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      in Environment

      HPI-MIT design research collaboration creates powerful teams

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      The recent ransomware attack on ChangeHealthcare, which severed the network connecting health care providers, pharmacies, and hospitals with health insurance companies, demonstrates just how disruptive supply chain attacks can be. In this case, it hindered the ability of those providing medical services to submit insurance claims and receive payments.This sort of attack and other forms of data theft are becoming increasingly common and often target large, multinational corporations through the small and mid-sized vendors in their corporate supply chains, enabling breaks in these enormous systems of interwoven companies.Cybersecurity researchers at MIT and the Hasso Plattner Institute (HPI) in Potsdam, Germany, are focused on the different organizational security cultures that exist within large corporations and their vendors because it’s that difference that creates vulnerabilities, often due to the lack of emphasis on cybersecurity by the senior leadership in these small to medium-sized enterprises (SMEs).Keri Pearlson, executive director of Cybersecurity at MIT Sloan (CAMS); Jillian Kwong, a research scientist at CAMS; and Christian Doerr, a professor of cybersecurity and enterprise security at HPI, are co-principal investigators (PIs) on the research project, “Culture and the Supply Chain: Transmitting Shared Values, Attitudes and Beliefs across Cybersecurity Supply Chains.”Their project was selected in the 2023 inaugural round of grants from the HPI-MIT Designing for Sustainability program, a multiyear partnership funded by HPI and administered by the MIT Morningside Academy for Design (MAD). The program awards about 10 grants annually of up to $200,000 each to multidisciplinary teams with divergent backgrounds in computer science, artificial intelligence, machine learning, engineering, design, architecture, the natural sciences, humanities, and business and management. The 2024 Call for Applications is open through June 3.Designing for Sustainability grants support scientific research that promotes the United Nations’ Sustainable Development Goals (SDGs) on topics involving sustainable design, innovation, and digital technologies, with teams made up of PIs from both institutions. The PIs on these projects, who have common interests but different strengths, create more powerful teams by working together.Transmitting shared values, attitudes, and beliefs to improve cybersecurity across supply chainsThe MIT and HPI cybersecurity researchers say that most ransomware attacks aren’t reported. Smaller companies hit with ransomware attacks just shut down, because they can’t afford the payment to retrieve their data. This makes it difficult to know just how many attacks and data breaches occur. “As more data and processes move online and into the cloud, it becomes even more important to focus on securing supply chains,” Kwong says. “Investing in cybersecurity allows information to be exchanged freely while keeping data safe. Without it, any progress towards sustainability is stalled.”One of the first large data breaches in the United States to be widely publicized provides a clear example of how an SME cybersecurity can leave a multinational corporation vulnerable to attack. In 2013, hackers entered the Target Corporation’s own network by obtaining the credentials of a small vendor in its supply chain: a Pennsylvania HVAC company. Through that breach, thieves were able to install malware that stole the financial and personal information of 110 million Target customers, which they sold to card shops on the black market.To prevent such attacks, SME vendors in a large corporation’s supply chain are required to agree to follow certain security measures, but the SMEs usually don’t have the expertise or training to make good on these cybersecurity promises, leaving their own systems, and therefore any connected to them, vulnerable to attack.“Right now, organizations are connected economically, but not aligned in terms of organizational culture, values, beliefs, and practices around cybersecurity,” explains Kwong. “Basically, the big companies are realizing the smaller ones are not able to implement all the cybersecurity requirements. We have seen some larger companies address this by reducing requirements or making the process shorter. However, this doesn’t mean companies are more secure; it just lowers the bar for the smaller suppliers to clear it.”Pearlson emphasizes the importance of board members and senior management taking responsibility for cybersecurity in order to change the culture at SMEs, rather than pushing that down to a single department, IT office, or in some cases, one IT employee.The research team is using case studies based on interviews, field studies, focus groups, and direct observation of people in their natural work environments to learn how companies engage with vendors, and the specific ways cybersecurity is implemented, or not, in everyday operations. The goal is to create a shared culture around cybersecurity that can be adopted correctly by all vendors in a supply chain.This approach is in line with the goals of the Charter of Trust Initiative, a partnership of large, multinational corporations formed to establish a better means of implementing cybersecurity in the supply chain network. The HPI-MIT team worked with companies from the Charter of Trust and others last year to understand the impacts of cybersecurity regulation on SME participation in supply chains and develop a conceptual framework to implement changes for stabilizing supply chains.Cybersecurity is a prerequisite needed to achieve any of the United Nations’ SDGs, explains Kwong. Without secure supply chains, access to key resources and institutions can be abruptly cut off. This could include food, clean water and sanitation, renewable energy, financial systems, health care, education, and resilient infrastructure. Securing supply chains helps enable progress on all SDGs, and the HPI-MIT project specifically supports SMEs, which are a pillar of the U.S. and European economies.Personalizing product designs while minimizing material wasteIn a vastly different Designing for Sustainability joint research project that employs AI with engineering, “Personalizing Product Designs While Minimizing Material Waste” will use AI design software to lay out multiple parts of a pattern on a sheet of plywood, acrylic, or other material, so that they can be laser cut to create new products in real time without wasting material.Stefanie Mueller, the TIBCO Career Development Associate Professor in the MIT Department of Electrical Engineering and Computer Science and a member of the Computer Science and Artificial Intelligence Laboratory, and Patrick Baudisch, a professor of computer science and chair of the Human Computer Interaction Lab at HPI, are co-PIs on the project. The two have worked together for years; Baudisch was Mueller’s PhD research advisor at HPI.Baudisch’s lab developed an online design teaching system called Kyub that lets students design 3D objects in pieces that are laser cut from sheets of wood and assembled to become chairs, speaker boxes, radio-controlled aircraft, or even functional musical instruments. For instance, each leg of a chair would consist of four identical vertical pieces attached at the edges to create a hollow-centered column, four of which will provide stability to the chair, even though the material is very lightweight.“By designing and constructing such furniture, students learn not only design, but also structural engineering,” Baudisch says. “Similarly, by designing and constructing musical instruments, they learn about structural engineering, as well as resonance, types of musical tuning, etc.”Mueller was at HPI when Baudisch developed the Kyub software, allowing her to observe “how they were developing and making all the design decisions,” she says. “They built a really neat piece for people to quickly design these types of 3D objects.” However, using Kyub for material-efficient design is not fast; in order to fabricate a model, the software has to break the 3D models down into 2D parts and lay these out on sheets of material. This takes time, and makes it difficult to see the impact of design decisions on material use in real-time.Mueller’s lab at MIT developed software based on a layout algorithm that uses AI to lay out pieces on sheets of material in real time. This allows AI to explore multiple potential layouts while the user is still editing, and thus provide ongoing feedback. “As the user develops their design, Fabricaide decides good placements of parts onto the user’s available materials, provides warnings if the user does not have enough material for a design, and makes suggestions for how the user can resolve insufficient material cases,” according to the project website.The joint MIT-HPI project integrates Mueller’s AI software with Baudisch’s Kyub software and adds machine learning to train the AI to offer better design suggestions that save material while adhering to the user’s design intent.“The project is all about minimizing the waste on these materials sheets,” Mueller says. She already envisions the next step in this AI design process: determining how to integrate the laws of physics into the AI’s knowledge base to ensure the structural integrity and stability of objects it designs.AI-powered startup design for the Anthropocene: Providing guidance for novel enterprisesThrough her work with the teams of MITdesignX and its international programs, Svafa Grönfeldt, faculty director of MITdesignX and professor of the practice in MIT MAD, has helped scores of people in startup companies use the tools and methods of design to ensure that the solution a startup proposes actually fits the problem it seeks to solve. This is often called the problem-solution fit.Grönfeldt and MIT postdoc Norhan Bayomi are now extending this work to incorporate AI into the process, in collaboration with MIT Professor John Fernández and graduate student Tyler Kim. The HPI team includes Professor Gerard de Melo; HPI School of Entrepreneurship Director Frank Pawlitschek; and doctoral student Michael Mansfeld.“The startup ecosystem is characterized by uncertainty and volatility compounded by growing uncertainties in climate and planetary systems,” Grönfeldt says. “Therefore, there is an urgent need for a robust model that can objectively predict startup success and guide design for the Anthropocene.”While startup-success forecasting is gaining popularity, it currently focuses on aiding venture capitalists in selecting companies to fund, rather than guiding the startups in the design of their products, services and business plans.“The coupling of climate and environmental priorities with startup agendas requires deeper analytics for effective enterprise design,” Grönfeldt says. The project aims to explore whether AI-augmented decision-support systems can enhance startup-success forecasting.“We’re trying to develop a machine learning approach that will give a forecasting of probability of success based on a number of parameters, including the type of business model proposed, how the team came together, the team members’ backgrounds and skill sets, the market and industry sector they’re working in and the problem-solution fit,” says Bayomi, who works with Fernández in the MIT Environmental Solutions Initiative. The two are co-founders of the startup Lamarr.AI, which employs robotics and AI to help reduce the carbon dioxide impact of the built environment.The team is studying “how company founders make decisions across four key areas, starting from the opportunity recognition, how they are selecting the team members, how they are selecting the business model, identifying the most automatic strategy, all the way through the product market fit to gain an understanding of the key governing parameters in each of these areas,” explains Bayomi.The team is “also developing a large language model that will guide the selection of the business model by using large datasets from different companies in Germany and the U.S. We train the model based on the specific industry sector, such as a technology solution or a data solution, to find what would be the most suitable business model that would increase the success probability of a company,” she says.The project falls under several of the United Nations’ Sustainable Development Goals, including economic growth, innovation and infrastructure, sustainable cities and communities, and climate action.Furthering the goals of the HPI-MIT Joint Research ProgramThese three diverse projects all advance the mission of the HPI-MIT collaboration. MIT MAD aims to use design to transform learning, catalyze innovation, and empower society by inspiring people from all disciplines to interweave design into problem-solving. HPI uses digital engineering concentrated on the development and research of user-oriented innovations for all areas of life.Interdisciplinary teams with members from both institutions are encouraged to develop and submit proposals for ambitious, sustainable projects that use design strategically to generate measurable, impactful solutions to the world’s problems. More

