NREL, University of Washington Scientists Elevate Quantum Dot Solar Cell World Record to 13.4 Percent



Researchers at the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) established a new world efficiency record for quantum dot solar cells, at 13.4 percent.

Colloidal quantum dots are electronic materials and because of their astonishingly small size (typically 3-20 nanometers in dimension) they possess fascinating optical properties. 


Quantum dot solar cells emerged in 2010 as the newest technology on an NREL chart that tracks research efforts to convert sunlight to electricity with increasing efficiency. 

The initial lead sulfide quantum dot solar cells had an efficiency of 2.9 percent. Since then, improvements have pushed that number into double digits for lead sulfide reaching a record of 12 percent set last year by the University of Toronto. 

The improvement from the initial efficiency to the previous record came from better understanding of the connectivity between individual quantum dots, better overall device structures and reducing defects in quantum dots.


 NREL scientists Joey Luther and Erin Sanehira are part of a team that has helped NREL set an efficiency record of 13.4% for a quantum dot solar cell.

The latest development in quantum dot solar cells comes from a completely different quantum dot material. The new quantum dot leader is cesium lead triiodide (CsPbI3), and is within the recently emerging family of halide perovskite materials. 

In quantum dot form, CsPbI3 produces an exceptionally large voltage (about 1.2 volts) at open circuit.

“This voltage, coupled with the material’s bandgap, makes them an ideal candidate for the top layer in a multijunction solar cell,” said Joseph Luther, a senior scientist and project leader in the Chemical Materials and Nanoscience team at NREL. 

The top cell must be highly efficient but transparent at longer wavelengths to allow that portion of sunlight to reach lower layers. 
Tandem cells can deliver a higher efficiency than conventional silicon solar panels that dominate today’s solar market.

This latest advance, titled “Enhanced mobility CsPbI3 quantum dot arrays for record-efficiency, high-voltage photovoltaic cells,” is published in Science Advances. The paper was co-authored by Erin Sanehira, Ashley Marshall, Jeffrey Christians, Steven Harvey, Peter Ciesielski, Lance Wheeler, Philip Schulz, and Matthew Beard, all from NREL; and Lih Lin from the University of Washington.

The multijunction approach is often used for space applications where high efficiency is more critical than the cost to make a solar module. 
The quantum dot perovskite materials developed by Luther and the NREL/University of Washington team could be paired with cheap thin-film perovskite materials to achieve similar high efficiency as demonstrated for space solar cells, but built at even lower costs than silicon technology–making them an ideal technology for both terrestrial and space applications.

“Often, the materials used in space and rooftop applications are totally different. It is exciting to see possible configurations that could be used for both situations,” said Erin Sanehira a doctoral student at the University of Washington who conducted research at NREL.

The NREL research was funded by DOE’s Office of Science, while Sanehira and Lin acknowledge a NASA space technology fellowship.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

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Connecting the Future of Electric Vehicles with Our Exploration of Space – “Back to the Future”



Special Contribution by Jason Torchinsky 




Yesterday, we reported on an alarming development for the future of electric cars: we may not have enough of the crucial minerals needed for their batteries to meet the expected demand. Supplies of nickel and cobalt are going to be needed in far larger quantities than ever before, and it’s looking like we may not have the necessary resources. 

Though, it’s worth mentioning that this is only a problem if you have what the intergalactic call a “planetary mindset.” There’s plenty of what we need just outside our door, in asteroids.

Asteroid mining has been discussed and planned and speculated about for decades, but so far there’s never really been a compelling economic reason to take the risks inherent in starting an entirely new, space-based industry.


Electric car demand may be that crucial factor that changes everything, though. Nickel and cobalt of sufficient quality and quantity may be becoming scarce on Earth, but there’s literally tons and tons and tons of the stuff pirouetting around in the inky black of space.

There’s incredibly, astoundingly valuable asteroids out there, and many we’ve already identified, like 241 Germania, which has as much mineral value in it as the entire Earth’s yearly GDP. Nickel and cobalt are abundant elements in these asteroids, and researchers have even already picked a dozen small asteroids close enough to Earth that they could be mined with just the technology that we have right now.

