complex contexts. The new catalyst provides an important base for the development of a new generation of water electrolysers.

Nanotechnology and the ‘NextGen’ of Sensors for: Medicine-Healthcare, Environment, and Biology.


Nano Photo Sensors NANOIDENTPhotodetectorFunction300

Flexible sensors hold great promise for various innovative applications in fields such as medicine, healthcare, environment, and biology.

 

Considering that most wearable systems, healthcare electronics, and laboratory-on-a-chip testing tools can be expected to come into contact with arbitrarily curved interfaces, the flexibility of sensors is essential for improving their interactions with target systems and improving the reliability and stability of the tests. Over the past decade, the development of flexible and stretchable sensors for various functions has been accelerated by rapid advances in materials, processing methods, and platforms. For practical applications, new expectations are arising in the pursuit of highly economical, multifunctional, biocompatible flexible sensors.

Schematic illustration of flexible electronics in development today across a broad range of applications

 

Schematic illustration of flexible electronics in development today across a broad range of applications. (Reprinted with permission by Wiley-VCH Verlag)

 

 

Nano Sensors id25891A new review article in Advanced Materials (“An Overview of the Development of Flexible Sensors”) aims to illustrate various types of flexible sensors. Rather than summarizing the huge body of relevant previous work, the authors select noteworthy work that may suggest crucial future trends of flexible sensors.

They summarize the recent state-of-the-art flexible electronics currently employed as flexible light sensors, flexible pH sensors, flexible ion sensors, and flexible biosensors.The selections of materials and the fabrications of devices are included in every part. The authors also provide a detailed description of engineering technologies with an emphasis on flexible sensor fabrication.They then present market analysis on the world sensor market, printed sensors, and wearable sensors.

Relative market size by wearable sensor type by 2020

Relative market size by wearable sensor type by 2020. (© IDTechEx)

 

Numerous opportunities and challenges remain in the future research and development of high-performance flexible sensors.For flexible sensors attached to the human body or its organs, the biocompatibility of the active materials and flexible substrates, including long-term toxicity analyses, is a crucial research area, especially for invasive applications.Innovative utilization of device designs, materials, assembly methods, and surface engineering, as well as interface engineering, can address these challenges.

The development of new materials for active layers, substrates, and conductive layers can give rise to soft, stretchable sensors; this emerging paradigm can extend the scope of current technologies for different sensing functions.Improvement of both flexibility and sensitivity is another challenge for state-of-the-art flexible sensors. The development of novel elastic materials for flexible and stretchable substrates, geometrical electrode designs, combinations of molecular designs in organic materials, and utilization of conceptually novel materials could optimize the trade-off between sensitivity and flexibility.Battery NANOIDENTPhotodetectorStructure300

High-density sensor arrays with multiple functions must be integrated for enabling a high spatiotemporal resolution to realize fully functional flexible electronics. Take for example human micromotion sensor (read more here: “Nanocurve-based sensor reads facial expressions“):

 

nanoparticle curve array printed to flexible electronic devicesSchematic illustration of a nanoparticle curve array printed to flexible electronic devices and adopted to multi analysis for skin micromotion sensing. Nanoparticle curve arrays were printed on the PDMS substrate by pillar-patterned template induced printing with sliver nanoparticle ink. These flexible electronic sensors can be directly attached to human facial skin, and perform real-time multi analysis for skin micromotion monitoring. (Reprinted with permission by Wiley-VCH Verlag)

Nevertheless, raising the density of sensors leads to increased crosstalk. Reducing the size of sensors diminishes the amplitude of signals. These problems can be addressed by connecting each sensor with active devices such as transistors to enable local signal amplification and transduction.The development of sensors is the enabling technology for Internet of Things (IoT). A surge in IoT provides plentiful opportunities for spreading out of flexible sensors with reconfigurable shape and size.Thanks to their light weight, thinness, and robustness, flexible sensors can be seamlessly integrated onto any surface to provide users more improved avenues, which is difficult to realize in conventional electromechanical sensors.

With the development of polymers, oxides, printing technologies, and CMOS technologies, flexible sensors will unlock a completely novel set of IoT products. The achievement of these fantastic sensing applications will bring us closer to the new electronic era promised by flexible sensors.

Applications for Nano and Sensors

Uses of Nano car

U of Washington: Fast, Cheap method to make supercapacitor electrodes for EV’s and High-Powered Lasers


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Supercapacitors are an aptly named type of device that can store and deliver energy faster than conventional batteries. They are in high demand for applications including electric cars, wireless telecommunications and high-powered lasers.