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      in Environment

      Understanding the impacts of mining on local environments and communities

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      Hydrosocial displacement refers to the idea that resolving water conflict in one area can shift the conflict to a different area. The concept was coined by Scott Odell, a visiting researcher in MIT’s Environmental Solutions Initiative (ESI). As part of ESI’s Program on Mining and the Circular Economy, Odell researches the impacts of extractive industries on local environments and communities, especially in Latin America. He discovered that hydrosocial displacements are often in regions where the mining industry is vying for use of precious water sources that are already stressed due to climate change.

      Odell is working with John Fernández, ESI director and professor in the Department of Architecture, on a project that is examining the converging impacts of climate change, mining, and agriculture in Chile. The work is funded by a seed grant from MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS). Specifically, the project seeks to answer how the expansion of seawater desalination by the mining industry is affecting local populations, and how climate change and mining affect Andean glaciers and the agricultural communities dependent upon them.By working with communities in mining areas, Odell and Fernández are gaining a sense of the burden that mining minerals needed for the clean energy transition is placing on local populations, and the types of conflicts that arise when water sources become polluted or scarce. This work is of particular importance considering over 100 countries pledged a commitment to the clean energy transition at the recent United Nations climate change conference, known as COP28.

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      J-WAFS Community Spotlight on Scott Odell

      Water, humanity’s lifebloodAt the March 2023 United Nations (U.N.) Water Conference in New York, U.N. Secretary-General António Guterres warned “water is in deep trouble. We are draining humanity’s lifeblood through vampiric overconsumption and unsustainable use and evaporating it through global heating.” A quarter of the world’s population already faces “extremely high water stress,” according to the World Resources Institute. In an effort to raise awareness of major water-related issues and inspire action for innovative solutions, the U.N. created World Water Day, observed every year on March 22. This year’s theme is “Water for Peace,” underscoring the fact that even though water is a basic human right and intrinsic to every aspect of life, it is increasingly fought over as supplies dwindle due to problems including drought, overuse, or mismanagement.  

      The “Water for Peace” theme is exemplified in Fernández and Odell’s J-WAFS project, where findings are intended to inform policies to reduce social and environmental harms inflicted on mining communities and their limited water sources.“Despite broad academic engagement with mining and climate change separately, there has been a lack of analysis of the societal implications of the interactions between mining and climate change,” says Odell. “This project is helping to fill the knowledge gap. Results will be summarized in Spanish and English and distributed to interested and relevant parties in Chile, ensuring that the results can be of benefit to those most impacted by these challenges,” he adds.

      The effects of mining for the clean energy transition

      Global climate change is understood to be the most pressing environmental issue facing humanity today. Mitigating climate change requires reducing carbon emissions by transitioning away from conventional energy derived from burning fossil fuels, to more sustainable energy sources like solar and wind power. Because copper is an excellent conductor of electricity, it will be a crucial element in the clean energy transition, in which more solar panels, wind turbines, and electric vehicles will be manufactured. “We are going to see a major increase in demand for copper due to the clean energy transition,” says Odell.

      In 2021, Chile produced 26 percent of the world’s copper, more than twice as much as any other country, Odell explains. Much of Chile’s mining is concentrated in and around the Atacama Desert — the world’s driest desert. Unfortunately, mining requires large amounts of water for a variety of processes, including controlling dust at the extraction site, cooling machinery, and processing and transporting ore.

      Chile is also one of the world’s largest exporters of agricultural products. Farmland is typically situated in the valleys downstream of several mines in the high Andes region, meaning mines get first access to water. This can lead to water conflict between mining operations and agricultural communities. Compounding the problem of mining for greener energy materials to combat climate change, are the very effects of climate change. According to the Chilean government, the country has suffered 13 years of the worst drought in history. While this is detrimental to the mining industry, it is also concerning for those working in agriculture, including the Indigenous Atacameño communities that live closest to the Escondida mine, the largest copper mine in the world. “There was never a lot of water to go around, even before the mine,” Odell says. The addition of Escondida stresses an already strained water system, leaving Atacameño farmers and individuals vulnerable to severe water insecurity.

      What’s more, waste from mining, known as tailings, includes minerals and chemicals that can contaminate water in nearby communities if not properly handled and stored. Odell says the secure storage of tailings is a high priority in earthquake-prone Chile. “If an earthquake were to hit and damage a tailings dam, it could mean toxic materials flowing downstream and destroying farms and communities,” he says.

      Chile’s treasured glaciers are another piece of the mining, climate change, and agricultural puzzle. Caroline White-Nockleby, a PhD candidate in MIT’s Program in Science, Technology, and Society, is working with Odell and Fernández on the J-WAFS project and leading the research specifically on glaciers. “These may not be the picturesque bright blue glaciers that you might think of, but they are, nonetheless, an important source of water downstream,” says White-Nockleby. She goes on to explain that there are a few different ways that mines can impact glaciers.

      In some cases, mining companies have proposed to move or even destroy glaciers to get at the ore beneath. Other impacts include dust from mining that falls on glaciers. White-Nockleby says, “this makes the glaciers a darker color, so, instead of reflecting the sun’s rays away, [the glacier] may absorb the heat and melt faster.” This shows that even when not directly intervening with glaciers, mining activities can cause glacial decline, adding to the threat glaciers already face due to climate change. She also notes that “glaciers are an important water storage facility,” describing how, on an annual cycle, glaciers freeze and melt, allowing runoff that downstream agricultural communities can utilize. If glaciers suddenly melt too quickly, flooding of downstream communities can occur.

      Desalination offers a possible, but imperfect, solution

      Chile’s extensive coastline makes it uniquely positioned to utilize desalination — the removal of salts from seawater — to address water insecurity. Odell says that “over the last decade or so, there’s been billions of dollars of investments in desalination in Chile.”

      As part of his dissertation work at Clark University, Odell found broad optimism in Chile for solving water issues in the mining industry through desalination. Not only was the mining industry committed to building desalination plants, there was also political support, and support from some community members in highland communities near the mines. Yet, despite the optimism and investment, desalinated water was not replacing the use of continental water. He concluded that “desalination can’t solve water conflict if it doesn’t reduce demand for continental water supplies.”

      However, after publishing those results, Odell learned that new estimates at the national level showed that desalination operations had begun to replace the use of continental water after 2018. In two case studies that he currently focuses on — the Escondida and Los Pelambres copper mines — the mining companies have expanded their desalination objectives in order to reduce extraction from key continental sources. This seems to be due to a variety of factors. For one thing, in 2022, Chile’s water code was reformed to prioritize human water consumption and environmental protection of water during scarcity and in the allocation of future rights. It also shortened the granting of water rights from “in perpetuity” to 30 years. Under this new code, it is possible that the mining industry may have expanded its desalination efforts because it viewed continental water resources as less secure, Odell surmises.