Those 12 asteroids are close enough to the L1 or L2 Lagrangian Points–stable areas where the gravity between two bodies, like the Earth and moon, cancel one another out–that getting them to these stable, accessible orbits is easy enough that researchers call them EROs, for Easily Retrievable Objects.

Companies like Planetary Resources have been working on asteroid mining for years, but have mostly been focused on the in-space uses of those resources, as opposed to bringing those resources back to Earth. This animation gives a sense of the way they’ve been thinking so far:

While in-space use of asteroid mineral resources is absolutely important, the recently seen expected demand for electric cars–most obviously seen in the amount of interest and pre-orders Tesla got for its upcoming Model 3–changes things dramatically. Electric car demand could easily be the backbone of the justification for asteroid mining that returns resources to Earth.

Where it was once thought that it didn’t make economic sense to mine asteroids for terrestrial use, that thinking is changing. In fact, a recent study by Noah Poponak of Goldman Sachs says the opposite:

“While the psychological barrier to mining asteroids is high, the actual financial and technological barriers are far lower. Prospecting probes can likely be built for tens of millions of dollars each and Caltech has suggested an asteroid-grabbing spacecraft could cost $2.6 billion.”

For comparison, $2.6 billion is how much money Lyft has raised. Lyft! What have they produced? Fuzzy pink car-moustaches and an app, neither of which can grab asteroid one.

Legally, things are looking good, too. An Obama-era law, the U.S. Commercial Space Launch Competitiveness Act, was passed that acknowledges that while legally no one can own the moon or an asteroid, private companies can own any materials taken from those celestial objects, which means asteroid mining for profit is legal.

If electric cars provide the economic push needed to get us to send grizzled robot space prospectors out to get that sweet, sweet space-cobalt, it’s hard not to see a possible significant competitive advantage for one of the key players, Tesla.

That’s because as we all know, Elon Musk is behind not just Tesla but SpaceX, likely the most successful private space-launch company around. SpaceX has capable launch vehicles and likely the expertise to design and build robotic mining spacecraft, which could give Tesla total control of their entire vertical from mining the resources in space, transporting them back to Earth (humans have been sending material from space to Earth since the start of the space program, remember), manufacturing those resources into batteries, and from there into electric cars.

Has this been Elon’s plan all along? Has all the Mars colonization hype just been a red-planet herring to distract us from his real preparations for large-scale asteroid mining?

Probably not, but it’s fun to think about. There’s also an environmental argument in favor of asteroid mining for electric car batteries. Where electric cars are far cleaner at the car level, they still take an environmental toll to build, since mining isn’t exactly the most eco-friendly endeavor. Moving that part of the equation off-planet would made the overall life cycle of an electric car vastly better for the Earth, for the simple reason it’s just not happening there.

NREL Research Yields Significant Thermoelectric Performance



Addition of thin films to fabrics could power portable electronics, sensorsScientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) reported significant advances in the thermoelectric performance of organic semiconductors based on carbon nanotube thin films that could be integrated into fabrics to convert waste heat into electricity or serve as a small power source.

The research demonstrates significant potential for semiconducting single-walled carbon nanotubes (SWCNTs) as the primary material for efficient thermoelectric generators, rather than being used as a component in a “composite” thermoelectric material containing, for example, carbon nanotubes and a polymer.

The discovery is outlined in the new Energy & Environmental Science paper, Large n- and p-type thermoelectric power factors from doped semiconducting single-walled carbon nanotube thin films.

NREL scientists Andrew Ferguson, left, and Jeffrey Blackburn stand in front of a screen displaying single-walled carbon nanotubes. (Photo by Dennis Schroeder/NREL)

“There are some inherent advantages to doing things this way,” said Jeffrey Blackburn, a senior scientist in NREL’s Chemical and Materials Science and Technology center and co-lead author of the paper with Andrew Ferguson.

These advantages include the promise of solution-processed semiconductors that are lightweight and flexible and inexpensive to manufacture. Other NREL authors are Bradley MacLeod, Rachelle Ihly, Zbyslaw Owczarczyk, and Katherine Hurst.

