NextGen Vanadium Batteries: Berkeley & Texas A&M Scientists may have solved ‘electron bottleneck’


vanadium small batt night-battery-theme-minimalismAs the appetite grows for more efficient vehicles and mobile devices based on cleaner, renewable energy sources, so does the demand for batteries that pack more punch, last longer, and charge or discharge more quickly. The compound vanadium pentoxide has grabbed the spotlight as a way to improve lithium-ion batteries. However, it’s less-than-stellar behavior has been problematic.

 

An international team working at the Molecular Foundry (Berkeley) revealed why the material may not perform as expected. The team discovered how interactions between electrons and ions slow the performance of electrodes made with vanadium pentoxide (Nature Communications, “Mapping polaronic states and lithiation gradients in individual V2O5 nanowires”).

 

This work answers, in part, why the material gets bogged down. Vanadium pentoxide’s layered atomic structure results in a vast surface area, but a bottleneck occurs. If scientists can address the bottleneck, this material may lead to the next generation of batteries, which pack more punch, last longer, and charge or discharge more quickly.
A scanning electron microscopy image of vanadium pentoxide nanowires
A scanning electron microscopy image of vanadium pentoxide nanowires. The inset shows a ball-and-stick model of vanadium pentoxide’s atomic structure before and after inserting lithium ions (green). (Image: Texas A&M University)
An international team of scientists working at the Molecular Foundry has revealed how interactions between electrons and ions can slow down the performance of vanadium pentoxide, a material considered key to the next generation of batteries.
The compound vanadium pentoxide has grabbed the spotlight as a potential nanostructured material for state-of-the-art lithium-ion batteries because it can provide a greater surface area for the arrival and insertion of lithium ions. That quality makes vanadium pentoxide a good candidate as a cathode, the part of a battery where electrons and lithium ions enter.
The speed with which electrons can enter and exit the cathode determines how much power the battery can provide. The entry and exit speed also determine how quickly a battery recharges.
Power density and charging are both critical factors in the world of mobile electronics or electrification of our automotive fleet. But despite vanadium pentoxide’s potential, it has yet to be widely adopted commercially because of its less-than-stellar performance when put to the test in the real world.
The new findings shed light on the slowdown. The results show that the flow of electrons in vanadium pentoxide nanowires gets bogged down as it interacts with lithium ions in a phenomenon known as small polaron formation.
The research group, which involved scientists at Texas A&M University, made 2D maps of the electronic properties of synthesized vanadium pentoxide nanowires serving as a model lithium-ion cathode using scanning transmission x-ray microscopy at the Canadian Light Source. They came to the Molecular Foundry to interpret their findings.
Source: Molecular Foundry, Berkeley Lab

Vanadium Redox Flow Batteries for Large Scale Energy Storage

vanadium batt medium windcarrier_cellcube-281x300Lithium batteries may reign supreme when it comes to cellphones, laptops and electric vehicles. But for larger-scale energy storage, some are looking at alternative metals and technologies.

Enter Vanadium redox batteries. First successfully created by Dr. Maria Skyllas-Kazacos of the University of New South Wales in the 1980’s, Vanadium redox flow batteries use sulfuric solutions to power themselves. A vanadium electrolyte passing through a proton exchange membrane allows the battery to work, with a solution filling two tanks on either side.

Click Here to Read More: What are Vanadium Redox Batteries?

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‘Light as a Feather’-metal Cathodes for stable lithium-oxygen batteries – Li2-O2


Light Cathode id46819Nanoporous nickel cathodes for lithium oxygen batteries are ultralight, shown here balanced on flower stamens. (© ACS)

Lithium-oxygen systems could someday outperform today’s lithium-ion batteries because of their potential for high energy density. However, a number of important issues, such as their poor electrochemical stability must be addressed before these systems can successfully compete with current rechargeable batteries.Today, in ACS Central Science (“Nanoengineered Ultralight and Robust All-Metal Cathode for High-Capacity, Stable Lithium–Oxygen Batteries”), researchers report a new type of cathode, which could make lithium-oxygen batteries a practical option.