But to realize these applications, supercapacitors need better electrodes, which connect the supercapacitor to the devices that depend on their energy. These electrodes need to be both quicker and cheaper to make on a large scale and also able to charge and discharge their electrical load faster. A team of engineers at the University of Washington thinks they’ve come up with a process for manufacturing supercapacitor electrode materials that will meet these stringent industrial and usage demands.
The researchers, led by UW assistant professor of materials science and engineering Peter Pauzauskie, published a paper on July 17 in the journal Nature Microsystems and Nanoengineering (“Rapid synthesis of transition metal dichalcogenide–carbon aerogel composites for supercapacitor electrodes”) describing their supercapacitor electrode and the fast, inexpensive way they made it.
Their novel method starts with carbon-rich materials that have been dried into a low-density matrix called an aerogel. This aerogel on its own can act as a crude electrode, but Pauzauskie’s team more than doubled its capacitance, which is its ability to store electric charge.
These inexpensive starting materials, coupled with a streamlined synthesis process, minimize two common barriers to industrial application: cost and speed.
“In industrial applications, time is money,” said Pauzauskie. “We can make the starting materials for these electrodes in hours, rather than weeks. And that can significantly drive down the synthesis cost for making high-performance supercapacitor electrodes.”
A coin-cell battery
Full x-ray reconstruction of a coin cell supercapacitor.
Effective supercapacitor electrodes are synthesized from carbon-rich materials that also have a high surface area. The latter requirement is critical because of the unique way supercapacitors store electric charge. While a conventional battery stores electric charges via the chemical reactions occurring within it, a supercapacitor instead stores and separates positive and negative charges directly on its surface.
“Supercapacitors can act much faster than batteries because they are not limited by the speed of the reaction or byproducts that can form,” said co-lead author Matthew Lim, a UW doctoral student in the Department of Materials Science & Engineering. “Supercapacitors can charge and discharge very quickly, which is why they’re great at delivering these ‘pulses’ of power.”
“They have great applications in settings where a battery on its own is too slow,” said fellow lead author Matthew Crane, a doctoral student in the UW Department of Chemical Engineering. “In moments where a battery is too slow to meet energy demands, a supercapacitor with a high surface area electrode could ‘kick’ in quickly and make up for the energy deficit.”
To get the high surface area for an efficient electrode, the team used aerogels. These are wet, gel-like substances that have gone through a special treatment of drying and heating to replace their liquid components with air or another gas. These methods preserve the gel’s 3-D structure, giving it a high surface area and extremely low density. It’s like removing all the water out of Jell-O with no shrinking.
“One gram of aerogel contains about as much surface area as one football field,” said Pauzauskie.
Crane made aerogels from a gel-like polymer, a material with repeating structural units, created from formaldehyde and other carbon-based molecules. This ensured that their device, like today’s supercapacitor electrodes, would consist of carbon-rich materials.
Previously, Lim demonstrated that adding graphene — which is a sheet of carbon just one atom thick — to the gel imbued the resulting aerogel with supercapacitor properties. But, Lim and Crane needed to improve the aerogel’s performance, and make the synthesis process cheaper and easier.
In Lim’s previous experiments, adding graphene hadn’t improved the aerogel’s capacitance. So they instead loaded aerogels with thin sheets of either molybdenum disulfide or tungsten disulfide. Both chemicals are used widely today in industrial lubricants.
The researchers treated both materials with high-frequency sound waves to break them up into thin sheets and incorporated them into the carbon-rich gel matrix. They could synthesize a fully-loaded wet gel in less than two hours, while other methods would take many days. After obtaining the dried, low-density aerogel, they combined it with adhesives and another carbon-rich material to create an industrial “dough,” which Lim could simply roll out to sheets just a few thousandths of an inch thick. They cut half-inch discs from the dough and assembled them into simple coin cell battery casings to test the material’s effectiveness as a supercapacitor electrode.
A coin-cell battery
Slice from x-ray computed tomography image of a supercapacitor coin cell assembled with the electrode materials. The thin layers — just below the coin cell lid — are layers of electrode materials and a separator. (Image: William Kuykendall)
Not only were their electrodes fast, simple and easy to synthesize, but they also sported a capacitance at least 127 percent greater than the carbon-rich aerogel alone.
Lim and Crane expect that aerogels loaded with even thinner sheets of molybdenum disulfide or tungsten disulfide — theirs were about 10 to 100 atoms thick — would show an even better performance. But first, they wanted to show that loaded aerogels would be faster and cheaper to synthesize, a necessary step for industrial production. The fine-tuning comes next.
The team believes that these efforts can help advance science even outside the realm of supercapacitor electrodes. Their aerogel-suspended molybdenum disulfide might remain sufficiently stable to catalyze hydrogen production. And their method to trap materials quickly in aerogels could be applied to high capacitance batteries or catalysis.
Source: By James Urton, University of Washington

 

Long-Term Health Monitoring Possible through Breathable, Wearable Electronics on Our Skin


Nano Skin breathablewe
The diagram at top illustrates the structure of gold nanomesh conductors laminated onto the skin surface. The nanomesh, constructed from polyvinyl alcohol (PVA) nanofibers and a gold (Au) layer, adheres to the skin when sprayed with water, …more

A hypoallergenic electronic sensor can be worn on the skin continuously for a week without discomfort, and is so light and thin that users forget they even have it on, says a Japanese group of scientists. The elastic electrode constructed of breathable nanoscale meshes holds promise for the development of noninvasive e-skin devices that can monitor a person’s health continuously over a long period.