      As part of the J-WAFS project, Odell has found that recent reactions have been mixed when it comes to the rapid increase in the use of desalination. He spent over two months doing fieldwork in Chile by conducting interviews with members of government, industry, and civil society at the Escondida, Los Pelambres, and Andina mining sites, as well as in Chile’s capital city, Santiago. He has spoken to local and national government officials, leaders of fishing unions, representatives of mining and desalination companies, and farmers. He observed that in the communities where the new desalination plants are being built, there have been concerns from community members as to whether they will get access to the desalinated water, or if it will belong solely to the mines.

      Interviews at the Escondida and Los Pelambres sites, in which desalination operations are already in place or under construction, indicate acceptance of the presence of desalination plants combined with apprehension about unknown long-term environmental impacts. At a third mining site, Andina, there have been active protests against a desalination project that would supply water to a neighboring mine, Los Bronces. In that community, there has been a blockade of the desalination operation by the fishing federation. “They were blockading that operation for three months because of concerns over what the desalination plant would do to their fishing grounds,” Odell says. And this is where the idea of hydrosocial displacement comes into the picture, he explains. Even though desalination operations are easing tensions with highland agricultural communities, new issues are arising for the communities on the coast. “We can’t just look to desalination to solve our problems if it’s going to create problems somewhere else” Odell advises.

      Within the process of hydrosocial displacement, interacting geographical, technical, economic, and political factors constrain the range of responses to address the water conflict. For example, communities that have more political and financial power tend to be better equipped to solve water conflict than less powerful communities. In addition, hydrosocial concerns usually follow the flow of water downstream, from the highlands to coastal regions. Odell says that this raises the need to look at water from a broader perspective.

      “We tend to address water concerns one by one and that can, in practice, end up being kind of like whack-a-mole,” says Odell. “When we think of the broader hydrological system, water is very much linked, and we need to look across the watershed. We can’t just be looking at the specific community affected now, but who else is affected downstream, and will be affected in the long term. If we do solve a water issue by moving it somewhere else, like moving a tailings dam somewhere else, or building a desalination plant, resources are needed in the receiving community to respond to that,” suggests Odell.

      The company building the desalination plant and the fishing federation ultimately reached an agreement and the desalination operation will be moving forward. But Odell notes, “the protest highlights concern about the impacts of the operation on local livelihoods and environments within the much larger context of industrial pollution in the area.”

      The power of communities

      The protest by the fishing federation is one example of communities coming together to have their voices heard. Recent proposals by mining companies that would affect glaciers and other water sources used by agriculture communities have led to other protests that resulted in new agreements to protect local water supplies and the withdrawal of some of the mining proposals.Odell observes that communities have also gone to the courts to raise their concerns. The Atacameño communities, for example, have drawn attention to over-extraction of water resources by the Escondida mine. “Community members are also pursuing education in these topics so that there’s not such a power imbalance between mining companies and local communities,” Odell remarks. This demonstrates the power local communities can have to protect continental water resources.The political and social landscape of Chile may also be changing in favor of local communities. Beginning with what is now referred to as the Estallido Social (social outburst) over inequality in 2019, Chile has undergone social upheaval that resulted in voters calling for a new constitution. Gabriel Boric, a progressive candidate, whose top priorities include social and environmental issues, was elected president during this period. These trends have brought major attention to issues of economic inequality, environmental harms of mining, and environmental justice, which is putting pressure on the mining industry to make a case for its operations in the country, and to justify the environmental costs of mining.

      What happens after the mine dries up?

      From his fieldwork interviews, Odell has learned that the development of mines within communities can offer benefits. Mining companies typically invest directly in communities through employment, road construction, and sometimes even by building or investing in schools, stadiums, or health clinics. Indirectly, mines can have spillover effects in the economy since miners might support local restaurants, hotels, or stores. But what happens when the mine closes? As one community member Odell interviewed stated: “When the mine is gone, what are we going to have left besides a big hole in the ground?”

      Odell suggests that a multi-pronged approach should be taken to address the future state of water and mining. First, he says we need to have broader conversations about the nature of our consumption and production at domestic and global scales. “Mining is driven indirectly by our consumption of energy and directly by our consumption of everything from our buildings to devices to cars,” Odell states. “We should be looking for ways to moderate our consumption and consume smarter through both policy and practice so that we don’t solve climate change while creating new environmental harms through mining.”One of the main ways we can do this is by advancing the circular economy by recycling metals already in the system, or even in landfills, to help build our new clean energy infrastructure. Even so, the clean energy transition will still require mining, but according to Odell, that mining can be done better. “Mining companies and government need to do a better job of consulting with communities. We need solid plans and financing for mine closures in place from the beginning of mining operations, so that when the mine dries up, there’s the money needed to secure tailings dams and protect the communities who will be there forever,” Odell concludes.Overall, it will take an engaged society — from the mining industry to government officials to individuals — to think critically about the role we each play in our quest for a more sustainable planet, and what that might mean for the most vulnerable populations among us. More

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      in Environment

      Reducing pesticide use while increasing effectiveness

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      Farming can be a low-margin, high-risk business, subject to weather and climate patterns, insect population cycles, and other unpredictable factors. Farmers need to be savvy managers of the many resources they deal, and chemical fertilizers and pesticides are among their major recurring expenses.

      Despite the importance of these chemicals, a lack of technology that monitors and optimizes sprays has forced farmers to rely on personal experience and rules of thumb to decide how to apply these chemicals. As a result, these chemicals tend to be over-sprayed, leading to their runoff into waterways and buildup up in the soil.

      That could change, thanks to a new approach of feedback-optimized spraying, invented by AgZen, an MIT spinout founded in 2020 by Professor Kripa Varanasi and Vishnu Jayaprakash SM ’19, PhD ’22.

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      AgZen has developed a system for farming that can monitor exactly how much of the sprayed chemicals adheres to plants, in real time, as the sprayer drives through a field. Built-in software running on a tablet shows the operator exactly how much of each leaf has been covered by the spray.

      Over the past decade, AgZen’s founders have developed products and technologies to control the interactions of droplets and sprays with plant surfaces. The Boston-based venture-backed company launched a new commercial product in 2024 and is currently piloting another related product. Field tests of both have shown the products can help farmers spray more efficiently and effectively, using fewer chemicals overall.

      “Worldwide, farms spend approximately $60 billion a year on pesticides. Our objective is to reduce the number of pesticides sprayed and lighten the financial burden on farms without sacrificing effective pest management,” Varanasi says.

      Getting droplets to stick

      While the world pesticide market is growing rapidly, a lot of the pesticides sprayed don’t reach their target. A significant portion bounces off the plant surfaces, lands on the ground, and becomes part of the runoff that flows to streams and rivers, often causing serious pollution. Some of these pesticides can be carried away by wind over very long distances.

      “Drift, runoff, and poor application efficiency are well-known, longstanding problems in agriculture, but we can fix this by controlling and monitoring how sprayed droplets interact with leaves,” Varanasi says.

      With support from MIT Tata Center and the Abdul Latif Jameel Water and Food Systems Lab, Varanasi and his team analyzed how droplets strike plant surfaces, and explored ways to increase application efficiency. This research led them to develop a novel system of nozzles that cloak droplets with compounds that enhance the retention of droplets on the leaves, a product they call EnhanceCoverage.

      Field studies across regions — from Massachusetts to California to Italy and France —showed that this droplet-optimization system could allow farmers to cut the amount of chemicals needed by more than half because more of the sprayed substances would stick to the leaves.

      Measuring coverage

      However, in trying to bring this technology to market, the researchers faced a sticky problem: Nobody knew how well pesticide sprays were adhering to the plants in the first place, so how could AgZen say that the coverage was better with its new EnhanceCoverage system?

      “I had grown up spraying with a backpack on a small farm in India, so I knew this was an issue,” Jayaprakash says. “When we spoke to growers, they told me how complicated spraying is when you’re on a large machine. Whenever you spray, there are so many things that can influence how effective your spray is. How fast do you drive the sprayer? What flow rate are you using for the chemicals? What chemical are you using? What’s the age of the plants, what’s the nozzle you’re using, what is the weather at the time? All these things influence agrochemical efficiency.”

      Agricultural spraying essentially comes down to dissolving a chemical in water and then spraying droplets onto the plants. “But the interaction between a droplet and the leaf is complex,” Varanasi says. “We were coming in with ways to optimize that, but what the growers told us is, hey, we’ve never even really looked at that in the first place.”

      Although farmers have been spraying agricultural chemicals on a large scale for about 80 years, they’ve “been forced to rely on general rules of thumb and pick all these interlinked parameters, based on what’s worked for them in the past. You pick a set of these parameters, you go spray, and you’re basically praying for outcomes in terms of how effective your pest control is,” Varanasi says.

