Quantum Dots from a Familiar Energy Source, Coal: Video

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The prospect of turning coal into fluorescent particles may sound too good to be true, but the possibility exists, thanks to scientists at Rice University.

The Rice lab of chemist James Tour found simple methods to reduce three kinds of coal into graphene quantum dots (GQDs), microscopic discs of atom-thick graphene oxide that could be used in medical imaging as well as sensing, electronic and photovoltaic applications.

Coal yields production of graphene quantum dots

Band gaps determine how a semiconducting material carries an electric current. In quantum dots, band gaps are responsible for their fluorescence and can be tuned by changing the dots’ size. The process by Tour and company allows a measure of control over their size, generally from 2 to 20 nanometers, depending on the source of the coal.

An illustration shows the nanostructure of bituminous coal before separation into graphene quantum dots. Courtesy of the Tour…

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Quantum Dots from Coal + Graphene Could Dramatically Cut the Cost of Energy from Fuel Cells

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Rice University’s cheap hybrid outperforms rare metal as fuel-cell catalyst

Graphene quantum dots created at Rice University grab onto graphene platelets like barnacles attach themselves to the hull of a boat. But these dots enhance the properties of the mothership, making them better than platinum catalysts for certain reactions within fuel cells.

The Rice lab of chemist James Tour created dots known as GQDs from coal last year and have now combined these nanoscale dots with microscopic sheets of graphene, the one-atom-thick form of carbon, to create a hybrid that could greatly cut the cost of generating energy with fuel cells.

Rice University scientists combined graphene quantum dots, graphene oxide, nitrogen and boron into a catalyst capable of replacing platinum in fuel cells at a fraction of the cost. Illustration courtesy of the Tour Group – See more at: http://news.rice.edu/2014/09/30/platinum-meets-its-match-in-quantum-dots-from-coal-2/#sthash.0maP4c7c.dpuf

The research is the subject of a new…

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Rice University: Graphene Quantum Dots: The Next Big “Small Thing”

A Rice University laboratory has found a way to turn common carbon fiber into graphene quantum dots, tiny specks of matter with properties expected to prove useful in electronic, optical and biomedical applications.

The Rice lab of materials scientist Pulickel Ajayan, in collaboration with colleagues in China, India, Japan and the Texas Medical Center, discovered a one-step chemical process that is markedly simpler than established techniques for makinggraphene quantum dots. The results were published online this month in the American Chemical Society’s journal Nano Letters.

“There have been several attempts to make graphene-based quantum dots with specific electronic and luminescent properties using chemical breakdown or e-beam lithography of graphene layers,” said Ajayan, Rice’s Benjamin M. and Mary Greenwood Anderson Professor of Mechanical Engineering and Materials Science and of Chemistry. “We thought that as these nanodomains of graphitized carbons already exist in carbon fibers, which are cheap and plenty, why not use them as the precursor?”

Quantum dots, discovered in the 1980s, are semiconductors that contain a size- and shape-dependent band gap. These have been promising structures for applications that range from computers, LEDs, solar cells and lasers to medical imaging devices. The sub-5 nanometer carbon-based quantum dots produced in bulk through the wet chemical process discovered at Rice are highly soluble, and their size can be controlled via the temperature at which they’re created.

Green-fluorescing graphene quantum dots created at Rice University surround a blue-stained nucleus in a human breast cancer cell. Cells were placed in a solution with the quantum dots for four hours. The dots, each smaller than 5 …more

The Rice researchers were attempting another experiment when they came across the technique. “We tried to selectively oxidize carbon fiber, and we found that was really hard,” said Wei Gao, a Rice graduate student who worked on the project with lead author Juan Peng, a visiting student from Nanjing University who studied in Ajayan’s lab last year. “We ended up with a solution and decided to look at a few drops with a transmission electron microscope.”

The specks they saw were bits of graphene or, more precisely, oxidized nanodomains of graphene extracted via chemical treatment of carbon fiber. “That was a complete surprise,” Gao said. “We call them quantum dots, but they’re two-dimensional, so what we really have here are graphene quantum discs.” Gao said other techniques are expensive and take weeks to make small batches of graphene quantum dots. “Our starting material is cheap, commercially available carbon fiber. In a one-step treatment, we get a large amount of quantum dots. I think that’s the biggest advantage of our work,” she said.