Wearable electronics that monitor heart rate and other vital health signals have made headway in recent years, with next-generation gadgets employing lightweight, highly elastic materials attached directly onto the skin for more sensitive, precise measurements. However, although the  and rubber sheets used in these devices adhere and conform well to the skin, their lack of breathability is deemed unsafe for long-term use: dermatological tests show the fine, stretchable materials prevent sweating and block airflow around the skin, causing irritation and inflammation, which ultimately could lead to lasting physiological and psychological effects.

“We learned that devices that can be worn for a week or longer for continuous monitoring were needed for practical use in medical and sports applications,” says Professor Takao Someya at the University of Tokyo’s Graduate School of Engineering whose research group had previously developed an on-skin patch that measured oxygen in blood.

In the current research, the group developed an electrode constructed from nanoscale meshes containing a water-soluble polymer, polyvinyl alcohol (PVA), and a gold layer—materials considered safe and biologically compatible with the body. The  can be applied by spraying a tiny amount of water, which dissolves the PVA nanofibers and allows it to stick easily to the skin—it conformed seamlessly to curvilinear surfaces of human skin, such as sweat pores and the ridges of an index finger’s fingerprint pattern.

Breathable, wearable electronics on skin for long-term health monitoring
An array of nanomesh conductors attached to a fingertip, top, and a scanning electron microscope (SEM) image of a nanomesh conductor on a skin replica, bottom. Credit: 2017 Someya Laboratory.

The researchers next conducted a skin patch test on 20 subjects and detected no inflammation on the participants’  after they had worn the device for a week. The group also evaluated the permeability, with water vapor, of the nanomesh conductor—along with those of other substrates like ultrathin plastic foil and a thin rubber sheet—and found that its porous mesh structure exhibited superior gas permeability compared to that of the other materials.

Furthermore, the scientists proved the device’s mechanical durability through repeated bending and stretching, exceeding 10,000 times, of a conductor attached on the forefinger; they also established its reliability as an electrode for electromyogram recordings when its readings of the electrical activity of muscles were comparable to those obtained through conventional gel electrodes.

Breathable, wearable electronics on skin for long-term health monitoring
The electric current from a flexible battery placed near the knuckle flows through the conductor and powers the LED just below the fingernail. Credit: 2017 Someya Laboratory.

“It will become possible to monitor patients’ vital signs without causing any stress or discomfort,” says Someya about the future implications of the team’s research. In addition to nursing care and medical applications, the new device promises to enable continuous, precise monitoring of athletes’ physiological signals and bodily motion without impeding their training or performance.

 Explore further: Novel e-skin may monitor health, vital signs

More information: Akihito Miyamoto et al, Inflammation-free, gas-permeable, lightweight, stretchable on-skin electronics with nanomeshes, Nature Nanotechnology (2017). DOI: 10.1038/nnano.2017.125

 

Chasing the ‘Holey’ Grail of Batteries ~ Will Porous Graphene Provide the Next ‘Quantum Leap’?


Holy Grail Battery sk-2017_04_article_main_desktop

A porous form of graphene, the world’s thinnest and lightest nanomaterial, could help bring about the quantum leap in battery efficiency that’s needed to better harness renewable energy

The future, we’re told, will run on batteries. Fully electric vehicles will become the industry standard, running fast and far on a single charge. Our phone and laptop batteries will last for days and recharge in minutes. Our homes may even power themselves, storing energy from rooftop solar panels in lightweight and long-lasting battery packs.

One thing’s clear, though: If this battery-powered future is going to happen, we need a quantum leap in battery technology. Current lithium-ion batteries have hit a wall. For the past decade, researchers have been experimenting with new materials and novel designs to build batteries that are more powerful, last longer, and charge faster. energy_storage_2013 042216 _11-13-1 LARGE

This week, a team of researchers from the United States, China, and Saudi Arabia unveiled a new type of battery electrode made with “holey” graphene. In a paper published in Science, the researchers describe a porous form of graphene — the world’s thinnest and lightest nanomaterial — that overcomes some key challenges in creating next-generation batteries.

To understand how the porous graphene helps, first you need to know how today’s lithium-ion batteries work. Like all batteries, lithium-ion cells contain a positive electrode (cathode) and a negative electrode (anode) separated by a chemical medium called an electrolyte and a semi-permeable barrier called a separator.

RELATED: Fern-Like Sheets of Graphene Could Boost Solar Panel Efficiency

When the battery is charged, lithium ions flow to the anode, which is made of graphite. The lithium ions stick to the surface of the graphite and also bury themselves deep in its layers, which is how the energy is stored. When the battery goes to work powering a device, the ions flow from the anode to the cathode, passing through the separator at a steady rate. At the same time, electrons are released at the anode, flow out into the external circuit, and eventually return to the cathode.

To recap, there are two processes that make batteries work, the transport and storage of ions between electrodes, and the release of electrons into the external circuit. To build a battery that stores more energy and recharges faster, you need to optimize the flow of both ions and electrons.

That’s where nanomaterials come in.

