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    An interdisciplinary approach to fighting climate change through clean energy solutions

    In early 2021, the U.S. government set an ambitious goal: to decarbonize its power grid, the system that generates and transmits electricity throughout the country, by 2035. It’s an important goal in the fight against climate change, and will require a switch from current, greenhouse-gas producing energy sources (such as coal and natural gas), to predominantly renewable ones (such as wind and solar).

    Getting the power grid to zero carbon will be a challenging undertaking, as Audun Botterud, a principal research scientist at the MIT Laboratory for Information and Decision Systems (LIDS) who has long been interested in the problem, knows well. It will require building lots of renewable energy generators and new infrastructure; designing better technology to capture, store, and carry electricity; creating the right regulatory and economic incentives; and more. Decarbonizing the grid also presents many computational challenges, which is where Botterud’s focus lies. Botterud has modeled different aspects of the grid — the mechanics of energy supply, demand, and storage, and electricity markets — where economic factors can have a huge effect on how quickly renewable solutions get adopted.

    On again, off again

    A major challenge of decarbonization is that the grid must be designed and operated to reliably meet demand. Using renewable energy sources complicates this, as wind and solar power depend on an infamously volatile system: the weather. A sunny day becomes gray and blustery, and wind turbines get a boost but solar farms go idle. This will make the grid’s energy supply variable and hard to predict. Additional resources, including batteries and backup power generators, will need to be incorporated to regulate supply. Extreme weather events, which are becoming more common with climate change, can further strain both supply and demand. Managing a renewables-driven grid will require algorithms that can minimize uncertainty in the face of constant, sometimes random fluctuations to make better predictions of supply and demand, guide how resources are added to the grid, and inform how those resources are committed and dispatched across the entire United States.

    “The problem of managing supply and demand in the grid has to happen every second throughout the year, and given how much we rely on electricity in society, we need to get this right,” Botterud says. “You cannot let the reliability drop as you increase the amount of renewables, especially because I think that will lead to resistance towards adopting renewables.”

    That is why Botterud feels fortunate to be working on the decarbonization problem at LIDS — even though a career here is not something he had originally planned. Botterud’s first experience with MIT came during his time as a graduate student in his home country of Norway, when he spent a year as a visiting student with what is now called the MIT Energy Initiative. He might never have returned, except that while at MIT, Botterud met his future wife, Bilge Yildiz. The pair both ended up working at the Argonne National Laboratory outside of Chicago, with Botterud focusing on challenges related to power systems and electricity markets. Then Yildiz got a faculty position at MIT, where she is a professor of nuclear and materials science and engineering. Botterud moved back to the Cambridge area with her and continued to work for Argonne remotely, but he also kept an eye on local opportunities. Eventually, a position at LIDS became available, and Botterud took it, while maintaining his connections to Argonne.

    “At first glance, it may not be an obvious fit,” Botterud says. “My work is very focused on a specific application, power system challenges, and LIDS tends to be more focused on fundamental methods to use across many different application areas. However, being at LIDS, my lab [the Energy Analytics Group] has access to the most recent advances in these fundamental methods, and we can apply them to power and energy problems. Other people at LIDS are working on energy too, so there is growing momentum to address these important problems.”

    Weather, space, and time

    Much of Botterud’s research involves optimization, using mathematical programming to compare alternatives and find the best solution. Common computational challenges include dealing with large geographical areas that contain regions with different weather, different types and quantities of renewable energy available, and different infrastructure and consumer needs — such as the entire United States. Another challenge is the need for granular time resolution, sometimes even down to the sub-second level, to account for changes in energy supply and demand.

    Often, Botterud’s group will use decomposition to solve such large problems piecemeal and then stitch together solutions. However, it’s also important to consider systems as a whole. For example, in a recent paper, Botterud’s lab looked at the effect of building new transmission lines as part of national decarbonization. They modeled solutions assuming coordination at the state, regional, or national level, and found that the more regions coordinate to build transmission infrastructure and distribute electricity, the less they will need to spend to reach zero carbon.

    In other projects, Botterud uses game theory approaches to study strategic interactions in electricity markets. For example, he has designed agent-based models to analyze electricity markets. These assume each actor will make strategic decisions in their own best interest and then simulate interactions between them. Interested parties can use the models to see what would happen under different conditions and market rules, which may lead companies to make different investment decisions, or governing bodies to issue different regulations and incentives. These choices can shape how quickly the grid gets decarbonized.