      Before AgZen could sell farmers on the new system to improve droplet coverage, the company had to invent a way to measure precisely how much spray was adhering to plants in real-time.

      Comparing before and after

      The system they came up with, which they tested extensively on farms across the country last year, involves a unit that can be bolted onto the spraying arm of virtually any sprayer. It carries two sensor stacks, one just ahead of the sprayer nozzles and one behind. Then, built-in software running on a tablet shows the operator exactly how much of each leaf has been covered by the spray. It also computes how much those droplets will spread out or evaporate, leading to a precise estimate of the final coverage.

      “There’s a lot of physics that governs how droplets spread and evaporate, and this has been incorporated into software that a farmer can use,” Varanasi says. “We bring a lot of our expertise into understanding droplets on leaves. All these factors, like how temperature and humidity influence coverage, have always been nebulous in the spraying world. But now you have something that can be exact in determining how well your sprays are doing.”

      “We’re not only measuring coverage, but then we recommend how to act,” says Jayaprakash, who is AgZen’s CEO. “With the information we collect in real-time and by using AI, RealCoverage tells operators how to optimize everything on their sprayer, from which nozzle to use, to how fast to drive, to how many gallons of spray is best for a particular chemical mix on a particular acre of a crop.”

      The tool was developed to prove how much AgZen’s EnhanceCoverage nozzle system (which will be launched in 2025) improves coverage. But it turns out that monitoring and optimizing droplet coverage on leaves in real-time with this system can itself yield major improvements.

      “We worked with large commercial farms last year in specialty and row crops,” Jayaprakash says. “When we saved our pilot customers up to 50 percent of their chemical cost at a large scale, they were very surprised.” He says the tool has reduced chemical costs and volume in fallow field burndowns, weed control in soybeans, defoliation in cotton, and fungicide and insecticide sprays in vegetables and fruits. Along with data from commercial farms, field trials conducted by three leading agricultural universities have also validated these results.

      “Across the board, we were able to save between 30 and 50 percent on chemical costs and increase crop yields by enabling better pest control,” Jayaprakash says. “By focusing on the droplet-leaf interface, our product can help any foliage spray throughout the year, whereas most technological advancements in this space recently have been focused on reducing herbicide use alone.” The company now intends to lease the system across thousands of acres this year.

      And these efficiency gains can lead to significant returns at scale, he emphasizes: In the U.S., farmers currently spend $16 billion a year on chemicals, to protect about $200 billion of crop yields.

      The company launched its first product, the coverage optimization system called RealCoverage, this year, reaching a wide variety of farms with different crops and in different climates. “We’re going from proof-of-concept with pilots in large farms to a truly massive scale on a commercial basis with our lease-to-own program,” Jayaprakash says.

      “We’ve also been tapped by the USDA to help them evaluate practices to minimize pesticides in watersheds,” Varanasi says, noting that RealCoverage can also be useful for regulators, chemical companies, and agricultural equipment manufacturers.

      Once AgZen has proven the effectiveness of using coverage as a decision metric, and after the RealCoverage optimization system is widely in practice, the company will next roll out its second product, EnhanceCoverage, designed to maximize droplet adhesion. Because that system will require replacing all the nozzles on a sprayer, the researchers are doing pilots this year but will wait for a full rollout in 2025, after farmers have gained experience and confidence with their initial product.

      “There is so much wastage,” Varanasi says. “Yet farmers must spray to protect crops, and there is a lot of environmental impact from this. So, after all this work over the years, learning about how droplets stick to surfaces and so on, now the culmination of it in all these products for me is amazing, to see all this come alive, to see that we’ll finally be able to solve the problem we set out to solve and help farmers.” More

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      in Environment

      Technologies for water conservation and treatment move closer to commercialization

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      The Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) provides Solutions Grants to help MIT researchers launch startup companies or products to commercialize breakthrough technologies in water and food systems. The Solutions Grant Program began in 2015 and is supported by Community Jameel. In addition to one-year, renewable grants of up to $150,000, the program also matches grantees with industry mentors and facilitates introductions to potential investors. Since its inception, the J-WAFS Solutions Program has awarded over $3 million in funding to the MIT community. Numerous startups and products, including a portable desalination device and a company commercializing a novel food safety sensor, have spun out of this support.

      The 2023 J-WAFS Solutions Grantees are Professor C. Cem Tasan of the Department of Materials Science and Engineering and Professor Andrew Whittle of the Department of Civil and Environmental Engineering. Tasan’s project involves reducing water use in steel manufacturing and Whittle’s project tackles harmful algal blooms in water. Project work commences this September.

      “This year’s Solutions Grants are being award to professors Tasan and Whittle to help commercialize technologies they have been developing at MIT,” says J-WAFS executive director Renee J. Robins. “With J-WAFS’ support, we hope to see the teams move their technologies from the lab to the market, so they can have a beneficial impact on water use and water quality challenges,” Robins adds.

      Reducing water consumption by solid-state steelmaking

      Water is a major requirement for steel production. The steel industry ranks fourth in industrial freshwater consumption worldwide, since large amounts of water are needed mainly for cooling purposes in the process. Unfortunately, a strong correlation has also been shown to exist between freshwater use in steelmaking and water contamination. As the global demand for steel increases and freshwater availability decreases due to climate change, improved methods for more sustainable steel production are needed.

      A strategy to reduce the water footprint of steelmaking is to explore steel recycling processes that avoid liquid metal processing. With this motivation, Cem Tasan, the Thomas B. King Associate Professor of Metallurgy in the Department of Materials Science and Engineering, and postdoc Onur Guvenc PhD created a new process called Scrap Metal Consolidation (SMC). SMC is based on a well-established metal forming process known as roll bonding. Conventionally, roll bonding requires intensive prior surface treatment of the raw material, specific atmospheric conditions, and high deformation levels. Tasan and Guvenc’s research revealed that SMC can overcome these restrictions by enabling the solid-state bonding of scrap into a sheet metal form, even when the surface quality, atmospheric conditions, and deformation levels are suboptimal. Through lab-scale proof-of-principle investigations, they have already identified SMC process conditions and validated the mechanical formability of resulting steel sheets, focusing on mild steel, the most common sheet metal scrap.

      The J-WAFS Solutions Grant will help the team to build customer product prototypes, design the processing unit, and develop a scale-up strategy and business model. By simultaneously decreasing water usage, energy demand, contamination risk, and carbon dioxide burden, SMC has the potential to decrease the energy need for steel recycling by up to 86 percent, as well as reduce the linked carbon dioxide emissions and safeguard the freshwater resources that would otherwise be directed to industrial consumption. 

      Detecting harmful algal blooms in water before it’s too late

      Harmful algal blooms (HABs) are a growing problem in both freshwater and saltwater environments worldwide, causing an estimated $13 billion in annual damage to drinking water, water for recreational use, commercial fishing areas, and desalination activities. HABs pose a threat to both human health and aquaculture, thereby threatening the food supply. Toxins in HABs are produced by some cyanobacteria, or blue-green algae, whose communities change in composition in response to eutrophication from agricultural runoff, sewer overflows, or other events. Mitigation of risks from HABs are most effective when there is advance warning of these changes in algal communities. 

      Most in situ measurements of algae are based on fluorescence spectroscopy that is conducted with LED-induced fluorescence (LEDIF) devices, or probes that induce fluorescence of specific algal pigments using LED light sources. While LEDIFs provide reasonable estimates of concentrations of individual pigments, they lack resolution to discriminate algal classes within complex mixtures found in natural water bodies. In prior research, Andrew Whittle, the Edmund K. Turner Professor of Civil and Environmental Engineering, worked with colleagues to design REMORA, a low-cost, field-deployable prototype spectrofluorometer for measuring induced fluorescence. This research was part of a collaboration between MIT and the AMS Institute. Whittle and the team successfully trained a machine learning model to discriminate and quantify cell concentrations for mixtures of different algal groups in water samples through an extensive laboratory calibration program using various algae cultures. The group demonstrated these capabilities in a series of field measurements at locations in Boston and Amsterdam. 

      Whittle will work with Fábio Duarte of the Department of Urban Studies and Planning, the Senseable City Lab, and MIT’s Center for Real Estate to refine the design of REMORA. They will develop software for autonomous operation of the sensor that can be deployed remotely on mobile vessels or platforms to enable high-resolution spatiotemporal monitoring for harmful algae. Sensor commercialization will hopefully be able to exploit the unique capabilities of REMORA for long-term monitoring applications by water utilities, environmental regulatory agencies, and water-intensive industries.  More

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      Will the charging networks arrive in time?