Xin-Bo Zhang and colleagues note that most of the problems associated with lithium-oxygen battery systems arise from two highly reduced oxygen species that react readily with the electrolyte and the cathode. Carbon is a common strong-performing cathode, but it is unstable in these systems.

LI Ox Cathode oc-2017-00120z_0005

The successful development of Li–O2 battery technology depends on resolving the issue of cathode corrosion by the discharge product (Li2O2) and/or by the intermediates (LiO2) generated during cell cycling. As an important step toward this goal, we report for the first time the nanoporous Ni with a nanoengineered AuNi alloy surface directly attached to Ni foam as a new all-metal cathode system.

 

So, the team hypothesized that the key to unlocking lithium-oxygen batteries’ potential could be to create cathodes that are unreactive to the reduced oxygen species, but that still have the same highly conductive, low-weight, porous characteristics of carbon cathodes. The researchers succeeded in creating an ultralight all-metal cathode.

The design incorporated three forms of nickel including a nanoporous nickel interior and a gold-nickel alloy surface directly attached to nickel foam. Compared to carbon cathodes, the system has much higher capacity and is stable for 286 cycles, which is amongst the best for lithium-oxygen systems, and is nearly competitive with current commercial lithium-ion systems.
Further experimentation showed that the stability and performance arise from both the metal used and its nanoporous structure, and that both these aspects could be optimized to further improve performance.

State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
Source: American Chemical Society

UC San Diego: Printed, flexible and rechargeable battery can power Wearable Sensors, Solar Cells, Electronics


 

Nanoengineers at the University of California San Diego have developed the first printed battery that is flexible, stretchable and rechargeable. The zinc batteries could be used to power everything from wearable sensors to solar cells and other kinds of electronics.

The work appears in the April 19, 2017 issue of Advanced Energy Materials.

The researchers made the printed batteries flexible and stretchable by incorporating a hyper-elastic polymer material made from isoprene, one of the main ingredients in rubber, and polystyrene, a resin-like component. The substance, known as SIS, allows the batteries to stretch to twice their size, in any direction, without suffering damage.

The ink used to print the batteries is made of zinc silver oxide mixed with SIS. While zinc batteries have been in use for a long time, they are typically non-rechargeable. The researchers added bismuth oxide to the batteries to make them rechargeable.

“This is a significant step toward self-powered stretchable electronics,” said Joseph Wang, one of the paper’s senior authors and a nanoengineering professor at the Jacobs School of Engineering at UC San Diego, where he directs the school’s Center for Wearable Sensors. “We expect this technology to pave the way to enhance other forms of energy storage and printable, stretchable electronics, not just for zinc-based batteries but also for Lithium-ion batteries, as well as supercapacitors and photovoltaic cells.”

The prototype battery the researchers developed has about 1/5 the capacity of a rechargeable hearing aid battery. But it is 1/10 as thick, cheaper and uses commercially available materials. It takes two of these batteries to power a 3 Volt LED. The researchers are still working to improve the battery’s performance. Next steps include expanding the use of the technology to different applications, such as solar and fuel cells; and using the battery to power different kinds of electronic devices.

Researchers used standard screen printing techniques to make the batteries–a method that dramatically drives down the costs of the technology. Typical materials for one battery cost only $0.50. A comparable commercially available rechargeable battery costs $5.00 Batteries can be printed directly on fabric or on materials that allow wearables to adhere to the skin. They also can be printed as a strip, to power a device that needs more energy. They are stable and can be worn for a long period of time.

Making the batteries rechargeable

The key ingredient that makes the batteries rechargeable is a molecule called bismuth oxide which, when mixed into the batteries’ zinc electrodes, prolongs the life of devices and allows them to recharge. Adding bismuth oxide to zinc batteries is standard practice in industry to improve performance, but until recently, there hasn’t been a thorough scientific explanation for why.