    Botterud is also collaborating with researchers in MIT’s chemical engineering department who are working on improving battery storage technologies. Batteries will help manage variable renewable energy supply by capturing surplus energy during periods of high generation to release during periods of insufficient generation. Botterud’s group models the sort of charge cycles that batteries are likely to experience in the power grid, so that chemical engineers in the lab can test their batteries’ abilities in more realistic scenarios. In turn, this also leads to a more realistic representation of batteries in power system optimization models.

    These are only some of the problems that Botterud works on. He enjoys the challenge of tackling a spectrum of different projects, collaborating with everyone from engineers to architects to economists. He also believes that such collaboration leads to better solutions. The problems created by climate change are myriad and complex, and solving them will require researchers to cooperate and explore.

    “In order to have a real impact on interdisciplinary problems like energy and climate,” Botterud says, “you need to get outside of your research sweet spot and broaden your approach.” More

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    Minimizing electric vehicles’ impact on the grid

    National and global plans to combat climate change include increasing the electrification of vehicles and the percentage of electricity generated from renewable sources. But some projections show that these trends might require costly new power plants to meet peak loads in the evening when cars are plugged in after the workday. What’s more, overproduction of power from solar farms during the daytime can waste valuable electricity-generation capacity.

    In a new study, MIT researchers have found that it’s possible to mitigate or eliminate both these problems without the need for advanced technological systems of connected devices and real-time communications, which could add to costs and energy consumption. Instead, encouraging the placing of charging stations for electric vehicles (EVs) in strategic ways, rather than letting them spring up anywhere, and setting up systems to initiate car charging at delayed times could potentially make all the difference.

    The study, published today in the journal Cell Reports Physical Science, is by Zachary Needell PhD ’22, postdoc Wei Wei, and Professor Jessika Trancik of MIT’s Institute for Data, Systems, and Society.

    In their analysis, the researchers used data collected in two sample cities: New York and Dallas. The data were gathered from, among other sources, anonymized records collected via onboard devices in vehicles, and surveys that carefully sampled populations to cover variable travel behaviors. They showed the times of day cars are used and for how long, and how much time the vehicles spend at different kinds of locations — residential, workplace, shopping, entertainment, and so on.

    The findings, Trancik says, “round out the picture on the question of where to strategically locate chargers to support EV adoption and also support the power grid.”

    Better availability of charging stations at workplaces, for example, could help to soak up peak power being produced at midday from solar power installations, which might otherwise go to waste because it is not economical to build enough battery or other storage capacity to save all of it for later in the day. Thus, workplace chargers can provide a double benefit, helping to reduce the evening peak load from EV charging and also making use of the solar electricity output.

    These effects on the electric power system are considerable, especially if the system must meet charging demands for a fully electrified personal vehicle fleet alongside the peaks in other demand for electricity, for example on the hottest days of the year. If unmitigated, the evening peaks in EV charging demand could require installing upwards of 20 percent more power-generation capacity, the researchers say.

    “Slow workplace charging can be more preferable than faster charging technologies for enabling a higher utilization of midday solar resources,” Wei says.

    Meanwhile, with delayed home charging, each EV charger could be accompanied by a simple app to estimate the time to begin its charging cycle so that it charges just before it is needed the next day. Unlike other proposals that require a centralized control of the charging cycle, such a system needs no interdevice communication of information and can be preprogrammed — and can accomplish a major shift in the demand on the grid caused by increasing EV penetration. The reason it works so well, Trancik says, is because of the natural variability in driving behaviors across individuals in a population.

    By “home charging,” the researchers aren’t only referring to charging equipment in individual garages or parking areas. They say it’s essential to make charging stations available in on-street parking locations and in apartment building parking areas as well.

    Trancik says the findings highlight the value of combining the two measures — workplace charging and delayed home charging — to reduce peak electricity demand, store solar energy, and conveniently meet drivers’ charging needs on all days. As the team showed in earlier research, home charging can be a particularly effective component of a strategic package of charging locations; workplace charging, they have found, is not a good substitute for home charging for meeting drivers’ needs on all days.

    “Given that there’s a lot of public money going into expanding charging infrastructure,” Trancik says, “how do you incentivize the location such that this is going to be efficiently and effectively integrated into the power grid without requiring a lot of additional capacity expansion?” This research offers some guidance to policymakers on where to focus rules and incentives.