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      For many owners of electric vehicles (EVs), or for prospective EV owners, a thorny problem is where to charge them. Even as legacy automakers increasingly invest in manufacturing more all-electric cars and trucks, there is not a dense network of charging stations serving many types of vehicles, which would make EVs more convenient to use.

      “We’re going to have the ability to produce and deliver millions of EVs,” said MIT Professor Charles Fine at the final session this semester of the MIT Mobility Forum. “It’s not clear we’re going to have the ability to charge them. That’s a huge, huge mismatch.”

      Indeed, making EV charging stations as ubiquitous as gas stations could spur a major transition within the entire U.S. vehicle fleet. While the automaker Tesla has built a network of almost 2,000 charging stations across the U.S., and might make some interoperable with other makes of vehicles, independent companies trying to develop a business out of it are still trying to gain significant traction.

      “They don’t have a business model that works yet,” said Fine, the Chrysler Leaders for Global Operations Professor of Management at the MIT Sloan School of Management, speaking of startup firms. “They haven’t figured out their supply chains. They haven’t figured out the customer value proposition. They haven’t figured out their technology standards. It’s a very, very immature domain.”

      The May 12 event drew nearly 250 people as well as an online audience. The MIT Mobility Forum is a weekly set of talks and discussions during the academic year, ranging widely across the field of transportation and design. It is hosted by the MIT Mobility Initiative, which works to advance sustainable, accessible, and safe forms of transportation.

      Fine is a prominent expert in the areas of operations strategy, entrepreneurship, and supply chain management. He has been at MIT Sloan for over 30 years; from 2015 to 2022, he also served as the founding president, dean, and CEO of the Asia School of Business in Kuala Lumpur, Malaysia, a collaboration between MIT Sloan and Bank Negara Malaysia. Fine is also author of “Faster, Smarter, Greener: The Future of the Car and Urban Mobility” (MIT Press, 2017).

      In Fine’s remarks, he discussed the growth stages of startup companies, highlighting three phases where firms try to “nail it, scale it, and sail it” — that is, figure out the concept and workability of their enterprise, try to expand it, and then operate as a larger company. The charging-business startups are still somewhere within the first of these phases.

      At the same time, the established automakers have announced major investments in EVs — a collective $860 billion over the next decade, Fine noted. Among others, Ford says it will invest $50 billion in EV production by 2026; General Motors plans to spend $35 billion on EVs by 2025; and Toyota has announced it will invest $35 billion in EV manufacturing by 2030.

      With all these vehicles potentially coming to market, Fine suggested, the crux of the issue is a kind of “chicken and egg” problem between EVs and the network needed to support them.

      “If you’re a startup company in the charging business, if there aren’t many EVs out there, you’re not going to be making much money, and that doesn’t give you the capital to continue to invest and grow,” Fine said. “So, they need to wait until they have revenue before they can grow further. On the other hand, why should anybody buy an electric car if they don’t think they’re going to be able to charge it?”

      Those living in single-family homes can install chargers. But many others are not in that situation, Fine noted: “For people who don’t have fixed parking spaces and have to rely on the public network, there is this chicken-and-egg problem. They can’t buy an EV unless they know how they’re going to be able to charge it, and charging companies can’t build out their networks unless they know how they’re going to get their revenue.”

      The event featured a question-and-answer session and audience discussion, with a range of questions, and comments from some industry veterans, including Robin Chase SM ’86, the co-founder and former CEO of Zipcar. She expressed some optimism that startup charging companies will be able to get traction in the nascent market before long.

      “The right companies can learn very fast,” Chase said. “There’s no reason why they can’t correct those scaling problems in short-ish order.”

      In answer to other audience questions, Fine noted some of the challenges that will have to be addressed by independent charging firms, such as unified standards and interoperability among automakers and charging stations.

      “For a driver to have to have six different apps, or [their] car doesn’t fit in the plug here or there, or my software doesn’t talk to my credit card … connectivity, standards, technical issues need to be worked out as well,” Fine said.

      There are also varying regulatory issues, including grid policies and what consumers can be billed for, which have to be worked out on a state-by-state basis, meaning that even modest-size startups will have to have knowledgeable and productive legal departments.

      All of which makes it possible, as Fine suggested, that the large legacy automakers will start investing more heavily in the charging business in the near future. Mercedes, he noted, just announced in January that it is entering into a partnership with charging firms ChargePoint and MN8 Energy to develop about 400 charging stations across North America by 2027. By necessity, others might have to follow suit if they want to protect their massive planned investments in the EV sector.

      “I’m not in the business of telling [automakers] what to do, but I do think they have a lot at risk,” Fine said. “They’re spending billions and billions of dollars to produce these cars, and I don’t think they can afford an epic failure [if] people don’t buy them because there’s no charging infrastructure. If they’re waiting for the startups to build out rapidly, then they may be waiting longer than they hope to wait.” More

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      Moving perovskite advancements from the lab to the manufacturing floor

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      The following was issued as a joint announcement from MIT.nano and the MIT Research Laboratory for Electronics; CubicPV; Verde Technologies; Princeton University; and the University of California at San Diego.

      Tandem solar cells are made of stacked materials — such as silicon paired with perovskites — that together absorb more of the solar spectrum than single materials, resulting in a dramatic increase in efficiency. Their potential to generate significantly more power than conventional cells could make a meaningful difference in the race to combat climate change and the transition to a clean-energy future.

      However, current methods to create stable and efficient perovskite layers require time-consuming, painstaking rounds of design iteration and testing, inhibiting their development for commercial use. Today, the U.S. Department of Energy Solar Energy Technologies Office (SETO) announced that MIT has been selected to receive an $11.25 million cost-shared award to establish a new research center to address this challenge by using a co-optimization framework guided by machine learning and automation.

      A collaborative effort with lead industry participant CubicPV, solar startup Verde Technologies, and academic partners Princeton University and the University of California San Diego (UC San Diego), the center will bring together teams of researchers to support the creation of perovskite-silicon tandem solar modules that are co-designed for both stability and performance, with goals to significantly accelerate R&D and the transfer of these achievements into commercial environments.

      “Urgent challenges demand rapid action. This center will accelerate the development of tandem solar modules by bringing academia and industry into closer partnership,” says MIT professor of mechanical engineering Tonio Buonassisi, who will direct the center. “We’re grateful to the Department of Energy for supporting this powerful new model and excited to get to work.”

      Adam Lorenz, CTO of solar energy technology company CubicPV, stresses the importance of thinking about scale, alongside quality and efficiency, to accelerate the perovskite effort into the commercial environment. “Instead of chasing record efficiencies with tiny pixel-sized devices and later attempting to stabilize them, we will simultaneously target stability, reproducibility, and efficiency,” he says. “It’s a module-centric approach that creates a direct channel for R&D advancements into industry.”

      The center will be named Accelerated Co-Design of Durable, Reproducible, and Efficient Perovskite Tandems, or ADDEPT. The grant will be administered through the MIT Research Laboratory for Electronics (RLE).

      David Fenning, associate professor of nanoengineering at UC San Diego, has worked with Buonassisi on the idea of merging materials, automation, and computation, specifically in this field of artificial intelligence and solar, since 2014. Now, a central thrust of the ADDEPT project will be to deploy machine learning and robotic screening to optimize processing of perovskite-based solar materials for efficiency and durability.

      “We have already seen early indications of successful technology transfer between our UC San Diego robot PASCAL and industry,” says Fenning. “With this new center, we will bring research labs and the emerging perovskite industry together to improve reproducibility and reduce time to market.”

      “Our generation has an obligation to work collaboratively in the fight against climate change,” says Skylar Bagdon, CEO of Verde Technologies, which received the American-Made Perovskite Startup Prize. “Throughout the course of this center, Verde will do everything in our power to help this brilliant team transition lab-scale breakthroughs into the world where they can have an impact.”

      Several of the academic partners echoed the importance of the joint effort between academia and industry. Barry Rand, professor of electrical and computer engineering at the Andlinger Center for Energy and the Environment at Princeton University, pointed to the intersection of scientific knowledge and market awareness. “Understanding how chemistry affects films and interfaces will empower us to co-design for stability and performance,” he says. “The center will accelerate this use-inspired science, with close guidance from our end customers, the industry partners.”

      A critical resource for the center will be MIT.nano, a 200,000-square-foot research facility set in the heart of the campus. MIT.nano Director Vladimir Bulović, the Fariborz Maseeh (1990) Professor of Emerging Technology, says he envisions MIT.nano as a hub for industry and academic partners, facilitating technology development and transfer through shared lab space, open-access equipment, and streamlined intellectual property frameworks.

      “MIT has a history of groundbreaking innovation using perovskite materials for solar applications,” says Bulović. “We’re thrilled to help build on that history by anchoring ADDEPT at MIT.nano and working to help the nation advance the future of these promising materials.”

      MIT was selected as a part of the SETO Fiscal Year 2022 Photovoltaics (PV) funding program, an effort to reduce costs and supply chain vulnerabilities, further develop durable and recyclable solar technologies, and advance perovskite PV technologies toward commercialization. ADDEPT is one project that will tackle perovskite durability, which will extend module life. The overarching goal of these projects is to lower the levelized cost of electricity generated by PV.

      Research groups involved with the ADDEPT project at MIT include Buonassisi’s Accelerated Materials Laboratory for Sustainability (AMLS), Bulović’s Organic and Nanostructured Electronics (ONE) Lab, and the Bawendi Group led by Lester Wolfe Professor in Chemistry Moungi Bawendi. Also working on the project is Jeremiah Mwaura, research scientist in the ONE Lab. More

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      Flow batteries for grid-scale energy storage

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      In the coming decades, renewable energy sources such as solar and wind will increasingly dominate the conventional power grid. Because those sources only generate electricity when it’s sunny or windy, ensuring a reliable grid — one that can deliver power 24/7 — requires some means of storing electricity when supplies are abundant and delivering it later when they’re not. And because there can be hours and even days with no wind, for example, some energy storage devices must be able to store a large amount of electricity for a long time.

      A promising technology for performing that task is the flow battery, an electrochemical device that can store hundreds of megawatt-hours of energy — enough to keep thousands of homes running for many hours on a single charge. Flow batteries have the potential for long lifetimes and low costs in part due to their unusual design. In the everyday batteries used in phones and electric vehicles, the materials that store the electric charge are solid coatings on the electrodes. “A flow battery takes those solid-state charge-storage materials, dissolves them in electrolyte solutions, and then pumps the solutions through the electrodes,” says Fikile Brushett, an associate professor of chemical engineering at MIT. That design offers many benefits and poses a few challenges.

      Flow batteries: Design and operation

      A flow battery contains two substances that undergo electrochemical reactions in which electrons are transferred from one to the other. When the battery is being charged, the transfer of electrons forces the two substances into a state that’s “less energetically favorable” as it stores extra energy. (Think of a ball being pushed up to the top of a hill.) When the battery is being discharged, the transfer of electrons shifts the substances into a more energetically favorable state as the stored energy is released. (The ball is set free and allowed to roll down the hill.)

      At the core of a flow battery are two large tanks that hold liquid electrolytes, one positive and the other negative. Each electrolyte contains dissolved “active species” — atoms or molecules that will electrochemically react to release or store electrons. During charging, one species is “oxidized” (releases electrons), and the other is “reduced” (gains electrons); during discharging, they swap roles. Pumps are used to circulate the two electrolytes through separate electrodes, each made of a porous material that provides abundant surfaces on which the active species can react. A thin membrane between the adjacent electrodes keeps the two electrolytes from coming into direct contact and possibly reacting, which would release heat and waste energy that could otherwise be used on the grid.

      When the battery is being discharged, active species on the negative side oxidize, releasing electrons that flow through an external circuit to the positive side, causing the species there to be reduced. The flow of those electrons through the external circuit can power the grid. In addition to the movement of the electrons, “supporting” ions — other charged species in the electrolyte — pass through the membrane to help complete the reaction and keep the system electrically neutral.

      Once all the species have reacted and the battery is fully discharged, the system can be recharged. In that process, electricity from wind turbines, solar farms, and other generating sources drives the reverse reactions. The active species on the positive side oxidize to release electrons back through the wires to the negative side, where they rejoin their original active species. The battery is now reset and ready to send out more electricity when it’s needed. Brushett adds, “The battery can be cycled in this way over and over again for years on end.”

      Benefits and challenges

      A major advantage of this system design is that where the energy is stored (the tanks) is separated from where the electrochemical reactions occur (the so-called reactor, which includes the porous electrodes and membrane). As a result, the capacity of the battery — how much energy it can store — and its power — the rate at which it can be charged and discharged — can be adjusted separately. “If I want to have more capacity, I can just make the tanks bigger,” explains Kara Rodby PhD ’22, a former member of Brushett’s lab and now a technical analyst at Volta Energy Technologies. “And if I want to increase its power, I can increase the size of the reactor.” That flexibility makes it possible to design a flow battery to suit a particular application and to modify it if needs change in the future.

      However, the electrolyte in a flow battery can degrade with time and use. While all batteries experience electrolyte degradation, flow batteries in particular suffer from a relatively faster form of degradation called “crossover.” The membrane is designed to allow small supporting ions to pass through and block the larger active species, but in reality, it isn’t perfectly selective. Some of the active species in one tank can sneak through (or “cross over”) and mix with the electrolyte in the other tank. The two active species may then chemically react, effectively discharging the battery. Even if they don’t, some of the active species is no longer in the first tank where it belongs, so the overall capacity of the battery is lower.

      Recovering capacity lost to crossover requires some sort of remediation — for example, replacing the electrolyte in one or both tanks or finding a way to reestablish the “oxidation states” of the active species in the two tanks. (Oxidation state is a number assigned to an atom or compound to tell if it has more or fewer electrons than it has when it’s in its neutral state.) Such remediation is more easily — and therefore more cost-effectively — executed in a flow battery because all the components are more easily accessed than they are in a conventional battery.

      The state of the art: Vanadium

      A critical factor in designing flow batteries is the selected chemistry. The two electrolytes can contain different chemicals, but today the most widely used setup has vanadium in different oxidation states on the two sides. That arrangement addresses the two major challenges with flow batteries.

      First, vanadium doesn’t degrade. “If you put 100 grams of vanadium into your battery and you come back in 100 years, you should be able to recover 100 grams of that vanadium — as long as the battery doesn’t have some sort of a physical leak,” says Brushett.

      And second, if some of the vanadium in one tank flows through the membrane to the other side, there is no permanent cross-contamination of the electrolytes, only a shift in the oxidation states, which is easily remediated by re-balancing the electrolyte volumes and restoring the oxidation state via a minor charge step. Most of today’s commercial systems include a pipe connecting the two vanadium tanks that automatically transfers a certain amount of electrolyte from one tank to the other when the two get out of balance.

      However, as the grid becomes increasingly dominated by renewables, more and more flow batteries will be needed to provide long-duration storage. Demand for vanadium will grow, and that will be a problem. “Vanadium is found around the world but in dilute amounts, and extracting it is difficult,” says Rodby. “So there are limited places — mostly in Russia, China, and South Africa — where it’s produced, and the supply chain isn’t reliable.” As a result, vanadium prices are both high and extremely volatile — an impediment to the broad deployment of the vanadium flow battery.

      Beyond vanadium

      The question then becomes: If not vanadium, then what? Researchers worldwide are trying to answer that question, and many are focusing on promising chemistries using materials that are more abundant and less expensive than vanadium. But it’s not that easy, notes Rodby. While other chemistries may offer lower initial capital costs, they may be more expensive to operate over time. They may require periodic servicing to rejuvenate one or both of their electrolytes. “You may even need to replace them, so you’re essentially incurring that initial (low) capital cost again and again,” says Rodby.

      Indeed, comparing the economics of different options is difficult because “there are so many dependent variables,” says Brushett. “A flow battery is an electrochemical system, which means that there are multiple components working together in order for the device to function. Because of that, if you are trying to improve a system — performance, cost, whatever — it’s very difficult because when you touch one thing, five other things change.”

      So how can we compare these new and emerging chemistries — in a meaningful way — with today’s vanadium systems? And how do we compare them with one another, so we know which ones are more promising and what the potential pitfalls are with each one? “Addressing those questions can help us decide where to focus our research and where to invest our research and development dollars now,” says Brushett.

      Techno-economic modeling as a guide

      A good way to understand and assess the economic viability of new and emerging energy technologies is using techno-economic modeling. With certain models, one can account for the capital cost of a defined system and — based on the system’s projected performance — the operating costs over time, generating a total cost discounted over the system’s lifetime. That result allows a potential purchaser to compare options on a “levelized cost of storage” basis.

      Using that approach, Rodby developed a framework for estimating the levelized cost for flow batteries. The framework includes a dynamic physical model of the battery that tracks its performance over time, including any changes in storage capacity. The calculated operating costs therefore cover all services required over decades of operation, including the remediation steps taken in response to species degradation and crossover.

      Analyzing all possible chemistries would be impossible, so the researchers focused on certain classes. First, they narrowed the options down to those in which the active species are dissolved in water. “Aqueous systems are furthest along and are most likely to be successful commercially,” says Rodby. Next, they limited their analyses to “asymmetric” chemistries; that is, setups that use different materials in the two tanks. (As Brushett explains, vanadium is unusual in that using the same “parent” material in both tanks is rarely feasible.) Finally, they divided the possibilities into two classes: species that have a finite lifetime and species that have an infinite lifetime; that is, ones that degrade over time and ones that don’t.

      Results from their analyses aren’t clear-cut; there isn’t a particular chemistry that leads the pack. But they do provide general guidelines for choosing and pursuing the different options.

      Finite-lifetime materials

      While vanadium is a single element, the finite-lifetime materials are typically organic molecules made up of multiple elements, among them carbon. One advantage of organic molecules is that they can be synthesized in a lab and at an industrial scale, and the structure can be altered to suit a specific function. For example, the molecule can be made more soluble, so more will be present in the electrolyte and the energy density of the system will be greater; or it can be made bigger so it won’t fit through the membrane and cross to the other side. Finally, organic molecules can be made from simple, abundant, low-cost elements, potentially even waste streams from other industries.

      Despite those attractive features, there are two concerns. First, organic molecules would probably need to be made in a chemical plant, and upgrading the low-cost precursors as needed may prove to be more expensive than desired. Second, these molecules are large chemical structures that aren’t always very stable, so they’re prone to degradation. “So along with crossover, you now have a new degradation mechanism that occurs over time,” says Rodby. “Moreover, you may figure out the degradation process and how to reverse it in one type of organic molecule, but the process may be totally different in the next molecule you work on, making the discovery and development of each new chemistry require significant effort.”

      Research is ongoing, but at present, Rodby and Brushett find it challenging to make the case for the finite-lifetime chemistries, mostly based on their capital costs. Citing studies that have estimated the manufacturing costs of these materials, Rodby believes that current options cannot be made at low enough costs to be economically viable. “They’re cheaper than vanadium, but not cheap enough,” says Rodby.

      The results send an important message to researchers designing new chemistries using organic molecules: Be sure to consider operating challenges early on. Rodby and Brushett note that it’s often not until way down the “innovation pipeline” that researchers start to address practical questions concerning the long-term operation of a promising-looking system. The MIT team recommends that understanding the potential decay mechanisms and how they might be cost-effectively reversed or remediated should be an upfront design criterion.

      Infinite-lifetime species

      The infinite-lifetime species include materials that — like vanadium — are not going to decay. The most likely candidates are other metals; for example, iron or manganese. “These are commodity-scale chemicals that will certainly be low cost,” says Rodby.

      Here, the researchers found that there’s a wider “design space” of feasible options that could compete with vanadium. But there are still challenges to be addressed. While these species don’t degrade, they may trigger side reactions when used in a battery. For example, many metals catalyze the formation of hydrogen, which reduces efficiency and adds another form of capacity loss. While there are ways to deal with the hydrogen-evolution problem, a sufficiently low-cost and effective solution for high rates of this side reaction is still needed.

      In addition, crossover is a still a problem requiring remediation steps. The researchers evaluated two methods of dealing with crossover in systems combining two types of infinite-lifetime species.

      The first is the “spectator strategy.” Here, both of the tanks contain both active species. Explains Brushett, “You have the same electrolyte mixture on both sides of the battery, but only one of the species is ever working and the other is a spectator.” As a result, crossover can be remediated in similar ways to those used in the vanadium flow battery. The drawback is that half of the active material in each tank is unavailable for storing charge, so it’s wasted. “You’ve essentially doubled your electrolyte cost on a per-unit energy basis,” says Rodby.

      The second method calls for making a membrane that is perfectly selective: It must let through only the supporting ion needed to maintain the electrical balance between the two sides. However, that approach increases cell resistance, hurting system efficiency. In addition, the membrane would need to be made of a special material — say, a ceramic composite — that would be extremely expensive based on current production methods and scales. Rodby notes that work on such membranes is under way, but the cost and performance metrics are “far off from where they’d need to be to make sense.”

      Time is of the essence

      The researchers stress the urgency of the climate change threat and the need to have grid-scale, long-duration storage systems at the ready. “There are many chemistries now being looked at,” says Rodby, “but we need to hone in on some solutions that will actually be able to compete with vanadium and can be deployed soon and operated over the long term.”

      The techno-economic framework is intended to help guide that process. It can calculate the levelized cost of storage for specific designs for comparison with vanadium systems and with one another. It can identify critical gaps in knowledge related to long-term operation or remediation, thereby identifying technology development or experimental investigations that should be prioritized. And it can help determine whether the trade-off between lower upfront costs and greater operating costs makes sense in these next-generation chemistries.

      The good news, notes Rodby, is that advances achieved in research on one type of flow battery chemistry can often be applied to others. “A lot of the principles learned with vanadium can be translated to other systems,” she says. She believes that the field has advanced not only in understanding but also in the ability to design experiments that address problems common to all flow batteries, thereby helping to prepare the technology for its important role of grid-scale storage in the future.

      This research was supported by the MIT Energy Initiative. Kara Rodby PhD ’22 was supported by an ExxonMobil-MIT Energy Fellowship in 2021-22.

      This article appears in the Winter 2023 issue of Energy Futures, the magazine of the MIT Energy Initiative. More

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      Using combustion to make better batteries

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      For more than a century, much of the world has run on the combustion of fossil fuels. Now, to avert the threat of climate change, the energy system is changing. Notably, solar and wind systems are replacing fossil fuel combustion for generating electricity and heat, and batteries are replacing the internal combustion engine for powering vehicles. As the energy transition progresses, researchers worldwide are tackling the many challenges that arise.

      Sili Deng has spent her career thinking about combustion. Now an assistant professor in the MIT Department of Mechanical Engineering and the Class of 1954 Career Development Professor, Deng leads a group that, among other things, develops theoretical models to help understand and control combustion systems to make them more efficient and to control the formation of emissions, including particles of soot.

      “So we thought, given our background in combustion, what’s the best way we can contribute to the energy transition?” says Deng. In considering the possibilities, she notes that combustion refers only to the process — not to what’s burning. “While we generally think of fossil fuels when we think of combustion, the term ‘combustion’ encompasses many high-temperature chemical reactions that involve oxygen and typically emit light and large amounts of heat,” she says.

      Given that definition, she saw another role for the expertise she and her team have developed: They could explore the use of combustion to make materials for the energy transition. Under carefully controlled conditions, combusting flames can be used to produce not polluting soot, but rather valuable materials, including some that are critical in the manufacture of lithium-ion batteries.

      Improving the lithium-ion battery by lowering costs

      The demand for lithium-ion batteries is projected to skyrocket in the coming decades. Batteries will be needed to power the growing fleet of electric cars and to store the electricity produced by solar and wind systems so it can be delivered later when those sources aren’t generating. Some experts project that the global demand for lithium-ion batteries may increase tenfold or more in the next decade.

      Given such projections, many researchers are looking for ways to improve the lithium-ion battery technology. Deng and her group aren’t materials scientists, so they don’t focus on making new and better battery chemistries. Instead, their goal is to find a way to lower the high cost of making all of those batteries. And much of the cost of making a lithium-ion battery can be traced to the manufacture of materials used to make one of its two electrodes — the cathode.

      The MIT researchers began their search for cost savings by considering the methods now used to produce cathode materials. The raw materials are typically salts of several metals, including lithium, which provides ions — the electrically charged particles that move when the battery is charged and discharged. The processing technology aims to produce tiny particles, each one made up of a mixture of those ingredients, with the atoms arranged in the specific crystalline structure that will deliver the best performance in the finished battery.

      For the past several decades, companies have manufactured those cathode materials using a two-stage process called coprecipitation. In the first stage, the metal salts — excluding the lithium — are dissolved in water and thoroughly mixed inside a chemical reactor. Chemicals are added to change the acidity (the pH) of the mixture, and particles made up of the combined salts precipitate out of the solution. The particles are then removed, dried, ground up, and put through a sieve.

      A change in pH won’t cause lithium to precipitate, so it is added in the second stage. Solid lithium is ground together with the particles from the first stage until lithium atoms permeate the particles. The resulting material is then heated, or “annealed,” to ensure complete mixing and to achieve the targeted crystalline structure. Finally, the particles go through a “deagglomerator” that separates any particles that have joined together, and the cathode material emerges.