The NREL authors also teamed with collaborators from the University of Denver and partners at International Thermodyne, Inc., based in Charlotte, N.C.

Ferguson, also a senior scientist in the Chemical and Materials Science and Technology center, said the introduction of SWCNT into fabrics could serve an important function for “wearable” personal electronics.

By capturing body heat and converting it into electricity, the semiconductor could power portable electronics or sensors embedded in clothing.

Blackburn and Ferguson published two papers last year on SWCNTs, and the new research builds on their earlier work. The first paper, in Nature Energy, showed the potential that SWCNTs have for thermoelectric applications, but the films prepared in this study retained a large amount of insulating polymer.

The second paper, in ACS Energy Letters, demonstrated that removing this “sorting” polymer from an exemplary SWNCT thin film improved thermoelectric properties.

The newest paper revealed that removing polymers from all SWCNT starting materials served to boost the thermoelectric performance and lead to improvements in how charge carriers move through the semiconductor.

The paper also demonstrated that the same SWCNT thin film achieved identical performance when doped with either positive or negative charge carriers. These two types of material–called the p-type and the n-type legs, respectively–are needed to generate sufficient power in a thermoelectric device.

Semiconducting polymers, another heavily studied organic thermoelectric material, typically produce n-type materials that perform much worse than their p-type counterparts. The fact that SWCNT thin films can make p-type and n-type legs out of the same material with identical performance means that the electrical current in each leg is inherently balanced, which should simplify the fabrication of a device.

The highest performing materials had performance metrics that exceed current state-of-the-art solution-processed semiconducting polymer organic thermoelectrics materials.

“We could actually fabricate the device from a single material,” Ferguson said. “In traditional thermoelectric materials you have to take one piece that’s p-type and one piece that’s n-type and then assemble those into a device.”

The research was funded by a cooperative research and development agreement (CRADA) with partner International Thermodyne. The fundamental research in SWCNT separation and optical/electrical characterization is supported by the U.S. Department of Energy’s Office of Science.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

NREL Inks Technology Agreement for High Efficiency Multijunction Solar Cells


October 24, 2017

MicroLink Devices opens the door for new multijunction solar cell applications

October 24, 2017

The U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) has entered into a license agreement with MicroLink Devices, Inc. (Niles, IL) to commercialize NREL’s patented inverted metamorphic (IMM) multijunction solar cells. 

While high-efficiency multijunction solar cells are commonly used for space satellites, researchers have continued to look for ways to improve cost and performance to enable a broader range of applications. 

The IMM technique licensed by MicroLink Devices enables multijunction III-V solar cells to be grown with both higher efficiencies and lower costs than traditional multijunction solar cells by reversing the order in which individual sub-cells are typically grown.



Two hands holding the IMM solar cellA 6-inch MicroLink Devices high-efficiency, lightweight and flexible ELO IMM solar cell wafer. Photo courtesy of MicroLink Devices

The IMM architecture enables greater power extraction from the higher-bandgap sub-cells and further allows the use of more efficient low-bandgap sub-cell materials such as Indium Gallium Arsenide. 

In contrast to traditional III-V multijunction solar cells, IMM devices are removed from their growth substrate, allowing the substrate to be reused over multiple growth runs – a significant component in reducing overall device costs. Removing the substrate also reduces the weight of the solar cell, which is important for applications such as solar-powered unmanned aerial vehicles.

MicroLink Devices is an Illinois-based ISO 9001 certified semiconductor manufacturer specializing in removing active semiconductor device layers from their growth substrate via a proprietary epitaxial liftoff (ELO) process. 

By utilizing its ELO capabilities, MicroLink will be able to make thin, lightweight, and highly flexible IMM solar cells which are ideal for use in unmanned aerial vehicles, space-based vehicles and equipment, and portable power generation applications. 

“IMM makes multijunction solar cells practical for a wide variety of weight-, geometry-, and space-constrained applications where high efficiency is critical,” said Jeff Carapella, one of the researchers in NREL’s III-V multijunction materials and devices research group that developed the technology.

“Former NREL Scientist Mark Wanlass pioneered the use of metamorphic buffer layers to form tandem III-V solar cells with three or more junctions. 