    “I think one of the fascinating things about these findings is that by being strategic you can avoid a lot of physical infrastructure that you would otherwise need,” she adds. “Your electric vehicles can displace some of the need for stationary energy storage, and you can also avoid the need to expand the capacity of power plants, by thinking about the location of chargers as a tool for managing demands — where they occur and when they occur.”

    Delayed home charging could make a surprising amount of difference, the team found. “It’s basically incentivizing people to begin charging later. This can be something that is preprogrammed into your chargers. You incentivize people to delay the onset of charging by a bit, so that not everyone is charging at the same time, and that smooths out the peak.”

    Such a program would require some advance commitment on the part of participants. “You would need to have enough people committing to this program in advance to avoid the investment in physical infrastructure,” Trancik says. “So, if you have enough people signing up, then you essentially don’t have to build those extra power plants.”

    It’s not a given that all of this would line up just right, and putting in place the right mix of incentives would be crucial. “If you want electric vehicles to act as an effective storage technology for solar energy, then the [EV] market needs to grow fast enough in order to be able to do that,” Trancik says.

    To best use public funds to help make that happen, she says, “you can incentivize charging installations, which would go through ideally a competitive process — in the private sector, you would have companies bidding for different projects, but you can incentivize installing charging at workplaces, for example, to tap into both of these benefits.” Chargers people can access when they are parked near their residences are also important, Trancik adds, but for other reasons. Home charging is one of the ways to meet charging needs while avoiding inconvenient disruptions to people’s travel activities.

    The study was supported by the European Regional Development Fund Operational Program for Competitiveness and Internationalization, the Lisbon Portugal Regional Operation Program, and the Portuguese Foundation for Science and Technology. More

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    A more sustainable way to generate phosphorus

    Phosphorus is an essential ingredient in thousands of products, including herbicides, lithium-ion batteries, and even soft drinks. Most of this phosphorus comes from an energy-intensive process that contributes significantly to global carbon emissions.

    In an effort to reduce that carbon footprint, MIT chemists have devised an alternative way to generate white phosphorus, a critical intermediate in the manufacture of those phosphorus-containing products. Their approach, which uses electricity to speed up a key chemical reaction, could reduce the carbon emissions of the process by half or even more, the researchers say.

    “White phosphorus is currently an indispensable intermediate, and our process dramatically reduces the carbon footprint of converting phosphate to white phosphorus,” says Yogesh Surendranath, an associate professor of chemistry at MIT and the senior author of the study.

    The new process reduces the carbon footprint of white phosphorus production in two ways: It reduces the temperatures required for the reaction, and it generates significantly less carbon dioxide as a waste product.

    Recent MIT graduate Jonathan “Jo” Melville PhD ’21 and MIT graduate student Andrew Licini are the lead authors of the paper, which appears today in ACS Central Science.

    Purifying phosphorus

    When phosphorus is mined out of the ground, it is in the form of phosphate, a mineral whose basic unit comprises one atom of phosphorus bound to four oxygen atoms. About 95 percent of this phosphate ore is used to make fertilizer. The remaining phosphate ore is processed separately into white phosphorus, a molecule composed of four phosphorus atoms bound to each other. White phosphorus is then fed into a variety of chemical processes that are used to manufacture many different products, such as lithium battery electrolytes and semiconductor dopants.

    Converting those mined phosphates into white phosphorus accounts for a substantial fraction of the carbon footprint of the entire phosphorus industry, Surendranath says. The most energy-intensive part of the process is breaking the bonds between phosphorus and oxygen, which are very stable.

    Using the traditional “thermal process,” those bonds are broken by heating carbon coke and phosphate rock to a temperature of 1,500 degrees Celsius. In this process, the carbon serves to strip away the oxygen atoms from phosphorus, leading to the eventual generation of CO2 as a byproduct. In addition, sustaining those temperatures requires a great deal of energy, adding to the carbon footprint of the process.

    “That process hasn’t changed substantially since its inception over a century ago. Our goal was to figure out how we could develop a process that would substantially lower the carbon footprint of this process,” Surendranath says. “The idea was to combine it with renewable electricity and drive that conversion of phosphate to white phosphorus with electrons rather than using carbon.”

    To do that, the researchers had to come up with an alternative way to weaken the strong phosphorus-oxygen bonds found in phosphates. They achieved this by controlling the environment in which the reaction occurs. The researchers found that the reaction could be promoted using a dehydrated form of phosphoric acid, which contains long chains of phosphate salts held together by bonds called phosphoryl anhydrides. These bonds help to weaken the phosphorus-oxygen bonds.