Graphene Anodes 1 id35611Nanomaterials are named for their impossibly small dimensions, measured in nanometers (one millionth of a millimeter). A number of nanoscale materials have been explored as potential electrode materials that could promise far higher performance than today’s batteries. However, those extraordinary results have only been achieved in the lab using research devices with ultrathin electrodes, not the thicker electrodes required for real-world devices.

Graphene is a nanomaterial with some very unique properties. A single sheet of graphene is only one atom thick and consists of a 2D lattice of tightly bonded carbon atoms. Its structure makes it one of the best conductors of electricity on the planet. So if you incorporate graphene into a battery, you can greatly speed up the flow of electrons.

The problem with graphene is that while it’s terrific at moving electrons, it’s impenetrable to ions. If you tried to make an electrode purely out of graphene, the charge/discharge rate of the battery would be slowed by ions having to take detours around the broken edges of the graphene. That’s why researchers decided to punch holes straight through the graphene. Graphene Anodes 2images

Xiangfeng Duan from the UCLA, one of the authors of the Science paper, explained that the “holey” graphene is used as a conductive scaffold to speed the flow of electrons and direct the transport of ions with maximum efficiency. The graphene scaffold has a three-dimensional “hierarchical” structure with large holes feeding into smaller holes, ensuring that ions are funneled to every available nanometer of the electrode.

“It’s like a transportation network in a city,” said Duan. “You start with wide highways and then you move to narrow local roads to access every home. In the battery, the scaffold allows for the efficient transport of ions across a porous network to directly deliver charge to all of the electrode material.”

RELATED: Seaweed Could Provide a Powerful Boost to Next-Gen Batteries

In their experiments, Duan and his team placed the graphene as a conductive scaffold on niobia (Nb2O5) nanoparticles, a material known for its fast charge/discharge rate. Other labs have experimented with building electrodes solely from materials like niobia in super-thin sheets weighing almost nothing. But Duan said that the performance of the active material in such tiny amounts is canceled out by the bulkier inactive components of an electrode, like the current collectors. In other words, what works in the lab won’t cut it in real-world devices.

By loading the niobia on a graphene scaffold, Duan and his team achieved performance results that were several times greater than with a thin nanomaterial alone. Duan pointed out that the same porous scaffold design they used with niobia could be used with other active materials like silicon or tin oxide, which boast high energy density, the ability to store lots of ions for longer-lasting batteries.

It will still be a while before we see “holey” graphene batteries in real-world devices, said Duan, who calls this paper “a critical step, but just a starting point toward commercialization.” Looking ahead, he could easily see niobia-based batteries that charge up to five or 10 times faster than today’s lithium-ion cells. And batteries made with energy-dense materials like silicon could power laptops for 20 or 30 hours on a single charge, and triple the driving range of an electric vehicle.

“I think this really gives us a pathway toward using these high-performance materials in real-world devices,” Duan said.

U of Pennsylvania: Large Scale Production of Graphene + Graphene Updates and Videos


Graphene Mem 050815 3-anewapproach
Draw a line with a pencil and it’s likely that somewhere along that black smudge is a material that earned two scientists the 2010 Nobel Prize in Physics. The graphite of that pencil tip is simply multiple layers of carbon atoms; where those layers are only one atom thick, it is known as graphene.

The properties of a material change at the nanoscopic scale, making graphene the strongest and most conductive substance known. Instead of marking mini-golf scores on paper, this form of carbon is suited for making faster and smaller electronic circuitry, flexible touchscreens, chemical sensors, diagnostic devices, and applications yet to be imagined.

Graphene is not yet as ubiquitous as plastic or silicon, however, and producing the material in bulk remains a challenge. Because graphene’s properties rely on it being only one atom thick, until recently, it was only possible to make it in small patches or flakes.

Physicists at Penn have discovered a way around these limitations, and have spun out their research into a company called Graphene Frontiers. Graphene Frontiers

 


More About Graphene

Turning saltwater into clean drinking water is an expensive, energy-intensive process, but could the wonder material graphene make it more accessible?

New Discovery Could Unlock Graphene’s Full Potential – 


Read More:

3D GrapheneFollow this direct link to Seeker.com for more information and Videos about the ‘Wonder Material’ of Graphene.

Seeker.com



Graphene sieve turns seawater into drinking water

“Graphene-oxide membranes have attracted considerable attention as promising candidates for new filtration technologies. Now the much sought-after development of making membranes capable of sieving common salts has been achieved. New research demonstrates the real-world potential of providing clean drinking water for millions of people who struggle to access adequate clean water sources.
The new findings from a group of scientists at The University of Manchester were published today in the journal Nature Nanotechnology. Previously graphene-oxide membranes have shown exciting potential for gas separation and water filtration.”