Last year, UC San Diego nanoengineers led by Professor Y. Shirley Meng published a detailed molecular study addressing this question (download PDF here). When zinc batteries discharge, their electrodes react with the liquid electrolyte inside the battery, producing zinc salts that dissolve into a solution. This eventually short circuits the battery. Adding bismuth oxide keeps the electrode from losing zinc to the electrolyte. This ensures that the batteries continue to work and can be recharged.

The work shows that it is possible to use small amounts of additives, such as bismuth oxide, to change the properties of materials. “Understanding the scientific mechanism to do this will allow us to turn non-rechargeable batteries into rechargeable batteries—not just zinc batteries but also for other electro-chemistries, such as Lithium-oxygen,” said Meng, who directs the Sustainable Power and Energy Center at the UC San Diego Jacobs School of Engineering

From Innovation to Market

Rajan Kumar, a co-first author on this Advanced Energy Materials paper, is a nanoengineering Ph.D. student at the Jacobs School of Engineering. He and nanoengineering professor Wang are leading a team focused on commercializing aspects of this work. The team is one of five to be selected to join a new technology accelerator at UC San Diego. The technology accelerator is run by the UC San Diego Institute for the Global Entrepreneur, which is a collaboration between the Jacobs School of Engineering and Rady School of Management.

Kumar is excited at the prospect of taking advantage of all that the IGE Technology Accelerator has to offer.

“For us, it’s strategically perfect,” said Kumar, referring to the $50,000 funding for prototype improvements, the focus on prototype testing with a strategic partner, and the entrepreneurship mentoring.

Kumar is confident in the team’s innovations, which includes the ability to replace coin batteries with thin, stretchable batteries. Making the right strategic moves now is critical for commercialization success.

“It’s now about making sure our energies are focused in the right direction,” said Kumar.

In addition to the IGE Technology Accelerator, the team was also recently selected to participate in the NSF Innovation-Corps (I-Corps) program at UC San Diego, also administered by the Institute for the Global Entrepreneur. One of the key tenets of the I-Corps program is helping startup teams validate their target markets and business models early in the commercialization process. Through NSF I-Corps, for example, Kumar has already started interviewing potential customers which has helped the team better focus their commercialization strategy.

Through these programs, Kumar is focused on leading the team through a series of milestones in order to best position their innovations to refine “both what to build and who to build it for,” he said.

Paper Citation

“All-Printed, Stretchable Zn-Ag2O Rechargeable Battery via Hyperelastic Binder for Self-Powering Wearable Electronics” in the journal Advanced Energy Materials.http://onlinelibrary.wiley.com/doi/10.1002/aenm.201602096/full

Authors: Rajan Kumar, Jaewook Shin, Lu Yin, Jung-Min You, Prof. Shirley Meng and Prof. Joseph Wang, Department of Nanoengineering, Jacobs School of Engineering, University of California San Diego.

Joseph Wang is a distinguished professor, holds the SAIC endowed chair, and serves as chair of the Department of NanoEngineering at the UC San Diego Jacobs School of Engineering where he directs the Center for Wearable Sensors.

Shirley Meng is a professor in the Department of NanoEngineering and Director of the Sustainable Power and Energy Center at the UC San Diego Jacobs School of Engineering.

Research funders include: Advanced Research Projects Agency-Energy (DE-AR0000535); Rajan Kumar acknowledges the U.S. National Science Foundation (NSF) Graduate Research Fellowship under Grant No (DGE-1144086).

This work was performed in part at the San Diego Nanotechnology Infrastructure (SDNI), a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the U.S. National Science Foundation (NSF).

MIT: A BIG step toward mass-producible quantum computers


Quantum Computer Big Step Mass P id46842

A team of researchers from MIT, Harvard University, and Sandia National Laboratories reports a new technique for creating targeted defects in diamond materials, which is simpler and more precise than its predecessors and could benefit diamond-based quantum computing devices.

Quantum computers are experimental devices that offer large speedups on some computational problems. One promising approach to building them involves harnessing nanometer-scale atomic defects in diamond materials.But practical, diamond-based quantum computing devices will require the ability to position those defects at precise locations in complex diamond structures, where the defects can function as qubits, the basic units of information in quantum computing. In Nature Communications (“Scalable focused ion beam creation of nearly lifetime-limited single quantum emitters in diamond nanostructures”), a team of researchers from MIT, Harvard University, and Sandia National Laboratories reports a new technique for creating targeted defects, which is simpler and more precise than its predecessors.