    When the researchers run an electric current through these salts, electrons break the weakened bonds, allowing the phosphorus atoms to break free and bind to each other to form white phosphorus. At the temperatures needed for this system (about 800 C), phosphorus exists as a gas, so it can bubble out of the solution and be collected in an external chamber.

    Decarbonization

    The electrode that the researchers used for this demonstration relies on carbon as a source of electrons, so the process generates some carbon dioxide as a byproduct. However, they are now working on swapping that electrode out for one that would use phosphate itself as the electron source, which would further reduce the carbon footprint by cleanly separating phosphate into phosphorus and oxygen.

    With the process reported in this paper, the researchers have reduced the overall carbon footprint for generating white phosphorus by about 50 percent. With future modifications, they hope to bring the carbon emissions down to nearly zero, in part by using renewable energy such as solar or wind power to drive the electric current required.

    If the researchers succeed in scaling up their process and making it widely available, it could allow industrial users to generate white phosphorus on site instead of having it shipped from the few places in the world where it is currently manufactured. That would cut down on the risks of transporting white phosphorus, which is an explosive material.

    “We’re excited about the prospect of doing on-site generation of this intermediate, so you don’t have to do the transportation and distribution,” Surendranath says. “If you could decentralize this production, the end user could make it on site and use it in an integrated fashion.”

    In order to do this study, the researchers had to develop new tools for controlling the electrolytes (such as salts and acids) present in the environment, and for measuring how those electrolytes affect the reaction. Now, they plan to use the same approach to try to develop lower-carbon processes for isolating other industrially important elements, such as silicon and iron.

    “This work falls within our broader interests in decarbonizing these legacy industrial processes that have a huge carbon footprint,” Surendranath says. “The basic science that leads us there is understanding how you can tailor the electrolytes to foster these processes.”

    The research was funded by the UMRP Partnership for Progress on Sustainable Development in Africa, a fellowship from the MIT Tata Center for Technology and Design, and a National Defense Science and Engineering Graduate Fellowship. More

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    Using combustion to make better batteries

    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

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    Mining for the clean energy transition

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

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

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

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

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

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

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

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

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

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

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

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

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

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    Reversing the charge

    Owners of electric vehicles (EVs) are accustomed to plugging into charging stations at home and at work and filling up their batteries with electricity from the power grid. But someday soon, when these drivers plug in, their cars will also have the capacity to reverse the flow and send electrons back to the grid. As the number of EVs climbs, the fleet’s batteries could serve as a cost-effective, large-scale energy source, with potentially dramatic impacts on the energy transition, according to a new paper published by an MIT team in the journal Energy Advances.

    “At scale, vehicle-to-grid (V2G) can boost renewable energy growth, displacing the need for stationary energy storage and decreasing reliance on firm [always-on] generators, such as natural gas, that are traditionally used to balance wind and solar intermittency,” says Jim Owens, lead author and a doctoral student in the MIT Department of Chemical Engineering. Additional authors include Emre Gençer, a principal research scientist at the MIT Energy Initiative (MITEI), and Ian Miller, a research specialist for MITEI at the time of the study.

    The group’s work is the first comprehensive, systems-based analysis of future power systems, drawing on a novel mix of computational models integrating such factors as carbon emission goals, variable renewable energy (VRE) generation, and costs of building energy storage, production, and transmission infrastructure.

    “We explored not just how EVs could provide service back to the grid — thinking of these vehicles almost like energy storage on wheels — but also the value of V2G applications to the entire energy system and if EVs could reduce the cost of decarbonizing the power system,” says Gençer. “The results were surprising; I personally didn’t believe we’d have so much potential here.”

    Displacing new infrastructure

    As the United States and other nations pursue stringent goals to limit carbon emissions, electrification of transportation has taken off, with the rate of EV adoption rapidly accelerating. (Some projections show EVs supplanting internal combustion vehicles over the next 30 years.) With the rise of emission-free driving, though, there will be increased demand for energy. “The challenge is ensuring both that there’s enough electricity to charge the vehicles and that this electricity is coming from renewable sources,” says Gençer.

    But solar and wind energy is intermittent. Without adequate backup for these sources, such as stationary energy storage facilities using lithium-ion batteries, for instance, or large-scale, natural gas- or hydrogen-fueled power plants, achieving clean energy goals will prove elusive. More vexing, costs for building the necessary new energy infrastructure runs to the hundreds of billions.

