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.
Storage devices, like this one-megawatt battery at the National Wind Technology Center, can reduce variable generation curtailments. Photo by Dennis Schroeder / NREL 47219
Increasing the penetration of variable energy sources such as solar and wind energy in the grid—without introducing heavy curtailment—does not require costly, very-long-duration storage, says a new study by National Renewable Energy Laboratory researchers Paul Denholm and Trieu Mai.
Historically, energy storage has been considered too pricey an option for integrating wind and solar into the grid, and utilities have relied on less expensive options. However, declining costs indicate that energy storage solutions may play a greater role in providing grid flexibility and storing because of their ability to decrease the amounts of curtained wind and solar generation.
When wind and solar are curtailed, grid operators cannot use all of the available renewable resources (i.e., there is more wind blowing than the grid can utilize). Often, this means that the grid must rely on a fossil-fuel energy generation source, rather than a cleaner source of energy. But with storage solutions, operators can save some of that excess energy, and thereby incorporate more renewable energy into the grid.
“Interest in very-high-renewable systems warrants further exploration into storage’s role in the future grid,” says Mai.
The team’s study, “Timescales of Energy Storage Needed for Reducing Renewable Energy CurtailmentPDF,” examines the amount and configuration of energy storage required to decrease variable-generation curtailments under high-renewable scenarios. Researchers developed a case study based on the U.S. Department of Energy’s Wind Vision report, in which variable generation provides 55% of the electricity demand in the Electricity Reliability Council of Texas (ERCOT) grid system in 2050. Analysis results showed that the amount of avoided curtailment falls off rapidly with storage durations longer than 8 hours, with the first 4 hours providing the largest benefit.
Denholm and Mai developed several energy mix scenarios based on the isolated ERCOT grid system, and found that deploying wind and solar together produced much lower levels of curtailment than when deployed individually.
“Wind and photovoltaics play well together,” Denholm says. However, the mix that produces the least amount of curtailment uses about twice as much wind as solar.
Among all energy mixes analyzed, there was little incremental benefit to deploying costly, very-long-duration or seasonal storage—at penetrations of up to 55%, the greatest benefit is found with the first 4 hours of storage.
Berkeley Lab leads discovery of the fastest magnesium-ion solid-state conductor to date.
A team of Department of Energy (DOE) scientists at the Joint Center for Energy Storage Research (JCESR) has discovered the fastest magnesium-ion solid-state conductor, a major step towards making solid-state magnesium-ion batteries that are both energy dense and safe.
Argonne scientist Baris Key, shown on left at work in his nuclear magnetic resonance lab, worked with researchers at Berkeley Lab on the discovery of the fastest ever magnesium-ion solid-state conductor. (Credit: Argonne National Laboratory)
The electrolyte, which carries charge back and forth between the battery’s cathode and anode, is a liquid in all commercial batteries, which makes them potentially flammable, especially in lithium-ion batteries. A solid-state conductor, which has the potential to become an electrolyte, would be far more fire-resistant.
Researchers at DOE’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Argonne National Laboratory were working on a magnesium battery, which offers higher energy density than lithium, but were stymied by the dearth of good options for a liquid electrolyte, most of which tend to be corrosive against other parts of the battery. “Magnesium is such a new technology, it doesn’t have any good liquid electrolytes,” said Gerbrand Ceder, a Berkeley Lab Senior Faculty Scientist. “We thought, why not leapfrog and make a solid-state electrolyte?”
The material they came up with, magnesium scandium selenide spinel, has magnesium mobility comparable to solid-state electrolytes for lithium batteries. Their findings were reported in Nature Communications in a paper titled, “High magnesium mobility in ternary spinel chalcogenides.”JCESR, a DOE Innovation Hub, sponsored the study, and the lead authors are Pieremanuele Canepa and Shou-Hang Bo, postdoctoral fellows at Berkeley Lab.
“With the help of a concerted effort bringing together computational materials science methodologies, synthesis, and a variety of characterization techniques, we have identified a new class of solid conductors that can transport magnesium ions at unprecedented speed,” Canepa said.
Collaboration with MIT and Argonne
The research team also included scientists at MIT, who provided computational resources, and Argonne, who provided key experimental confirmation of the magnesium scandium selenide spinel material to document its structure and function.