In experiments, the defects produced by the technique were, on average, within 50 nanometers of their ideal locations.
“The dream scenario in quantum information processing is to make an optical circuit to shuttle photonic qubits and then position a quantum memory wherever you need it,” says Dirk Englund, an associate professor of electrical engineering and computer science who led the MIT team. “We’re almost there with this. These emitters are almost perfect.”
The new paper has 15 co-authors. Seven are from MIT, including Englund and first author Tim Schröder, who was a postdoc in Englund’s lab when the work was done and is now an assistant professor at the University of Copenhagen’s Niels Bohr Institute. Edward Bielejec led the Sandia team, and physics professor Mikhail Lukin led the Harvard team.

Appealing defects

Quantum computers, which are still largely hypothetical, exploit the phenomenon of quantum “superposition,” or the counterintuitive ability of small particles to inhabit contradictory physical states at the same time. An electron, for instance, can be said to be in more than one location simultaneously, or to have both of two opposed magnetic orientations.
Where a bit in a conventional computer can represent zero or one, a “qubit,” or quantum bit, can represent zero, one, or both at the same time. It’s the ability of strings of qubits to, in some sense, simultaneously explore multiple solutions to a problem that promises computational speedups.
Diamond-defect qubits result from the combination of “vacancies,” which are locations in the diamond’s crystal lattice where there should be a carbon atom but there isn’t one, and “dopants,” which are atoms of materials other than carbon that have found their way into the lattice. Together, the dopant and the vacancy create a dopant-vacancy “center,” which has free electrons associated with it. The electrons’ magnetic orientation, or “spin,” which can be in superposition, constitutes the qubit.
A perennial problem in the design of quantum computers is how to read information out of qubits. Diamond defects present a simple solution, because they are natural light emitters. In fact, the light particles emitted by diamond defects can preserve the superposition of the qubits, so they could move quantum information between quantum computing devices.

Silicon switch

The most-studied diamond defect is the nitrogen-vacancy center, which can maintain superposition longer than any other candidate qubit. But it emits light in a relatively broad spectrum of frequencies, which can lead to inaccuracies in the measurements on which quantum computing relies.
In their new paper, the MIT, Harvard, and Sandia researchers instead use silicon-vacancy centers, which emit light in a very narrow band of frequencies. They don’t naturally maintain superposition as well, but theory suggests that cooling them down to temperatures in the millikelvin range — fractions of a degree above absolute zero — could solve that problem. (Nitrogen-vacancy-center qubits require cooling to a relatively balmy 4 kelvins.)
To be readable, however, the signals from light-emitting qubits have to be amplified, and it has to be possible to direct them and recombine them to perform computations. That’s why the ability to precisely locate defects is important: It’s easier to etch optical circuits into a diamond and then insert the defects in the right places than to create defects at random and then try to construct optical circuits around them.
In the process described in the new paper, the MIT and Harvard researchers first planed a synthetic diamond down until it was only 200 nanometers thick. Then they etched optical cavities into the diamond’s surface. These increase the brightness of the light emitted by the defects (while shortening the emission times).
Then they sent the diamond to the Sandia team, who have customized a commercial device called the Nano-Implanter to eject streams of silicon ions. The Sandia researchers fired 20 to 30 silicon ions into each of the optical cavities in the diamond and sent it back to Cambridge.