Dark spots on a transmission electron microscope grid are graphene quantum dots made through a wet chemical process at Rice University. The inset is a closeup of one dot. Graphene quantum dots may find use in electronic, optical and …more

Further experimentation revealed interesting bits of information: The size of the dots, and thus their photoluminescent properties, could be controlled through processing at relatively low temperatures, from 80 to 120 degrees Celsius. “At 120, 100 and 80 degrees, we got blue, green and yellow luminescing dots,” she said.

They also found the dots’ edges tended to prefer the form known as zigzag. The edge of a sheet of graphene — the single-atom-thick form of carbon — determines its electrical characteristics, and zigzags are semiconducting.

Their luminescent properties give graphene quantum dots potential for imaging, protein analysis, cell tracking and other biomedical applications, Gao said. Tests at Houston’s MD Anderson Cancer Center and Baylor College of Medicine on two human breast cancer lines showed the dots easily found their way into the cells’ cytoplasm and did not interfere with their proliferation.

“The green quantum dots yielded a very good image,” said co-author Rebeca Romero Aburto, a graduate student in the Ajayan Lab who also studies at MD Anderson. “The advantage of graphene dots over fluorophores is that their fluorescence is more stable and they don’t photobleach. They don’t lose their fluorescence as easily. They have a depth limit, so they may be good for in vitro and in vivo (small animal) studies, but perhaps not optimal for deep tissues in humans.

“But everything has to start in the lab, and these could be an interesting approach to further explore for bioimaging,” Romero Alburto said. “In the future, these graphene quantum dotscould have high impact because they can be conjugated with other entities for sensing applications, too.”

Explore further: Single Atom Quantum Dots Bring Real Devices Closer (Video)

More information: Nano Lett., Article ASAP DOI: 10.1021/nl2038979

Provided by:Rice University

 

Graphene Quantum Dot Based Invisible ink for secret data, product and document security

Ciphers and invisible ink – many of us experimented with these when we were children. A team of Chinese scientists has now developed a clever, high-tech version of “invisible ink”. As reported in the journal Angewandte Chemie, the ink is based on carbon nitride quantum dots. Information written with this ink is not visible under ambient or UV light; however, it can be seen with a fluorescence microplate reader. The writing can be further encrypted or decrypted by quenching or recovering the fluorescence with different reagents.

Fluorescing security inks are primarily used to ensure the authenticity of products or documents, such as certificates, stock certificates, transport documents, currency notes, or identity cards. Counterfeits may cost affected companies lost profits, and the poor quality of the false products may damage their reputations. In the case of sensitive products like pharmaceuticals and parts for airplanes and cars, human lives and health may be endangered. Counterfeiters have discovered how to imitate UV tags but it is significantly harder to copy security inks that are invisible under UV light.
Researchers working with Xinchen Wang and Liangqia Guo at Fuzhou University have now introduced an inexpensive “invisible” ink that increases the security of encoded data while also making it possible to encrypt and decrypt secure information.
The new ink is based on water-soluble quantum dots, nanoscopic “heaps” of a semiconducting material. Quantum dots have special optoelectronic properties that can be controlled by changing the size of the dots.

The scientists used quantum dots made from graphitic carbon nitride. This material consists of ring systems made of carbon and nitrogen atoms linked into two-dimensional molecular layers. The structure is similar to that of graphite (or graphene), one of the forms of pure carbon, but also has semiconductor properties.
Information written with this new ink is invisible under ambient and UV light because it is almost transparent in the visible light range and emits fluorescence with a peak in the UV range. The writing only becomes visible under a microplate reader like those used in biological fluorescence tests. In addition, the writing can be further encrypted and decrypted: treatment with oxalic acid renders it invisible to the microplate reader. Treatment with sodium bicarbonate reverses this process, making the writing visible to the reader once more.
Explore further: Luminescent ink from eggs
More information: Zhiping Song et al. Invisible Security Ink Based on Water-Soluble Graphitic Carbon Nitride Quantum Dots, Angewandte Chemie International Edition (2016). DOI: 10.1002/anie.201510945
Journal reference: Angewandte Chemie Angewandte Chemie International Edition
Provided by: Angewandte Chemie

Safe Lithium-Metal Batteries with Graphene

Recently, researchers at Tsinghua University, China have proposed a graphene-based nanostructured lithium metal anode for lithium metal batteries to inhibit dendrite growth and improve electrochemistry performance. They report their findings in Advanced Materials, published on March 16, 2016.

