Manufacturing

Subterms

    More stories

    • 75 Shares99 Views

      in Energy

      Preparing students for the new nuclear

      by

      As nuclear power has gained greater recognition as a zero-emission energy source, the MIT Leaders for Global Operations (LGO) program has taken notice.

      Two years ago, LGO began a collaboration with MIT’s Department of Nuclear Science and Engineering (NSE) as a way to showcase the vital contribution of both business savvy and scientific rigor that LGO’s dual-degree graduates can offer this growing field.

      “We saw that the future of fission and fusion required business acumen and management acumen,” says Professor Anne White, NSE department head. “People who are going to be leaders in our discipline, and leaders in the nuclear enterprise, are going to need all of the technical pieces of the puzzle that our engineering department can provide in terms of education and training. But they’re also going to need a much broader perspective on how the technology connects with society through the lens of business.”

      The resulting response has been positive: “Companies are seeing the value of nuclear technology for their operations,” White says, and this often happens in unexpected ways.

      For example, graduate student Santiago Andrade recently completed a research project at Caterpillar Inc., a preeminent manufacturer of mining and construction equipment. Caterpillar is one of more than 20 major companies that partner with the LGO program, offering six-month internships to each student. On the surface, it seemed like an improbable pairing; what could Andrade, who was pursuing his master’s in nuclear science and engineering, do for a manufacturing company? However, Caterpillar wanted to understand the technical and commercial feasibility of using nuclear energy to power mining sites and data centers when wind and solar weren’t viable.

      “They are leaving no stone unturned in the search of financially smart solutions that can support the transition to a clean energy dependency,” Andrade says. “My project, along with many others’, is part of this effort.”

      “The research done through the LGO program with Santiago is enabling Caterpillar to understand how alternative technologies, like the nuclear microreactor, could participate in these markets in the future,” says Brian George, product manager for large electric power solutions at Caterpillar. “Our ability to connect our customers with the research will provide for a more accurate understanding of the potential opportunity, and helps provide exposure for our customers to emerging technologies.”

      With looming threats of climate change, White says, “We’re going to require more opportunities for nuclear technologies to step in and be part of those solutions. A cohort of LGO graduates will come through this program with technical expertise — a master’s degree in nuclear engineering — and an MBA. There’s going to be a tremendous talent pool out there to help companies and governments.”

      Andrade, who completed an undergraduate degree in chemical engineering and had a strong background in thermodynamics, applied to LGO unsure of which track to choose, but he knew he wanted to confront the world’s energy challenge. When MIT Admissions suggested that he join LGO’s new nuclear track, he was intrigued by how it could further his career.

      “Since the NSE department offers opportunities ranging from energy to health care and from quantum engineering to regulatory policy, the possibilities of career tracks after graduation are countless,” he says.

      He was also inspired by the fact that, as he says, “Nuclear is one of the less-popular solutions in terms of our energy transition journey. One of the things that attracted me is that it’s not one of the most popular, but it’s one of the most useful.”

      In addition to his work at Caterpillar, Andrade connected deeply with professors. He worked closely with professors Jacopo Buongiorno and John Parsons as a research assistant, helping them develop a business model to successfully support the deployment of nuclear microreactors. After graduation, he plans to work in the clean energy sector with an eye to innovations in the nuclear energy technology space.

      His LGO classmate, Lindsey Kennington, a control systems engineer, echoes his sentiments: This is a revolutionary time for nuclear technology.

      “Before MIT, I worked on a lot of nuclear waste or nuclear weapons-related projects. All of them were fission-related. I got disillusioned because of all the bureaucracy and the regulation,” Kennington says. “However, now there are a lot of new nuclear technologies coming straight out of MIT. Commonwealth Fusion Systems, a fusion startup, represents a prime example of MIT’s close relationship to new nuclear tech. Small modular reactors are another emerging technology being developed by MIT. Exposure to these cutting-edge technologies was the main sell factor for me.”

      Kennington conducted an internship with National Grid, where she used her expertise to evaluate how existing nuclear power plants could generate hydrogen. At MIT, she studied nuclear and energy policy, which offered her additional perspective that traditional engineering classes might not have provided. Because nuclear power has long been a hot-button issue, Kennington was able to gain nuanced insight about the pathways and roadblocks to its implementation.

      “I don’t think that other engineering departments emphasize that focus on policy quite as much. [Those classes] have been one of the most enriching parts of being in the nuclear department,” she says.

      Most of all, she says, it’s a pivotal time to be part of a new, blossoming program at the forefront of clean energy, especially as fusion research grows more prevalent.

      “We’re at an inflection point,” she says. “Whether or not we figure out fusion in the next five, 10, or 20 years, people are going to be working on it — and it’s a really exciting time to not only work on the science but to actually help the funding and business side grow.”

      White puts it simply.

      “This is not your parents’ nuclear,” she says. “It’s something totally different. Our discipline is evolving so rapidly that people who have technical expertise in nuclear will have a huge advantage in this next generation.” More

    • 88 Shares169 Views

      in Environment

      Rescuing small plastics from the waste stream

      by

      As plastic pollution continues to mount, with growing risks to ecosystems and wildlife, manufacturers are beginning to make ambitious commitments to keep new plastics out of the environment. A growing number have signed onto the U.S. Plastics Pact, which pledges to make 100 percent of plastic packaging reusable, recyclable, or compostable, and to see 50 percent of it effectively recycled or composted, by 2025.

      But for companies that make large numbers of small, disposable plastics, these pocket-sized objects are a major barrier to realizing their recycling goals.

      “Think about items like your toothbrush, your travel-size toothpaste tubes, your travel-size shampoo bottles,” says Alexis Hocken, a second-year PhD student in the MIT Department of Chemical Engineering. “They end up actually slipping through the cracks of current recycling infrastructure. So you might put them in your recycling bin at home, they might make it all the way to the sorting facility, but when it comes down to actually sorting them, they never make it into a recycled plastic bale at the very end of the line.”

      Now, a group of five consumer products companies is working with MIT to develop a sorting process that can keep their smallest plastic products inside the recycling chain. The companies — Colgate-Palmolive, Procter & Gamble, the Estée Lauder Companies, L’Oreal, and Haleon — all manufacture a large volume of “small format” plastics, or products less than two inches long in at least two dimensions. In a collaboration with Brad Olsen, the Alexander and I. Michael Kasser (1960) Professor of Chemical Engineering; Desiree Plata, an associate professor of civil and environmental engineering; the MIT Environmental Solutions Initiative; and the nonprofit The Sustainability Consortium, these companies are seeking a prototype sorting technology to bring to recycling facilities for large-scale testing and commercial development.

      Working in Olsen’s lab, Hocken is coming to grips with the complexity of the recycling systems involved. Material recovery facilities, or MRFs, are expected to handle products in any number of shapes, sizes, and materials, and sort them into a pure stream of glass, metal, paper, or plastic. Hocken’s first step in taking on the recycling project was to tour one of these MRFs in Portland, Maine, with Olsen and Plata.