This approach is very synergistic with our ELO process technology, and MicroLink Devices is excited to now be commercializing IMM solar cells for high-performance space and UAV applications,” said Noren Pan, CEO of MicroLink Devices.

MicroLink and NREL have collaborated to evaluate the use of ELO for producing IMM solar cells since 2009, when MicroLink was the recipient of a DOE PV Incubator subcontract from NREL. 

Tests of MicroLink-produced IMM solar cells conducted at NREL have demonstrated multiple successful substrate reuses and efficiencies exceeding 30%.

NREL has more than 800 technologies available for licensing and continues to engage in advanced research and development of next-generation IMM and ultra-high-efficiency multijunction solar cells with both academic and commercial collaborators. 

Companies interested in partnering to advance research on or commercialize renewable energy technologies can visit the EERE Energy Innovation Portal, which features descriptions of all renewable energy technologies funded by the DOE’s Office of Energy Efficiency and Renewable Energy. 

Parties interested specifically in ongoing development of IMM solar cells can contact Dan Friedman, Manager of NREL’s High Efficiency Crystalline Photovoltaics Group, for more information.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

The Graphene Roadmap: Commercializing Graphene – Featured Graphene Latest Innovations



Graphene Engineering Innovation Centre

James Baker, Business Director for Graphene at The University of Manchester, talks to AZoNano about the current state of the graphene market and the key next steps needed.

When we last spoke back in 2015 the National Graphene Institute (NGI) had been focused on the successful commercialisation of graphene through collaborative work between research and industry. How has the graphene community developed since then?

The University of Manchester (UoM) now has over 250 researchers working on graphene and 2D materials and the National Graphene Institute (NGI) has now been open for over 2 years. The NGI has provided a key facility and capability in bringing together the multi-disciplinary research from across the University together with developing partnerships and collaborations with industry to accelerate the development of graphene products and applications. 




We are also close to opening our second graphene building, the Graphene Engineering Innovation Centre, next year. This will allow the University to create a unique hub for 2D materials knowledge and commercialisation in Manchester alongside close links with industry.




The graphene roadmap was a crucial part of the conversation two years ago. Where do you think the industry currently stands in-line with these predictions?

Road-mapping is a key part of the commercialisation journey but I am now seeing a much more significant “applications pull” from industry which is resulting in increasing engagement of activity and translation into projects and the development of new graphene enhanced concepts and applications.

You recently spoke about commercialisation at Graphene Week 2017. What were the key areas of discussion this year?

As always there is a significant amount of new science being presented at Graphene Week, but there was also evidence of industry now starting to get “interesting” and “beneficial” results from their engagements and projects involving graphene with a significant amount of progress having taken place over the past two years.



New approach yields graphene-based sensors that are quieter and more sensitive


A common challenge when attempting to make a graphene-based sensor is the high levels of electronic noise that are caused, reducing its effectiveness. In a recent work, an international team of researchers proposed a graphene-based semiconductor device that reduces electronic noise when its electric charge is neutral (referred to as its neutrality point). The group achieved this neutrality point without the need for bulky magnetic equipment that had previously prevented these approaches from being used in portable sensor applications.

In a proof-of-concept device, the researchers used their new sensing scheme to detect HIV-related DNA hybridization at picomolar concentrations. The team fabricated a charge detector out of graphene that can detect very small amounts of charges close to its surface. The sensing principle of the device relies on charge species detection through the field-effect, which brings about a change in electrical conductance of graphene upon adsorption of a charged molecule on the sensor surface.

“Graphene is perfect for such application,” explained members of the team. “Graphene is unique among other solid-state materials in that all carbon atoms are located on the surface, making the graphene surface highly sensitive for detection of changes in the environment.” 

However, the team notes that the ability to create practical electrochemically gated graphene-based field-effect transistors to detect charged species also requires a small amount of electronic noise, the existence of which fundamentally limits a sensor’s resolution.

“I believe we have discovered an elegant and simple approach to improve the sensitivity of next generation graphene electronic biochemical sensor devices,” said the team. “Our device is able to function at its low-noise neutrality point without the need for complicated magnetic equipment that other approaches using graphene have depended upon.”