“Widely used lithium-ion batteries cannot satisfy the increasing requirement of energy storage systems in portable electronics and electric vehicles. New lithium metal anode batteries, like Li-S and Li-air batteries, are highly sought. Lithium metal provides an extremely high theoretical specific capacity, which is almost 10 times more energy than graphite,” said Prof. Qiang Zhang, at the Department of Chemical Engineering, Tsinghua University. “However, the practical applications of lithium metals are strongly hindered by lithium dendrite growth in continuous cycles. This induces safety concerns. The lithium dendrites may cause internal short circuits resulting in fire. Furthermore, the formation of lithium dendrites induces very low cycling efficiency.” The dendrite growth and unstable solid electrolyte interphase consume large amount of lithium and electrolyte, and therefore leading to irreversible battery capacity losses. Consequently, inhibiting the dendrites growth is highly expected.

Many approaches have been proposed to retard the growth of dendrites through electrolyte modification, artificial solid electrolyte interphase layers, electrode construction, and others. “We noticed that by decreasing the local current density heavily, lithium dendrite growth could be efficiently inhibited. Based on this concept, we employed unstacked graphene with an ultrahigh specific surface area to build a nanostructured anode. And it turned out to be a very efficient idea,” said Rui Zhang, a Ph.D. student and the first author. “Additionally, we have employed the dual-salt electrolyte to acquire more stable and more flexible solid electrolyte interphase, which can protect the lithium metal from further reactions with electrolyte.”

This graphene-based anode offered great improvement, including (1) ultralow local current density on the surface of graphene anode (a ten-thousandth of that on routine Cu foil-based anodes) induced by the large specific surface area of 1666 m² g^-1, which inhibited dendrite growth and brought uniform lithium deposition morphology; (2) high stable cycling capacity of 4.0 mAh mg^-1 induced by the high pore volume (1.65 cm³ g^-1) of unstacked graphene, over 10 times of the graphite anode in lithium-ion batteries (0.372 mAh mg^-1); (3) high electrical conductivity (435 S cm^-1), leading to low interface impedance, stable charging/discharging performance, and high cycling efficiencies.

“We hope that our research can point out a new strategy to deal with the dendrite challenge in lithium metal anodes. The ultralow local current density induced by conductive nanostructured anodes with high specific surface area can help improve the stability and electrochemistry performance of lithium metal anodes,” said Xin-Bing Cheng, a co-author of the work. Future investigation is required to design preferable anode structures and to produce more protective solid electrolyte interphase layers. The researchers also call for additional study of the diffusion behavior of Li ions and electrons in the process of lithium depositing and stripping to advance the commercial applications of lithium metal anodes.

Explore further: Nanostructure enlightening dendrite-free metal anode

More information: R. Zhang, X.-B. Cheng, C.-Z. Zhao, H.-J. Peng, J.-L. Shi, J.-Q. Huang, J. Wang, F. Wei, Q. Zhang. Conductive Nanostructured Scaffolds Render Low Local Current Density to Inhibit Lithium Dendrite Growth. Adv. Mater. 2016, 28, 2155-2162. DOI: 10.1002/adma.201504117.

Journal reference: Advanced Materials

Provided by: Tsinghua University

 

Nanocones from “Down Under” ~ Boost Solar Cell Efficiency by 15 percent

A team of scientists at Royal Melbourne Institute of Technology in Australia has announced the development of a nanostructure material made of what they are calling nanocones—it is a type of nanomaterial that can be added to boost the efficiency of photovoltaics by increasing their light absorbing abilities. In their paper published in the journal Science Advances, the team describes the new material, how it works, and their hopes for its use in a wide variety of photovoltaic applications.

The new cone structured material’s positive attributes come about due to an ultrahigh refractive index—each cone is made of a type of material that acts inside as an insulator and outside as a conductor—under a microscope the material looks like a mass of bullets stood up on end atop a flat base. It, like other topological insulators, exploits oscillations that occur as a result of changes in the concentration of electrons that come about when the material is struck by photons. Each cone has a metal shell coating and a core that is based on a dielectric—a material made with them would be able to provide superior light absorption properties, making it ideal for not just solar cells, but a wide variety of photovoltaic applications ranging from optical fibers to waveguides and even lenses. The researchers suggest that if such a material were to be used as part of a traditional thin-film solar cell, it could increase light absorption by up to 15 percent in both the visible and ultraviolet range.

