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      New tool makes generative AI models more likely to create breakthrough materials

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      The artificial intelligence models that turn text into images are also useful for generating new materials. Over the last few years, generative materials models from companies like Google, Microsoft, and Meta have drawn on their training data to help researchers design tens of millions of new materials.But when it comes to designing materials with exotic quantum properties like superconductivity or unique magnetic states, those models struggle. That’s too bad, because humans could use the help. For example, after a decade of research into a class of materials that could revolutionize quantum computing, called quantum spin liquids, only a dozen material candidates have been identified. The bottleneck means there are fewer materials to serve as the basis for technological breakthroughs.Now, MIT researchers have developed a technique that lets popular generative materials models create promising quantum materials by following specific design rules. The rules, or constraints, steer models to create materials with unique structures that give rise to quantum properties.“The models from these large companies generate materials optimized for stability,” says Mingda Li, MIT’s Class of 1947 Career Development Professor. “Our perspective is that’s not usually how materials science advances. We don’t need 10 million new materials to change the world. We just need one really good material.”The approach is described today in a paper published by Nature Materials. The researchers applied their technique to generate millions of candidate materials consisting of geometric lattice structures associated with quantum properties. From that pool, they synthesized two actual materials with exotic magnetic traits.“People in the quantum community really care about these geometric constraints, like the Kagome lattices that are two overlapping, upside-down triangles. We created materials with Kagome lattices because those materials can mimic the behavior of rare earth elements, so they are of high technical importance.” Li says.Li is the senior author of the paper. His MIT co-authors include PhD students Ryotaro Okabe, Mouyang Cheng, Abhijatmedhi Chotrattanapituk, and Denisse Cordova Carrizales; postdoc Manasi Mandal; undergraduate researchers Kiran Mak and Bowen Yu; visiting scholar Nguyen Tuan Hung; Xiang Fu ’22, PhD ’24; and professor of electrical engineering and computer science Tommi Jaakkola, who is an affiliate of the Computer Science and Artificial Intelligence Laboratory (CSAIL) and Institute for Data, Systems, and Society. Additional co-authors include Yao Wang of Emory University, Weiwei Xie of Michigan State University, YQ Cheng of Oak Ridge National Laboratory, and Robert Cava of Princeton University.Steering models toward impactA material’s properties are determined by its structure, and quantum materials are no different. Certain atomic structures are more likely to give rise to exotic quantum properties than others. For instance, square lattices can serve as a platform for high-temperature superconductors, while other shapes known as Kagome and Lieb lattices can support the creation of materials that could be useful for quantum computing.To help a popular class of generative models known as a diffusion models produce materials that conform to particular geometric patterns, the researchers created SCIGEN (short for Structural Constraint Integration in GENerative model). SCIGEN is a computer code that ensures diffusion models adhere to user-defined constraints at each iterative generation step. With SCIGEN, users can give any generative AI diffusion model geometric structural rules to follow as it generates materials.AI diffusion models work by sampling from their training dataset to generate structures that reflect the distribution of structures found in the dataset. SCIGEN blocks generations that don’t align with the structural rules.To test SCIGEN, the researchers applied it to a popular AI materials generation model known as DiffCSP. They had the SCIGEN-equipped model generate materials with unique geometric patterns known as Archimedean lattices, which are collections of 2D lattice tilings of different polygons. Archimedean lattices can lead to a range of quantum phenomena and have been the focus of much research.“Archimedean lattices give rise to quantum spin liquids and so-called flat bands, which can mimic the properties of rare earths without rare earth elements, so they are extremely important,” says Cheng, a co-corresponding author of the work. “Other Archimedean lattice materials have large pores that could be used for carbon capture and other applications, so it’s a collection of special materials. In some cases, there are no known materials with that lattice, so I think it will be really interesting to find the first material that fits in that lattice.”The model generated over 10 million material candidates with Archimedean lattices. One million of those materials survived a screening for stability. Using the supercomputers in Oak Ridge National Laboratory, the researchers then took a smaller sample of 26,000 materials and ran detailed simulations to understand how the materials’ underlying atoms behaved. The researchers found magnetism in 41 percent of those structures.From that subset, the researchers synthesized two previously undiscovered compounds, TiPdBi and TiPbSb, at Xie and Cava’s labs. Subsequent experiments showed the AI model’s predictions largely aligned with the actual material’s properties.“We wanted to discover new materials that could have a huge potential impact by incorporating these structures that have been known to give rise to quantum properties,” says Okabe, the paper’s first author. “We already know that these materials with specific geometric patterns are interesting, so it’s natural to start with them.”Accelerating material breakthroughsQuantum spin liquids could unlock quantum computing by enabling stable, error-resistant qubits that serve as the basis of quantum operations. But no quantum spin liquid materials have been confirmed. Xie and Cava believe SCIGEN could accelerate the search for these materials.“There’s a big search for quantum computer materials and topological superconductors, and these are all related to the geometric patterns of materials,” Xie says. “But experimental progress has been very, very slow,” Cava adds. “Many of these quantum spin liquid materials are subject to constraints: They have to be in a triangular lattice or a Kagome lattice. If the materials satisfy those constraints, the quantum researchers get excited; it’s a necessary but not sufficient condition. So, by generating many, many materials like that, it immediately gives experimentalists hundreds or thousands more candidates to play with to accelerate quantum computer materials research.”“This work presents a new tool, leveraging machine learning, that can predict which materials will have specific elements in a desired geometric pattern,” says Drexel University Professor Steve May, who was not involved in the research. “This should speed up the development of previously unexplored materials for applications in next-generation electronic, magnetic, or optical technologies.”The researchers stress that experimentation is still critical to assess whether AI-generated materials can be synthesized and how their actual properties compare with model predictions. Future work on SCIGEN could incorporate additional design rules into generative models, including chemical and functional constraints.“People who want to change the world care about material properties more than the stability and structure of materials,” Okabe says. “With our approach, the ratio of stable materials goes down, but it opens the door to generate a whole bunch of promising materials.”The work was supported, in part, by the U.S. Department of Energy, the National Energy Research Scientific Computing Center, the National Science Foundation, and Oak Ridge National Laboratory. More