Researchers develop blue-, yellow-, and red-emitting Graphene Quantum Dots


Graphene QD's China id47457_1

PL spectra of GQDs (a), PEI1800 GQDs (b), and PEI600 GQDs (c) at different excitation wavelengths. Inset: photograph of aqueous solution of these three GQDs under room light (left) and 365 nm UV irradiation lamp (right). UV-vis absorption spectra (d) of GQDs, PEI1800 GQDs, and PEI600 GQDs dispersed in water. (© ACS) 

Graphene quantum dots (GQDs) show great potential in the fields of photoelectronics, photovoltaics, biosensing, and bioimaging owing to their unique photoluminescence (PL) properties, including excellent biocompatibility, low toxicity, and high stability against photobleaching and photoblinking.

However, further development of GQDs is limited by their synthetic methodology and unclear PL mechanism. Therefore, it is urgent to find efficient and universal methods for the synthesis of GQDs with high stability, controllable surface properties, and tunable PL emission wavelength.In new work reported in ACS Applied Materials & Interfaces (“Red, Yellow, and Blue Luminescence by Graphene Quantum Dots: Syntheses, Mechanism, and Cellular Imaging”), researchers in China have synthesized PL-tunable GQDs with blue, yellow, and red emission colors by coating with polyethyleneimine (PEI) of different molecular weights.

photoluminescence spectra of graphene quantum dotsPL spectra of GQDs (a), PEI1800 GQDs (b), and PEI600 GQDs (c) at different excitation wavelengths. Inset: photograph of aqueous solution of these three GQDs under room light (left) and 365 nm UV irradiation lamp (right). UV-vis absorption spectra (d) of GQDs, PEI1800 GQDs, and PEI600 GQDs dispersed in water. (© ACS) (click on image to enlarge)

Read More About a Company Commercializing Graphene Quantum Dots

dnlogo_top

 

DotzNano … The Next Big Small Thing

Dotz Nano Ltd. is the world’s premier manufacturer of Graphene Quantum Dots (GQDs), commercializing an innovative technology that produces GQDs out of Coal and Carbon sources. Dotz Nano can supply high quality GQDs for use in a variety of applications that include:

  • Medical imaging
  • Displays/Consumer Electronics
  • Sensing
  • Optical brighteners
  • Energy Storage
  • Solar Cell
  • Data Storage
  • Anti-counterfeiting

With its modern labs and manufacturing facility, Dotz Nano is capturing the market utilizing GQDs as an alternative material in hundreds of applications.

 

(continued from above)

The team employed TEM, AFM, XRD, FTIR, XPS, DLS, and zeta potential to characterize the structures of the as-prepared GQDs and they stufied the PL mechanism by theoretical calculations.The average sizes of uncoated yellow-emitting GQDs, blue-emitting PEI1800 GQDs, and red-emitting PEI600 GQDs were 2.37, 6.05, and 57.31 nm, respectively. The yellow-emitting and blue-emitting GQDs were monolayer structures, whereas the red-emitting GQDs were multilayer structures. The red-emitting GQDs possessed a big PEI cage with multiple GQDs inside, whereas the blue-emitting PEI-coated GQDs had a single GQD core.The scientists found that carboxyl groups were changed to amide groups on the surface of GQDs and that this amidation reaction was crucial for PL change. By analyzing the molecular orbital and charge density, it was found that amide bonds decreased the conjugation and increased the energy gap thus inducing the blue shift of the PL.For the red-emitting GQDs, the conjugation area was enlarged by the interaction of GQDs in the PEI cage; thus, the PL peak exhibited a red shift.Remarkably, as the team points out, all GQDs exhibited good stability at high ionic strength and resisted photobleaching. Cell viability after treatment with the as-prepared GQDs indicated that GQDs had quite low cytotoxicity.”The GQDs could be used for bioimaging and are expected to be widely applied in multicolor imaging and bioanalysis applications,” the authors cocnlude their report. “We hope that this work will inspire the design of even better GQDs with tunable PL properties.”

Primary Story Contributed by Micheal Berger Nanowerk

Volvo goes ALL EV/ Hybrid by 2019 ~ Is it a BIG Deal? + Video NextGen ‘Battery Pack’ that could propel Tesla ‘S’ 2X farther at 1/2 the Cost


Still from animation - Mild hybrid, 48 volts

Original Report from IDTechEX

Volvo Cars has been in the news recently in relation to their announcement this Wednesday on their decision to leave the internal combustion engine only based automotive industry.   The Chinese-European company announced that from 2019 all their vehicles will be either pure electric or hybrid electric. In this way it has been argued the company is making a bold move towards electrification of vehicles. Volvo to capture potential market in China The company will launch a pure electric car in 2019 and that is a great move indeed, considering that the company has been owned by Chinese vehicle manufacturer Geely since 2010.

The Chinese electric vehicle market has been booming in the last years reaching a sales level of 350,000 plug-in EVs (pure electric and plug-in hybrid electric cars) in 2016. The Chinese plug-in EV market grew 300% from 2014 to 2015 but cooled down to 69% growth in 2016 vs 2015, still pushing a triple digit growth in pure electric cars. The Chinese government has announced that in 2017 sales will reach 800,000 NEV  (new energy vehicles including passenger and bus, both pure electric and hybrid electric).   IDTechEx believes that China will not make it to that level, but will definitely push the figures close to that mark.