Co-author Baris Key, a research chemist at Argonne, conducted nuclear magnetic resonance (NMR) spectroscopy experiments. These tests were among the first steps to experimentally prove that magnesium ions could move through the material as rapidly as the theoretical studies had predicted.
“It was crucial to confirm the fast magnesium hopping experimentally. It is not often that the theory and the experiment agree closely with each other,” Key said. “The solid state NMR experiments for this chemistry were very challenging and would not be possible without dedicated resources and a funding source such as JCESR.
As we’ve shown in this study, an in-depth understanding of short- and long-range structure and ion dynamics will be the key for magnesium ion battery research.”
NMR is akin to magnetic resonance imaging (MRI), which is routinely used in medical settings, where it shows hydrogen atoms of water in human muscles, nerves, fatty tissue, and other biological substances. But researchers can also tune NMR frequency to detect other elements, including the lithium or magnesium ions that are found in battery materials.
The NMR data from the magnesium scandium selenide material, however, involved material of unknown structure with complex properties, making them challenging to interpret.
Canepa noted the challenges of testing materials that are so new. “Protocols are basically non-existent,” he said. “These findings were only possible by combining a multi-technique approach (solid-state NMR and synchrotron measurements at Argonne) in addition to conventional electrochemical characterization.”
Doing the impossible
The team plans to do further work to use the conductor in a battery. “This probably has a long way to go before you can make a battery out of it, but it’s the first demonstration you can make solid-state materials with really good magnesium mobility through it,” Ceder said. “Magnesium is thought to move slowly in most solids, so nobody thought this would be possible.”
Additionally, the research identified two related fundamental phenomena that could significantly affect the development of magnesium solid electrolytes in the near future, namely, the role of anti-site defects and the interplay of electronic and magnesium conductivity, both published recently in Chemistry of Materials.
Bo, now an assistant professor at Shanghai Jiao Tong University, said the discovery could have a dramatic effect on the energy landscape. “This work brought together a great team of scientists from various scientific disciplines, and took the first stab at the formidable challenge of building a solid-state magnesium battery,” he said. “Although currently in its infancy, this emerging technology may have a transformative impact on energy storage in the near future.”
Gopalakrishnan Sai Gautam, another co-author who was an affiliate at Berkeley Lab and is now at Princeton, said the team approach made possible by a DOE hub such as JCESR was critical. “The work shows the importance of using a variety of theoretical and experimental techniques in a highly collaborative environment to make important fundamental discoveries,” he said.
Ceder was excited at the prospects for the finding but cautioned that work remains to be done. “There are enormous efforts in industry to make a solid-state battery. It’s the holy grail because you would have the ultimate safe battery. But we still have work to do. This material shows a small amount of electron leakage, which has to be removed before it can be used in a battery.”
Funding for the project was provided by the DOE Office of Science through the Joint Center for Energy Storage Research, a Department of Energy Innovation Hub. The Advanced Photon Source, a DOE Office of Science User Facility at Argonne, added vital data to the study regarding the structure of the solid conductor.
The National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility at Berkeley Lab, provided computing resources. Other co-authors on the paper are Juchaun Li of Berkeley Lab, William Richards and Yan Wang of MIT, and Tan Shi and Yaosen Tian of UC Berkeley.
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Lawrence Berkeley National Laboratory addresses the world’s most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab’s scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy’s Office of Science. For more, visit www.lbl.gov.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state, and municipal agencies to help them solve their specific problems, advance America’s scientific leadership, and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.
DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
The Joint Center for Energy Storage Research (JCESR), a DOE Energy Innovation Hub, is a major partnership that integrates researchers from many disciplines to overcome critical scientific and technical barriers and create new breakthrough energy storage technology. Led by the U.S. Department of Energy’s Argonne National Laboratory, partners include national leaders in science and engineering from academia, the private sector, and national laboratories. Their combined expertise spans the full range of the technology-development pipeline from basic research to prototype development to product engineering to market delivery.
Hydrogen-powered vehicles are slowly hitting the streets, but although it’s a clean and plentiful fuel source, a lack of infrastructure for mass producing, distributing and storing hydrogen is still a major roadblock.