The researchers add that electronic noise can be reduced without compromising the sensing response, enabling significant improvement to the signal-to-noise ratio compared to that of a conventionally operated graphene transistor to measure conductance. This noise reduction and maintaining of the sensing response is achieved by making use of one of the unique properties of graphene field-effect transistors: its ambipolar (being both n- or p-type) behavior near the neutrality point.

This neutrality point appears in graphene as the lowest point of conductance in the material and is the result of graphene’s unique electronic band structure. At this low conductance point, the graphene sensors can operate at a lower noise level. While this doesn’t compromise the sensing response, it does lower the signal-to-noise ratio of the device, resulting in an overall improved sensing response.

Another feature of the latest device is the use of so-called in-situ ‘electrochemical cleaning’ to ensure a clean graphene surface, which is a new technique meant to enable graphene electronic biosensors to provide reliable performance.
While they were able to test their sensing scheme on HIV, more work must be done before this device could find its way into the next generation of biochemical sensors. 

First of all, the team believes that there is a need to scale up the miniaturized graphene electronic arrays. In addition, microfluidic or nanofludic liquid handling should also be integrated into the arrays. 

There will also be a need for on-site electrochemical cleaning on each of the devices and the more surface functionalization to suit different cases of biomolecule detection.

The researchers intend to adopt this low-noise technology for other single molecule detection methods and evaluate the sensor performances when scaled up.

Source: spectrum.ieee.com Science Advances

Breaking through the sunlight-to-electricity conversion limit



Solar-excited “hot” electrons are usually wasted as heat in conventional silicon solar cells. In a new type of solar cell, known as a hybrid organic-inorganic perovskite cell, scientists found these “hot” electrons last longer. These hot electrons have lifetimes more than a 1000 times longer than those formed in silicon cells. 

The rotation of oppositely charged ions plays a key role in protecting “hot” electrons from adverse energy-depleting interactions (Science, “Screening in crystalline liquids protects energetic carriers in hybrid perovskites”).


In the illustration of a perovskite structure, a “hot” electron is located at the center of the image. Positive molecules (red and blue dumbbells) surround the “hot” electron. The distortion of the crystal structure and the liquid-like environment of the positive molecules (blurred dumbbells at the periphery of the image) screen (yellow circle, partially shown) the “hot” electron. The “shield” protects the hot electron and allows it to survive 1000 times longer than it would in conventional silicon solar cells. (Image: Xiaoyang Zhu, Columbia University)

This research identified a possible route to dramatically increase the efficiency of solar cells. By slowing the cooling of excited “hot” electrons, scientists could produce more electricity. They could devise cells that function above the predicted efficiency limit, around 33 percent, for conventional solar cells.

Hybrid organic-inorganic lead halide perovskites (HOIP) are promising new materials for use in low-cost solar cells. HOIPs have already been demonstrated in solar cells with solar-to-electricity conversion efficiency exceeding 20 percent, which is on par with the best crystalline silicon solar cells.

Research is ongoing to discover why HOIPs work so well for solar energy harvesting and to determine their efficiency limit. A team led by Columbia University has discovered that electrons in HOIPs acquire protective shields that make them nearly invisible to defects and other electrons, which allows the electrons to avoid losing energy. The mechanism of protection is dynamic screening correlated with liquid-like molecular motions in the crystal structure.

Moreover, the researchers discovered that the protection mechanism works for electrons with excess energy (with energy greater than the semiconductor band gap); as a result, these so-called “hot” electrons are very long-lived in HOIPs. In a conventional solar cell, such as the silicon cell widely in use today, only part of the solar spectrum is used, and the energy of the “hot” electrons is wasted. Excess electron energy generated initially from the absorption of high-energy photons in the solar spectrum is lost as heat before the electron is harvested for electricity production.

For conventional solar cells, this loss is partially responsible for the theoretical efficiency limit of around 33 percent, called the Shockley-Queisser limit. However, the long lifetime of “hot” electrons in HOIPs makes it possible to harvest the “hot” electrons to produce electricity, thus increasing the efficiency of HOIP solar cells beyond the conventional limit.