      Coprecipitation produces the needed materials, but the process is time-consuming. The first stage takes about 10 hours, and the second stage requires about 13 hours of annealing at a relatively low temperature (750 degrees Celsius). In addition, to prevent cracking during annealing, the temperature is gradually “ramped” up and down, which takes another 11 hours. The process is thus not only time-consuming but also energy-intensive and costly.

      For the past two years, Deng and her group have been exploring better ways to make the cathode material. “Combustion is very effective at oxidizing things, and the materials for lithium-ion batteries are generally mixtures of metal oxides,” says Deng. That being the case, they thought this could be an opportunity to use a combustion-based process called flame synthesis.

      A new way of making a high-performance cathode material

      The first task for Deng and her team — mechanical engineering postdoc Jianan Zhang, Valerie L. Muldoon ’20, SM ’22, and current graduate students Maanasa Bhat and Chuwei Zhang — was to choose a target material for their study. They decided to focus on a mixture of metal oxides consisting of nickel, cobalt, and manganese plus lithium. Known as “NCM811,” this material is widely used and has been shown to produce cathodes for batteries that deliver high performance; in an electric vehicle, that means a long driving range, rapid discharge and recharge, and a long lifetime. To better define their target, the researchers examined the literature to determine the composition and crystalline structure of NCM811 that has been shown to deliver the best performance as a cathode material.

      They then considered three possible approaches to improving on the coprecipitation process for synthesizing NCM811: They could simplify the system (to cut capital costs), speed up the process, or cut the energy required.

      “Our first thought was, what if we can mix together all of the substances — including the lithium — at the beginning?” says Deng. “Then we would not need to have the two stages” — a clear simplification over coprecipitation.

      Introducing FASP

      One process widely used in the chemical and other industries to fabricate nanoparticles is a type of flame synthesis called flame-assisted spray pyrolysis, or FASP. Deng’s concept for using FASP to make their targeted cathode powders proceeds as follows.

      The precursor materials — the metal salts (including the lithium) — are mixed with water, and the resulting solution is sprayed as fine droplets by an atomizer into a combustion chamber. There, a flame of burning methane heats up the mixture. The water evaporates, leaving the precursor materials to decompose, oxidize, and solidify to form the powder product. The cyclone separates particles of different sizes, and the baghouse filters out those that aren’t useful. The collected particles would then be annealed and deagglomerated.

      To investigate and optimize this concept, the researchers developed a lab-scale FASP setup consisting of a homemade ultrasonic nebulizer, a preheating section, a burner, a filter, and a vacuum pump that withdraws the powders that form. Using that system, they could control the details of the heating process: The preheating section replicates conditions as the material first enters the combustion chamber, and the burner replicates conditions as it passes the flame. That setup allowed the team to explore operating conditions that would give the best results.

      Their experiments showed marked benefits over coprecipitation. The nebulizer breaks up the liquid solution into fine droplets, ensuring atomic-level mixing. The water simply evaporates, so there’s no need to change the pH or to separate the solids from a liquid. As Deng notes, “You just let the gas go, and you’re left with the particles, which is what you want.” With lithium included at the outset, there’s no need for mixing solids with solids, which is neither efficient 
nor effective.

      They could even control the structure, or “morphology,” of the particles that formed. In one series of experiments, they tried exposing the incoming spray to different rates of temperature change over time. They found that the temperature “history” has a direct impact on morphology. With no preheating, the particles burst apart; and with rapid preheating, the particles were hollow. The best outcomes came when they used temperatures ranging from 175-225 C. Experiments with coin-cell batteries (laboratory devices used for testing battery materials) confirmed that by adjusting the preheating temperature, they could achieve a particle morphology that would optimize the performance of their materials.

      Best of all, the particles formed in seconds. Assuming the time needed for conventional annealing and deagglomerating, the new setup could synthesize the finished cathode material in half the total time needed for coprecipitation. Moreover, the first stage of the coprecipitation system is replaced by a far simpler setup — a savings in capital costs.

      “We were very happy,” says Deng. “But then we thought, if we’ve changed the precursor side so the lithium is mixed well with the salts, do we need to have the same process for the second stage? Maybe not!”

      Improving the second stage

      The key time- and energy-consuming step in the second stage is the annealing. In today’s coprecipitation process, the strategy is to anneal at a low temperature for a long time, giving the operator time to manipulate and control the process. But running a furnace for some 20 hours — even at a low temperature — consumes a lot of energy.

      Based on their studies thus far, Deng thought, “What if we slightly increase the temperature but reduce the annealing time by orders of magnitude? Then we could cut energy consumption, and we might still achieve the desired crystal structure.”

      However, experiments at slightly elevated temperatures and short treatment times didn’t bring the results they had hoped for. In transmission electron microscope (TEM) images, the particles that formed had clouds of light-looking nanoscale particles attached to their surfaces. When the researchers performed the same experiments without adding the lithium, those nanoparticles didn’t appear. Based on that and other tests, they concluded that the nanoparticles were pure lithium. So, it seemed like long-duration annealing would be needed to ensure that the lithium made its way inside the particles.

      But they then came up with a different solution to the lithium-distribution problem. They added a small amount — just 1 percent by weight — of an inexpensive compound called urea to their mixture. In TEM images of the particles formed, the “undesirable nanoparticles were largely gone,” says Deng.

      Experiments in the laboratory coin cells showed that the addition of urea significantly altered the response to changes in the annealing temperature. When the urea was absent, raising the annealing temperature led to a dramatic decline in performance of the cathode material that formed. But with the urea present, the performance of the material that formed was unaffected by any temperature change.

      That result meant that — as long as the urea was added with the other precursors — they could push up the temperature, shrink the annealing time, and omit the gradual ramp-up and cool-down process. Further imaging studies confirmed that their approach yields the desired crystal structure and the homogeneous elemental distribution of the cobalt, nickel, manganese, and lithium within the particles. Moreover, in tests of various performance measures, their materials did as well as materials produced by coprecipitation or by other methods using long-time heat treatment. Indeed, the performance was comparable to that of commercial batteries with cathodes made of NCM811.

      So now the long and expensive second stage required in standard coprecipitation could be replaced by just 20 minutes of annealing at about 870 C plus 20 minutes of cooling down at room temperature.

      Theory, continuing work, and planning for scale-up

      While experimental evidence supports their approach, Deng and her group are now working to understand why it works. “Getting the underlying physics right will help us design the process to control the morphology and to scale up the process,” says Deng. And they have a hypothesis for why the lithium nanoparticles in their flame synthesis process end up on the surfaces of the larger particles — and why the presence of urea solves that problem.

      According to their theory, without the added urea, the metal and lithium atoms are initially well-mixed within the droplet. But as heating progresses, the lithium diffuses to the surface and ends up as nanoparticles attached to the solidified particle. As a result, a long annealing process is needed to move the lithium in among the other atoms.

      When the urea is present, it starts out mixed with the lithium and other atoms inside the droplet. As temperatures rise, the urea decomposes, forming bubbles. As heating progresses, the bubbles burst, increasing circulation, which keeps the lithium from diffusing to the surface. The lithium ends up uniformly distributed, so the final heat treatment can be very short.

      The researchers are now designing a system to suspend a droplet of their mixture so they can observe the circulation inside it, with and without the urea present. They’re also developing experiments to examine how droplets vaporize, employing tools and methods they have used in the past to study how hydrocarbons vaporize inside internal combustion engines.

      They also have ideas about how to streamline and scale up their process. In coprecipitation, the first stage takes 10 to 20 hours, so one batch at a time moves on to the second stage to be annealed. In contrast, the novel FASP process generates particles in 20 minutes or less — a rate that’s consistent with continuous processing. In their design for an “integrated synthesis system,” the particles coming out of the baghouse are deposited on a belt that carries them for 10 or 20 minutes through a furnace. A deagglomerator then breaks any attached particles apart, and the cathode powder emerges, ready to be fabricated into a high-performance cathode for a lithium-ion battery. The cathode powders for high-performance lithium-ion batteries would thus be manufactured at unprecedented speed, low cost, and low energy use.

      Deng notes that every component in their integrated system is already used in industry, generally at a large scale and high flow-through rate. “That’s why we see great potential for our technology to be commercialized and scaled up,” she says. “Where our expertise comes into play is in designing the combustion chamber to control the temperature and heating rate so as to produce particles with the desired morphology.” And while a detailed economic analysis has yet to be performed, it seems clear that their technique will be faster, the equipment simpler, and the energy use lower than other methods of manufacturing cathode materials for lithium-ion batteries — potentially a major contribution to the ongoing energy transition.

      This research was supported by the MIT Department of Mechanical Engineering.

      This article appears in the Winter 2023 issue of Energy Futures, the magazine of the MIT Energy Initiative. More