Mobile vacancies

At this point, only about 2 percent of the cavities had associated silicon-vacancy centers. But the MIT and Harvard researchers have also developed processes for blasting the diamond with beams of electrons to produce more vacancies, and then heating the diamond to about 1,000 degrees Celsius, which causes the vacancies to move around the crystal lattice so they can bond with silicon atoms.
After the researchers had subjected the diamond to these two processes, the yield had increased tenfold, to 20 percent. In principle, repetitions of the processes should increase the yield of silicon vacancy centers still further.
When the researchers analyzed the locations of the silicon-vacancy centers, they found that they were within about 50 nanometers of their optimal positions at the edge of the cavity. That translated to emitted light that was about 85 to 90 percent as bright as it could be, which is still very good.
Source: By Larry Hardesty, MIT

 

Water is surprisingly ordered on the nanoscale



Nanometric-sized water drops are everywhere – in the air as droplets or aerosols, in our bodies as medication, and in the earth, within rocks and oil fields. To understand the behavior of these drops, it is necessary to know how they interact with their hydrophobic environment. 

This interaction takes places at the curved droplet interface, a sub-nanometric region that surrounds the small pocket of water. Researchers from EPFL, in collaboration with the institute AMOLF in the Netherlands, were able to observe what was going on in this particular region. 

They discovered that molecules on the surface of the drops were much more ordered than expected. Their surprising results have been published in Nature 
Communications. They pave the way to a better understanding of atmospheric, biological and geological processes.

 Unique perspective on miniscule droplets

 

At EPFL, Sylvie Roke, director of the Julia Jacobi Chair of Photomedicine -Laboratory for Fundamental BioPhotonics, has developed a unique method for examining the surface of these droplets that are as thick as one thousandth of a hair, with a volume of an attoliter (18 zeros behind the comma). 

“The method involves overlapping ultrashort laser pulses in a mixture of water droplets in liquid oil and detecting photons that are scattered only from the interface”, explains Roke. “These photons have the sum frequency of the incoming photons and are thus of a different color. With this newly generated color we can know the structure of the only the interface.”

Hydrogen bonding as strong as in ice


 The surface of the water droplets turns out to be much more ordered than that of normal water and is comparable to super cooled (liquid < 0 °C water) water in which the water molecules have very strong hydrogen bond interactions. In ice, these interactions lead to a stable tetrahedral surrounding of each water molecule. Surprisingly, this type of structure was found on the surface of the droplets even at the room temperature – 50 °C above were it would normally appear. 

Chemical processes


This research provides valuable insight into the properties of nanometric water drops. “The chemical properties of these drops depend on how the water molecules are organized on the surface, so it’s really important to understand what’s going on there,” explained Roke. Further research could target the surface properties of water droplets with adding salt, a more realistic model of marine aerosols that consist of salty water surrounded by a hydrophobic environment. Salt may either enhance the water network or reduce its strength. “Or, it may not do anything at all. Given the surprising results found here, we can only speculate”, says Roke.

 

The surface of the water droplets turns out to be much more ordered than that of normal water and is comparable to super cooled (liquid < 0 °C water) water in which the water molecules have very strong hydrogen bond interactions. @ EPFL- Julia Jacobi Chair of Photomedicine – Laboratory for fundamental BioPhotonics

 

The interfacial structure of water droplets in a hydrophobic liquid

Nikolay Smolentsev, Wilbert J. Smit, Huib J. Bakker & Sylvie Roke

Nature Communications 8, Article number: 15548 (2017)

doi:10.1038/ncomms15548

The Lilium Jet – The world’s first all-electric VTOL jet (vertical take-off and landing): Video


lilium-jet-5-seater

*** From Lilium All-Electric Jet Services

We have incredibly exciting news to share. The Lilium Jet successfully completed its maiden test flight series in the skies above Bavaria. The 2-seater Eagle prototype executed a range of complex maneuvers, including its signature mid-air transition from hover mode to wing-borne forward flight.

Seeing the Lilium Jet take to the sky and performing sophisticated maneuvers with apparent ease is testament to the skill and perseverance of our amazing team. We have solved some of the toughest engineering challenges in aviation to get to this point. The successful test flight programme shows that our ground-breaking technical design works exactly as we envisioned. We can now turn our focus to designing a 5-seater production aircraft.

Watch the Video

Lilium enables you to travel 5 times faster than a car by introducing the world’s first all-electric vertical take-off and landing jet: an air taxi for up to 5 people. You won’t have to own one, you will simply pay per ride and call it with a push of a button. It’s our mission to make air taxis available to everyone and as affordable as riding a car.