But new work out of the University of California, Los Angeles (UCLA) could help lower the barrier to entry for consumers, with a device that uses sunlight to produce both hydrogen and electricity.
The UCLA device is a hybrid unit that combines a supercapacitor with a hydrogen fuel cell, and runs the whole shebang on solar power.
Along with the usual positive and negative electrodes, the device has a third electrode that can either store energy electrically or use it to split water into its constituent hydrogen and oxygen atoms – a process called water electrolysis.
To make the electrodes as efficient as possible, the team maximized the amount of surface area that comes into contact with water, right down to the nanoscale. That increases the amount of hydrogen the system can produce, as well as how much energy the supercapacitor can store.
“People need fuel to run their vehicles and electricity to run their devices,” says Richard Kaner, senior author of the study. “Now you can make both fuel and electricity with a single device.”
Hydrogen itself may be clean, but producing it on a commercial scale might not be. It’s often created by converting natural gas, which not only results in a lot of carbon dioxide emissions but can be costly.
Using renewable sources like solar can help solve both of those problems at once. And it helps that the UCLA device uses materials like nickel, iron and cobalt, which are much more abundant than the precious metals like platinum that are currently used to produce hydrogen.
“Hydrogen is a great fuel for vehicles: It is the cleanest fuel known, it’s cheap and it puts no pollutants into the air – just water,” says Kaner. “And this could dramatically lower the cost of hydrogen cars.”
The new system could also help solve some of the infrastructure woes as well. Hydrogen vehicles can’t really take off until consumers can easily find places to fill up, and while strides are being made in that department, with the UCLA device users can hook into the sun almost anywhere to produce their own fuel, which could be particularly handy for those living in rural or remote areas.
As an added bonus, the supercapacitor part of the system can chemically store the harvested solar energy as hydrogen. Doing so could help bolster energy storage for the grid. Although the current device is palm-sized, the researchers say that it should be relatively easy to scale up for those applications.
The research was published in the journal Energy Storage Materials.
Making renewable power more viable for the grid
“Air-breathing” battery can store electricity for months, for about a fifth the cost of current technologies.
Wind and solar power are increasingly popular sources for renewable energy. But intermittency issues keep them from connecting widely to the U.S. grid: They require energy-storage systems that, at the cheapest, run about $100 per kilowatt hour and function only in certain locations.
Now MIT researchers have developed an “air-breathing” battery that could store electricity for very long durations for about one-fifth the cost of current technologies, with minimal location restraints and zero emissions. The battery could be used to make sporadic renewable power a more reliable source of electricity for the grid.
For its anode, the rechargeable flow battery uses cheap, abundant sulfur dissolved in water. An aerated liquid salt solution in the cathode continuously takes in and releases oxygen that balances charge as ions shuttle between the electrodes. Oxygen flowing into the cathode causes the anode to discharge electrons to an external circuit. Oxygen flowing out sends electrons back to the anode, recharging the battery.
“This battery literally inhales and exhales air, but it doesn’t exhale carbon dioxide, like humans — it exhales oxygen,” says Yet-Ming Chiang, the Kyocera Professor of Materials Science and Engineering at MIT and co-author of a paper describing the battery.
The research appears today in the journal Joule.
The battery’s total chemical cost — the combined price of the cathode, anode, and electrolyte materials — is about 1/30th the cost of competing batteries, such as lithium-ion batteries. Scaled-up systems could be used to store electricity from wind or solar power, for multiple days to entire seasons, for about $20 to $30 per kilowatt hour.
Co-authors with Chiang on the paper are: first author Zheng Li, who was a postdoc at MIT during the research and is now a professor at Virginia Tech; Fikile R. Brushett, the Raymond A. and Helen E. St. Laurent Career Development Professor of Chemical Engineering; research scientist Liang Su; graduate students Menghsuan Pan and Kai Xiang; and undergraduate students Andres Badel, Joseph M. Valle, and Stephanie L. Eiler.
Finding the right balance
Development of the battery began in 2012, when Chiang joined the Department of Energy’s Joint Center for Energy Storage Research, a five-year project that brought together about 180 researchers to collaborate on energy-saving technologies. Chiang, for his part, focused on developing an efficient battery that could reduce the cost of grid-scale energy storage.
A major issue with batteries over the past several decades, Chiang says, has been a focus on synthesizing materials that offer greater energy density but are very expensive. The most widely used materials in lithium-ion batteries for cellphones, for instance, have a cost of about $100 for each kilowatt hour of energy stored.
“This meant maybe we weren’t focusing on the right thing, with an ever-increasing chemical cost in pursuit of high energy-density,” Chiang says. He brought the issue to other MIT researchers. “We said, ‘If we want energy storage at the terawatt scale, we have to use truly abundant materials.’”
The researchers first decided the anode needed to be sulfur, a widely available byproduct of natural gas and petroleum refining that’s very energy dense, having the lowest cost per stored charge next to water and air. The challenge then was finding an inexpensive liquid cathode material that remained stable while producing a meaningful charge.
That seemed improbable — until a serendipitous discovery in the lab.
On a short list of candidates was a compound called potassium permanganate. If used as a cathode material, that compound is “reduced” — a reaction that draws ions from the anode to the cathode, discharging electricity. However, the reduction of the permanganate is normally impossible to reverse, meaning the battery wouldn’t be rechargeable.
Still, Li tried. As expected, the reversal failed. However, the battery was, in fact, recharging, due to an unexpected oxygen reaction in the cathode, which was running entirely on air. “I said, ‘Wait, you figured out a rechargeable chemistry using sulfur that does not require a cathode compound?’ That was the ah-ha moment,” Chiang says.
Using that concept, the team of researchers created a type of flow battery, where electrolytes are continuously pumped through electrodes and travel through a reaction cell to create charge or discharge.
The battery consists of a liquid anode (anolyte) of polysulfide that contains lithium or sodium ions, and a liquid cathode (catholyte) that consists of an oxygenated dissolved salt, separated by a membrane.
Upon discharging, the anolyte releases electrons into an external circuit and the lithium or sodium ions travel to the cathode.
At the same time, to maintain electroneutrality, the catholyte draws in oxygen, creating negatively charged hydroxide ions. When charging, the process is simply reversed. Oxygen is expelled from the catholyte, increasing hydrogen ions, which donate electrons back to the anolyte through the external circuit.
“What this does is create a charge balance by taking oxygen in and out of the system,” Chiang says.
Because the battery uses ultra-low-cost materials, its chemical cost is one of the lowest — if not the lowest — of any rechargeable battery to enable cost-effective long-duration discharge. Its energy density is slightly lower than today’s lithium-ion batteries.
“It’s a creative and interesting new concept that could potentially be an ultra-low-cost solution for grid storage,” says Venkat Viswanathan, an assistant professor of mechanical engineering at Carnegie Mellon University who studies energy-storage systems.
Lithium-sulfur and lithium-air batteries — where sulfur or oxygen are used in the cathode — exist today. But the key innovation of the MIT research, Viswanathan says, is combining the two concepts to create a lower-cost battery with comparable efficiency and energy density. The design could inspire new work in the field, he adds: “It’s something that immediately captures your imagination.”
Making renewables more reliable
The prototype is currently about the size of a coffee cup. But flow batteries are highly scalable, Chiang says, and cells can be combined into larger systems.
As the battery can discharge over months, the best use may be for storing electricity from notoriously unpredictable wind and solar power sources. “The intermittency for solar is daily, but for wind it’s longer-scale intermittency and not so predictable.
When it’s not so predictable you need more reserve — the capability to discharge a battery over a longer period of time — because you don’t know when the wind is going to come back next,” Chiang says. Seasonal storage is important too, he adds, especially with increasing distance north of the equator, where the amount of sunlight varies more widely from summer to winter.
Chiang says this could be the first technology to compete, in cost and energy density, with pumped hydroelectric storage systems, which provide most of the energy storage for renewables around the world but are very restricted by location.
“The energy density of a flow battery like this is more than 500 times higher than pumped hydroelectric storage. It’s also so much more compact, so that you can imagine putting it anywhere you have renewable generation,” Chiang says.
The research was supported by the Department of Energy.
Photos: Tata Center for Technology and Design, MITEI, Joel Jean and Anna Osherov, Bob Mumgaard/PSFC, Energy Laboratory Archives, Bryce Vickmark
Research, education, and student activities help create a robust community focused on fueling the world’s future.
On any given day at MIT, undergraduates design hydro-powered desalination systems, graduate students test alternative fuels, and professors work to tap the huge energy-generating potential of nuclear fusion, biomaterials, and more. While some MIT researchers are modeling the impacts of policy on energy markets, others are experimenting with electrochemical forms of energy storage.
This is the robust energy community at MIT. Developed over the past 10 years with the guidance and support of the MIT Energy Initiative (MITEI) — and with roots extending back into the early days of the Institute — it has engaged more than 300 faculty members and spans more than 900 research projects across all five schools.
In addition, MIT offers a multidisciplinary energy minor and myriad energy-related events and activities throughout the year. Together, these efforts ensure that students who arrive on campus with an interest in energy have free rein to pursue their ambitions.
Opportunities for students
“The MIT energy ecosystem is an incredible system, and it’s built from the ground up,” says Robert C. Armstrong, a professor of chemical engineering and the director of MITEI, which is overseen at the Institute level by Vice President for Research Maria Zuber. “It begins with extensive student involvement in energy.”
Opportunities begin the moment undergraduates arrive on campus, with a freshman pre-orientation program offered through MITEI that includes such hands-on activities as building motors and visiting the Institute’s nuclear research reactor.
“I got accepted into the pre-orientation program and from there, I was just hooked. I learned about solar technology, wind technology, different types of alternative fuels, bio fuels, even wave power,” says graduate student Priyanka Chatterjee ’15, who minored in energy studies and majored in mechanical and ocean engineering.
Those who choose the minor take a core set of subjects encompassing energy science, technology, and social science. Those interested in a deep dive into research can participate in the Energy Undergraduate Research Opportunities Program (UROP), which provides full-time summer positions. UROP students are mentored by graduate students and postdocs, many of them members of the Society of Energy Fellows, who are also conducting their own energy research at MIT.
For extracurricular activities, students can join the MIT Energy Club, which is among the largest student-run organizations at MIT with more than 5,000 members. They can also compete for the MIT Clean Energy Prize, a student competition that awards more than $200,000 each year for energy innovation. And there are many other opportunities.
The Tata Center for Technology and Design, now in its sixth year, extends MIT’s reach abroad. It supports 65 graduate students every year who conduct research central to improving life in developing countries — including lowering costs of rural electrification and using solar energy in novel ways.
Students have other opportunities to conduct and share energy research internationally as well.
“Over the years, MITEI has made it possible for several of the students I’ve advised to engage more directly in global energy and climate policy negotiations,” says Valerie Karplus, an assistant professor of global economics and management. “In 2015, I joined them at the Paris climate conference, which was a tremendous educational and outreach experience for all of us.”
“What is important is to provide our students a holistic understanding of the energy challenges,” says MIT Associate Dean for Innovation Vladimir Bulović.
Adds Karplus: “There’s been an evolution in thinking from ‘How do we build a better mousetrap?’ to ‘How do we bring about change in society at a system level?’”
This kind of thinking is at the root of MIT’s multidisciplinary approach to addressing the global energy challenge — and it has been since MITEI was conceived and launched by then-MIT President Susan Hockfield, a professor of neuroscience. While energy research has been part of the Institute since its founding (MIT’s first president, William Barton Rogers, famously collapsed and died after uttering the words “bituminous coal” at the 1882 commencement), the concerted effort to connect researchers across the five schools for collaborative projects is a more recent development.
“The objective of MITEI was really to solve the big energy problems, which we feel needs all of the schools’ and departments’ contributions,” says Ernest J. Moniz, a professor emeritus of physics and special advisor to MIT’s president. Moniz was the founding director of MITEI before serving as U.S. Secretary of Energy during President Obama’s administration.
Hockfield says great technology by itself “can’t go anywhere without great policy.”
“It’s the economics, it’s the sociology, it’s the science and the engineering, it’s the architecture — it’s all of the pieces of MIT that had to come together if we were going to develop really impactful sustainable energy solutions,” she says.
This multidisciplinary approach is evident in much of MIT’s energy research — notably the series of comprehensive studies MITEI has conducted on such topics as the future of solar energy, natural gas, the electric grid, and more.
“To make a better world, it’s essential that we figure out how to take what we’ve learned at MIT in energy and get that out into the world,” Armstrong says.
MITEI’s eight low-carbon energy research centers — focused on a range of topics from materials design to solar generation to carbon capture and storage — similarly address challenges on multiple technology and policy fronts. These centers are a core component of MIT’s five-year Plan for Action on Climate Change, announced by President L. Rafael Reif in October 2015. The centers employ a strategy that has been fundamental to MIT’s energy work since the founding of MITEI: broad, sustained collaboration with stakeholders from industry, government, and the philanthropic and non-governmental organization communities.
“It’s one thing to do research that’s interesting in a laboratory. It’s something very different to take that laboratory discovery into the world and deliver practical applications,” Hockfield says. “Our collaboration with industry allowed us to do that with a kind of alacrity that we could never have done on our own.”
For example, MITEI’s members have supported more than 160 energy-focused research projects, representing $21.4 million in funding over the past nine years, through the Seed Fund Program. Projects have led to follow-on federal and industry funding, startup companies, and pilot plants for solar desalinization systems in India and Gaza, among other outcomes.
What has MIT’s energy community as a whole accomplished over the past decade? Hockfield says it’s raised the visibility of the world’s energy problems, contributed solutions — both technical and sociopolitical — and provided “an army of young people” to lead the way to a sustainable energy future.
“I couldn’t be prouder of what MIT has contributed,” she says. “We are in the midst of a reinvention of how we make energy and how we use energy. And we will develop sustainable energy practices for a larger population, a wealthier population, and a healthier planet.”
A supercapacitor can store far more electrical energy than a standard capacitor. They are able to charge and discharge far more rapidly than batteries, making them a much-discussed alternative to traditional batteries.
The main drawback of supercapacitors as a replacement for batteries is their limited storage: while they can store 10 to 100 times more electrical energy than a standard capacitor, this is still not enough to be useful as a battery replacement in smartphones, laptops, electric vehicles and other machines.
At present, supercapacitors can store enough energy to power laptops and other small devices for approximately a tenth as long as rechargeable batteries do.
Increases in the storage capacity of supercapacitors could allow for them to be made smaller and lighter, such that they can replace batteries in some devices that require fast charging and discharging.
A team of engineers at the University of Waterloo were able to create a new supercapacitor design which approximately doubles the amount of electrical energy that it can hold.
They did this by coating graphene with an oily liquid salt in the electrodes of supercapacitors. By adding a mixture of detergent and water, the droplets of the liquid salt were reduced to nanoscale sizes.
This salt acts as an electrolyte (which is required for storage of electrical charge), as well as preventing the atom-thick graphene sheets sticking together, hugely increasing their exposed surface area and optimising energy storage capacity.
“We’re showing record numbers for the energy-storage capacity of supercapacitors,” said Professor Michael Pope, a chemical engineer at the University of Waterloo. “And the more energy-dense we can make them, the more batteries we can start displacing.”
According to Professor Pope, supercapacitors could be a green replacement for lead-acid batteries in vehicles, capturing the energy otherwise wasted by buses and high-speed trains during braking. In the longer term, they could be used to power mobile phones and other consumer technology, as well as devices in remote locations, such as in orbit around Earth.
“If they are marketed in the correct ways for the right applications, we’ll start seeing more and more of them in our everyday lives,” said Professor Pope.
Colloidal quantum dots are electronic materials and because of their astonishingly small size (typically 3-20 nanometers in dimension) they possess fascinating optical properties.
The initial lead sulfide quantum dot solar cells had an efficiency of 2.9 percent. Since then, improvements have pushed that number into double digits for lead sulfide reaching a record of 12 percent set last year by the University of Toronto.
The improvement from the initial efficiency to the previous record came from better understanding of the connectivity between individual quantum dots, better overall device structures and reducing defects in quantum dots.
The latest development in quantum dot solar cells comes from a completely different quantum dot material. The new quantum dot leader is cesium lead triiodide (CsPbI3), and is within the recently emerging family of halide perovskite materials.
In quantum dot form, CsPbI3 produces an exceptionally large voltage (about 1.2 volts) at open circuit.
“This voltage, coupled with the material’s bandgap, makes them an ideal candidate for the top layer in a multijunction solar cell,” said Joseph Luther, a senior scientist and project leader in the Chemical Materials and Nanoscience team at NREL.