Source: U.S. Department of Energy, Office of Science

NREL Charges Forward to Reduce Time at EV Stations



Shortening recharge times may diminish range anxiety, increase EV market viability, however Speeding up battery charging will be crucial to improving the convenience of owning and driving an electric vehicle (EV). 




The Energy Department’s National Renewable Energy Laboratory (NREL) is collaborating with Argonne National Laboratory (ANL), Idaho National Laboratory (INL), and industry stakeholders to identify the technical, infrastructure, and economic requirements for establishing a national extreme fast charging (XFC) network.


Today’s high power EV charging stations take 20 minutes or more to provide a fraction of the driving range car owners get from 10 minutes at the gasoline pump. 

Porsche is leading the industry with the deployment of two XFC 350kW EV charging stations in Europe that will begin to approach the refueling time of gasoline vehicles. Photo courtesy of Porsche.

Drivers can pump enough gasoline in 10 minutes to carry them a few hundred miles. Most of today’s fast charging stations take 20 minutes to provide 50-70 miles of electric driving range. 

A series of articles in the current edition of the Journal of Power Sources summarizes the NREL team’s findings on how battery, vehicle, infrastructure, and economic factors impact XFC feasibility.

“You can charge an EV today at one of 44,000 stations across the country, but if you can’t leave your car plugged in for a few hours, you may only get enough juice to travel across town a few times,” says NREL Senior Engineer and XFC Project Lead Matthew Keyser

“We’re working to match the time, cost, and distance that generations of drivers have come to expect—with the additional benefits of clean, energy-saving technology.”

While XFC can help overcome real (and perceived) EV driving range limitations, the technology also introduces a series of new challenges. More rapid and powerful charging generates higher temperatures, which can lead to battery degradation and safety issues. 

Power electronics found in commercially available EVs are built for slower overnight charging and may not be able to withstand the stresses of higher voltage battery systems which are expected for higher power charging systems. XFC’s extreme, intermittent demands for electricity could also pose challenges to grid stability.

The XFC research team is exploring solutions for these issues, examining factors related to vehicle technology, gaps in existing technology, new demands on system design, and additional thermal management requirements. Researchers are also looking beyond vehicle systems to consider equipment and station design and potential impact on the grid.


NREL’s intercity travel analysis revealed that recharge times comparable to the time it takes to pump gas will require charge rates of at least 400 kW. 

Current DC Fast Charging rates are limited to 50-120 kW, and most public charging stations are limited to 7kW. 




XFC researchers have concluded that this will necessitate increases in battery charging density and new designs to minimize potential related increases in component size, weight, and cost. 

It appears that a more innovative battery thermal management system will be needed if XFC is to become a reality, and new strategies and materials will be needed to improve battery cell and pack cooling, as well as the thermal efficiency of cathodes and anodes.




“Yes, this substantial increase in charging rate will create new technical issues, but they are far from insurmountable—now that we’ve identified them,” says NREL Engineer Andrew Meintz.

Development of a network of XFC stations will depend on cost, market demand, and management of intermittent power demands. 
The team’s research revealed a need for more extensive analysis of potential station siting, travel patterns, grid resources, and business cases. 

At the same time, it is clear that any XFC network will call for new infrastructure technology and operational practices, along with cooperation and standardization across utilities, station operators, and manufacturers of charging systems and EVs.

These studies provide an initial framework for effectively establishing XFC technology. The initiative has attracted keen interest from industry members, who realize that faster charging will ultimately lead to wider market adoption of EV technologies.

This research is supported by the DOE Vehicle Technologies Office. Learn more about NREL’s energy storage and EV grid integration research.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

A Hydrogen Fuel-Powered Truck hits the Road, emitting only Water Vapor!


Hydrogen Truck Project-Portal-Toyota-fuel-cell-truck-full-grilleA concept truck by Toyota is powered by hydrogen fuel cells and emits nothing but water vapor. Photo Credit: Toyota

 

Vehicles powered by alternatives to fossil fuel are on the roll. Literally. The Japanese automaker Toyota is rolling out a new line of vehicles powered by hydrogen fuel cells. A concept version of a long-haul truck with the car manufacturer’s new hydrogen-based engine in it will set out with a full load of cargo from Los Angeles and make its way to Long Beach.