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      in Energy

      Working to make fusion a viable energy source

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      George Tynan followed a nonlinear path to fusion.Following his undergraduate degree in aerospace engineering, Tynann’s work in the industry spurred his interest in rocket propulsion technology. Because most methods for propulsion involve the manipulation of hot ionized matter, or plasmas, Tynan focused his attention on plasma physics.It was then that he realized that plasmas could also drive nuclear fusion. “As a potential energy source, it could really be transformative, and the idea that I could work on something that could have that kind of impact on the future was really attractive to me,” he says.That same drive, to realize the promise of fusion by researching both plasma physics and fusion engineering, drives Tynan today. It’s work he will be pursuing as the Norman C. Rasmussen Adjunct Professor in the Department of Nuclear Science and Engineering (NSE) at MIT.An early interest in fluid flowTynan’s enthusiasm for science and engineering traces back to his childhood. His electrical engineer father found employment in the U.S. space program and moved the family to Cape Canaveral in Florida.“This was in the ’60s, when we were launching Saturn V to the moon, and I got to watch all the launches from the beach,” Tynan remembers. That experience was formative and Tynan became fascinated with how fluids flow.“I would stick my hand out the window and pretend it was an airplane wing and tilt it with oncoming wind flow and see how the force would change on my hand,” Tynan laughs. The interest eventually led to an undergraduate degree in aerospace engineering at California State Polytechnic University in Pomona.The switch to a new career would happen after work in the private sector, when Tynan discovered an interest in the use of plasmas for propulsion systems. He moved to the University of California at Los Angeles for graduate school, and it was here that the realization that plasmas could also anchor fusion moved Tynan into this field.This was in the ’80s, when climate change was not as much in the public consciousness as it is today. Even so, “I knew there’s not an infinite amount of oil and gas around, and that at some point we would have to have widespread adoption of nuclear-based sources,” Tynan remembers. He was also attracted by the sustained effort it would take to make fusion a reality.Doctoral workTo create energy from fusion, it’s important to get an accurate measurement of the “energy confinement time,” which is a measure of how long it takes for the hot fuel to cool down when all heat sources are turned off. When Tynan started graduate school, this measure was still an empirical guess. He decided to focus his research on the physics of observable confinement time.It was during this doctoral research that Tynan was able to study the fundamental differences in the behavior of turbulence in plasma as compared to conventional fluids. Typically, when an ordinary fluid is stirred with increasing vigor, the fluid’s motion eventually becomes chaotic or turbulent. However, plasmas can act in a surprising way: confined plasmas, when heated sufficiently strongly, would spontaneously quench the turbulent transport at the boundary of the plasmaAn experiment in Germany had unexpectedly discovered this plasma behavior. While subsequent work on other experimental devices confirmed this surprising finding, all earlier experiments lacked the ability to measure the turbulence in detail.Brian LaBombard, now a senior research scientist at MIT’s Plasma Science and Fusion Center (PSFC), was a postdoc at UCLA at the time. Under LaBombard’s direction, Tynan developed a set of Langmuir probes, which are reasonably simple diagnostics for plasma turbulence studies, to further investigate this unusual phenomenon. It formed the basis for his doctoral dissertation. “I happened to be at the right place at the right time so I could study this turbulence quenching phenomenon in much more detail than anyone else could, up until that time,” Tynan says.As a PhD student and then postdoc, Tynan studied the phenomenon in depth, shuttling between research facilities in Germany, Princeton University’s Plasma Physics Laboratory, and UCLA.Fusion at UCSDAfter completing his doctorate and postdoctoral work, Tynan worked at a startup for a few years when he learned that the University of California at San Diego was launching a new fusion research group at the engineering school. When they reached out, Tynan joined the faculty and built a research program focused on plasma turbulence and plasma-material interactions in fusion systems. Eventually, he became associate dean of engineering, and later, chair of the Department of Mechanical and Aerospace Engineering, serving in these roles for nearly a decade.Tynan visited MIT on sabbatical in 2023, when his conversations with NSE faculty members Dennis Whyte, Zach Hartwig, and Michael Short excited him about the challenges the private sector faces in making fusion a reality. He saw opportunities to solve important problems at MIT that complemented his work at UC San Diego.Tynan is excited to tackle what he calls, “the big physics and engineering challenges of fusion plasmas” at NSE: how to remove the heat and exhaust generated by burning plasma so it doesn’t damage the walls of the fusion device and the plasma does not choke on the helium ash. He also hopes to explore robust engineering solutions for practical fusion energy, with a particular focus on developing better materials for use in fusion devices that will make them longer-lasting, while  minimizing the production of radioactive waste.“Ten or 15 years ago, I was somewhat pessimistic that I would ever see commercial exploitation of fusion in my lifetime,” Tynan says. But that outlook has changed, as he has seen collaborations between MIT and Commonwealth Fusion Systems (CFS) and other private-sector firms that seek to accelerate the timeline to the deployment of fusion in the real world.In 2021, for example, MIT’s PSFC and CFS took a significant step toward commercial carbon-free power generation. They designed and built a high-temperature superconducting magnet, the strongest fusion magnet in the world.The milestone was especially exciting because the promise of realizing the dream of fusion energy now felt closer. And being at MIT “seemed like a really quick way to get deeply connected with what’s going on in the efforts to develop fusion energy,” Tynan says.In addition, “while on sabbatical at MIT, I saw how quickly research staff and students can capitalize on a suggestion of a new idea, and that intrigued me,” he adds.Tynan brings his special blend of expertise to the table. In addition to extensive experience in plasma physics, he has spent a lot more time on hardcore engineering issues like materials, as well. “The key is to integrate the whole thing into a workable and viable system,” Tynan says. More