We think that the global plug-in electric vehicle market will surpass 1 million sales per year for the first time at the end of 2017.   Until recently this market has been mostly dominated by Chinese manufacturers, being BYD the best seller of electric cars in the country with 100,000 plug-in EVs sold in 2016. Tesla polemically could not penetrate the market but in 2016 sold around 11,000 units.  

Whilst the owner of Volvo Cars, Geely, is active in China selling around 17,000 pure electric cars per year, it might be that Volvo has now realized that they can leverage on their brand in the Chinese premium market to catch the huge growth opportunity in China and need to participate as soon as possible.   More information on market forecasts can be found in IDTechEx Research’s report Electric Vehicles 2017-2037: Forecasts, Analysis and Opportunities.

Volvo 4 Sedan volvo-40-series-concepts-16-1080x720

Is Volvo Cars’ move a revolutionary one? Not really, as technically speaking the company is not entirely making a bold movement to only 100% “strong” hybrid electric and pure electric vehicles.   This is because the company will launch in 2019 a “mild” hybrid electric vehicles, this is also known in the industry as 48V hybrid electric platform. This is a stepping stone between traditional internal combustion engine companies and “strong” hybrid electric vehicles such as the Toyota Prius.

The 48V platform is being adopted by many automotive manufacturers, not only Volvo. OEMs like Continental developed this platform to provide a “bridge technology”  towards full EVs for automotive manufacturers, providing 6 to 20 kW electric assistance. By comparison, a full hybrid system typically offers 20-40-kW and a plug-in hybrid, 50-90 kW.   Volvo had already launched the first diesel plug-in hybrid in 2012 and the company will launch a new plug-in hybrid platform in 2018 in addition to the launch of the 2019 pure electric vehicle platform.   Going only pure electric and plug-in hybrid electric would be really revolutionary.   See IDTechEx Research’s report Mild Hybrid 48V Vehicles 2017-2027 for more information on 48V platforms.

Tesla Model 3hqdefaultAdditional Information: The Tesla Model ‘S’

The Tesla Model S is a full-sized all-electric five-door, luxury liftback, produced by Tesla, Inc., and introduced on 22 June 2012.[14] It scored a perfect 5.0 NHTSA automobile safety rating.[15] The EPA official rangefor the 2017 Model S 100D,[16] which is equipped with a 100 kWh(360 MJbattery pack, is 335 miles (539 km), higher than any other electric car.[17] The EPA rated the 2017 90D Model S’s energy consumption at 200.9 watt-hours per kilometer (32.33 kWh/100 mi or 20.09 kWh/100 km) for a combined fuel economy of 104 miles per gallon gasoline equivalent (2.26 L/100 km or 125 mpg‑imp).[18] In 2016, Tesla updated the design of the Model S to closely match that of the Model X. As of July 2017, the following versions are available: 75, 75D, 90D, 100D and P100D.[19]

 

Tesla Battery Pack 2014-08-19-19.10.42-1280

 

For more specific details on the updated Tesla Battery Pack go here:

Teardown of new 100 kWh Tesla battery pack reveals new cooling system and 102 kWh capacity

 

 

 

Volvo 3 Truck imagesA radical move would be to drop diesel engines On-road diesel vehicles produce approximately 20% of global anthropogenic emissions of nitrogen oxides (NOx), which are key PM and ozone precursors.   Diesel emission pollutions has been confirmed as a major source of premature mortality. A recent study published in Nature  by the Environmental Health Analytics LLC and the International Council on Clean Transportation both based in Washington, USA found that whilst regulated NOx emission limits in leading markets have been progressively tightened, current diesel vehicles emit far more NOx under real-world operating conditions than during laboratory certification testing. The authors show that across 11 markets, representing approximately 80% of global diesel vehicle sales, nearly one-third of on-road heavy-duty diesel vehicle emissions and over half of on-road light-duty diesel vehicle emissions are in excess of certification limits.   These emissions were associated with about 38,000 premature deaths globally in 2015.

The authors conclude that more stringent standards are required in order to avoid 174,000 premature deaths globally in 2040.   Diesel cars account for over 50 percent of all new registrations in Europe, making the region by far the world’s biggest diesel market. Volvo Cars, sells 90 percent of its XC 90 off roaders in Europe with diesel engines.   “From today’s perspective, we will not develop any more new generation diesel engines,” said Volvo’s CEO Hakan Samuelsson told German’s Frankfurter Allgemeine Zeitung in an interview .   Samuelsson declared  that Volvo Cars aims to sell 1 million “electrified” cars by 2025, nevertheless he refused to be drawn on when Volvo Cars will sell its last diesel powered vehicle.

Goldman Sachs believes  a regulatory crackdown could add 300 euros ($325) per engine to diesel costs that are already some 1,300 euros above their petrol-powered equivalents, as carmakers race to bring real NOx emissions closer to their much lower test-bench scores. Scandinavia’s vision of a CO2-free economy Volvo’s decision should also be placed in a wider context regarding the transition to an environmentally sustainable economy.