“If you see a big-rig driving around the Ports of Los Angeles and Long Beach that seems oddly quiet and quick, do not be alarmed! It’s just the future,” Toyota quips in a statement issued to the press. The trial is part of the Japanese company’s feasibility studies for its brand-new “Project Portal” – a hydrogen fuel cell systemdesigned for heavy-duty trucks. Toyota touts its Project Portal as the next step in its development of zero-emission fuel cell technology for industrial uses.

“[The trial’s] localized, frequent route patterns are designed to test the demanding drayage duty-cycle capabilities of the fuel cell system while capturing real world performance data,” Toyota explains  of its upcoming test runs. “As the study progresses, longer haul routes will be introduced.”

Toyota’s heavy-duty concept truck boasts a beast of an engine with more than 670 horsepower and 1,325 pound feet of torque thanks to a pair of Mirai fuel cell stacks and a relatively small 12kWh battery. The truck’s gross weight capacity is over 36,000kg while its projected driving range is more than 320km per fill under normal drayage conditions.

Comparable long-haul trucks, if powered by gasoline, emit plenty of CO2. Not this new one, though. “The zero-emission class 8 truck proof of concept has completed more than 4,000 successful development miles, while progressively pulling drayage rated cargo weight, and emitting nothing but water vapor,” the company explains.

You’ve read that right: the truck will emit water vapor and nothing else. This means that the technology, once it is put into use on a wider scale, can help us reduce our CO2 emissions in an effort to mitigate the effects of climate change.

Nanosheets Make Batteries Better: New method may be the next step for high performance lithium-ion batteries.


Graphene Sheets 20170627-ASTAR-lithium-343yoafotmqoi1thc5hj40

Lithium-ion batteries are used to power many things from mobile phones, laptops, tablets to electric cars. But they have some drawbacks, including limited energy storage capacity, low durability and long charging time.

Now, researchers at the Institute of Bioengineering and Nanotechnology (IBN) at Singapore’s Agency for Science, Technology and Research (A*STAR) have developed a way of producing more durable and longer lasting lithium-ion batteries. This finding was reported in Advanced Materials. Led by IBN Executive Director Professor Jackie Y. Ying, the researchers invented a generalized method of producing anode materials for lithium-ion batteries. The anodes are made from metal oxide nanosheets, which are ultrathin, two-dimensional materials with excellent electrochemical and mechanical properties.

These nanosheets are 50,000 times thinner than a sheet of paper, allowing faster charging of power compared to current battery technology. The wide surface area of the nanosheets makes better contact with the electrolyte, thus increasing the storage capacity. The material used is also highly durable and does not break easily, which improves the battery shelf life. Existing methods of making metal oxide nanosheets are time-consuming and difficult to scale up.

The IBN researchers came up with a simpler and faster way to synthesize metal oxide nanosheets using graphene oxide. Graphene oxide is a 2D carbon material with chemical reactivity that facilities the growth of metal oxides on its surface. Graphene oxide was used as the template to grow metal oxides into nanosheet structures via a simple mixing process, followed by heat treatment. The researchers were able to synthesize a wide variety of metal oxides as nanosheets, with control over the composition and properties. The new technique produces the nanosheets in one day, compared to one week for previously reported methods.

It does not require the use of a pressure chamber and involves only two steps in the synthesis process, making the nanosheets easy to manufacture on a large scale. Tests showed that the nanosheets produced using this generalized approach have excellent lithium-ion battery anode performance, with some materials lasting three times longer than graphite anodes used in current batteries. “Our nanosheets have shown great promise for use as lithium-ion anodes.

This new method could be the next step toward the development of metal oxide nanosheets for high performance lithium-ion batteries. It can also be used to advance other applications in energy storage, catalysis and sensors,” said Ying.

The article can be found at: AbdelHamid et al. (2017) Generalized Synthesis of Metal Oxide Nanosheets and Their Application as Li-Ion Battery Anodes. ——— Source: A*STAR.

Read more from Asian Scientist Magazine at: https://www.asianscientist.com/2017/07/tech/nanosheet-lithium-batteries/