In 1894, Otto Lilienthal began experimenting with the first gliders and imagined a future in which we could all fly wherever we want, whenever we want. Lilium is turning that dream into reality. We are bringing personalized, clean and affordable air travel to everyone.

lilium-rooftop-landing-pad-1536w

Read about the Lilium Jet Story and Technology

The world’s first electric vertical take-⁠off and landing jet.

** Information obtained for this article is from the Company’s News Release and Website It is for informational purposes only and does not represent any form of  endorsement. **

 

 

 

 

 

 

New Battery Could Power Electric Cars 620 Miles (@ 1,000km) on Single Charge



The average American drives about 30 miles (48 kilometers) per day, according to AAA, yet many people are still reluctant to buy electric cars that can travel three times that distance on a single charge. 

This so-called range anxiety is one reason gasoline-powered vehicles still rule the road, but a team of scientists is working to ease those fears.

Mareike Wolter, Project Manager of Mobile Energy Storage Systems at Fraunhofer-Gesellschaft in Dresden, Germany, is working with a team on a new battery that would give electric cars a range of about 620 miles (1,000 km) on a single charge.



Wolter said the project began about three years ago when researchers from Fraunhofer as well as ThyssenKrupp System Engineering and IAV Automotive Engineering started brainstorming about how they could improve the energy density of automotive lithium batteries. 



They turned to the popular all-electric car, the Tesla, as a starting point. Tesla’s latest vehicle, the Model S 100D has a 100-kilowatt-hour battery pack, which reportedly gives it a range of 335 miles (540 km). 

The pack is large, about 16 feet long, 6 feet wide and 4 inches thick. It contains more than 8,000 lithium-ion battery cells, each one individually packaged inside a cylinder housing that measures about 2 to 3 inches (6 to 7 centimeters) high and about 0.8 inches (2 cm) across.

“We thought if we could use the same space as the battery in the Tesla, but improve the energy density and finally drive 1,000 km, this would be nice,” Wolter told Live Science.

One way of doing this would be to refine the materials inside the battery so that it could store more energy, she said. But another way would be to improve the system’s design as a whole, Wolter said. 

Nearly 50 percent of each cell is devoted to components such as the housing, the anode (the battery’s negative terminal), the cathode (the battery’s positive terminal) and the electrolyte, the liquid that transports the charged particles. 

Additional space is needed inside the car to wire the battery packs to the vehicle’s electrical system.

“It’s a lot of wasted space,” Wolter said. “You have a lot of inactive components in the system, and that’s a problem from our point of view.”

The scientists decided to reimagine the entire design, they said.


An illustration that shows how the new electric battery is stacked like a ream of paper. Credit: Fraunhofer IKTS

To do so, they got rid of the housings that encase individual batteries and turned to a thin, sheet-like design instead of a cylinder. 

Their metallic sheet is coated with an energy-storage material made from powdered ceramic mixed with a polymer binder. One side serves as the cathode, and other side serves as the anode.

The researchers stacked several of these so-called bipolar electrodes one on top of the other, like sheets of paper in a ream, separating the electrodes by thin layers of electrolyte and a material that prevents electrical charges from shorting out the whole system.

The “ream” is sealed within a package measuring about 10 square feet (1square meter), and contacts on the top and bottom connect to the car’s electrical system.

The goal is to build a battery system that fits in the same space as the one used by Tesla’s vehicles or other electric vehicles, the researchers said.

“We can put more electrodes storing the energy in the same space,” Wolter said.

She added that the researchers aim to have such a system ready to test in cars by 2020.

Original article on Live Science.

MIT: Tesla Not the Only Battery Game in Town ~ Electric Cars Could Be Cheaper Than Internal Combustion by 2030


German chancellor Angela Merkel visits Accumotive’s plant in Kamenz, Germany.

Tesla gets the headlines, but big battery factories are being built all over the world, driving down prices.

Battery production is booming, and Tesla is far from the only game in town.