      “We could literally see plastics just falling from the conveyor belts,” she says. “Leaving that tour, I thought, my gosh! There’s so much improvement that can be made. There’s so much impact that we can have on this industry.”

      From designing plastics to managing them

      Hocken always knew she wanted to work in engineering. Growing up in Scottsdale, Arizona, she was able to spend time in the workplace with her father, an electrical engineer who designs biomedical devices. “Seeing him working as an engineer, and how he’s solving these really important problems, definitely sparked my interest,” she says. “When it came time to begin my undergraduate degree, it was a really easy decision to choose engineering after seeing the day-to-day that my dad was doing in his career.”

      At Arizona State University, she settled on chemical engineering as a major and began working with polymers, coming up with combinations of additives for 3D plastics printing that could help fine-tune how the final products behaved. But even working with plastics every day, she rarely thought about the implications of her work for the environment.

      “And then in the spring of my final year at ASU, I took a class about polymers through the lens of sustainability, and that really opened my eyes,” Hocken remembers. The class was taught by Professor Timothy Long, director of the Biodesign Center for Sustainable Macromolecular Materials and Manufacturing and a well-known expert in the field of sustainable plastics. “That first session, where he laid out all of the really scary facts surrounding the plastics crisis, got me very motivated to look more into that field.”

      At MIT the next year, Hocken sought out Olsen as her advisor and made plastics sustainability her focus from the start.

      “Coming to MIT was my first time venturing outside of the state of Arizona for more than a three-month period,” she says. “It’s been really fun. I love living in Cambridge and the Boston area. I love my labmates. Everyone is so supportive, whether it’s to give me advice about some science that I’m trying to figure out, or just give me a pep talk if I’m feeling a little discouraged.”

      A challenge to recycle

      A lot of plastics research today is devoted to creating new materials — including biodegradable ones that are easier for natural ecosystems to absorb, and highly recyclable ones that hold their properties better after being melted down and recast.

      But Hocken also sees a huge need for better ways to handle the plastics we’re already making. “While biodegradable and sustainable polymers represent a very important route, and I think they should certainly be further pursued, we’re still a ways away from that being a reality universally across all plastic packaging,” she says. As long as large volumes of conventional plastic are coming out of factories, we’ll need innovative ways to stop it from piling onto the mountain of plastic pollution. In one of her projects, Hocken is trying to come up with new uses for recycled plastic that take advantage of its lost strength to produce a useful, flexible material similar to rubber.

      The small-format recycling project also falls in this category. The companies supporting the project have challenged the MIT team to work with their products exactly as currently manufactured — especially because their competitors use similar packaging materials that will also need to be covered by any solution the MIT team devises.

      The challenge is a large one. To kick the project off, the participating companies sent the MIT team a wide range of small-format products that need to make it through the sorting process. These include containers for lip balm, deodorant, pills, and shampoo, and disposable tools like toothbrushes and flossing picks. “A constraint, or problem I foresee, is just how variable the shapes are,” says Hocken. “A flossing pick versus a toothbrush are very different shapes.”

      Nor are they all made of the same kind of plastic. Many are made of polyethylene terephthalate (PET, type 1 in the recycling label system) or high-density polyethylene (HDPE, type 2), but nearly all of the seven recycling categories are represented among the sample products. The team’s solution will have to handle them all.

      Another obstacle is that the sorting process at a large MRF is already very complex and requires a heavy investment in equipment. The waste stream typically goes through a “glass breaker screen” that shatters glass and collects the shards; a series of rotating rubber stars to pull out two-dimensional objects, collecting paper and cardboard; a system of magnets and eddy currents to attract or repel different metals; and finally, a series of optical sorters that use infrared spectroscopy to identify the various types of plastics, then blow them down different chutes with jets of air. MRFs won’t be interested in adopting additional sorters unless they’re inexpensive and easy to fit into this elaborate stream.

      “We’re interested in creating something that could be retrofitted into current technology and current infrastructure,” Hocken says.

      Shared solutions

      “Recycling is a really good example of where pre-competitive collaboration is needed,” says Jennifer Park, collective action manager at The Sustainability Consortium (TSC), who has been working with corporate stakeholders on small format recyclability and helped convene the sponsors of this project and organize their contributions. “Companies manufacturing these products recognize that they cannot shift entire systems on their own. Consistency around what is and is not recyclable is the only way to avoid confusion and drive impact at scale.

      “Additionally, it is interesting that consumer packaged goods companies are sponsoring this research at MIT which is focused on MRF-level innovations. They’re investing in innovations that they hope will be adopted by the recycling industry to make progress on their own sustainability goals.”

      Hocken believes that, despite the challenges, it’s well worth pursuing a technology that can keep small-format plastics from slipping through MRFs’ fingers.

      “These are products that would be more recyclable if they were easier to sort,” she says. “The only thing that’s different is the size. So you can recycle both your large shampoo bottle and the small travel-size one at home, but the small one isn’t guaranteed to make it into a plastic bale at the end. If we can come up with a solution that specifically targets those while they’re still on the sorting line, they’re more likely to end up in those plastic bales at the end of the line, which can be sold to plastic reclaimers who can then use that material in new products.”

      “TSC is really excited about this project and our collaboration with MIT,” adds Park. “Our project stakeholders are very dedicated to finding a solution.”

      To learn more about this project, contact Christopher Noble, director of corporate engagement at the MIT Environmental Solutions Initiative. More

    • 50 Shares129 Views

      in Energy

      Manufacturing a cleaner future

      by

      Manufacturing had a big summer. The CHIPS and Science Act, signed into law in August, represents a massive investment in U.S. domestic manufacturing. The act aims to drastically expand the U.S. semiconductor industry, strengthen supply chains, and invest in R&D for new technological breakthroughs. According to John Hart, professor of mechanical engineering and director of the Laboratory for Manufacturing and Productivity at MIT, the CHIPS Act is just the latest example of significantly increased interest in manufacturing in recent years.

      “You have multiple forces working together: reflections from the pandemic’s impact on supply chains, the geopolitical situation around the world, and the urgency and importance of sustainability,” says Hart. “This has now aligned incentives among government, industry, and the investment community to accelerate innovation in manufacturing and industrial technology.”

      Hand-in-hand with this increased focus on manufacturing is a need to prioritize sustainability.

      Roughly one-quarter of greenhouse gas emissions came from industry and manufacturing in 2020. Factories and plants can also deplete local water reserves and generate vast amounts of waste, some of which can be toxic.

      To address these issues and drive the transition to a low-carbon economy, new products and industrial processes must be developed alongside sustainable manufacturing technologies. Hart sees mechanical engineers as playing a crucial role in this transition.

      “Mechanical engineers can uniquely solve critical problems that require next-generation hardware technologies, and know how to bring their solutions to scale,” says Hart.

      Several fast-growing companies founded by faculty and alumni from MIT’s Department of Mechanical Engineering offer solutions for manufacturing’s environmental problem, paving the path for a more sustainable future.