The top cell must be highly efficient but transparent at longer wavelengths to allow that portion of sunlight to reach lower layers.
Tandem cells can deliver a higher efficiency than conventional silicon solar panels that dominate today’s solar market.
This latest advance, titled “Enhanced mobility CsPbI3 quantum dot arrays for record-efficiency, high-voltage photovoltaic cells,” is published in Science Advances. The paper was co-authored by Erin Sanehira, Ashley Marshall, Jeffrey Christians, Steven Harvey, Peter Ciesielski, Lance Wheeler, Philip Schulz, and Matthew Beard, all from NREL; and Lih Lin from the University of Washington.
The multijunction approach is often used for space applications where high efficiency is more critical than the cost to make a solar module.
The quantum dot perovskite materials developed by Luther and the NREL/University of Washington team could be paired with cheap thin-film perovskite materials to achieve similar high efficiency as demonstrated for space solar cells, but built at even lower costs than silicon technology–making them an ideal technology for both terrestrial and space applications.
“Often, the materials used in space and rooftop applications are totally different. It is exciting to see possible configurations that could be used for both situations,” said Erin Sanehira a doctoral student at the University of Washington who conducted research at NREL.
The NREL research was funded by DOE’s Office of Science, while Sanehira and Lin acknowledge a NASA space technology fellowship.
NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.
October 24, 2017
The U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) has entered into a license agreement with MicroLink Devices, Inc. (Niles, IL) to commercialize NREL’s patented inverted metamorphic (IMM) multijunction solar cells.
While high-efficiency multijunction solar cells are commonly used for space satellites, researchers have continued to look for ways to improve cost and performance to enable a broader range of applications.
The IMM technique licensed by MicroLink Devices enables multijunction III-V solar cells to be grown with both higher efficiencies and lower costs than traditional multijunction solar cells by reversing the order in which individual sub-cells are typically grown.
The IMM architecture enables greater power extraction from the higher-bandgap sub-cells and further allows the use of more efficient low-bandgap sub-cell materials such as Indium Gallium Arsenide.
In contrast to traditional III-V multijunction solar cells, IMM devices are removed from their growth substrate, allowing the substrate to be reused over multiple growth runs – a significant component in reducing overall device costs. Removing the substrate also reduces the weight of the solar cell, which is important for applications such as solar-powered unmanned aerial vehicles.
MicroLink Devices is an Illinois-based ISO 9001 certified semiconductor manufacturer specializing in removing active semiconductor device layers from their growth substrate via a proprietary epitaxial liftoff (ELO) process.
By utilizing its ELO capabilities, MicroLink will be able to make thin, lightweight, and highly flexible IMM solar cells which are ideal for use in unmanned aerial vehicles, space-based vehicles and equipment, and portable power generation applications.
“IMM makes multijunction solar cells practical for a wide variety of weight-, geometry-, and space-constrained applications where high efficiency is critical,” said Jeff Carapella, one of the researchers in NREL’s III-V multijunction materials and devices research group that developed the technology.
“Former NREL Scientist Mark Wanlass pioneered the use of metamorphic buffer layers to form tandem III-V solar cells with three or more junctions.
This approach is very synergistic with our ELO process technology, and MicroLink Devices is excited to now be commercializing IMM solar cells for high-performance space and UAV applications,” said Noren Pan, CEO of MicroLink Devices.
MicroLink and NREL have collaborated to evaluate the use of ELO for producing IMM solar cells since 2009, when MicroLink was the recipient of a DOE PV Incubator subcontract from NREL.
Tests of MicroLink-produced IMM solar cells conducted at NREL have demonstrated multiple successful substrate reuses and efficiencies exceeding 30%.
NREL has more than 800 technologies available for licensing and continues to engage in advanced research and development of next-generation IMM and ultra-high-efficiency multijunction solar cells with both academic and commercial collaborators.
Companies interested in partnering to advance research on or commercialize renewable energy technologies can visit the EERE Energy Innovation Portal, which features descriptions of all renewable energy technologies funded by the DOE’s Office of Energy Efficiency and Renewable Energy.
Parties interested specifically in ongoing development of IMM solar cells can contact Dan Friedman, Manager of NREL’s High Efficiency Crystalline Photovoltaics Group, for more information.
NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.