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      in Security

      J-WAFS welcomes Daniela Giardina as new executive director

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      The Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) announced that Daniela Giardina has been named the new J-WAFS executive director. Giardina stepped into the role at the start of the fall semester, replacing founding executive director Renee J. Robins ’83, who is retiring after leading the program since its launch in 2014.“Daniela brings a deep background in water and food security, along with excellent management and leadership skills,” says Robins. “Since I first met her nearly 10 years ago, I have been impressed with her commitment to working on global water and food challenges through research and innovation. I am so happy to know that I will be leaving J-WAFS in her experienced and capable hands.”A decade of impactJ-WAFS fuels research, innovation, and collaboration to solve global water and food systems challenges. The mission of J-WAFS is to ensure safe and resilient supplies of water and food to meet the local and global needs of a dramatically growing population on a rapidly changing planet. J-WAFS funding opportunities are open to researchers in every MIT department, lab, and center, spanning all disciplines. Supported research projects include those involving engineering, science, technology, business, social science, economics, architecture, urban planning, and more. J-WAFS research and related activities include early-stage projects, sponsored research, commercialization efforts, student activities and mentorship, events that convene local and global experts, and international-scale collaborations.The global water, food, and climate emergency makes J-WAFS’ work both timely and urgent. J-WAFS-funded researchers are achieving tangible, real-time solutions and results. Since its inception, J-WAFS has distributed nearly $26 million in grants, fellowships, and awards to the MIT community, supporting roughly 10 percent of MIT’s faculty and 300 students, postdocs, and research staff from 40 MIT departments, labs, and centers. J-WAFS grants have also helped researchers launch 13 startups and receive over $25 million in follow-on funding.Giardina joins J-WAFS at an exciting time in the program’s history; in the spring, J-WAFS celebrated 10 years of supporting water and food research at MIT. The milestone was commemorated at a special event attended by MIT leadership, researchers, students, staff, donors, and others in the J-WAFS community. As J-WAFS enters its second decade, interest and opportunities for water and food research continue to grow. “I am truly honored to join J-WAFS at such a pivotal moment,” Giardina says.Putting research into real-world practiceGiardina has nearly two decades of experience working with nongovernmental organizations and research institutions on humanitarian and development projects. Her work has taken her to Africa, Latin America, the Caribbean, and Central and Southeast Asia, where she has focused on water and food security projects. She has conducted technical trainings and assessments, and managed projects from design to implementation, including monitoring and evaluation.Giardina comes to MIT from Oxfam America, where she directed disaster risk reduction and climate resilience initiatives, working on approaches to strengthen local leadership, community-based disaster risk reduction, and anticipatory action. Her role at Oxfam required her to oversee multimillion-dollar initiatives, supervising international teams, managing complex donor portfolios, and ensuring rigorous monitoring across programs. She connected hands-on research with community-oriented implementation, for example, by partnering with MIT’s D-Lab to launch an innovation lab in rural El Salvador. Her experience will help guide J-WAFS as it pursues impactful research that will make a difference on the ground.Beyond program delivery, Giardina has played a strategic leadership role in shaping Oxfam’s global disaster risk reduction strategy and representing the organization at high-level U.N. and academic forums. She is multilingual and adept at building partnerships across cultures, having worked with governments, funders, and community-based organizations to strengthen resilience and advance equitable access to water and food.Giardina holds a PhD in sustainable development from the University of Brescia in Italy. She also holds a master’s degree in environmental engineering from the Politecnico of Milan in Italy and is a chartered engineer since 2005 (equivalent to a professional engineering license in the United States). She also serves as vice chair of the Boston Network for International Development, a nonprofit that connects and strengthens Boston’s global development community.“I have seen first-hand how climate change, misuse of resources, and inequality are undermining water and food security around the globe,” says Giardina. “What particularly excites me about J-WAFS is its interdisciplinary approach in facilitating meaningful partnerships to solve many of these problems through research and innovation. I am eager to help expand J-WAFS’ impact by strengthening existing programs, developing new initiatives, and building strategic partnerships that translate MIT’s groundbreaking research into real-world solutions,” she adds.A legacy of leadershipRenee Robins will retire with over 23 years of service to MIT. Years before joining the staff, she graduated from MIT with dual bachelor’s degrees in both biology and humanities/anthropology. She then went on to earn a master’s degree in public policy from Carnegie Mellon University. In 1998, she came back to MIT to serve in various roles across campus, including with the Cambridge MIT Institute, the MIT Portugal Program, the Mexico City Program, the Program on Emerging Technologies, and the Technology and Policy Program. She also worked at the Harvard Graduate School of Education, where she managed a $15 million research program as it scaled from implementation in one public school district to 59 schools in seven districts across North Carolina.In late 2014, Robins joined J-WAFS as its founding executive director, playing a pivotal role in building it from the ground up and expanding the team to six full-time professionals. She worked closely with J-WAFS founding director Professor John H. Lienhard V to develop and implement funding initiatives, develop, and shepherd corporate-sponsored research partnerships, and mentor students in the Water Club and Food and Agriculture Club, as well as numerous other students. Throughout the years, Robins has inspired a diverse range of researchers to consider how their capabilities and expertise can be applied to water and food challenges. Perhaps most importantly, her leadership has helped cultivate a vibrant community, bringing together faculty, students, and research staff to be exposed to unfamiliar problems and new methodologies, to explore how their expertise might be applied, to learn from one another, and to collaborate.At the J-WAFS 10th anniversary event in May, Robins noted, “it has been a true privilege to work alongside John Lienhard, our dedicated staff, and so many others. It’s been particularly rewarding to see the growth of an MIT network of water and food researchers that J-WAFS has nurtured, which grew out of those few individuals who saw themselves to be working in solitude on these critical challenges.”Lienhard also spoke, thanking Robins by saying she “was my primary partner in building J-WAFS and [she is] a strong leader and strategic thinker.”Not only is Robins a respected leader, she is also a dear friend to so many at MIT and beyond. In 2021, she was recognized for her outstanding leadership and commitment to J-WAFS and the Institute with an MIT Infinite Mile Award in the area of the Offices of the Provost and Vice President for Research.Outside of MIT, Robins has served on the Board of Trustees for the International Honors Program — a comparative multi-site study abroad program, where she previously studied comparative culture and anthropology in seven countries around the world. Robins has also acted as an independent consultant, including work on program design and strategy around the launch of the Université Mohammed VI Polytechnique in Morocco.Continuing the tradition of excellenceGiardina will report to J-WAFS director Rohit Karnik, the Abdul Latif Jameel Professor of Water and Food in the MIT Department of Mechanical Engineering. Karnik was named the director of J-WAFS in January, succeeding John Lienhard, who retired earlier this year.As executive director, Giardina will be instrumental in driving J-WAFS’ mission and impact. She will work with Karnik to help shape J-WAFS’ programs, long-term strategy, and goals. She will also be responsible for supervising J-WAFS staff, managing grant administration, and overseeing and advising on financial decisions.“I am very grateful to John and Renee, who have helped to establish J-WAFS as the Institute’s preeminent program for water and food research and significantly expanded MIT’s research efforts and impact in the water and food space,” says Karnik. “I am confident that with Daniela as executive director, J-WAFS will continue in the tradition of excellence that Renee and John put into place, as we move into the program’s second decade,” he notes.Giardina adds, “I am inspired by the lab’s legacy of Renee Robins and Professor Lienhard, and I look forward to working with Professor Karnik and the J-WAFS staff.” More