In interviews with the press, the researchers pointed out that theirs is the first time that such a nanocone structure has been created and perhaps just as importantly, noted that creating them would not require any new fabrication techniques. Also, they suggested that because of the better light absorption properties of the new material, “both the short circuit current and photoelectric conversion efficiency could be enhanced.”

The researchers also note that unlike other nanostructures the oscillations generated by the nanocones are polarization insensitive, which means they do not have to be directionally perpendicular to nanoslits making them more useful in a wider array of applications because they can be directly integrated into current hardware. They add that they next plan to shift their efforts towards focusing on plasmonics that occur in other sorts of structures with different types of shapes.

Explore further: Nanocones could be key to making inexpensive solar cells

More information: Z. Yue et al. Intrinsically core-shell plasmonic dielectric nanostructures with ultrahigh refractive index, Science Advances (2016). DOI: 10.1126/sciadv.1501536

Abstract
Topological insulators are a new class of quantum materials with metallic (edge) surface states and insulating bulk states. They demonstrate a variety of novel electronic and optical properties, which make them highly promising electronic, spintronic, and optoelectronic materials. We report on a novel conic plasmonic nanostructure that is made of bulk-insulating topological insulators and has an intrinsic core-shell formation. The insulating (dielectric) core of the nanocone displays an ultrahigh refractive index of up to 5.5 in the near-infrared frequency range. On the metallic shell, plasmonic response and strong backward light scattering were observed in the visible frequency range. Through integrating the nanocone arrays into a-Si thin film solar cells, up to 15% enhancement of light absorption was predicted in the ultraviolet and visible ranges. With these unique features, the intrinsically core-shell plasmonic nanostructure paves a new way for designing low-loss and high-performance visible to infrared optical devices.

Journal reference: Science Advances

 

Map: Here’s where the world is running out of groundwater

Some of the world’s most important farming regions rely on freshwater from large underground aquifers that have filled up slowly over thousands of years. Think of the Central Valley aquifer system in California. Or the Indus basin in Pakistan and India. This groundwater is particularly valuable when rain is scarce or during droughts.

But that groundwater may not last forever. Data from NASA’s Grace satellites suggests that 13 of the world’s 37 biggest aquifers are being seriously depleted by irrigation and other uses much faster than they can be recharged by rain or runoff. And, disturbingly, we don’t even know how much water is left in these basins. That’s according to a 2015 paper in Water Resources Research.

The map below gives an overview. There were 21 major groundwater basins — in red, orange, and yellow — that lost water faster than they could be recharged between 2003 and 2013. The 16 major aquifers in blue, by contrast, gained water during that period. Click to enlarge:

 

(UC Irvine/NASA)

The researchers found that 13 basins around the world — fully one-third of the total — appeared to be in serious trouble.

Eight aquifer systems could be categorized as “overstressed”: that is, there’s hardly any natural recharge to offset the water being consumed. In the direst state was the Arabian aquifer system beneath Saudi Arabia and Yemen, which provides water for 60 million people and is being depleted by irrigation for agriculture. Also in bad shape were the Indus Basin that straddles India and Pakistan and the Murzuq-Djado Basin in Africa.

Another five aquifer systems were categorized as “extremely” or “highly” stressed — they’re being replenished by some rainwater, but not nearly enough to offset withdrawals. That list includes the aquifers underneath California’s Central Valley. During California’s recent brutal, five-year drought, many farmers compensated for the lack of surface water by pumping groundwater at increasing rates. (There are few regulations around this, though California’s legislature recently passed laws that will gradually regulate groundwater withdrawals.)

The result? The basins beneath the Central Valley are being depleted, and the ground is actually sinking, which in turn means these aquifers will be able to store less water in the future. Farmers are losing a crucial buffer against both this drought, if it persists, and future droughts.

The big question: How soon until these aquifers run dry?

Here’s the other troubling bit: It’s unclear exactly when some of these stressed aquifers might be completely depleted — no one knows for sure how much water they actually contain.

In a companion paper in Water Resources Research, the researchers took stock of how little we know about these basins. In the highly stressed Northwest Sahara Aquifer System, for instance, estimates of when the system will be fully drained run anywhere from 10 years to 21,000 years. In order to get better measurements, researchers would have to drill down through many rock layers to measure how much water is there — a difficult task, but not impossible.

“We don’t actually know how much is stored in each of these aquifers. Estimates of remaining storage might vary from decades to millennia,” said Alexandra Richey, a graduate student at UC Irvine and lead author on both papers, in a press release. “In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”

The researchers note that we should figure this out if we want to manage these aquifers properly — and make sure they last for many years to come. Hundreds of millions of people now rely on aquifers that are rapidly being depleted. And once they’re gone, they can’t easily be refilled.

Further reading

— Saudi Arabia squandered its groundwater and agriculture collapsed. The rest of the world should take note.

Catching more of the sun with Quantum Dots and Organic Molecules

Published online Mar 20, 2016

Combining quantum dots and organic molecules can enable solar cells to capture more of the sun’s light.

Organic molecules aid charge transfer from large lead sulfide quantum dots for improved solar-cell performance. Light from the sun is our most abundant source of renewable energy, and learning how best to harvest this radiation is key for the world’s future power needs.

Researchers at KAUST have discovered that the efficiency of solar cells can be boosted by combining inorganic semiconductor nanocrystals with organic molecules.

Quantum dots are crystals that only measure roughly 10 nanometers across. An electron trapped by the dot has quite different properties from those of an electron free to move through a larger material. “One of the greatest advantages of quantum dots for solar cell technologies is their optical properties’ tunability,” explained KAUST Assistant Professor of Chemical Science Omar Mohammed. “They can be controlled by varying the size of the quantum dot.”

Mohammed and his colleagues are developing lead sulfide quantum dots for optical energy harvesting; these tend to be larger than dots made from other materials.

Accordingly, lead sulfide quantum dots can absorb light over a wider range of frequencies. This means they can absorb a greater proportion of the light from the sun when compared to other smaller dots. To make a fully functioning solar cell, electrons must be able to move away from the quantum dot absorption region and flow toward an electrode. Ironically, the property of large lead sulfide quantum dots that makes them useful for broadband absorption—a smaller electron energy bandgap—also hinders this energy harvesting process.

Previously, efficient electron transfer had only been achieved for lead sulfide quantum dots smaller than 4.3 nanometers across, which caused a cut-off in the frequency of light converted. The innovation by Mohammed and the team was to mix lead sulfide quantum dots of various sizes with molecules from a family known as porphyrins. 

The researchers showed that by changing the porphyrin used, it is possible to control the charge transfer from large lead sulfide dots; while one molecule switched off charge transfer altogether, another one enabled transfer at a rate faster than 120 femtoseconds.

The team believe this improvement in energy harvesting ability is due to the interfacial electrostatic interactions between the negatively charged quantum dot surface and the positively charged porphyrin.
“With this approach, we can now extend the quantum dot size for efficient charge transfer to include most of the near-infrared spectral region, reaching beyond the previously reported cut-off,” stated Mohammed. “We hope next to implement this idea in solar-cells with different architectures to optimize efficiency.”
Reference
El-Ballouli, A. O., Alarousu, E., Kirmani, A. R., Amassian, A., Bakr, O. M. & Mohammed O. F. Overcoming the cut-off charge transfer bandgaps at the PbS quantum dot interface. Advanced Functional Materials 25, 7435–7441 (2015). | article

UC Berkeley: Nanotechnology Can Help Deliver Affordable, Clean Water with Graphene Membrane: Video

Clean drinking water is essential for good health and disease prevention. But according to the World Health Organization, some 663 million people — one out of every 10 people in the world — do not have access to safe water. But science may soon help. As Faiza Elmasry tells us, researchers have developed nano-scaled membranes that could filter contaminants from water faster and more cheaply than current methods. Faith Lapidus narrates.

Click Here and Watch the Video

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MIT: New Chemistry for Liquid Batteries: Energy Storage

Grid-scale approach to rechargeable power storage gets new arsenal of possible materials.

Liquid metal batteries, invented by MIT professor Donald Sadoway and his students a decade ago, are a promising candidate for making renewable energy more practical. The batteries, which can store large amounts of energy and thus even out the ups and downs of power production and power use, are in the process of being commercialized by a Cambridge-based startup company, Ambri.

Now, Sadoway and his team have found yet another set of chemical constituents that could make the technology even more practical and affordable, and open up a whole family of potential variations that could make use of local resources.

The latest findings are reported in the journal Nature Communications, in a paper by Sadoway, who is the John F. Elliott Professor of Materials Chemistry, and postdoc Takanari Ouchi, along with Hojong Kim (now a professor at Penn State University) and PhD student Brian Spatocco at MIT. They show that calcium, an abundant and inexpensive element, can form the basis for both the negative electrode layer and the molten salt that forms the middle layer of the three-layer battery.

That was a highly unexpected finding, Sadoway says. Calcium has some properties that made it seem like an especially unlikely candidate to work in this kind of battery. For one thing, calcium easily dissolves in salt, and yet a crucial feature of the liquid battery is that each of its three constituents forms a separate layer, based on the materials’ different densities, much as different liqueurs separate in some novelty cocktails. It’s essential that these layers not mix at their boundaries and maintain their distinct identities.

It was the seeming impossibility of making calcium work in a liquid battery that attracted Ouchi to the problem, he says. “It was the most difficult chemistry” to make work but had potential benefits due to calcium’s low cost as well as its inherent high voltage as a negative electrode. “For me, I’m happiest with whatever is most difficult,” he says — which, Sadoway points out, is a very typical attitude at MIT.

Another problem with calcium is its high melting point, which would have forced the liquid battery to operate at almost 900 degrees Celsius, “which is ridiculous,” Sadoway says. But both of these problems were solvable.

First, the researchers tackled the temperature problem by alloying the calcium with another inexpensive metal, magnesium, which has a much lower melting point. The resulting mix provides a lower operating temperature — about 300 degrees less than that of pure calcium — while still keeping the high-voltage advantage of the calcium.

The other key innovation was in the formulation of the salt used in the battery’s middle layer, called the electrolyte, that charge carriers, or ions, must cross as the battery is used. The migration of those ions is accompanied by an electric current flowing through wires that are connected to the upper and lower molten metal layers, the battery’s electrodes.

The new salt formulation consists of a mix of lithium chloride and calcium chloride, and it turns out that the calcium-magnesium alloy does not dissolve well in this kind of salt, solving the other challenge to the use of calcium.

But solving that problem also led to a big surprise: Normally there is a single “itinerant ion” that passes through the electrolyte in a rechargeable battery, for example, lithium in lithium-ion batteries or sodium in sodium-sulfur. But in this case, the researchers found that multiple ions in the molten-salt electrolyte contribute to the flow, boosting the battery’s overall energy output. That was a totally serendipitous finding that could open up new avenues in battery design, Sadoway says.

And there’s another potential big bonus in this new battery chemistry, Sadoway says. “There’s an irony here. If you’re trying to find high-purity ore bodies, magnesium and calcium are often found together,” he says. It takes great effort and energy to purify one or the other, removing the calcium “contaminant” from the magnesium or vice versa. But since the material that will be needed for the electrode in these batteries is a mixture of the two, it may be possible to save on the initial materials costs by using “lower” grades of the two metals that already contain some of the other.

“There’s a whole level of supply-chain optimization that people haven’t thought about,” he says.

Sadoway and Ouchi stress that these particular chemical combinations are just the tip of the iceberg, which could represent a starting point for new approaches to devising battery formulations. And since all these liquid batteries, including the original liquid battery materials from his lab and those under development at Ambri, would use similar containers, insulating systems, and electronic control systems, the actual internal chemistry of the batteries could continue to evolve over time. They could also adapt to fit local conditions and materials availability while still using mostly the same components.

“The lesson here is to explore different chemistries and be ready for changing market conditions,” Sadoway says. What they have developed “is not a battery; it’s a whole battery field. As time passes, people can explore more parts of the periodic table” to find ever-better formulations, he says.

“This paper brings together innovative engineering advances in cell design and component materials within a strategic framework of ‘cost-based discovery’ that is amenable to the massive scale-up required of grid-scale applications,” says Richard Alkire, a professor of Chemical and Biomolecular Engineering at the University of Illinois, who was not involved in this research.

Because this work builds on a base of well-developed electrochemical systems used for aluminum production, Alkire says, “the path forward to grid-scale applications can therefore take advantage of a large body of existing engineering experience in areas of sustainability, environmental, life cycle, materials, manufacturing cost, and scale-up.”

The research was supported by the U.S. Department of Energy’s Advanced Research Projects Energy (ARPA-E) and by the French energy company Total S.A.