According to Bloomberg New Energy Finance, global battery production is forecast to more than double between now and 2021. The expansion is in turn driving prices down, good news both for the budding electric-car industry and for energy companies looking to build out grid-scale storage to back up renewable forms of energy.


While Tesla gets tons of attention for its “gigafactories”—one in Nevada that will produce batteries, and another in New York that will produce solar panels
—the fact is, the company has a lot of battery-building competition.

Exhibit A is a new battery plant in Kamenz, Germany, run by Accumotive. The half-billion-euro facility broke ground on Monday with a visit from German chancellor Angela Merkel and will supply batteries to its parent company, Daimler, which is betting heavily on the burgeoning electric-vehicle market.

But the lion’s share of growth is expected to be in Asia. BYD, Samsung, LG, and Panasonic (which has partnered with Tesla) are all among the world’s top battery producers, and nine of the world’s largest new battery factories are under construction in China (paywall), according to Benchmark Minerals.

That competition means the steady downward trend in battery prices is going to continue. On a per-kilowatt-hour basis, costs have fallen from $542 in 2012 to around $139 today, according to analysis by Benchmark.

That makes for a huge difference in the cost of an electric car, of which 40 percent is usually down to the battery itself.


Bloomberg’s analysts have already said that the 2020s could be the decade in which electric cars take off—and one even went so far as to say that by 2030, electric cars could be cheaper than those powered by internal combustion.

Those watching the industry might worry that a flood of cheap batteries could end up hurting profitability for producers, as happened in the solar-panel business.

That could happen, but India and China, two huge rising automotive markets, are bullish about using electric cars to help solve problems like traffic congestion and air pollution. So even as supply ramps up, there is likely to be plenty of demand to go around.

MIT Technology Review: M. Reilly Sr. Editor

A Holey Graphene Electrode framework that enables highly efficient charge delivery – Making Better Batteries for the Future


Holey Graphene II grapheneThis visualisation shows layers of graphene used for membranes. Credit: University of Manchester

A team of researchers affiliated with institutions in the U.S., China and the Kingdom of Saudi Arabia has developed a new type of porous graphene electrode framework that is capable of highly efficient charge delivery. In their paper published in the journal Science, the group describes how they overcame traditional conflicts arising between trade-offs involving density and speed to produce an electrode capable of facilitating rapid ion transport. Hui-Ming Cheng and Feng Li with the Chinese Academy of Sciences offer a Perspective piece on the work done by the team in the same journal issue, and include some opinions of their own regarding where such work is likely heading.

In a perfect world, batteries would have unlimited energy storage delivered at speeds high enough to power devices with unlimited needs. The phaser from Star Trek, for example, would require far more power and speed than is possible in today’s devices.

While it is unlikely that such technology will ever come about, it does appear possible that batteries of the future will perform much better than today, likely due to nano-structured materials—they have already shown promise when used as material due to their unique properties. Unfortunately, their use has been limited thus far due to the ultra-thin nature of the resulting electrodes and their extremely low mass loadings compared to those currently in use. In this new effort, the researchers report on a new way to create an electrode using that overcomes such limitations.

The electrode they built is porous, which in this case means that it has holes in it. Those holes, as Cheng and Li note, allow better charge transport while also offering improved capacity retention density. The graphene framework they built, they note, offers a superior means of electron transport and its porous nature allows for a high ion diffusion rate—the holes force the ions to take shortcuts, reducing diffusion.

Cheng and Li suggest the new work is likely to inspire similar designs in the search for better electrode materials, which they further suggest appears likely to lead to new electrodes that are not only practical, but have high mass loadings.

Explore further: New graphene framework bridges gap between traditional capacitors, batteries

More information: Hongtao Sun et al. Three-dimensional holey-graphene/niobia composite architectures for ultrahigh-rate energy storage, Science (2017). DOI: 10.1126/science.aam5852

Abstract
Nanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) because of the increasing ion diffusion limitations in thicker electrodes.

We report the design of a three-dimensional (3D) holey-graphene/niobia (Nb2O5) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport.

By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications.