Representation of the three-dimensional electrodes:
When Henrik Fisker relaunched its electric car startup last year, he announced that their first car will be powered by a new graphene-based hybrid supercapacitor technology, but he later announced that they put those plans on the backburner and instead will use more traditional li-ion batteries.
Now the company is announcing a “breakthrough” in solid-state batteries to power their next-generation electric cars and they are filing for patents to protect their IP.
Get ready for some crazy claims here.
Solid-state batteries are thought to be a lot safer than common li-ion cells and could have more potential for higher energy density, but they also have limitations, like temperature ranges, electrode current density, and we have yet to see a company capable of producing it in large-scale and at an attractive price point competitive with li-ion.
Now Fisker announced that they are patenting a new solid-state electrode structure that would enable a viable battery with some unbelievable specs.
Here’s what they claim (via GreenCarCongress):
“Fisker’s solid-state batteries will feature three-dimensional electrodes with 2.5 times the energy density of lithium-ion batteries. Fisker claims that this technology will enable ranges of more than 500 miles on a single charge and charging times as low as one minute—faster than filling up a gas tank.”
Fisker has been all over the place with its new Emotion electric car and we have highlighted that in our look at Fisker’s unbelievable claims.
But its latest solid-state project is led by Dr. Fabio Albano, VP of battery systems at Fisker and the co-founder of Sakti3, which adds credibility to the effort.
Albano commented on the announcement:
“This breakthrough marks the beginning of a new era in solid-state materials and manufacturing technologies. We are addressing all of the hurdles that solid-state batteries have encountered on the path to commercialization, such as performance in cold temperatures; the use of low cost and scalable manufacturing methods; and the ability to form bulk solid-state electrodes with significant thickness and high active material loadings. We are excited to build on this foundation and move the needle in energy storage.”
Like any battery breakthrough announcement, it should be taken with a grain of salt. Most of those announcements never result in any kind of commercialization.
For this particular technology, Fisker says that it will be automotive production grade ready around 2023.
A lot of things can happen over the next 5 years.
In the meantime, Fisker plans to launch its Emotion electric car at CES 2018 in just 2 months.
It seems that we’re on the cusp of a solid-state battery revolution. The latest company to announce progress in developing the new type of battery is Fisker. It has filed patents for solid-state lithium-ion batteries and it expects the batteries to be produced on a mass scale around 2023.
Though Fisker is a very small car company that is currently taking deposits for its upcoming EMotion electric sedan, there are reasons to believe that the company could fulfill this promise. One of the members of the battery-development team was a co-founder of Sakti3, a company that formed to develop new batteries and announced its research into solid-state technology back in 2011. That company was purchased by Dyson, the vacuum cleaner company, which also intends on producing electric carsthat AutoExpress reports will feature solid-state batteries in 2020. Toyota is also expected to have solid-state batteries just ahead of Fisker around 2022.
The reason all these companies are working on developing solid-state batteries is because they present a whole host of advantages over what you’ll find in today’s phones, computers and cars. The two big ones are greater energy density and rapid charging times. Fisker claims the batteries it’s developing have an energy density 2.5 times that of current batteries, and they should be capable of providing a 500-mile driving range. The company also says the batteries could be recharged in as little as a minute. Both claims are similar to past claims from others, including Sakti3. Other benefits include lower estimated cost than conventional lithium-ion batteries as well as very little risk of fires or explosions.
Fisker also announced that it will display the new battery technology at the Consumer Electronics Show in January. It will be on display along with a close-to-production EMotion, which will be using more conventional lithium-ion batteries from LG Chem. That car has its own impressive claims with a range of more than 400 miles and the ability to regain around 125 miles of range in about 9 minutes. It will also retail for around $130,000, and the company is taking $2,000 reservations now. Fisker intends for it to go into production in 2019.
Cancer is often referred to as “smart,” and this term often refers to the ability of these cells to proliferate without purpose or restraint.
The ability of cancer cells to develop multidrug resistance (MDR), a major problem that patients can face, making treatment against this disease even more elusive.
In an effort to combat both cancer cell proliferation and MDR, a recent study conducted by researchers from the National Health Research Institutes of Taiwan and the National Science Council of Taiwan have developed a nanosystem capable of addressing both challenges in the field of cancer therapy.
Drug Resistance and Cancer
Patients with several forms of blood cancer and solid tumors in the breast, ovaries, lungs and lower gastrointestinal tract can become untreatable as a result of multidrug resistance (MDR).
In MDR, the cancer cells of these patients become resistant to commonly used therapeutic drugs as a result of an overexpression of ATP-binding cassette (ABC) transporters that effectively push out drug molecules following administration.
P-glycoprotein and what is termed as the multidrug resistance-associated protein (MRP) are two of the most studied pumps present in cancer cells that are capable of rejecting chemotherapeutic drugs.
By avoiding the toxic effects of these drugs, cancer cells are able to continue to proliferate and metastasize to other organs of the body.
Unfortunately, some of the most commonly used cancer therapeutic drugs such as colchicine, vinblastine, doxorubicin, etoposide, paclitaxel, certain vinca alkaloids and other small molecules have shown resistance in various cancer cells.
Current research efforts in the field of anticancer drug discovery have looked towards the administration of combinatorial technology to be administered with cancer to effectively prevent cancer cells from physically removing therapeutic drugs when administered together.
While blocking the action of pumps like MRP and P-glycoprotein has shown some efficacy, transcription factors, such as c-Jun, which plays a role in cell, proliferation and MDR, can still potentiate metastasis.
Therefore, there remains a need to develop cancer therapies that work against drug resistance and simultaneously prevent further metastasis.
The Efficacy of Administering Doxorubicin Mesoporous Silica Nanoparticles (MSNs)
Mesoporous silica nanoparticles (MSNs) are well-documented drug delivery vehicles that allow for a high drug loading capacity with minimal side effects upon administration.
The tunable size properties, thermal stability, photostability and ease of functionalization to different applications make MSNs one of the most promising options for therapeutic delivery systems.
In the recent study published in Nano Futures, the group of scientists led by Leu-Wei Lo covalently conjugated MSNs with doxorubicin and tested the ability of these nanosystems to be taken up by cancer cells in vitro.
The PC-3 cell line of metastatic human prostate carcinoma cells were treated with 100 μg/ml of either Dox-MSNs that were conjugated with DNAzyme, (Dox-MSN-Dz), Dox-MSNs or control MSNs for 24 hours to study the ability of these cells to survive following treatment.
The researchers found the Dox-MSN-Dz reduced cell survival rates by over 80%, whereas the Dox-MSNs alone still reduced cell survival rates by 60%.
The results of this study confirm the therapeutic potential of the developed multifunctional nanosystem, which incorporates doxorubicin, a widely used chemotherapeutic drug, MSNs and DNAzyme.
Not only did this nanosystem improve the cytotoxicity of doxorubicin to a resistance cancer cell line, but it also successfully reduced migration of cancer cells by inhibiting c-Jun.
While further in vivo studies need to be conducted to fully evaluate the ability of Dox-MSN-Dz to prevent metastasis and invade highly resistance cancer cells, the results of this study are promising.
Future research initiatives that incorporate different chemotherapeutic drugs into a similar nanosystem design could also show similar bifunctional properties as presented here.
1 “A co-delivery nanosystem of chemotherapeutics and DNAzyme overcomes cancer drug resistance and metastasis” S. Sun, C. Liu, et al. Nano Futures. (2017). DOI: 10.1088/2399-1984/aa996f.
For someone who’s all in for fossil fuels, President* Trump sure has a thing for electric vehicles.
Last October the US Energy Department announced $15 million in funding to jumpstart the next generation of “extremely” fast charging systems, and last week the agency’s SLAC National Accelerator Laboratory announced a breakthrough discovery for doubling the range of EV batteries.
Put the two together, and you have EVs that can go farther than any old car, and fuel up just about as quickly.
Add the convenience factor of charging up at home or at work, and there’s your recipe for killing oil. #ThanksTrump!
A Breakthrough Energy Storage Discovery For Electric Vehicles
Did you know that it’s possible to double the range of today’s electric vehicles?
No, really! The current crop of lithium-ion batteries use just half of their theoretical capacity, so there is much room for improvement.
To get closer to 100%, all you have to do is “overstuff” the positive electrode — the cathode — with more lithium. Theoretically, that would enable the battery to absorb more ions in the same space. Theoretically.
Unfortunately, previous researchers have demonstrated that supercharged cathodes lose voltage too quickly to be useful in EVs, because their atomic structure changes.
During the charge cycle, lithium ions leave the supercharged cathode and transition metal atoms move in. When the battery discharges, not all of the transition metal atoms go back to where they came from, leaving less space for the lithium ions to return.
It’s kind of like letting two friends crash on your couch, and one of them never leaves.
That’s the problem tackled by a research team based at the SLAC National Accelerator Laboratory (SLAC is located at Stanford University and the name is a long story involving some trademark issues, but apparently it’s all good now).
Here’s Stanford grad student and study leader William E. Gent enthusing over the new breakthrough:
It gives us a promising new pathway for optimizing the voltage performance of lithium-rich cathodes by controlling the way their atomic structure evolves as a battery charges and discharges.
In other words, the SLAC team discovered a way to manipulate the atomic structure of supercharged cathodes, so the battery doesn’t lose voltage during the charge/discharge cycle.
And, here’s where oil dies:
The more ions an electrode can absorb and release in relation to its size and weight — a factor known as capacity — the more energy it can store and the smaller and lighter a battery can be, allowing batteries to shrink and electric cars to travel more miles between charges.
No, Really — How Does It Work?
To get to the root of the problem, the research team deployed some fancy equipment at SLAC’s SSRL (Stanford Synchotron Radiation Lightsource) to track the atomic-level changes that a lithium-rich battery undergoes during charging cycles.
First, they defined the problem:
…clarifying the nature of anion redox and its effect on electrochemical stability requires an approach that simultaneously probes the spatial distribution of anion redox chemistry and the evolution of local structure.
The research team “unambiguously confirmed” the interplay between oxygen and the transition metal, along with the mechanism for controlling that reaction:
Our results further suggest that anion redox chemistry can be tuned through control of the crystal structure and resulting TM migration pathways, providing an alternative route to improve Li-rich materials without altering TM–O bond covalency through substitution with heavier 4d and 5d TMs.
The equipment angle is essential, btw. Apparently, until the new SLAC study nailed it down there was widespread disagreement on the root cause of the problem.
The new research was made possible in part by a new soft X-ray RIXS system, which was just installed at the lab last year (RIX stands for resonant inelastic X-ray scattering).
You can get all the details from the study, “Coupling between oxygen redox and cation migration explains unusual electrochemistry in lithium-rich layered oxides,” which just came out in the journal Nature Communications.
So, Now What?
The SLAC team points out that until now, RIXS has been mainly used in foundational research. The new study goes a long way to confirming the practical application of RIXS.
In other words, the floodgates are open to a new wave of advanced energy storage research leading to better, cheaper EV batteries and faster charging systems.
In that regard its worth noting that along with the Energy Department, Samsung partnered in the new study and chipped in some of the funding.
That’s a pretty clear indication that Samsung is looking to crack open the Panasonic/Tesla partnership and take over global leadership of the energy storage field. Last September, Samsung unveiled a new 600-km (430-mile) battery for EVs, but the company was mum on the details.
Last November, Samsung unveiled a new version of its SM3 ZE sedan, in which the size of the battery was doubled without increasing the weight of the vehicle. That’s a significant achievement and the company has been tight-lipped on that score, too.
Samsung is also exploring graphene for advanced, long range batteries, so there’s that.
“Perhaps News of My (Oil) premature Death has been misreported”
As for the death of oil, electric vehicles are getting their place in the sun, no matter how much Trump talks up fossil fuels.
That still leaves the issue of petrochemicals.
Although the green chemistry movement is gathering steam, the US petrochemical industry has been taking off like a rocket in recent years. That means both oil and natural gas production could continue apace for the foreseeable future, with or without gasmobiles.
ExxonMobil has been making huge moves into the Texas epicenter of US petrochemicals, and just last week the Houston Chronicle noted this development:
Michigan and Delware-based DowDuPont announced earlier this year that it would spend $4 billion expanding its industrial campus in Freeport.
The expansion will give Freeport the largest ethylene plant in the world. Houston-based Freeport LNG is also building an LNG export terminal in the area.
Then there’s this:
By 2019, Freeport’s power demand is expected to be 92 percent higher than it was in 2016, according to ERCOT.
The $246.7 million project will include a new 48 mile transmission line and upgrades to shorter line in the area, according to ERCOT.
Toyota’s Project Portal and … a possibly “game-changing” semi from upstart Nikola Motors might prove FCEVs are the winning tech for the long-haul industry.
Last month, Tesla CEO Elon Musk rode onto the dais at Tesla’s design studio in Hawthorne, California aboard a futuristic semi truck.
He exited the vehicle, collar popped, to introduce what looked to be a sleeker version of the colossal, decidedly unsexy commercial vehicles that rumble endlessly across America—and received the type of hysterical fanfare usually reserved for the Beyonces and Biebers of the world.
This marked one of the most anticipated, and curious, new-vehicle reveals of 2017: the Tesla Semi, a battery-electric-powered long-haul truck.
In his signature #humblebrag tone, Musk ticked off the Class 8 truck’s impressive capabilities: It can tow 80,000 pounds, the most allowed on US highways, for a range of 500 miles.
It has aerodynamics better than a Bugatti Chiron, a unique central seating position, and comes standard with enhanced AutoPilot, meaning it should never jackknife.
Also: it’s guaranteed not to break down for one million miles; it has a shatterproof windshield; and it implements a kinetic-energy-recovery system (KERS) in such a way that it will never need brake pads – in short WOW!
Plus, with a motor on each of the four rear wheels, it can rocket from 0-60 mph in five seconds flat—one-third the time of the average diesel semi.
Even fully loaded, that number increases to a scant 20 seconds, or a full minute faster than its smog-belching contemporaries. When towing up a five-percent grade, the Tesla can reach speeds of 65 mph, which is 20 mph faster than a diesel.
Taken in aggregate, these features and numbers would greatly benefit a trucker’s route in both speed and cost savings. They are eye-popping metrics; almost unbelievable. Which is perhaps why some are having a hard time believing them.
More important than what Musk said during his November announcement was what he didn’t say. For instance, there was no mention at all about the battery pack that will power the Tesla Semi to these magical thresholds. There was no mention of total weight or cost, which are arguably the two most important variables for long-haul shippers.
In terms of charging these unknown batteries, Musk promised a 400-mile recharge in the course of about 30 minutes. Based on recent estimates in Bloomberg New Energy Finance, hitting those numbers would require a charging system ten times more powerful than Tesla’s own Superchargers—currently the fastest consumer charging network in the world.
The cost building stations that could hit those figures would be profound, as would be the potential stress on the electrical system from multiple trucks charging simultaneously.
Bloomberg estimated that in order to fulfill Musk’s promises the truck would require a battery capacity between 600 and 1,000 kilowatt-hours.
Assuming a down-the-middle number of 800 kWh, that would necessitate a battery of more than 10,000 pounds, with a likely price tag north of $100,000. Musk also claims the Semi will be 20 percent less expensive than a diesel truck per mile—but that is with customers only paying $0.07/kWh.
Experts estimate that Tesla will have to pay, on average, a minimum of $0.40/kWh* for “green” electricity—meaning the company would have to heavily subsidize charging costs for fleets of trucks sucking down terawatts of electricity.
￼So, in order to hit Musk’s stated targets, Tesla will require batteries that don’t, as far as anyone knows, exist; charging capability faster than anything on the planet; and rates far below current market value.
“I don’t understand how that works,” electric vehicle analyst Salim Morsy told Bloomberg. “I really don’t.” Investor’s Business Daily dubbed Musk’s claims “monuments of envelope pushing.”
“The biggest concern that I have is that this is a typical Elon Musk ‘shiny object’ announcement to prop up Tesla’s stock price and distract from all of the issues he is having with Model 3 production,” an engineer associated with the hydrogen industry, who asked to remain anonymous, told us, referencing recent production delays and Tesla’s loss of over $1.3 billion year-to-date.
“I don’t mean to be negative; I do believe in battery technology and its merits, and I also believe that we will continue to see significant improvements in battery cost and performance during the coming decades.
But as a scientist and engineer I have always found Elon Musk’s lack of scientific accuracy and ability to overstate and exaggerate truth, and get away with it, very annoying and disingenuous.”
Tesla did not respond to requests to clarify these apparent discrepancies for this article.
Musk is not alone in the world of heavy-duty battery-electric trucks. VW recently announced a $1.7 billion investment towards developing electric powertrains for trucks and buses. Daimler, the world’s largest truck maker, unveiled an all-electric heavy-duty concept dubbed the E-FUSO Vision ONE at the Tokyo Motor Show, in late October. Daimler’s Class 8 truck promises a significantly more modest 220-mile range, with a payload 1.8 tons less than its diesel counterpart, and utilizing a 300 kWh battery pack. On paper, these figures make the E-FUSO Vision ONE more plausible than the Tesla Semi.
Of course Musk, a man who has promised to colonize Mars and builds spaceships to commute to the International Space Station, has never been known for making anything less than bold announcements.
But shorter-range BEV trucks do have a place in the transportation ecosystem.This is known as “last mile” and “short haul,” where deliveries are made inter-city, or within 100 miles. In such a capacity, the Tesla Semi could be greatly successful.
The semi truck business is a $30-billion-per-year industry in the United States alone, so there’s plenty of money to go around. But the Semi’s utility in true long-haul applications remains questionable.
Toyota’s Project Portal
Researchers in Sweden have succeeded in taking the next step toward using man-made nanoscale compounds in the fight against cancer. A recent proof-of-concept study showed that dendrimers, which were first introduced in the 1980s, may be used to introduce compounds that essentially trick cancer cells into performing self-destructive tasks.
Dendrimers, or cascade molecules, are organically synthesized large molecules that match nature’s peptides and proteins with respect to size and structure. Researchers from KTH Royal Institute of Technology took advantage of these qualities – and cancer cells’ appetite for adsorbing large molecules – by loading the material with an organic sulfur compound (OSC) which is also a key ingredient in amino acids, peptides and proteins.
Applying these to cultured human cancer cells sets in motion a process that distracts cancer cells from their normal task of multiplying, and instead go to work on picking apart disulfide bonds in the dendrimers, says Michael Malkoch, a professor of fiber and polymer technology at KTH.
Malkoch says that this activity releases an increased concentration of reactive oxygen radicals (ROS), which eventually induces cell death. Unlike treatments like chemotherapy, the effect is selective toward cancer cells, leaving the healthy ones unaffected since healthy cells have a higher tolerance for ROS.
The nanomaterial is finally broken down by the body, he says.
The article was published in Journal of the American Chemical Society, and is co-authored by Malkoch, KTH doctoral student Oliver Andrén and Aristi P. Fernandes of Karolinska Institutet.
Their results show that the platform is worth continued research with clinical tests in which dendrimers are preprogrammed with large and specific numbers of organic disulfide bonds, Malkoch says.
“We’ve just scratched the surface for what you can do with dendrimers. We have previously tested using similar materials as a part of a leg patch – a type of adhesive that in some cases enables treatment of bone fractures without screws and plates,” he says. “You can imagine future applications where the material is used to coat implants around cancer tumors and thereby enable therapy treatment at a localized level.”
Explore further: ‘Spiders’ that battle cancer
More information: Oliver C. J. Andrén et al. Heterogeneous Rupturing Dendrimers, Journal of the American Chemical Society (2017). DOI: 10.1021/jacs.7b10377
In a successful collaboration between the Graphene Flagship and the European Space Agency, experiments testing graphene for two different space-related applications have shown extremely promising results. Based on these results, the Flagship are continuing to develop graphene devices for use in space.
“Graphene as we know has a lot of opportunities. One of them, recognised early on, is space applications, and this is the first time that graphene has been tested in space-like applications, worldwide,” said Prof. Andrea Ferrari (University of Cambridge, UK), Science and Technology Officer of the Graphene Flagship.
Graphene’s excellent thermal properties are promising for improving the performance of loop heat pipes, thermal management systems used in aerospace and satellite applications. Graphene could also have a use in space propulsion, due to its lightness and strong interaction with light. The Graphene Flagship tested both these applications in recent experiments in November and December 2017.
The main element of the loop heat pipe is the metallic wick, where heat is transferred from a hot object into a fluid, which cools the system. Two different types of graphene were tested in a collaboration between the Microgravity Research Centre, Université libre de Bruxelles, Belgium; the Cambridge Graphene Centre, University of Cambridge, UK; the Institute for Organic Synthesis and Photoreactivity and the Institute for Microelectronics and Microsystems, both at the National Research Council of Italy (CNR), Italy; and industry partner Leonardo Spa, Italy, a global leader in aerospace, operating in space systems and high-tech instrument manufacturing and in the management of launch and in-orbit services and satellite services.
“We are aiming at an increased lifetime and an improved autonomy of the satellites and space probes. By adding graphene, we will have a more reliable loop heat pipe, capable to operate autonomously in space,” said Dr Marco Molina, Chief Technical Officer of Leonardo’s space line of business.
After excellent results in laboratory tests, the wicks for the loop heat pipes were tested in two ESA parabolic flight campaigns in November and December. “We have good tests done on earth in the lab, and now of course because the applications will be in satellites, we needed to see how the wicks perform in low gravity conditions and also in hypergravity conditions, to simulate a satellite launch,” added Prof Ferrari.
“It was amazing, the feeling is incredible and its extremely interesting to do experiments in these kinds of conditions but also to enjoy the free-floating zone. The whole experience was really great,” said Vanja Miskovic, a student at Université libre de Bruxelles who performed the experiment in microgravity during a parabolic flight operated by Novespace.
The results of the parabolic flight confirm the improvements to the wick, and the Flagship will continue to develop the graphene-based heat pipes towards a commercial product. “I think this is a very nice example of how the Flagship is working. Bringing together three academic partners and one big industry with a clearly defined goal for an application,” said Vincenzo Palermo (CNR), Vice-Director of the Graphene Flagship. “At the moment, we have tested the principle and the core of the device. The next step will be to optimise the whole device, and have a full heat pipe that can go in a satellite.”
Testing graphene space-propulsion potential, a team of PhD students from Delft Technical University (TU Delft), Netherlands participated in ESA’s Drop Your Thesis! campaign, which offers students the chance to perform an experiment in microgravity at the ZARM Drop Tower in Bremen, Germany. To create extreme microgravity conditions, down to one millionth of the Earth’s gravitational force, a capsule containing the experiment is catapulted up and down the 146 metre tower, leading to 9.3 seconds of weightlessness. The TU Delft Space Institute, Netherlands, also provided support to the GrapheneX project.
The team – named GrapheneX – designed and built an experiment to test graphene for use in solar sails, using free-floating graphene membranes provided by Flagship partner Graphenea. The idea was to test how the graphene membranes would behave under radiation pressure from lasers. In total, the experiment ran five times over 13-17 November 2017.
“Our experiment is like a complex ‘clockwork’ where every component has to go off seamlessly at the right time” said Rocco Gaudenzi, a member of the GrapheneX team. “It does not often happen that you have to build up such a clockwork from scratch, and you cannot test it in real conditions but during the launch itself.”
The team worked hard to make the experiment successful. “Despite the initial technical difficulties, we managed to quickly figure out what was going on, fix the issues and get back on track. We are very happy with the results of the experiment as we observed laser-induced motion of a graphene light sail, and most importantly we had a great experience!” said Davide Stefani, GrapheneX team member.
Santiago J. Cartamil-Bueno, GrapheneX team leader, expressed that both the experience and the results were valuable to the team. “The most important lesson is that always something will happen, and you need to be ready to adapt or to change,” he said. “I think at the end of the day, it’s about the experience; you just need to create new challenges and learn from them, and be ready to grab more experience and go to the next level.”
Though the GrapheneX experiment is now finished, the team is considering further tests as part of a new and ambitious research project, to continue exploring the influence of radiation pressure on graphene light sails.
The results of the two projects demonstrate graphene’s versatility and are the first step towards expanding the frontiers of graphene research.
Explore further: Graphene tests set for zero-G flight
Imagine that instead of switching on a lamp when it gets dark, you could read by the light of a glowing plant on your desk.
MIT engineers have taken a critical first step toward making that vision a reality. By embedding specialized nanoparticles into the leaves of a watercress plant, they induced the plants to give off dim light for nearly four hours. They believe that, with further optimization, such plants will one day be bright enough to illuminate a workspace.
“The vision is to make a plant that will function as a desk lamp—a lamp that you don’t have to plug in. The light is ultimately powered by the energy metabolism of the plant itself,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the senior author of the study.
This technology could also be used to provide low-intensity indoor lighting, or to transform trees into self-powered streetlights, the researchers say.
MIT postdoc Seon-Yeong Kwak is the lead author of the study, which appears in the journal Nano Letters.
Plant nanobionics, a new research area pioneered by Strano’s lab, aims to give plants novel features by embedding them with different types of nanoparticles. The group’s goal is to engineer plants to take over many of the functions now performed by electrical devices. The researchers have previously designed plants that can detect explosives and communicate that information to a smartphone, as well as plants that can monitor drought conditions.
Lighting, which accounts for about 20 percent of worldwide energy consumption, seemed like a logical next target. “Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment,” Strano says. “We think this is an idea whose time has come. It’s a perfect problem for plant nanobionics.”
To create their glowing plants, the MIT team turned to luciferase, the enzyme that gives fireflies their glow. Luciferase acts on a molecule called luciferin, causing it to emit light. Another molecule called co-enzyme A helps the process along by removing a reaction byproduct that can inhibit luciferase activity.
The MIT team packaged each of these three components into a different type of nanoparticle carrier. The nanoparticles, which are all made of materials that the U.S. Food and Drug Administration classifies as “generally regarded as safe,” help each component get to the right part of the plant. They also prevent the components from reaching concentrations that could be toxic to the plants.
The researchers used silica nanoparticles about 10 nanometers in diameter to carry luciferase, and they used slightly larger particles of the polymers PLGA and chitosan to carry luciferin and coenzyme A, respectively. To get the particles into plant leaves, the researchers first suspended the particles in a solution. Plants were immersed in the solution and then exposed to high pressure, allowing the particles to enter the leaves through tiny pores called stomata.
Particles releasing luciferin and coenzyme A were designed to accumulate in the extracellular space of the mesophyll, an inner layer of the leaf, while the smaller particles carrying luciferase enter the cells that make up the mesophyll. The PLGA particles gradually release luciferin, which then enters the plant cells, where luciferase performs the chemical reaction that makes luciferin glow.
The researchers’ early efforts at the start of the project yielded plants that could glow for about 45 minutes, which they have since improved to 3.5 hours. The light generated by one 10-centimeter watercress seedling is currently about one-thousandth of the amount needed to read by, but the researchers believe they can boost the light emitted, as well as the duration of light, by further optimizing the concentration and release rates of the components.
Previous efforts to create light-emitting plants have relied on genetically engineering plants to express the gene for luciferase, but this is a laborious process that yields extremely dim light. Those studies were performed on tobacco plants and Arabidopsis thaliana, which are commonly used for plant genetic studies. However, the method developed by Strano’s lab could be used on any type of plant. So far, they have demonstrated it with arugula, kale, and spinach, in addition to watercress.
For future versions of this technology, the researchers hope to develop a way to paint or spray the nanoparticles onto plant leaves, which could make it possible to transform trees and other large plants into light sources.
“Our target is to perform one treatment when the plant is a seedling or a mature plant, and have it last for the lifetime of the plant,” Strano says. “Our work very seriously opens up the doorway to streetlamps that are nothing but treated trees, and to indirect lighting around homes.”
The researchers have also demonstrated that they can turn the light off by adding nanoparticles carrying a luciferase inhibitor. This could enable them to eventually create plants that shut off their light emission in response to environmental conditions such as sunlight, the researchers say.
Explore further: Nanobionic spinach plants can detect explosives
More information: Seon-Yeong Kwak et al. A Nanobionic Light-Emitting Plant, Nano Letters (2017). DOI: 10.1021/acs.nanolett.7b04369
Research at Sandia National Laboratories has identified a major obstacle to advancing solid-state lithium-ion battery performance in small electronics: the flow of lithium ions across battery interfaces.
Sandia’s three-year Laboratory Directed Research and Development project investigated the nanoscale chemistry of solid-state batteries, focusing on the region where electrodes and electrolytes make contact. Most commercial lithium-ion batteries contain a liquid electrolyte and two solid electrodes, but solid-state batteries instead have a solid electrolyte layer, allowing them to last longer and operate more safely.
“The underlying goal of the work is to make solid-state batteries more efficient and to improve the interfaces between different materials,” Sandia physicist Farid El Gabaly said. “In this project, all of the materials are solid; we don’t have a liquid-solid interface like in traditional lithium-ion batteries.”
The research was published in a Nano Letters paper titled, “Non-Faradaic Li+ Migration and Chemical Coordination across Solid-State Battery Interfaces.” Authors include Sandia postdoctoral scientist Forrest Gittleson and El Gabaly. The work was funded by the Laboratory Directed Research and Development program, with supplemental funding by the Department of Energy’s Office of Science.
El Gabaly explained that in any lithium battery, the lithium must travel back and forth from one electrode to the other when it is charged and discharged. However, the mobility of lithium ions is not the same in all materials and interfaces between materials are a major obstacle.
Speeding up the intersection
El Gabaly compares the work to figuring out how to make traffic move quickly through a busy intersection.
“For us, we are trying to reduce the traffic jam at the junction between two materials,” he said.
El Gabaly likened the electrode-electrolyte interface to a tollbooth or merge on a freeway.
“We are essentially taking away the cash tolls and saying everybody needs to go through the fast track, so you’re smoothing out or eliminating the slowdowns,” he said. “When you improve the process at the interface you have the right infrastructure for vehicles to pass easily. You still have to pay, but it is faster and more controlled than people searching for coins in the glove box.”
There are two important interfaces in solid state batteries, he explained, at the cathode-electrolyte junction and electrolyte-anode junction. Either could be dictating the performance limits of a full battery.
Gittleson adds, “When we identify one of these bottlenecks, we ask, ‘Can we modify it?’ And then we try to change the interface and make the chemical processes more stable over time.”
Sandia’s interest in solid-state batteries
El Gabaly said Sandia is interested in the research mainly because solid-state batteries are low maintenance, reliable and safe. Liquid electrolytes are typically reactive, volatile and highly flammable and are a leading cause of commercial battery failure. Eliminating the liquid component can make these devices perform better.
“Our focus wasn’t on large batteries, like in electric vehicles,” El Gabaly said. “It was more for small or integrated electronics.”
Since Sandia’s California laboratory did not conduct solid-state battery research, the project first built the foundation to prototype batteries and examine interfaces.
“This sort of characterization is not trivial because the interfaces that we are interested in are only a few atomic layers thick,” Gittleson said. “We use X-rays to probe the chemistry of those buried interfaces, seeing through only a few nanometers of material. Though challenging to design experiments, we have been successful in probing those regions and relating the chemistry to full battery performance.”
Processing the research
The research was conducted using materials that have been used in previous proof-of-concept solid-state batteries.
“Since these materials are not produced on a massive commercial scale, we needed to be able to fabricate full devices on-site,” El Gabaly said. “We sought methods to improve the batteries by either inserting or changing the interfaces in various ways or exchanging materials.”
The work used pulsed laser deposition and X-ray photoelectron spectroscopy combined with electrochemical techniques. This allowed very small-scale deposition since the batteries are thin and integrated on a silicon wafer.
“Using this method, we can engineer the interface down to the nanometer or even subnanometer level,” Gittleson said, adding that hundreds of samples were created.
Building batteries in this way allowed the researchers to get a precise view of what that interface looks like because the materials can be assembled so controllably.
The next phase of the research is to improve the performance of the batteries and to assemble them alongside other Sandia technologies.
“We can now start combining our batteries with LEDs, sensors, small antennas or any number of integrated devices,” El Gabaly said. “Even though we are happy with our battery performance, we can always try to improve it more.”
Explore further: Toward safer, longer-lasting batteries for electronics and vehicles
More information: Forrest S. Gittleson et al. Non-Faradaic Li+ Migration and Chemical Coordination across Solid-State Battery Interfaces, Nano Letters (2017). DOI: 10.1021/acs.nanolett.7b03498
Researchers at Columbia Engineering, experts at manipulating matter at the nanoscale, have made an important breakthrough in physics and materials science, recently reported in Nature Nanotechnology. Working with colleagues from Princeton and Purdue Universities and Istituto Italiano di Tecnologia, the team has engineered “artificial graphene” by recreating, for the first time, the electronic structure of graphene in a semiconductor device.
“This milestone defines a new state-of-the-art in condensed matter science and nanofabrication,” says Aron Pinczuk, professor of applied physics and physics at Columbia Engineering and senior author of the study. “While artificial graphene has been demonstrated in other systems such as optical, molecular, and photonic lattices, these platforms lack the versatility and potential offered by semiconductor processing technologies. Semiconductor artificial graphene devices could be platforms to explore new types of electronic switches, transistors with superior properties, and even, perhaps, new ways of storing information based on exotic quantum mechanical states.”
The discovery of graphene in the early 2000s generated tremendous excitement in the physics community not only because it was the first real-world realization of a true two-dimensional material but also because the unique atomic arrangement of the carbon atoms in graphene provided a platform for testing new quantum phenomena that are difficult to observe in conventional materials systems. With its unusual electronic properties—its electrons can travel great distances before they are scattered—graphene is an outstanding conductor. These properties also display other unique characteristics that make electrons behave as if they are relativistic particles that move close to the speed of light, conferring upon them exotic properties that “regular,” non-relativistic electrons do not have.
But graphene, a natural substance, comes in only one atomic arrangement: the positions of the atoms in the graphene lattice are fixed, and thus all experiments on graphene must adapt to those constraints. On the other hand, in artificial graphene the lattice can be engineered over a wide range of spacings and configurations, making it a holy grail of sorts for condensed matter researchers because it will have more versatile properties than the natural material.
“This is a rapidly expanding area of research, and we are uncovering new phenomena that couldn’t be accessed before,” says Shalom Wind, faculty member of the department of applied physics and applied mathematics and co-author of the study. “As we explore novel device concepts based on electrical control of artificial graphene, we can unlock the potential to expand frontiers in advanced optoelectronics and data processing.”
“This work is really a major advance in artificial graphene. Since the first theoretical prediction that system with graphene-like electronic properties may be artificially created and tuned with patterned 2D electron gas, no one had succeeded, until the Columbia work, in directly observing these characteristics in engineered semiconductor nanostructures,” says Steven G. Louie, professor of physics, University of California, Berkeley. “Previous work with molecules, atoms and photonic structures represent far less versatile and stable systems. The nanofabricated semiconductor structures open up tremendous opportunities for exploring exciting new science and practical applications.”
The researchers used the tools of conventional chip technology to develop the artificial graphene in a standard semiconductor material, gallium arsenide. They designed a layered structure so that the electrons could move only within a very narrow layer, effectively creating a 2D sheet. They used nanolithography and etching to pattern the gallium arsenide: the patterning created a hexagonal lattice of sites in which the electrons were confined in the lateral direction. By placing these sites, which could be thought of as “artificial atoms,” sufficiently close to one another (~ 50 nanometers apart), these artificial atoms could interact quantum mechanically, similar to the way atoms share their electrons in solids.
The team probed the electronic states of the artificial lattices by shining laser light on them and measuring the light that was scattered. The scattered light showed a loss of energy that corresponded to transitions in the electron energy from one state to another. When they mapped these transitions, the team found that they were approaching zero in a linear fashion around what is called the “Dirac point” where the electron density vanishes, a hallmark of graphene.
This artificial graphene has several advantages over natural graphene: for instance, researchers can design variations into the honeycomb lattice to modulate electronic behavior. And because the spacing between the quantum dots is much larger than the inter-atomic spacing in natural graphene, researchers can observe even more exotic quantum phenomena with the application of a magnetic field.
The discovery of new low-dimensional materials, such as graphene and other ultrathin, layered van der Waals films that exhibit exciting new physical phenomena that were previously inaccessible, laid the groundwork for this study. “What was really critical to our work was the impressive advancements in nanofabrication,” Pinczuk notes. “These offer us an ever-increasing toolbox for creating a myriad of high-quality patterns at nanoscale dimensions. This is an exciting time to be a physicist working in our field.”
Explore further: Scientists move graphene closer to transistor applications
More information: Sheng Wang et al, Observation of Dirac bands in artificial graphene in small-period nanopatterned GaAs quantum wells, Nature Nanotechnology (2017). DOI: 10.1038/s41565-017-0006-x