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      in Energy

      New self-assembling material could be the key to recyclable EV batteries

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      Today’s electric vehicle boom is tomorrow’s mountain of electronic waste. And while myriad efforts are underway to improve battery recycling, many EV batteries still end up in landfills.A research team from MIT wants to help change that with a new kind of self-assembling battery material that quickly breaks apart when submerged in a simple organic liquid. In a new paper published in Nature Chemistry, the researchers showed the material can work as the electrolyte in a functioning, solid-state battery cell and then revert back to its original molecular components in minutes.The approach offers an alternative to shredding the battery into a mixed, hard-to-recycle mass. Instead, because the electrolyte serves as the battery’s connecting layer, when the new material returns to its original molecular form, the entire battery disassembles to accelerate the recycling process.“So far in the battery industry, we’ve focused on high-performing materials and designs, and only later tried to figure out how to recycle batteries made with complex structures and hard-to-recycle materials,” says the paper’s first author Yukio Cho PhD ’23. “Our approach is to start with easily recyclable materials and figure out how to make them battery-compatible. Designing batteries for recyclability from the beginning is a new approach.”Joining Cho on the paper are PhD candidate Cole Fincher, Ty Christoff-Tempesta PhD ’22, Kyocera Professor of Ceramics Yet-Ming Chiang, Visiting Associate Professor Julia Ortony, Xiaobing Zuo, and Guillaume Lamour.Better batteriesThere’s a scene in one of the “Harry Potter” films where Professor Dumbledore cleans a dilapidated home with the flick of the wrist and a spell. Cho says that image stuck with him as a kid. (What better way to clean your room?) When he saw a talk by Ortony on engineering molecules so that they could assemble into complex structures and then revert back to their original form, he wondered if it could be used to make battery recycling work like magic.That would be a paradigm shift for the battery industry. Today, batteries require harsh chemicals, high heat, and complex processing to recycle. There are three main parts of a battery: the positively charged cathode, the negatively charged electrode, and the electrolyte that shuttles lithium ions between them. The electrolytes in most lithium-ion batteries are highly flammable and degrade over time into toxic byproducts that require specialized handling.To simplify the recycling process, the researchers decided to make a more sustainable electrolyte. For that, they turned to a class of molecules that self-assemble in water, named aramid amphiphiles (AAs), whose chemical structures and stability mimic that of Kevlar. The researchers further designed the AAs to contain polyethylene glycol (PEG), which can conduct lithium ions, on one end of each molecule. When the molecules are exposed to water, they spontaneously form nanoribbons with ion-conducting PEG surfaces and bases that imitate the robustness of Kevlar through tight hydrogen bonding. The result is a mechanically stable nanoribbon structure that conducts ions across its surface.“The material is composed of two parts,” Cho explains. “The first part is this flexible chain that gives us a nest, or host, for lithium ions to jump around. The second part is this strong organic material component that is used in the Kevlar, which is a bulletproof material. Those make the whole structure stable.”When added to water, the nanoribbons self-assemble to form millions of nanoribbons that can be hot-pressed into a solid-state material.“Within five minutes of being added to water, the solution becomes gel-like, indicating there are so many nanofibers formed in the liquid that they start to entangle each other,” Cho says. “What’s exciting is we can make this material at scale because of the self-assembly behavior.”The team tested the material’s strength and toughness, finding it could endure the stresses associated with making and running the battery. They also constructed a solid-state battery cell that used lithium iron phosphate for the cathode and lithium titanium oxide as the anode, both common materials in today’s batteries. The nanoribbons moved lithium ions successfully between the electrodes, but a side-effect known as polarization limited the movement of lithium ions into the battery’s electrodes during fast bouts of charging and discharging, hampering its performance compared to today’s gold-standard commercial batteries.“The lithium ions moved along the nanofiber all right, but getting the lithium ion from the nanofibers to the metal oxide seems to be the most sluggish point of the process,” Cho says.When they immersed the battery cell into organic solvents, the material immediately dissolved, with each part of the battery falling away for easier recycling. Cho compared the materials’ reaction to cotton candy being submerged in water.“The electrolyte holds the two battery electrodes together and provides the lithium-ion pathways,” Cho says. “So, when you want to recycle the battery, the entire electrolyte layer can fall off naturally and you can recycle the electrodes separately.”Validating a new approachCho says the material is a proof of concept that demonstrates the recycle-first approach.“We don’t want to say we solved all the problems with this material,” Cho says. “Our battery performance was not fantastic because we used only this material as the entire electrolyte for the paper, but what we’re picturing is using this material as one layer in the battery electrolyte. It doesn’t have to be the entire electrolyte to kick off the recycling process.”Cho also sees a lot of room for optimizing the material’s performance with further experiments.Now, the researchers are exploring ways to integrate these kinds of materials into existing battery designs as well as implementing the ideas into new battery chemistries.“It’s very challenging to convince existing vendors to do something very differently,” Cho says. “But with new battery materials that may come out in five or 10 years, it could be easier to integrate this into new designs in the beginning.”Cho also believes the approach could help reshore lithium supplies by reusing materials from batteries that are already in the U.S.“People are starting to realize how important this is,” Cho says. “If we can start to recycle lithium-ion batteries from battery waste at scale, it’ll have the same effect as opening lithium mines in the U.S. Also, each battery requires a certain amount of lithium, so extrapolating out the growth of electric vehicles, we need to reuse this material to avoid massive lithium price spikes.”The work was supported, in part, by the National Science Foundation and the U.S. Department of Energy. More

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      in Energy

      New method could monitor corrosion and cracking in a nuclear reactor

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      MIT researchers have developed a technique that enables real-time, 3D monitoring of corrosion, cracking, and other material failure processes inside a nuclear reactor environment.This could allow engineers and scientists to design safer nuclear reactors that also deliver higher performance for applications like electricity generation and naval vessel propulsion.During their experiments, the researchers utilized extremely powerful X-rays to mimic the behavior of neutrons interacting with a material inside a nuclear reactor.They found that adding a buffer layer of silicon dioxide between the material and its substrate, and keeping the material under the X-ray beam for a longer period of time, improves the stability of the sample. This allows for real-time monitoring of material failure processes.By reconstructing 3D image data on the structure of a material as it fails, researchers could design more resilient materials that can better withstand the stress caused by irradiation inside a nuclear reactor.“If we can improve materials for a nuclear reactor, it means we can extend the life of that reactor. It also means the materials will take longer to fail, so we can get more use out of a nuclear reactor than we do now. The technique we’ve demonstrated here allows to push the boundary in understanding how materials fail in real-time,” says Ericmoore Jossou, who has shared appointments in the Department of Nuclear Science and Engineering (NSE), where he is the John Clark Hardwick Professor, and the Department of Electrical Engineering and Computer Science (EECS), and the MIT Schwarzman College of Computing.Jossou, senior author of a study on this technique, is joined on the paper by lead author David Simonne, an NSE postdoc; Riley Hultquist, a graduate student in NSE; Jiangtao Zhao, of the European Synchrotron; and Andrea Resta, of Synchrotron SOLEIL. The research was published Tuesday by the journal Scripta Materiala.“Only with this technique can we measure strain with a nanoscale resolution during corrosion processes. Our goal is to bring such novel ideas to the nuclear science community while using synchrotrons both as an X-ray probe and radiation source,” adds Simonne.Real-time imagingStudying real-time failure of materials used in advanced nuclear reactors has long been a goal of Jossou’s research group.Usually, researchers can only learn about such material failures after the fact, by removing the material from its environment and imaging it with a high-resolution instrument.“We are interested in watching the process as it happens. If we can do that, we can follow the material from beginning to end and see when and how it fails. That helps us understand a material much better,” he says.They simulate the process by firing an extremely focused X-ray beam at a sample to mimic the environment inside a nuclear reactor. The researchers must use a special type of high-intensity X-ray, which is only found in a handful of experimental facilities worldwide.For these experiments they studied nickel, a material incorporated into alloys that are commonly used in advanced nuclear reactors. But before they could start the X-ray equipment, they had to prepare a sample.To do this, the researchers used a process called solid state dewetting, which involves putting a thin film of the material onto a substrate and heating it to an extremely high temperature in a furnace until it transforms into single crystals.“We thought making the samples was going to be a walk in the park, but it wasn’t,” Jossou says.As the nickel heated up, it interacted with the silicon substrate and formed a new chemical compound, essentially derailing the entire experiment. After much trial-and-error, the researchers found that adding a thin layer of silicon dioxide between the nickel and substrate prevented this reaction.But when crystals formed on top of the buffer layer, they were highly strained. This means the individual atoms had moved slightly to new positions, causing distortions in the crystal structure.Phase retrieval algorithms can typically recover the 3D size and shape of a crystal in real-time, but if there is too much strain in the material, the algorithms will fail.However, the team was surprised to find that keeping the X-ray beam trained on the sample for a longer period of time caused the strain to slowly relax, due to the silicon buffer layer. After a few extra minutes of X-rays, the sample was stable enough that they could utilize phase retrieval algorithms to accurately recover the 3D shape and size of the crystal.“No one had been able to do that before. Now that we can make this crystal, we can image electrochemical processes like corrosion in real time, watching the crystal fail in 3D under conditions that are very similar to inside a nuclear reactor. This has far-reaching impacts,” he says.They experimented with a different substrate, such as niobium doped strontium titanate, and found that only a silicon dioxide buffered silicon wafer created this unique effect.An unexpected resultAs they fine-tuned the experiment, the researchers discovered something else.They could also use the X-ray beam to precisely control the amount of strain in the material, which could have implications for the development of microelectronics.In the microelectronics community, engineers often introduce strain to deform a material’s crystal structure in a way that boosts its electrical or optical properties.“With our technique, engineers can use X-rays to tune the strain in microelectronics while they are manufacturing them. While this was not our goal with these experiments, it is like getting two results for the price of one,” he adds.In the future, the researchers want to apply this technique to more complex materials like steel and other metal alloys used in nuclear reactors and aerospace applications. They also want to see how changing the thickness of the silicon dioxide buffer layer impacts their ability to control the strain in a crystal sample.“This discovery is significant for two reasons. First, it provides fundamental insight into how nanoscale materials respond to radiation — a question of growing importance for energy technologies, microelectronics, and quantum materials. Second, it highlights the critical role of the substrate in strain relaxation, showing that the supporting surface can determine whether particles retain or release strain when exposed to focused X-ray beams,” says Edwin Fohtung, an associate professor at the Rensselaer Polytechnic Institute, who was not involved with this work.This work was funded, in part, by the MIT Faculty Startup Fund and the U.S. Department of Energy. The sample preparation was carried out, in part, at the MIT.nano facilities. More

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      in Energy

      Study sheds light on graphite’s lifespan in nuclear reactors

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      Graphite is a key structural component in some of the world’s oldest nuclear reactors and many of the next-generation designs being built today. But it also condenses and swells in response to radiation — and the mechanism behind those changes has proven difficult to study.Now, MIT researchers and collaborators have uncovered a link between properties of graphite and how the material behaves in response to radiation. The findings could lead to more accurate, less destructive ways of predicting the lifespan of graphite materials used in reactors around the world.“We did some basic science to understand what leads to swelling and, eventually, failure in graphite structures,” says MIT Research Scientist Boris Khaykovich, senior author of the new study. “More research will be needed to put this into practice, but the paper proposes an attractive idea for industry: that you might not need to break hundreds of irradiated samples to understand their failure point.”Specifically, the study shows a connection between the size of the pores within graphite and the way the material swells and shrinks in volume, leading to degradation.“The lifetime of nuclear graphite is limited by irradiation-induced swelling,” says co-author and MIT Research Scientist Lance Snead. “Porosity is a controlling factor in this swelling, and while graphite has been extensively studied for nuclear applications since the Manhattan Project, we still do not have a clear understanding of the porosity in both mechanical properties and swelling. This work addresses that.”The open-access paper appears this week in Interdisciplinary Materials. It is co-authored by Khaykovich, Snead, MIT Research Scientist Sean Fayfar, former MIT research fellow Durgesh Rai, Stony Brook University Assistant Professor David Sprouster, Oak Ridge National Laboratory Staff Scientist Anne Campbell, and Argonne National Laboratory Physicist Jan Ilavsky.A long-studied, complex materialEver since 1942, when physicists and engineers built the world’s first nuclear reactor on a converted squash court at the University of Chicago, graphite has played a central role in the generation of nuclear energy. That first reactor, dubbed the Chicago Pile, was constructed from about 40,000 graphite blocks, many of which contained nuggets of uranium.Today graphite is a vital component of many operating nuclear reactors and is expected to play a central role in next-generation reactor designs like molten-salt and high-temperature gas reactors. That’s because graphite is a good neutron moderator, slowing down the neutrons released by nuclear fission so they are more likely to create fissions themselves and sustain a chain reaction.“The simplicity of graphite makes it valuable,” Khaykovich explains. “It’s made of carbon, and it’s relatively well-known how to make it cleanly. Graphite is a very mature technology. It’s simple, stable, and we know it works.”But graphite also has its complexities.“We call graphite a composite even though it’s made up of only carbon atoms,” Khaykovich says. “It includes ‘filler particles’ that are more crystalline, then there is a matrix called a ‘binder’ that is less crystalline, then there are pores that span in length from nanometers to many microns.”Each graphite grade has its own composite structure, but they all contain fractals, or shapes that look the same at different scales.Those complexities have made it hard to predict how graphite will respond to radiation in microscopic detail, although it’s been known for decades that when graphite is irradiated, it first densifies, reducing its volume by up to 10 percent, before swelling and cracking. The volume fluctuation is caused by changes to graphite’s porosity and lattice stress.“Graphite deteriorates under radiation, as any material does,” Khaykovich says. “So, on the one hand we have a material that’s extremely well-known, and on the other hand, we have a material that is immensely complicated, with a behavior that’s impossible to predict through computer simulations.”For the study, the researchers received irradiated graphite samples from Oak Ridge National Laboratory. Co-authors Campbell and Snead were involved in irradiating the samples some 20 years ago. The samples are a grade of graphite known as G347A.The research team used an analysis technique known as X-ray scattering, which uses the scattered intensity of an X-ray beam to analyze the properties of material. Specifically, they looked at the distribution of sizes and surface areas of the sample’s pores, or what are known as the material’s fractal dimensions.“When you look at the scattering intensity, you see a large range of porosity,” Fayfar says. “Graphite has porosity over such large scales, and you have this fractal self-similarity: The pores in very small sizes look similar to pores spanning microns, so we used fractal models to relate different morphologies across length scales.”Fractal models had been used on graphite samples before, but not on irradiated samples to see how the material’s pore structures changed. The researchers found that when graphite is first exposed to radiation, its pores get filled as the material degrades.“But what was quite surprising to us is the [size distribution of the pores] turned back around,” Fayfar says. “We had this recovery process that matched our overall volume plots, which was quite odd. It seems like after graphite is irradiated for so long, it starts recovering. It’s sort of an annealing process where you create some new pores, then the pores smooth out and get slightly bigger. That was a big surprise.”The researchers found that the size distribution of the pores closely follows the volume change caused by radiation damage.“Finding a strong correlation between the [size distribution of pores] and the graphite’s volume changes is a new finding, and it helps connect to the failure of the material under irradiation,” Khaykovich says. “It’s important for people to know how graphite parts will fail when they are under stress and how failure probability changes under irradiation.”From research to reactorsThe researchers plan to study other graphite grades and explore further how pore sizes in irradiated graphite correlate with the probability of failure. They speculate that a statistical technique known as the Weibull Distribution could be used to predict graphite’s time until failure. The Weibull Distribution is already used to describe the probability of failure in ceramics and other porous materials like metal alloys.Khaykovich also speculated that the findings could contribute to our understanding of why materials densify and swell under irradiation.“There’s no quantitative model of densification that takes into account what’s happening at these tiny scales in graphite,” Khaykovich says. “Graphite irradiation densification reminds me of sand or sugar, where when you crush big pieces into smaller grains, they densify. For nuclear graphite, the crushing force is the energy that neutrons bring in, causing large pores to get filled with smaller, crushed pieces. But more energy and agitation create still more pores, and so graphite swells again. It’s not a perfect analogy, but I believe analogies bring progress for understanding these materials.”The researchers describe the paper as an important step toward informing graphite production and use in nuclear reactors of the future.“Graphite has been studied for a very long time, and we’ve developed a lot of strong intuitions about how it will respond in different environments, but when you’re building a nuclear reactor, details matter,” Khaykovich says. “People want numbers. They need to know how much thermal conductivity will change, how much cracking and volume change will happen. If components are changing volume, at some point you need to take that into account.”This work was supported, in part, by the U.S. Department of Energy. More

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      MIT gears up to transform manufacturing

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      “Manufacturing is the engine of society, and it is the backbone of robust, resilient economies,” says John Hart, head of MIT’s Department of Mechanical Engineering (MechE) and faculty co-director of the MIT Initiative for New Manufacturing (INM). “With manufacturing a lively topic in today’s news, there’s a renewed appreciation and understanding of the importance of manufacturing to innovation, to economic and national security, and to daily lives.”Launched this May, INM will “help create a transformation of manufacturing through new technology, through development of talent, and through an understanding of how to scale manufacturing in a way that enables imparts higher productivity and resilience, drives adoption of new technologies, and creates good jobs,” Hart says.INM is one of MIT’s strategic initiatives and builds on the successful three-year-old Manufacturing@MIT program. “It’s a recognition by MIT that manufacturing is an Institute-wide theme and an Institute-wide priority, and that manufacturing connects faculty and students across campus,” says Hart. Alongside Hart, INM’s faculty co-directors are Institute Professor Suzanne Berger and Chris Love, professor of chemical engineering.The initiative is pursuing four main themes: reimagining manufacturing technologies and systems, elevating the productivity and human experience of manufacturing, scaling up new manufacturing, and transforming the manufacturing base.Breaking manufacturing barriers for corporationsAmgen, Autodesk, Flex, GE Vernova, PTC, Sanofi, and Siemens are founding members of INM’s industry consortium. These industry partners will work closely with MIT faculty, researchers, and students across many aspects of manufacturing-related research, both in broad-scale initiatives and in particular areas of shared interests. Membership requires a minimum three-year commitment of $500,000 a year to manufacturing-related activities at MIT, including the INM membership fee of $275,000 per year, which supports several core activities that engage the industry members.One major thrust for INM industry collaboration is the deployment and adoption of AI and automation in manufacturing. This effort will include seed research projects at MIT, collaborative case studies, and shared strategy development.INM also offers companies participation in the MIT-wide New Manufacturing Research effort, which is studying the trajectories of specific manufacturing industries and examining cross-cutting themes such as technology and financing.Additionally, INM will concentrate on education for all professions in manufacturing, with alliances bringing together corporations, community colleges, government agencies, and other partners. “We’ll scale our curriculum to broader audiences, from aspiring manufacturing workers and aspiring production line supervisors all the way up to engineers and executives,” says Hart.In workforce training, INM will collaborate with companies broadly to help understand the challenges and frame its overall workforce agenda, and with individual firms on specific challenges, such as acquiring suitably prepared employees for a new factory.Importantly, industry partners will also engage directly with students. Founding member Flex, for instance, hosted MIT researchers and students at the Flex Institute of Technology in Sorocaba, Brazil, developing new solutions for electronics manufacturing.“History shows that you need to innovate in manufacturing alongside the innovation in products,” Hart comments. “At MIT, as more students take classes in manufacturing, they’ll think more about key manufacturing issues as they decide what research problems they want to solve, or what choices they make as they prototype their devices. The same is true for industry — companies that operate at the frontier of manufacturing, whether through internal capabilities or their supply chains, are positioned to be on the frontier of product innovation and overall growth.”“We’ll have an opportunity to bring manufacturing upstream to the early stage of research, designing new processes and new devices with scalability in mind,” he says.Additionally, MIT expects to open new manufacturing-related labs and to further broaden cooperation with industry at existing shared facilities, such as MIT.nano. Hart says that facilities will also invite tighter collaborations with corporations — not just providing advanced equipment, but working jointly on, say, new technologies for weaving textiles, or speeding up battery manufacturing.Homing in on the United StatesINM is a global project that brings a particular focus on the United States, which remains the world’s second-largest manufacturing economy, but has suffered a significant decline in manufacturing employment and innovation.One key to reversing this trend and reinvigorating the U.S. manufacturing base is advocacy for manufacturing’s critical role in society and the career opportunities it offers.“No one really disputes the importance of manufacturing,” Hart says. “But we need to elevate interest in manufacturing as a rewarding career, from the production workers to manufacturing engineers and leaders, through advocacy, education programs, and buy-in from industry, government, and academia.”MIT is in a unique position to convene industry, academic, and government stakeholders in manufacturing to work together on this vital issue, he points out.Moreover, in times of radical and rapid changes in manufacturing, “we need to focus on deploying new technologies into factories and supply chains,” Hart says. “Technology is not all of the solution, but for the U.S. to expand our manufacturing base, we need to do it with technology as a key enabler, embracing companies of all sizes, including small and medium enterprises.”“As AI becomes more capable, and automation becomes more flexible and more available, these are key building blocks upon which you can address manufacturing challenges,” he says. “AI and automation offer new accelerated ways to develop, deploy, and monitor production processes, which present a huge opportunity and, in some cases, a necessity.”“While manufacturing is always a combination of old technology, new technology, established practice, and new ways of thinking, digital technology gives manufacturers an opportunity to leapfrog competitors,” Hart says. “That’s very, very powerful for the U.S. and any company, or country, that aims to create differentiated capabilities.”Fortunately, in recent years, investors have increasingly bought into new manufacturing in the United States. “They see the opportunity to re-industrialize, to build the factories and production systems of the future,” Hart says.“That said, building new manufacturing is capital-intensive, and takes time,” he adds. “So that’s another area where it’s important to convene stakeholders and to think about how startups and growth-stage companies build their capital portfolios, how large industry can support an ecosystem of small businesses and young companies, and how to develop talent to support those growing companies.”All these concerns and opportunities in the manufacturing ecosystem play to MIT’s strengths. “MIT’s DNA of cross-disciplinary collaboration and working with industry can let us create a lot of impact,” Hart emphasizes. “We can understand the practical challenges. We can also explore breakthrough ideas in research and cultivate successful outcomes, all the way to new companies and partnerships. Sometimes those are seen as disparate approaches, but we like to bring them together.” More

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      Would you like that coffee with iron?

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      Around the world, about 2 billion people suffer from iron deficiency, which can lead to anemia, impaired brain development in children, and increased infant mortality.To combat that problem, MIT researchers have come up with a new way to fortify foods and beverages with iron, using small crystalline particles. These particles, known as metal-organic frameworks, could be sprinkled on food, added to staple foods such as bread, or incorporated into drinks like coffee and tea.“We’re creating a solution that can be seamlessly added to staple foods across different regions,” says Ana Jaklenec, a principal investigator at MIT’s Koch Institute for Integrative Cancer Research. “What’s considered a staple in Senegal isn’t the same as in India or the U.S., so our goal was to develop something that doesn’t react with the food itself. That way, we don’t have to reformulate for every context — it can be incorporated into a wide range of foods and beverages without compromise.”The particles designed in this study can also carry iodine, another critical nutrient. The particles could also be adapted to carry important minerals such as zinc, calcium, or magnesium.“We are very excited about this new approach and what we believe is a novel application of metal-organic frameworks to potentially advance nutrition, particularly in the developing world,” says Robert Langer, the David H. Koch Institute Professor at MIT and a member of the Koch Institute.Jaklenec and Langer are the senior authors of the study, which appears today in the journal Matter. MIT postdoc Xin Yang and Linzixuan (Rhoda) Zhang PhD ’24 are the lead authors of the paper.Iron stabilizationFood fortification can be a successful way to combat nutrient deficiencies, but this approach is often challenging because many nutrients are fragile and break down during storage or cooking. When iron is added to foods, it can react with other molecules in the food, giving the food a metallic taste.In previous work, Jaklenec’s lab has shown that encapsulating nutrients in polymers can protect them from breaking down or reacting with other molecules. In a small clinical trial, the researchers found that women who ate bread fortified with encapsulated iron were able to absorb the iron from the food.However, one drawback to this approach is that the polymer adds a lot of bulk to the material, limiting the amount of iron or other nutrients that end up in the food.“Encapsulating iron in polymers significantly improves its stability and reactivity, making it easier to add to food,” Jaklenec says. “But to be effective, it requires a substantial amount of polymer. That limits how much iron you can deliver in a typical serving, making it difficult to meet daily nutritional targets through fortified foods alone.”To overcome that challenge, Yang came up with a new idea: Instead of encapsulating iron in a polymer, they could use iron itself as a building block for a crystalline particle known as a metal-organic framework, or MOF (pronounced “moff”).MOFs consist of metal atoms joined by organic molecules called ligands to create a rigid, cage-like structure. Depending on the combination of metals and ligands chosen, they can be used for a wide variety of applications.“We thought maybe we could synthesize a metal-organic framework with food-grade ligands and food-grade micronutrients,” Yang says. “Metal-organic frameworks have very high porosity, so they can load a lot of cargo. That’s why we thought we could leverage this platform to make a new metal-organic framework that could be used in the food industry.”In this case, the researchers designed a MOF consisting of iron bound to a ligand called fumaric acid, which is often used as a food additive to enhance flavor or help preserve food.This structure prevents iron from reacting with polyphenols — compounds commonly found in foods such as whole grains and nuts, as well as coffee and tea. When iron does react with those compounds, it forms a metal polyphenol complex that cannot be absorbed by the body.The MOFs’ structure also allows them to remain stable until they reach an acidic environment, such as the stomach, where they break down and release their iron payload.Double-fortified saltsThe researchers also decided to include iodine in their MOF particle, which they call NuMOF. Iodized salt has been very successful at preventing iodine deficiency, and many efforts are now underway to create “double-fortified salts” that would also contain iron.Delivering these nutrients together has proven difficult because iron and iodine can react with each other, making each one less likely to be absorbed by the body. In this study, the MIT team showed that once they formed their iron-containing MOF particles, they could load them with iodine, in a way that the iron and iodine do not react with each other.In tests of the particles’ stability, the researchers found that the NuMOFs could withstand long-term storage, high heat and humidity, and boiling water.Throughout these tests, the particles maintained their structure. When the researchers then fed the particles to mice, they found that both iron and iodine became available in the bloodstream within several hours of the NuMOF consumption.The researchers are now working on launching a company that is developing coffee and other beverages fortified with iron and iodine. They also hope to continue working toward a double-fortified salt that could be consumed on its own or incorporated into staple food products.The research was partially supported by J-WAFS Fellowships for Water and Food Solutions.Other authors of the paper include Fangzheng Chen, Wenhao Gao, Zhiling Zheng, Tian Wang, Erika Yan Wang, Behnaz Eshaghi, and Sydney MacDonald. More