Scandinavia’s paper industry has made great strides towards marketing itself as green and eco-aware in the last decades, so much so that countries like Norway have tripled the amount of standing wood in forests compared to 100 years ago. Energy supply is also an overarching theme, with each one of the four Scandinavian countries producing more than 39% of their electricity with renewables (Finland 39%, Sweden and Denmark 56%, Norway 98%). Finally, strong public incentives have made it possible for electric vehicles to become a mainstream market in Norway, where in 2016, one in four cars sold was a plug-in electric, either pure or hybrid.   It is then of no surprise that the first battery Gigafactory announcement in Europe came from a Swedish company called Northvolt (previously SGF Energy).

The Li-ion factory will open in 4 steps, with each one adding 8 GWh of production capacity. This gives a projected final output of 32 GWh, but if higher energy cathodes are developed, 40-50 GWh capacity can be envisioned. A site has not yet been identified, but the choice has been narrowed down to 6-7 locations, all of them in the Scandinavian region. The main reasons to establish a Gigafactory there boil down to the low electricity prices (hydroelectric energy), presence of relevant mining sites, and the presence of local know-how from the pulp & paper industry.   After a long search for a European champion in the EV market, it finally seems that Sweden has accepted to take the lead, and compete with giants like BYD and rising stars like Tesla. This could be the wake-up call for many other European car makers, which have been rather bearish towards EV acceptance despite many bold announcements.   To learn more about IDTechEx’s view on electric vehicles, and our projections up to 2037, please check our master report on the subject http://www.IDTechEx.com/ev .

Top image source: Volvo Cars Learn more at the next leading event on the topic: Business and Technology Insight Forum. Korea 2017 on 19 – 21 Sep 2017 in Seoul, Korea hosted by IDTechEx.

More Information on ‘NextGen Magnum SuperCap-Battery Pack’ that could propel a Tesla Model ‘S’ 90% farther (almost double) and cost 1/2 (one-half) as much: Video

 

MIT Researchers develop new (low energy) way to Clear Pollutants from Water: w/ Video


MIT-PurifyingWater-1_0Researchers have developed a new method for removing even extremely low levels of unwanted compounds from water. The new method relies on an electrochemical process to selectively remove organic contaminants such as pesticides, chemical waste products, and pharmaceuticals. Photo: Melanie Gonick/MIT

Electrochemical method can remove even tiny amounts of contamination.

When it comes to removing very dilute concentrations of pollutants from water, existing separation methods tend to be energy- and chemical-intensive. Now, a new method developed at MIT could provide a selective alternative for removing even extremely low levels of unwanted compounds.

The new approach is described in the journal Energy and Environmental Science, in a paper by MIT postdoc Xiao Su, Ralph Landau Professor of Chemical Engineering T. Alan Hatton, and five others at MIT and at the Technical University of Darmstadt in Germany.

The system uses a novel method, relying on an electrochemical process to selectively remove organic contaminants such as pesticides, chemical waste products, and pharmaceuticals, even when these are present in small yet dangerous concentrations. The approach also addresses key limitations of conventional electrochemical separation methods, such as acidity fluctuations and losses in performance that can happen as a result of competing surface reactions. Watch the Video:

Current systems for dealing with such dilute contaminants include membrane filtration, which is expensive and has limited effectiveness at low concentrations, and electrodialysis and capacitive deionization, which often require high voltages that tend to produce side reactions, Su says. These processes also are hampered by excess background salts.

In the new system, the water flows between chemically treated, or “functionalized,” surfaces that serve as positive and negative electrodes. These electrode surfaces are coated with what are known as Faradaic materials, which can undergo reactions to become positively or negatively charged. These active groups can be tuned to bind strongly with a specific type of pollutant molecule, as the team demonstrated using ibuprofen and various pesticides. The researchers found that this process can effectively remove such molecules even at parts-per-million concentrations.

Previous studies have usually focused on conductive electrodes, or functionalized plates on just one electrode, but these often reach high voltages that produce contaminating compounds. By using appropriately functionalized electrodes on both the positive and negative sides, in an asymmetric configuration, the researchers almost completely eliminated these side reactions. Also, these asymmetric systems allow for simultaneous selective removal of both positive and negative toxic ions at the same time, as the team demonstrated with the herbicides paraquat and quinchlorac.

The same selective process should also be applied to the recovery of high-value compounds in a chemical or pharmaceutical production plant, where they might otherwise be wasted, Su says. “The system could be used for environmental remediation, for toxic organic chemical removal, or in a chemical plant to recover value-added products, as they would all rely on the same principle to pull out the minority ion from a complex multi-ion system.”

The system is inherently highly selective, but in practice it would likely be designed with multiple stages to deal with a variety of compounds in sequence, depending on the exact application, Su says. “Such systems might ultimately be useful,” he sugggests, “for water purification systems for remote areas in the developing world, where pollution from pesticides, dyes, and other chemicals are often an issue in the water supply. The highly efficient, electrically operated system could run on power from solar panels in rural areas for example.”

Unlike membrane-based systems that require high pressures, and other electrochemical systems that operate at high voltages, the new system works at relatively benign low voltages and pressures, Hatton says. And, he points out, in contrast to conventional ion exchange systems where release of the captured compounds and regeneration of the adsorbents would require the addition of chemicals, “in our case you can just flip a switch” to achieve the same result by switching the polarity of the electrodes.

The research team has already racked up a series of honors for the ongoing development of water treatment technology, including grants from the J-WAFS Solutions and Massachusetts Clean Energy Catalyst competitions, and the researchers were the top winners last year’s MIT Water Innovation Prize. The researchers have applied for a patent on the new process. “We definitely want to implement this in the real world,” Hatton says. In the meantime, they are working on scaling up their prototype devices in the lab and improving the chemical robustness.

This technique “is highly significant, as it extends the capabilities of electrochemical systems from basically nonselective toward highly selective removal of key pollutants,” says Matthew Suss, an assistant professor of mechanical engineering at Technion Institute of Technology in Israel, who was not involved in this work. “As with many emerging water purification techniques, it must still must be tested under real-world conditions and for long periods to check durability. However, the prototype system achieved over 500 cycles, which is a highly promising result.”

These researchers “have systematically explored a variety of device configurations and a variety of contaminants,” says Kyle Smith, a professor of mechanical science and engineering at the University of Illinois, who also was not involved in this work. “In the process they have identified general design principles by which to achieve selective removal of contaminants. In this regard, I find Hatton and co-workers’ study to be very thorough and thoughtful. It provides a framework or paradigm for other researchers to emulate.” But, he adds, “A significant challenge that remains is the scale-up of these technologies.”

The team also included Kai-Jher Tan, Johannes Elbert, and Robert R. Taylor Professor of Chemistry Timothy Jamison at MIT; and Christian Ruttiger and Markus Gallei at the Technical University of Darmstadt. The work was supported by a seed grant from the Abdul Latif Jameel World Water and Food Security Lab (J-WAFS) at MIT.

Chinese Academy of Sciences Researchers develop simple way to fabricate micro-super-capacitors with high energy density


Super Caps Chinese Academy microsuperca(Left) Photograph of nine interconnected microsupercapacitors. (Right) Microsupercapacitors in a highly folded state. Credit: Xiao et al. ©2017 American Chemical Society

“Micro-supercapacitors are very promising for on-chip energy storage,” Wu said. “Very recently, the emergence of wearable and smart electronics urgently call for highly flexible and multi-functional, integrated .”

One of the most promising microscale power sources for portable and wearable electronics is a micro-supercapacitor—they can be made thin, lightweight, highly flexible, and with a high power density. Normally, however, manufacturing these devices involves complicated techniques that often require high pressures, irradiation, and multiple steps.

In a new study, researchers have developed a simple “one-step method” for fabricating micro-supercapacitors and demonstrate that the final devices exhibit a very good overall performance, including a high power density (1500 mW/cm3) as well as an energy density (11.6 mWh/cm3) that is at least twice as high as similar micro-supercapacitors.

The researchers, Han Xiao et al. at the Chinese Academy of Sciences, have published their paper in a recent issue of ACS Nano.

“We have developed a versatile, simple and effective method for fabricating high-energy micro-supercapacitors with designed shapes,” coauthor Zhong-Shuai Wu at the Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, told Phys.org.

The essential step of fabricating the new micro-supercapacitor is integrating phosphorene nanosheets into the interlayer of graphene nanosheets, and the good performance is in large part due to the synergistic combination of these two materials. The different materials have complementary effects, with the phosphorene offering a high  capacity and preventing the graphene sheets from unwanted stacking, while the graphene forms the main skeleton and offers a high-speed electron transport network.

Among their other characteristics, the micro-supercapacitors demonstrate very good flexibility, which the researchers attribute to the layered structure and planar  geometry. The device also has a high capacitance, which is maintained at nearly 90% of its maximum capacity after 2000 cycles. In general, the simple fabrication process also contributes to improving the device performance because it avoids the contamination and oxidation that often occur during multiple-step processing.

As the researchers explain, the small energy-storage devices have the potential to be used in a wide variety of areas.

“Micro-supercapacitors are very promising for on-chip energy storage,” Wu said. “Very recently, the emergence of wearable and smart electronics urgently call for highly flexible and multi-functional, integrated . Overall, new micro-supercapacitors could keep up with the pace of the fast development of high-tech microsystems used in the precision instruments, materials, bio-medical and other fields.”

The researchers also expect that, in the future, the new fabrication process can be easily scaled up and eventually be used for commercial purposes. They also plan to investigate other materials and techniques for developing microscale .

“We are continuously developing a variety of ultrathin, structurally defined graphene and 2-D , safe high-voltage electrolytes, and device fabrication techniques for flexible, smart, and integrated microscale energy storage device systems, such as high- micro-supercapacitors,” Wu said.

 Explore further: Stretchy supercapacitors power wearable electronics

More information: Han Xiao et al. “One-Step Device Fabrication of Phosphorene and Graphene Interdigital Micro-Supercapacitors with High Energy Density.” ACS Nano. DOI: 10.1021/acsnano.7b03288