      Gradiant: Cleantech water solutions

      Manufacturing requires water, and lots of it. A medium-sized semiconductor fabrication plant uses upward of 10 million gallons of water a day. In a world increasingly plagued by droughts, this dependence on water poses a major challenge.

      Gradiant offers a solution to this water problem. Co-founded by Anurag Bajpayee SM ’08, PhD ’12 and Prakash Govindan PhD ’12, the company is a pioneer in sustainable — or “cleantech” — water projects.

      As doctoral students in the Rohsenow Kendall Heat Transfer Laboratory, Bajpayee and Govindan shared a pragmatism and penchant for action. They both worked on desalination research — Bajpayee with Professor Gang Chen and Govindan with Professor John Lienhard.

      Inspired by a childhood spent during a severe drought in Chennai, India, Govindan developed for his PhD a humidification-dehumidification technology that mimicked natural rainfall cycles. It was with this piece of technology, which they named Carrier Gas Extraction (CGE), that the duo founded Gradiant in 2013.

      The key to CGE lies in a proprietary algorithm that accounts for variability in the quality and quantity in wastewater feed. At the heart of the algorithm is a nondimensional number, which Govindan proposes one day be called the “Lienhard Number,” after his doctoral advisor.

      “When the water quality varies in the system, our technology automatically sends a signal to motors within the plant to adjust the flow rates to bring back the nondimensional number to a value of one. Once it’s brought back to a value of one, you’re running in optimal condition,” explains Govindan, who serves as chief operating officer of Gradiant.

      This system can treat and clean the wastewater produced by a manufacturing plant for reuse, ultimately conserving millions of gallons of water each year.

      As the company has grown, the Gradiant team has added new technologies to their arsenal, including Selective Contaminant Extraction, a cost-efficient method that removes only specific contaminants, and a brine-concentration method called Counter-Flow Reverse Osmosis. They now offer a full technology stack of water and wastewater treatment solutions to clients in industries including pharmaceuticals, energy, mining, food and beverage, and the ever-growing semiconductor industry.

      “We are an end-to-end water solutions provider. We have a portfolio of proprietary technologies and will pick and choose from our ‘quiver’ depending on a customer’s needs,” says Bajpayee, who serves as CEO of Gradiant. “Customers look at us as their water partner. We can take care of their water problem end-to-end so they can focus on their core business.”

      Gradiant has seen explosive growth over the past decade. With 450 water and wastewater treatment plants built to date, they treat the equivalent of 5 million households’ worth of water each day. Recent acquisitions saw their total employees rise to above 500.

      The diversity of Gradiant’s solutions is reflected in their clients, who include Pfizer, AB InBev, and Coca-Cola. They also count semiconductor giants like Micron Technology, GlobalFoundries, Intel, and TSMC among their customers.

      “Over the last few years, we have really developed our capabilities and reputation serving semiconductor wastewater and semiconductor ultrapure water,” says Bajpayee.

      Semiconductor manufacturers require ultrapure water for fabrication. Unlike drinking water, which has a total dissolved solids range in the parts per million, water used to manufacture microchips has a range in the parts per billion or quadrillion.

      Currently, the average recycling rate at semiconductor fabrication plants — or fabs — in Singapore is only 43 percent. Using Gradiant’s technologies, these fabs can recycle 98-99 percent of the 10 million gallons of water they require daily. This reused water is pure enough to be put back into the manufacturing process.

      “What we’ve done is eliminated the discharge of this contaminated water and nearly eliminated the dependence of the semiconductor fab on the public water supply,” adds Bajpayee.

      With new regulations being introduced, pressure is increasing for fabs to improve their water use, making sustainability even more important to brand owners and their stakeholders.

      As the domestic semiconductor industry expands in light of the CHIPS and Science Act, Gradiant sees an opportunity to bring their semiconductor water treatment technologies to more factories in the United States.

      Via Separations: Efficient chemical filtration

      Like Bajpayee and Govindan, Shreya Dave ’09, SM ’12, PhD ’16 focused on desalination for her doctoral thesis. Under the guidance of her advisor Jeffrey Grossman, professor of materials science and engineering, Dave built a membrane that could enable more efficient and cheaper desalination.

      A thorough cost and market analysis brought Dave to the conclusion that the desalination membrane she developed would not make it to commercialization.

      “The current technologies are just really good at what they do. They’re low-cost, mass produced, and they worked. There was no room in the market for our technology,” says Dave.

      Shortly after defending her thesis, she read a commentary article in the journal Nature that changed everything. The article outlined a problem. Chemical separations that are central to many manufacturing processes require a huge amount of energy. Industry needed more efficient and cheaper membranes. Dave thought she might have a solution.

      After determining there was an economic opportunity, Dave, Grossman, and Brent Keller PhD ’16 founded Via Separations in 2017. Shortly thereafter, they were chosen as one of the first companies to receive funding from MIT’s venture firm, The Engine.

      Currently, industrial filtration is done by heating chemicals at very high temperatures to separate compounds. Dave likens it to making pasta by boiling all of the water off until it evaporates and all you are left with is the pasta noodles. In manufacturing, this method of chemical separation is extremely energy-intensive and inefficient.

      Via Separations has created the chemical equivalent of a “pasta strainer.” Rather than using heat to separate, their membranes “strain” chemical compounds. This method of chemical filtration uses 90 percent less energy than standard methods.

      While most membranes are made of polymers, Via Separations’ membranes are made with graphene oxide, which can withstand high temperatures and harsh conditions. The membrane is calibrated to the customer’s needs by altering the pore size and tuning the surface chemistry.

      Currently, Dave and her team are focusing on the pulp and paper industry as their beachhead market. They have developed a system that makes the recovery of a substance known as “black liquor” more energy efficient.

      “When tree becomes paper, only one-third of the biomass is used for the paper. Currently the most valuable use for the remaining two-thirds not needed for paper is to take it from a pretty dilute stream to a pretty concentrated stream using evaporators by boiling off the water,” says Dave.

      This black liquor is then burned. Most of the resulting energy is used to power the filtration process.

      “This closed-loop system accounts for an enormous amount of energy consumption in the U.S. We can make that process 84 percent more efficient by putting the ‘pasta strainer’ in front of the boiler,” adds Dave.

      VulcanForms: Additive manufacturing at industrial scale

      The first semester John Hart taught at MIT was a fruitful one. He taught a course on 3D printing, broadly known as additive manufacturing (AM). While it wasn’t his main research focus at the time, he found the topic fascinating. So did many of the students in the class, including Martin Feldmann MEng ’14.

      After graduating with his MEng in advanced manufacturing, Feldmann joined Hart’s research group full time. There, they bonded over their shared interest in AM. They saw an opportunity to innovate with an established metal AM technology, known as laser powder bed fusion, and came up with a concept to realize metal AM at an industrial scale.

      The pair co-founded VulcanForms in 2015.

      “We have developed a machine architecture for metal AM that can build parts with exceptional quality and productivity,” says Hart. “And, we have integrated our machines in a fully digital production system, combining AM, postprocessing, and precision machining.”

      Unlike other companies that sell 3D printers for others to produce parts, VulcanForms makes and sells parts for their customers using their fleet of industrial machines. VulcanForms has grown to nearly 400 employees. Last year, the team opened their first production factory, known as “VulcanOne,” in Devens, Massachusetts.

      The quality and precision with which VulcanForms produces parts is critical for products like medical implants, heat exchangers, and aircraft engines. Their machines can print layers of metal thinner than a human hair.

      “We’re producing components that are difficult, or in some cases impossible to manufacture otherwise,” adds Hart, who sits on the company’s board of directors.

      The technologies developed at VulcanForms may help lead to a more sustainable way to manufacture parts and products, both directly through the additive process and indirectly through more efficient, agile supply chains.

      One way that VulcanForms, and AM in general, promotes sustainability is through material savings.

      Many of the materials VulcanForms uses, such as titanium alloys, require a great deal of energy to produce. When titanium parts are 3D-printed, substantially less of the material is used than in a traditional machining process. This material efficiency is where Hart sees AM making a large impact in terms of energy savings.

      Hart also points out that AM can accelerate innovation in clean energy technologies, ranging from more efficient jet engines to future fusion reactors.

      “Companies seeking to de-risk and scale clean energy technologies require know-how and access to advanced manufacturing capability, and industrial additive manufacturing is transformative in this regard,” Hart adds.

      LiquiGlide: Reducing waste by removing friction

      There is an unlikely culprit when it comes to waste in manufacturing and consumer products: friction. Kripa Varanasi, professor of mechanical engineering, and the team at LiquiGlide are on a mission to create a frictionless future, and substantially reduce waste in the process.

      Founded in 2012 by Varanasi and alum David Smith SM ’11, LiquiGlide designs custom coatings that enable liquids to “glide” on surfaces. Every last drop of a product can be used, whether it’s being squeezed out of a tube of toothpaste or drained from a 500-liter tank at a manufacturing plant. Making containers frictionless substantially minimizes wasted product, and eliminates the need to clean a container before recycling or reusing.

      Since launching, the company has found great success in consumer products. Customer Colgate utilized LiquiGlide’s technologies in the design of the Colgate Elixir toothpaste bottle, which has been honored with several industry awards for design. In a collaboration with world- renowned designer Yves Béhar, LiquiGlide is applying their technology to beauty and personal care product packaging. Meanwhile, the U.S. Food and Drug Administration has granted them a Device Master Filing, opening up opportunities for the technology to be used in medical devices, drug delivery, and biopharmaceuticals.

      In 2016, the company developed a system to make manufacturing containers frictionless. Called CleanTanX, the technology is used to treat the surfaces of tanks, funnels, and hoppers, preventing materials from sticking to the side. The system can reduce material waste by up to 99 percent.

      “This could really change the game. It saves wasted product, reduces wastewater generated from cleaning tanks, and can help make the manufacturing process zero-waste,” says Varanasi, who serves as chair at LiquiGlide.

      LiquiGlide works by creating a coating made of a textured solid and liquid lubricant on the container surface. When applied to a container, the lubricant remains infused within the texture. Capillary forces stabilize and allow the liquid to spread on the surface, creating a continuously lubricated surface that any viscous material can slide right down. The company uses a thermodynamic algorithm to determine the combinations of safe solids and liquids depending on the product, whether it’s toothpaste or paint.

      The company has built a robotic spraying system that can treat large vats and tanks at manufacturing plants on site. In addition to saving companies millions of dollars in wasted product, LiquiGlide drastically reduces the amount of water needed to regularly clean these containers, which normally have product stuck to the sides.

      “Normally when you empty everything out of a tank, you still have residue that needs to be cleaned with a tremendous amount of water. In agrochemicals, for example, there are strict regulations about how to deal with the resulting wastewater, which is toxic. All of that can be eliminated with LiquiGlide,” says Varanasi.

      While the closure of many manufacturing facilities early in the pandemic slowed down the rollout of CleanTanX pilots at plants, things have picked up in recent months. As manufacturing ramps up both globally and domestically, Varanasi sees a growing need for LiquiGlide’s technologies, especially for liquids like semiconductor slurry.

      Companies like Gradiant, Via Separations, VulcanForms, and LiquiGlide demonstrate that an expansion in manufacturing industries does not need to come at a steep environmental cost. It is possible for manufacturing to be scaled up in a sustainable way.

      “Manufacturing has always been the backbone of what we do as mechanical engineers. At MIT in particular, there is always a drive to make manufacturing sustainable,” says Evelyn Wang, Ford Professor of Engineering and former head of the Department of Mechanical Engineering. “It’s amazing to see how startups that have an origin in our department are looking at every aspect of the manufacturing process and figuring out how to improve it for the health of our planet.”

      As legislation like the CHIPS and Science Act fuels growth in manufacturing, there will be an increased need for startups and companies that develop solutions to mitigate the environmental impact, bringing us closer to a more sustainable future. More

    • 75 Shares99 Views

      in Energy

      Mining for the clean energy transition

      by

      In a world powered increasingly by clean energy, drilling for oil and gas will gradually give way to digging for metals and minerals. Today, the “critical minerals” used to make electric cars, solar panels, wind turbines, and grid-scale battery storage are facing soaring demand — and some acute bottlenecks as miners race to catch up.

      According to a report from the International Energy Agency, by 2040, the worldwide demand for copper is expected to roughly double; demand for nickel and cobalt will grow at least sixfold; and the world’s hunger for lithium could reach 40 times what we use today.

      “Society is looking to the clean energy transition as a way to solve the environmental and social harms of climate change,” says Scott Odell, a visiting scientist at the MIT Environmental Solutions Initiative (ESI), where he helps run the ESI Mining, Environment, and Society Program, who is also a visiting assistant professor at George Washington University. “Yet mining the materials needed for that transition would also cause social and environmental impacts. So we need to look for ways to reduce our demand for minerals, while also improving current mining practices to minimize social and environmental impacts.”

      ESI recently hosted the inaugural MIT Conference on Mining, Environment, and Society to discuss how the clean energy transition may affect mining and the people and environments in mining areas. The conference convened representatives of mining companies, environmental and human rights groups, policymakers, and social and natural scientists to identify key concerns and possible collaborative solutions.

      “We can’t replace an abusive fossil fuel industry with an abusive mining industry that expands as we move through the energy transition,” said Jim Wormington, a senior researcher at Human Rights Watch, in a panel on the first day of the conference. “There’s a recognition from governments, civil society, and companies that this transition potentially has a really significant human rights and social cost, both in terms of emissions […] but also for communities and workers who are on the front lines of mining.”

      That focus on communities and workers was consistent throughout the three-day conference, as participants outlined the economic and social dimensions of standing up large numbers of new mines. Corporate mines can bring large influxes of government revenue and local investment, but the income is volatile and can leave policymakers and communities stranded when production declines or mineral prices fall. On the other hand, “artisanal” mining operations are an important source of critical minerals, but are hard to regulate and subject to abuses from brokers. And large reserves of minerals are found in conservation areas, regions with fragile ecosystems and experiencing water shortages that can be exacerbated by mining, in particular on Indigenous-controlled lands and other places where mine openings are deeply fraught.

      “One of the real triggers of conflict is a dissatisfaction with the current model of resource extraction,” said Jocelyn Fraser of the University of British Columbia in a panel discussion. “One that’s failed to support the long-term sustainable development of regions that host mining operations, and yet imposes significant local social and environmental impacts.”

      All these challenges point toward solutions in policy and in mining companies’ relationships with the communities where they work. Participants highlighted newer models of mining governance that can create better incentives for the ways mines operate — from full community ownership of mines to recognizing community rights to the benefits of mining to end-of-life planning for mines at the time they open.

      Many of the conference speakers also shared technological innovations that may help reduce mining challenges. Some operations are investing in desalination as alternative water sources in water-scarce regions; low-carbon alternatives are emerging to many of the fossil fuel-powered heavy machines that are mainstays of the industry; and work is being done to reclaim valuable minerals from mine tailings, helping to minimize both waste and the need to open new extraction sites.

      Increasingly, the mining industry itself is recognizing that reforms will allow it to thrive in a rapid clean-energy transition. “Decarbonization is really a profitability imperative,” said Kareemah Mohammed, managing director for sustainability services at the technology consultancy Accenture, on the conference’s second day. “It’s about securing a low-cost and steady supply of either minerals or metals, but it’s also doing so in an optimal way.”

      The three-day conference attracted over 350 attendees, from large mining companies, industry groups, consultancies, multilateral institutions, universities, nongovernmental organizations (NGOs), government, and more. It was held entirely virtually, a choice that helped make the conference not only truly international — participants joined from over 27 countries on six continents — but also accessible to members of nonprofits and professionals in the developing world.

      “Many people are concerned about the environmental and social challenges of supplying the clean energy revolution, and we’d heard repeatedly that there wasn’t a forum for government, industry, academia, NGOs, and communities to all sit at the same table and explore collaborative solutions,” says Christopher Noble, ESI’s director of corporate engagement. “Convening, and researching best practices, are roles that universities can play. The conversations at this conference have generated valuable ideas and consensus to pursue three parallel programs: best-in-class models for community engagement, improving ESG metrics and their use, and civil-society contributions to government/industry relations. We are developing these programs to keep the momentum going.”

      The MIT Conference on Mining, Environment, and Society was funded, in part, by Accenture, as part of the MIT/Accenture Convergence Initiative. Additional funding was provided by the Inter-American Development Bank. More

    • 88 Shares159 Views

      in Environment

      Silk offers an alternative to some microplastics

      by

      Microplastics, tiny particles of plastic that are now found worldwide in the air, water, and soil, are increasingly recognized as a serious pollution threat, and have been found in the bloodstream of animals and people around the world.

      Some of these microplastics are intentionally added to a variety of products, including agricultural chemicals, paints, cosmetics, and detergents — amounting to an estimated 50,000 tons a year in the European Union alone, according to the European Chemicals Agency. The EU has already declared that these added, nonbiodegradable microplastics must be eliminated by 2025, so the search is on for suitable replacements, which do not currently exist.

      Now, a team of scientists at MIT and elsewhere has developed a system based on silk that could provide an inexpensive and easily manufactured substitute. The new process is described in a paper in the journal Small, written by MIT postdoc Muchun Liu, MIT professor of civil and environmental engineering Benedetto Marelli, and five others at the chemical company BASF in Germany and the U.S.

      The microplastics widely used in industrial products generally protect some specific active ingredient (or ingredients) from being degraded by exposure to air or moisture, until the time they are needed. They provide a slow release of the active ingredient for a targeted period of time and minimize adverse effects to its surroundings. For example, vitamins are often delivered in the form of microcapsules packed into a pill or capsule, and pesticides and herbicides are similarly enveloped. But the materials used today for such microencapsulation are plastics that persist in the environment for a long time. Until now, there has been no practical, economical substitute available that would biodegrade naturally.

      Much of the burden of environmental microplastics comes from other sources, such as the degradation over time of larger plastic objects such as bottles and packaging, and from the wear of car tires. Each of these sources may require its own kind of solutions for reducing its spread, Marelli says. The European Chemical Agency has estimated that the intentionally added microplastics represent approximately 10-15 percent of the total amount in the environment, but this source may be relatively easy to address using this nature-based biodegradable replacement, he says.

      “We cannot solve the whole microplastics problem with one solution that fits them all,” he says. “Ten percent of a big number is still a big number. … We’ll solve climate change and pollution of the world one percent at a time.”

      Unlike the high-quality silk threads used for fine fabrics, the silk protein used in the new alternative material is widely available and less expensive, Liu says. While silkworm cocoons must be painstakingly unwound to produce the fine threads needed for fabric, for this use, non-textile-quality cocoons can be used, and the silk fibers can simply be dissolved using a scalable water-based process. The processing is so simple and tunable that the resulting material can be adapted to work on existing manufacturing equipment, potentially providing a simple “drop in” solution using existing factories.

      Silk is recognized as safe for food or medical use, as it is nontoxic and degrades naturally in the body. In lab tests, the researchers demonstrated that the silk-based coating material could be used in existing, standard spray-based manufacturing equipment to make a standard water-soluble microencapsulated herbicide product, which was then tested in a greenhouse on a corn crop. The test showed it worked even better than an existing commercial product, inflicting less damage to the plants, Liu says.

      While other groups have proposed degradable encapsulation materials that may work at a small laboratory scale, Marelli says, “there is a strong need to achieve encapsulation of high-content actives to open the door to commercial use. The only way to have an impact is where we can not only replace a synthetic polymer with a biodegradable counterpart, but also achieve performance that is the same, if not better.”

      The secret to making the material compatible with existing equipment, Liu explains, is in the tunability of the silk material. By precisely adjusting the polymer chain arrangements of silk materials and addition of a surfactant, it is possible to fine-tune the properties of the resulting coatings once they dry out and harden. The material can be hydrophobic (water-repelling) even though it is made and processed in a water solution, or it can be hydrophilic (water-attracting), or anywhere in between, and for a given application it can be made to match the characteristics of the material it is being used to replace.

      In order to arrive at a practical solution, Liu had to develop a way of freezing the forming droplets of encapsulated materials as they were forming, to study the formation process in detail. She did this using a special spray-freezing system, and was able to observe exactly how the encapsulation works in order to control it better. Some of the encapsulated “payload” materials, whether they be pesticides or nutrients or enzymes, are water-soluble and some are not, and they interact in different ways with the coating material.

      “To encapsulate different materials, we have to study how the polymer chains interact and whether they are compatible with different active materials in suspension,” she says. The payload material and the coating material are mixed together in a solution and then sprayed. As droplets form, the payload tends to be embedded in a shell of the coating material, whether that’s the original synthetic plastic or the new silk material.

      The new method can make use of low-grade silk that is unusable for fabrics, and large quantities of which are currently discarded because they have no significant uses, Liu says. It can also use used, discarded silk fabric, diverting that material from being disposed of in landfills.

      Currently, 90 percent of the world’s silk production takes place in China, Marelli says, but that’s largely because China has perfected the production of the high-quality silk threads needed for fabrics. But because this process uses bulk silk and has no need for that level of quality, production could easily be ramped up in other parts of the world to meet local demand if this process becomes widely used, he says.

      “This elegant and clever study describes a sustainable and biodegradable silk-based replacement for microplastic encapsulants, which are a pressing environmental challenge,” says Alon Gorodetsky, an associate professor of chemical and biomolecular engineering at the University of California at Irvine, who was not associated with this research. “The modularity of the described materials and the scalability of the manufacturing processes are key advantages that portend well for translation to real-world applications.”

      This process “represents a potentially highly significant advance in active ingredient delivery for a range of industries, particularly agriculture,” says Jason White, director of the Connecticut Agricultural Experiment Station, who also was not associated with this work. “Given the current and future challenges related to food insecurity, agricultural production, and a changing climate, novel strategies such as this are greatly needed.”

      The research team also included Pierre-Eric Millard, Ophelie Zeyons, Henning Urch, Douglas Findley and Rupert Konradi from the BASF corporation, in Germany and in the U.S. The work was supported by BASF through the Northeast Research Alliance (NORA). More

    • 113 Shares189 Views

      in Energy

      New program bolsters innovation in next-generation artificial intelligence hardware

      by

      The MIT AI Hardware Program is a new academia and industry collaboration aimed at defining and developing translational technologies in hardware and software for the AI and quantum age. A collaboration between the MIT School of Engineering and MIT Schwarzman College of Computing, involving the Microsystems Technologies Laboratories and programs and units in the college, the cross-disciplinary effort aims to innovate technologies that will deliver enhanced energy efficiency systems for cloud and edge computing.

      “A sharp focus on AI hardware manufacturing, research, and design is critical to meet the demands of the world’s evolving devices, architectures, and systems,” says Anantha Chandrakasan, dean of the MIT School of Engineering and Vannevar Bush Professor of Electrical Engineering and Computer Science. “Knowledge-sharing between industry and academia is imperative to the future of high-performance computing.”

      Based on use-inspired research involving materials, devices, circuits, algorithms, and software, the MIT AI Hardware Program convenes researchers from MIT and industry to facilitate the transition of fundamental knowledge to real-world technological solutions. The program spans materials and devices, as well as architecture and algorithms enabling energy-efficient and sustainable high-performance computing.

      “As AI systems become more sophisticated, new solutions are sorely needed to enable more advanced applications and deliver greater performance,” says Daniel Huttenlocher, dean of the MIT Schwarzman College of Computing and Henry Ellis Warren Professor of Electrical Engineering and Computer Science. “Our aim is to devise real-world technological solutions and lead the development of technologies for AI in hardware and software.”

      The inaugural members of the program are companies from a wide range of industries including chip-making, semiconductor manufacturing equipment, AI and computing services, and information systems R&D organizations. The companies represent a diverse ecosystem, both nationally and internationally, and will work with MIT faculty and students to help shape a vibrant future for our planet through cutting-edge AI hardware research.

      The five inaugural members of the MIT AI Hardware Program are:  

      Amazon, a global technology company whose hardware inventions include the Kindle, Amazon Echo, Fire TV, and Astro; 
      Analog Devices, a global leader in the design and manufacturing of analog, mixed signal, and DSP integrated circuits; 
      ASML, an innovation leader in the semiconductor industry, providing chipmakers with hardware, software, and services to mass produce patterns on silicon through lithography; 
      NTT Research, a subsidiary of NTT that conducts fundamental research to upgrade reality in game-changing ways that improve lives and brighten our global future; and 
      TSMC, the world’s leading dedicated semiconductor foundry.

      The MIT AI Hardware Program will create a roadmap of transformative AI hardware technologies. Leveraging MIT.nano, the most advanced university nanofabrication facility anywhere, the program will foster a unique environment for AI hardware research.  

      “We are all in awe at the seemingly superhuman capabilities of today’s AI systems. But this comes at a rapidly increasing and unsustainable energy cost,” says Jesús del Alamo, the Donner Professor in MIT’s Department of Electrical Engineering and Computer Science. “Continued progress in AI will require new and vastly more energy-efficient systems. This, in turn, will demand innovations across the entire abstraction stack, from materials and devices to systems and software. The program is in a unique position to contribute to this quest.”

      The program will prioritize the following topics:

      analog neural networks;
      new roadmap CMOS designs;
      heterogeneous integration for AI systems;
      onolithic-3D AI systems;
      analog nonvolatile memory devices;
      software-hardware co-design;
      intelligence at the edge;
      intelligent sensors;
      energy-efficient AI;
      intelligent internet of things (IIoT);
      neuromorphic computing;
      AI edge security;
      quantum AI;
      wireless technologies;
      hybrid-cloud computing; and
      high-performance computation.

      “We live in an era where paradigm-shifting discoveries in hardware, systems communications, and computing have become mandatory to find sustainable solutions — solutions that we are proud to give to the world and generations to come,” says Aude Oliva, senior research scientist in the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) and director of strategic industry engagement in the MIT Schwarzman College of Computing.

      The new program is co-led by Jesús del Alamo and Aude Oliva, and Anantha Chandrakasan serves as chair. More

    • 100 Shares189 Views

      in Energy

      The reasons behind lithium-ion batteries’ rapid cost decline

      by

      Lithium-ion batteries, those marvels of lightweight power that have made possible today’s age of handheld electronics and electric vehicles, have plunged in cost since their introduction three decades ago at a rate similar to the drop in solar panel prices, as documented by a study published last March. But what brought about such an astonishing cost decline, of about 97 percent?

      Some of the researchers behind that earlier study have now analyzed what accounted for the extraordinary savings. They found that by far the biggest factor was work on research and development, particularly in chemistry and materials science. This outweighed the gains achieved through economies of scale, though that turned out to be the second-largest category of reductions.

      The new findings are being published today in the journal Energy and Environmental Science, in a paper by MIT postdoc Micah Ziegler, recent graduate student Juhyun Song PhD ’19, and Jessika Trancik, a professor in MIT’s Institute for Data, Systems and Society.

      The findings could be useful for policymakers and planners to help guide spending priorities in order to continue the pathway toward ever-lower costs for this and other crucial energy storage technologies, according to Trancik. Their work suggests that there is still considerable room for further improvement in electrochemical battery technologies, she says.

      The analysis required digging through a variety of sources, since much of the relevant information consists of closely held proprietary business data. “The data collection effort was extensive,” Ziegler says. “We looked at academic articles, industry and government reports, press releases, and specification sheets. We even looked at some legal filings that came out. We had to piece together data from many different sources to get a sense of what was happening.” He says they collected “about 15,000 qualitative and quantitative data points, across 1,000 individual records from approximately 280 references.”

      Data from the earliest times are hardest to access and can have the greatest uncertainties, Trancik says, but by comparing different data sources from the same period they have attempted to account for these uncertainties.

      Overall, she says, “we estimate that the majority of the cost decline, more than 50 percent, came from research-and-development-related activities.” That included both private sector and government-funded research and development, and “the vast majority” of that cost decline within that R&D category came from chemistry and materials research.

      That was an interesting finding, she says, because “there were so many variables that people were working on through very different kinds of efforts,” including the design of the battery cells themselves, their manufacturing systems, supply chains, and so on. “The cost improvement emerged from a diverse set of efforts and many people, and not from the work of only a few individuals.”

      The findings about the importance of investment in R&D were especially significant, Ziegler says, because much of this investment happened after lithium-ion battery technology was commercialized, a stage at which some analysts thought the research contribution would become less significant. Over roughly a 20-year period starting five years after the batteries’ introduction in the early 1990s, he says, “most of the cost reduction still came from R&D. The R&D contribution didn’t end when commercialization began. In fact, it was still the biggest contributor to cost reduction.”

      The study took advantage of an analytical approach that Trancik and her team initially developed to analyze the similarly precipitous drop in costs of silicon solar panels over the last few decades. They also applied the approach to understand the rising costs of nuclear energy. “This is really getting at the fundamental mechanisms of technological change,” she says. “And we can also develop these models looking forward in time, which allows us to uncover the levers that people could use to improve the technology in the future.”

      One advantage of the methodology Trancik and her colleagues have developed, she says, is that it helps to sort out the relative importance of different factors when many variables are changing all at once, which typically happens as a technology improves. “It’s not simply adding up the cost effects of these variables,” she says, “because many of these variables affect many different cost components. There’s this kind of intricate web of dependencies.” But the team’s methodology makes it possible to “look at how that overall cost change can be attributed to those variables, by essentially mapping out that network of dependencies,” she says.

      This can help provide guidance on public spending, private investments, and other incentives. “What are all the things that different decision makers could do?” she asks. “What decisions do they have agency over so that they could improve the technology, which is important in the case of low-carbon technologies, where we’re looking for solutions to climate change and we have limited time and limited resources? The new approach allows us to potentially be a bit more intentional about where we make those investments of time and money.”

      “This paper collects data available in a systematic way to determine changes in the cost components of lithium-ion batteries between 1990-1995 and 2010-2015,” says Laura Diaz Anadon, a professor of climate change policy at Cambridge University, who was not connected to this research. “This period was an important one in the history of the technology, and understanding the evolution of cost components lays the groundwork for future work on mechanisms and could help inform research efforts in other types of batteries.”

      The research was supported by the Alfred P. Sloan Foundation, the Environmental Defense Fund, and the MIT Technology and Policy Program. More

    • 75 Shares159 Views

      in Energy

      Designing better batteries for electric vehicles

      by

      The urgent need to cut carbon emissions is prompting a rapid move toward electrified mobility and expanded deployment of solar and wind on the electric grid. If those trends escalate as expected, the need for better methods of storing electrical energy will intensify.

      “We need all the strategies we can get to address the threat of climate change,” says Elsa Olivetti PhD ’07, the Esther and Harold E. Edgerton Associate Professor in Materials Science and Engineering. “Obviously, developing technologies for grid-based storage at a large scale is critical. But for mobile applications — in particular, transportation — much research is focusing on adapting today’s lithium-ion battery to make versions that are safer, smaller, and can store more energy for their size and weight.”

      Traditional lithium-ion batteries continue to improve, but they have limitations that persist, in part because of their structure. A lithium-ion battery consists of two electrodes — one positive and one negative — sandwiched around an organic (carbon-containing) liquid. As the battery is charged and discharged, electrically charged particles (or ions) of lithium pass from one electrode to the other through the liquid electrolyte.

      One problem with that design is that at certain voltages and temperatures, the liquid electrolyte can become volatile and catch fire. “Batteries are generally safe under normal usage, but the risk is still there,” says Kevin Huang PhD ’15, a research scientist in Olivetti’s group.

      Another problem is that lithium-ion batteries are not well-suited for use in vehicles. Large, heavy battery packs take up space and increase a vehicle’s overall weight, reducing fuel efficiency. But it’s proving difficult to make today’s lithium-ion batteries smaller and lighter while maintaining their energy density — that is, the amount of energy they store per gram of weight.

      To solve those problems, researchers are changing key features of the lithium-ion battery to make an all-solid, or “solid-state,” version. They replace the liquid electrolyte in the middle with a thin, solid electrolyte that’s stable at a wide range of voltages and temperatures. With that solid electrolyte, they use a high-capacity positive electrode and a high-capacity, lithium metal negative electrode that’s far thinner than the usual layer of porous carbon. Those changes make it possible to shrink the overall battery considerably while maintaining its energy-storage capacity, thereby achieving a higher energy density.

      “Those features — enhanced safety and greater energy density — are probably the two most-often-touted advantages of a potential solid-state battery,” says Huang. He then quickly clarifies that “all of these things are prospective, hoped-for, and not necessarily realized.” Nevertheless, the possibility has many researchers scrambling to find materials and designs that can deliver on that promise.

      Thinking beyond the lab

      Researchers have come up with many intriguing options that look promising — in the lab. But Olivetti and Huang believe that additional practical considerations may be important, given the urgency of the climate change challenge. “There are always metrics that we researchers use in the lab to evaluate possible materials and processes,” says Olivetti. Examples might include energy-storage capacity and charge/discharge rate. When performing basic research — which she deems both necessary and important — those metrics are appropriate. “But if the aim is implementation, we suggest adding a few metrics that specifically address the potential for rapid scaling,” she says.

      Based on industry’s experience with current lithium-ion batteries, the MIT researchers and their colleague Gerbrand Ceder, the Daniel M. Tellep Distinguished Professor of Engineering at the University of California at Berkeley, suggest three broad questions that can help identify potential constraints on future scale-up as a result of materials selection. First, with this battery design, could materials availability, supply chains, or price volatility become a problem as production scales up? (Note that the environmental and other concerns raised by expanded mining are outside the scope of this study.) Second, will fabricating batteries from these materials involve difficult manufacturing steps during which parts are likely to fail? And third, do manufacturing measures needed to ensure a high-performance product based on these materials ultimately lower or raise the cost of the batteries produced?

      To demonstrate their approach, Olivetti, Ceder, and Huang examined some of the electrolyte chemistries and battery structures now being investigated by researchers. To select their examples, they turned to previous work in which they and their collaborators used text- and data-mining techniques to gather information on materials and processing details reported in the literature. From that database, they selected a few frequently reported options that represent a range of possibilities.

      Materials and availability

      In the world of solid inorganic electrolytes, there are two main classes of materials — the oxides, which contain oxygen, and the sulfides, which contain sulfur. Olivetti, Ceder, and Huang focused on one promising electrolyte option in each class and examined key elements of concern for each of them.

      The sulfide they considered was LGPS, which combines lithium, germanium, phosphorus, and sulfur. Based on availability considerations, they focused on the germanium, an element that raises concerns in part because it’s not generally mined on its own. Instead, it’s a byproduct produced during the mining of coal and zinc.

      To investigate its availability, the researchers looked at how much germanium was produced annually in the past six decades during coal and zinc mining and then at how much could have been produced. The outcome suggested that 100 times more germanium could have been produced, even in recent years. Given that supply potential, the availability of germanium is not likely to constrain the scale-up of a solid-state battery based on an LGPS electrolyte.

      The situation looked less promising with the researchers’ selected oxide, LLZO, which consists of lithium, lanthanum, zirconium, and oxygen. Extraction and processing of lanthanum are largely concentrated in China, and there’s limited data available, so the researchers didn’t try to analyze its availability. The other three elements are abundantly available. However, in practice, a small quantity of another element — called a dopant — must be added to make LLZO easy to process. So the team focused on tantalum, the most frequently used dopant, as the main element of concern for LLZO.

      Tantalum is produced as a byproduct of tin and niobium mining. Historical data show that the amount of tantalum produced during tin and niobium mining was much closer to the potential maximum than was the case with germanium. So the availability of tantalum is more of a concern for the possible scale-up of an LLZO-based battery.

      But knowing the availability of an element in the ground doesn’t address the steps required to get it to a manufacturer. So the researchers investigated a follow-on question concerning the supply chains for critical elements — mining, processing, refining, shipping, and so on. Assuming that abundant supplies are available, can the supply chains that deliver those materials expand quickly enough to meet the growing demand for batteries?

      In sample analyses, they looked at how much supply chains for germanium and tantalum would need to grow year to year to provide batteries for a projected fleet of electric vehicles in 2030. As an example, an electric vehicle fleet often cited as a goal for 2030 would require production of enough batteries to deliver a total of 100 gigawatt hours of energy. To meet that goal using just LGPS batteries, the supply chain for germanium would need to grow by 50 percent from year to year — a stretch, since the maximum growth rate in the past has been about 7 percent. Using just LLZO batteries, the supply chain for tantalum would need to grow by about 30 percent — a growth rate well above the historical high of about 10 percent.

      Those examples demonstrate the importance of considering both materials availability and supply chains when evaluating different solid electrolytes for their scale-up potential. “Even when the quantity of a material available isn’t a concern, as is the case with germanium, scaling all the steps in the supply chain to match the future production of electric vehicles may require a growth rate that’s literally unprecedented,” says Huang.

      Materials and processing

      In assessing the potential for scale-up of a battery design, another factor to consider is the difficulty of the manufacturing process and how it may impact cost. Fabricating a solid-state battery inevitably involves many steps, and a failure at any step raises the cost of each battery successfully produced. As Huang explains, “You’re not shipping those failed batteries; you’re throwing them away. But you’ve still spent money on the materials and time and processing.”

      As a proxy for manufacturing difficulty, Olivetti, Ceder, and Huang explored the impact of failure rate on overall cost for selected solid-state battery designs in their database. In one example, they focused on the oxide LLZO. LLZO is extremely brittle, and at the high temperatures involved in manufacturing, a large sheet that’s thin enough to use in a high-performance solid-state battery is likely to crack or warp.

      To determine the impact of such failures on cost, they modeled four key processing steps in assembling LLZO-based batteries. At each step, they calculated cost based on an assumed yield — that is, the fraction of total units that were successfully processed without failing. With the LLZO, the yield was far lower than with the other designs they examined; and, as the yield went down, the cost of each kilowatt-hour (kWh) of battery energy went up significantly. For example, when 5 percent more units failed during the final cathode heating step, cost increased by about $30/kWh — a nontrivial change considering that a commonly accepted target cost for such batteries is $100/kWh. Clearly, manufacturing difficulties can have a profound impact on the viability of a design for large-scale adoption.

      Materials and performance

      One of the main challenges in designing an all-solid battery comes from “interfaces” — that is, where one component meets another. During manufacturing or operation, materials at those interfaces can become unstable. “Atoms start going places that they shouldn’t, and battery performance declines,” says Huang.

      As a result, much research is devoted to coming up with methods of stabilizing interfaces in different battery designs. Many of the methods proposed do increase performance; and as a result, the cost of the battery in dollars per kWh goes down. But implementing such solutions generally involves added materials and time, increasing the cost per kWh during large-scale manufacturing.

      To illustrate that trade-off, the researchers first examined their oxide, LLZO. Here, the goal is to stabilize the interface between the LLZO electrolyte and the negative electrode by inserting a thin layer of tin between the two. They analyzed the impacts — both positive and negative — on cost of implementing that solution. They found that adding the tin separator increases energy-storage capacity and improves performance, which reduces the unit cost in dollars/kWh. But the cost of including the tin layer exceeds the savings so that the final cost is higher than the original cost.

      In another analysis, they looked at a sulfide electrolyte called LPSCl, which consists of lithium, phosphorus, and sulfur with a bit of added chlorine. In this case, the positive electrode incorporates particles of the electrolyte material — a method of ensuring that the lithium ions can find a pathway through the electrolyte to the other electrode. However, the added electrolyte particles are not compatible with other particles in the positive electrode — another interface problem. In this case, a standard solution is to add a “binder,” another material that makes the particles stick together.

      Their analysis confirmed that without the binder, performance is poor, and the cost of the LPSCl-based battery is more than $500/kWh. Adding the binder improves performance significantly, and the cost drops by almost $300/kWh. In this case, the cost of adding the binder during manufacturing is so low that essentially all the of the cost decrease from adding the binder is realized. Here, the method implemented to solve the interface problem pays off in lower costs.

      The researchers performed similar studies of other promising solid-state batteries reported in the literature, and their results were consistent: The choice of battery materials and processes can affect not only near-term outcomes in the lab but also the feasibility and cost of manufacturing the proposed solid-state battery at the scale needed to meet future demand. The results also showed that considering all three factors together — availability, processing needs, and battery performance — is important because there may be collective effects and trade-offs involved.

      Olivetti is proud of the range of concerns the team’s approach can probe. But she stresses that it’s not meant to replace traditional metrics used to guide materials and processing choices in the lab. “Instead, it’s meant to complement those metrics by also looking broadly at the sorts of things that could get in the way of scaling” — an important consideration given what Huang calls “the urgent ticking clock” of clean energy and climate change.

      This research was supported by the Seed Fund Program of the MIT Energy Initiative (MITEI) Low-Carbon Energy Center for Energy Storage; by Shell, a founding member of MITEI; and by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, under the Advanced Battery Materials Research Program. The text mining work was supported by the National Science Foundation, the Office of Naval Research, and MITEI.

      This article appears in the Spring 2021 issue of Energy Futures, the magazine of the MIT Energy Initiative. More