    This is precisely where V2G can play a critical, and welcome, role, the researchers reported. In their case study of a theoretical New England power system meeting strict carbon constraints, for instance, the team found that participation from just 13.9 percent of the region’s 8 million light-duty (passenger) EVs displaced 14.7 gigawatts of stationary energy storage. This added up to $700 million in savings — the anticipated costs of building new storage capacity.

    Their paper also described the role EV batteries could play at times of peak demand, such as hot summer days. “V2G technology has the ability to inject electricity back into the system to cover these episodes, so we don’t need to install or invest in additional natural gas turbines,” says Owens. “The way that EVs and V2G can influence the future of our power systems is one of the most exciting and novel aspects of our study.”

    Modeling power

    To investigate the impacts of V2G on their hypothetical New England power system, the researchers integrated their EV travel and V2G service models with two of MITEI’s existing modeling tools: the Sustainable Energy System Analysis Modeling Environment (SESAME) to project vehicle fleet and electricity demand growth, and GenX, which models the investment and operation costs of electricity generation, storage, and transmission systems. They incorporated such inputs as different EV participation rates, costs of generation for conventional and renewable power suppliers, charging infrastructure upgrades, travel demand for vehicles, changes in electricity demand, and EV battery costs.

    Their analysis found benefits from V2G applications in power systems (in terms of displacing energy storage and firm generation) at all levels of carbon emission restrictions, including one with no emissions caps at all. However, their models suggest that V2G delivers the greatest value to the power system when carbon constraints are most aggressive — at 10 grams of carbon dioxide per kilowatt hour load. Total system savings from V2G ranged from $183 million to $1,326 million, reflecting EV participation rates between 5 percent and 80 percent.

    “Our study has begun to uncover the inherent value V2G has for a future power system, demonstrating that there is a lot of money we can save that would otherwise be spent on storage and firm generation,” says Owens.

    Harnessing V2G

    For scientists seeking ways to decarbonize the economy, the vision of millions of EVs parked in garages or in office spaces and plugged into the grid for 90 percent of their operating lives proves an irresistible provocation. “There is all this storage sitting right there, a huge available capacity that will only grow, and it is wasted unless we take full advantage of it,” says Gençer.

    This is not a distant prospect. Startup companies are currently testing software that would allow two-way communication between EVs and grid operators or other entities. With the right algorithms, EVs would charge from and dispatch energy to the grid according to profiles tailored to each car owner’s needs, never depleting the battery and endangering a commute.

    “We don’t assume all vehicles will be available to send energy back to the grid at the same time, at 6 p.m. for instance, when most commuters return home in the early evening,” says Gençer. He believes that the vastly varied schedules of EV drivers will make enough battery power available to cover spikes in electricity use over an average 24-hour period. And there are other potential sources of battery power down the road, such as electric school buses that are employed only for short stints during the day and then sit idle.

    The MIT team acknowledges the challenges of V2G consumer buy-in. While EV owners relish a clean, green drive, they may not be as enthusiastic handing over access to their car’s battery to a utility or an aggregator working with power system operators. Policies and incentives would help.

    “Since you’re providing a service to the grid, much as solar panel users do, you could be paid for your participation, and paid at a premium when electricity prices are very high,” says Gençer.

    “People may not be willing to participate ’round the clock, but if we have blackout scenarios like in Texas last year, or hot-day congestion on transmission lines, maybe we can turn on these vehicles for 24 to 48 hours, sending energy back to the system,” adds Owens. “If there’s a power outage and people wave a bunch of money at you, you might be willing to talk.”

    “Basically, I think this comes back to all of us being in this together, right?” says Gençer. “As you contribute to society by giving this service to the grid, you will get the full benefit of reducing system costs, and also help to decarbonize the system faster and to a greater extent.”

    Actionable insights

    Owens, who is building his dissertation on V2G research, is now investigating the potential impact of heavy-duty electric vehicles in decarbonizing the power system. “The last-mile delivery trucks of companies like Amazon and FedEx are likely to be the earliest adopters of EVs,” Owen says. “They are appealing because they have regularly scheduled routes during the day and go back to the depot at night, which makes them very useful for providing electricity and balancing services in the power system.”

    Owens is committed to “providing insights that are actionable by system planners, operators, and to a certain extent, investors,” he says. His work might come into play in determining what kind of charging infrastructure should be built, and where.

    “Our analysis is really timely because the EV market has not yet been developed,” says Gençer. “This means we can share our insights with vehicle manufacturers and system operators — potentially influencing them to invest in V2G technologies, avoiding the costs of building utility-scale storage, and enabling the transition to a cleaner future. It’s a huge win, within our grasp.”

    The research for this study was funded by MITEI’s Future Energy Systems Center. More

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    Engineers solve a mystery on the path to smaller, lighter batteries

    A discovery by MIT researchers could finally unlock the door to the design of a new kind of rechargeable lithium battery that is more lightweight, compact, and safe than current versions, and that has been pursued by labs around the world for years.

    The key to this potential leap in battery technology is replacing the liquid electrolyte that sits between the positive and negative electrodes with a much thinner, lighter layer of solid ceramic material, and replacing one of the electrodes with solid lithium metal. This would greatly reduce the overall size and weight of the battery and remove the safety risk associated with liquid electrolytes, which are flammable. But that quest has been beset with one big problem: dendrites.

    Dendrites, whose name comes from the Latin for branches, are projections of metal that can build up on the lithium surface and penetrate into the solid electrolyte, eventually crossing from one electrode to the other and shorting out the battery cell. Researchers haven’t been able to agree on what gives rise to these metal filaments, nor has there been much progress on how to prevent them and thus make lightweight solid-state batteries a practical option.

    The new research, being published today in the journal Joule in a paper by MIT Professor Yet-Ming Chiang, graduate student Cole Fincher, and five others at MIT and Brown University, seems to resolve the question of what causes dendrite formation. It also shows how dendrites can be prevented from crossing through the electrolyte.

    Chiang says in the group’s earlier work, they made a “surprising and unexpected” finding, which was that the hard, solid electrolyte material used for a solid-state battery can be penetrated by lithium, which is a very soft metal, during the process of charging and discharging the battery, as ions of lithium move between the two sides.

    This shuttling back and forth of ions causes the volume of the electrodes to change. That inevitably causes stresses in the solid electrolyte, which has to remain fully in contact with both of the electrodes that it is sandwiched between. “To deposit this metal, there has to be an expansion of the volume because you’re adding new mass,” Chiang says. “So, there’s an increase in volume on the side of the cell where the lithium is being deposited. And if there are even microscopic flaws present, this will generate a pressure on those flaws that can cause cracking.”

    Those stresses, the team has now shown, cause the cracks that allow dendrites to form. The solution to the problem turns out to be more stress, applied in just the right direction and with the right amount of force.

    While previously, some researchers thought that dendrites formed by a purely electrochemical process, rather than a mechanical one, the team’s experiments demonstrate that it is mechanical stresses that cause the problem.

    The process of dendrite formation normally takes place deep within the opaque materials of the battery cell and cannot be observed directly, so Fincher developed a way of making thin cells using a transparent electrolyte, allowing the whole process to be directly seen and recorded. “You can see what happens when you put a compression on the system, and you can see whether or not the dendrites behave in a way that’s commensurate with a corrosion process or a fracture process,” he says.

    The team demonstrated that they could directly manipulate the growth of dendrites simply by applying and releasing pressure, causing the dendrites to zig and zag in perfect alignment with the direction of the force.

    Applying mechanical stresses to the solid electrolyte doesn’t eliminate the formation of dendrites, but it does control the direction of their growth. This means they can be directed to remain parallel to the two electrodes and prevented from ever crossing to the other side, and thus rendered harmless.

    In their tests, the researchers used pressure induced by bending the material, which was formed into a beam with a weight at one end. But they say that in practice, there could be many different ways of producing the needed stress. For example, the electrolyte could be made with two layers of material that have different amounts of thermal expansion, so that there is an inherent bending of the material, as is done in some thermostats.

    Another approach would be to “dope” the material with atoms that would become embedded in it, distorting it and leaving it in a permanently stressed state. This is the same method used to produce the super-hard glass used in the screens of smart phones and tablets, Chiang explains. And the amount of pressure needed is not extreme: The experiments showed that pressures of 150 to 200 megapascals were sufficient to stop the dendrites from crossing the electrolyte.

    The required pressure is “commensurate with stresses that are commonly induced in commercial film growth processes and many other manufacturing processes,” so should not be difficult to implement in practice, Fincher adds.

    In fact, a different kind of stress, called stack pressure, is often applied to battery cells, by essentially squishing the material in the direction perpendicular to the battery’s plates — somewhat like compressing a sandwich by putting a weight on top of it. It was thought that this might help prevent the layers from separating. But the experiments have now demonstrated that pressure in that direction actually exacerbates dendrite formation. “We showed that this type of stack pressure actually accelerates dendrite-induced failure,” Fincher says.

    What is needed instead is pressure along the plane of the plates, as if the sandwich were being squeezed from the sides. “What we have shown in this work is that when you apply a compressive force you can force the dendrites to travel in the direction of the compression,” Fincher says, and if that direction is along the plane of the plates, the dendrites “will never get to the other side.”

    That could finally make it practical to produce batteries using solid electrolyte and metallic lithium electrodes. Not only would these pack more energy into a given volume and weight, but they would eliminate the need for liquid electrolytes, which are flammable materials.

    Having demonstrated the basic principles involved, the team’s next step will be to try to apply these to the creation of a functional prototype battery, Chiang says, and then to figure out exactly what manufacturing processes would be needed to produce such batteries in quantity. Though they have filed for a patent, the researchers don’t plan to commercialize the system themselves, he says, as there are already companies working on the development of solid-state batteries. “I would say this is an understanding of failure modes in solid-state batteries that we believe the industry needs to be aware of and try to use in designing better products,” he says.

    The research team included Christos Athanasiou and Brian Sheldon at Brown University, and Colin Gilgenbach, Michael Wang, and W. Craig Carter at MIT. The work was supported by the U.S. National Science Foundation, the U.S. Department of Defense, the U.S. Defense Advanced Research Projects Agency, and the U.S. Department of Energy. More

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    On batteries, teaching, and world peace

    Over his long career as an electrochemist and professor, Donald Sadoway has earned an impressive variety of honors, from being named one of Time magazine’s 100 most influential people in 2012 to appearing on “The Colbert Report,” where he talked about “renewable energy and world peace,” according to Comedy Central.

    What does he personally consider to be his top achievements?

    “That’s easy,” he says immediately. “For teaching, it’s 3.091,” the MIT course on solid-state chemistry he led for some 18 years. An MIT core requirement, 3.091 is also one of the largest classes at the Institute. In 2003 it was the largest, with 630 students. Sadoway, who retires this year after 45 years in the Department of Materials Science and Engineering, estimates that over the years he’s taught the course to some 10,000 undergraduates.

    A passion for teaching

    Along the way he turned the class into an MIT favorite, complete with music, art, and literature. “I brought in all that enrichment because I knew that 95 percent of the students in that room weren’t going to major in anything chemical and this might be the last class they’d take in the subject. But it’s a requirement. So they’re 18 years old, they’re very smart, and many of them are very bored. You have to find a hook [to reach them]. And I did.”

    In 1995, Sadoway was named a Margaret MacVicar Faculty Fellow, an honor that recognizes outstanding classroom teaching at the Institute. Among the communications in support of his nomination:

    “His contributions are enormous and the class is in rapt attention from beginning to end. His lectures are highly articulate yet animated and he has uncommon grace and style. I was awed by his ability to introduce playful and creative elements into a core lecture…”

    Bill Gates would agree. In the early 2000s Sadoway’s lectures were shared with the world through OpenCourseWare, the web-based publication of MIT course materials. Gates was so inspired by the lectures that he asked to meet with Sadoway to learn more about his research. (Sadoway initially ignored Gates’ email because he thought his account had been hacked by MIT pranksters.)

    Research breakthroughs

    Teaching is not Sadoway’s only passion. He’s also proud of his accomplishments in electrochemistry. The discipline that involves electron transfer reactions is key to everything from batteries to the primary extraction of metals like aluminum and magnesium. “It’s quite wide-ranging,” says the John F. Elliott Professor Emeritus of Materials Chemistry.

    Sadoway’s contributions include two battery breakthroughs. First came the liquid metal battery, which could enable the large-scale storage of renewable energy. “That represents a huge step forward in the transition to green energy,” said António Campinos, president of the European Patent Office, earlier this year when Sadoway won the 2022 European Inventor Award for the invention in the category for Non-European Patent Office Countries.

    On “The Colbert Report,” Sadoway alluded to that work when he told Stephen Colbert that electrochemistry is the key to world peace. Why? Because it could lead to a battery capable of storing energy from the sun when the sun doesn’t shine and otherwise make renewables an important part of the clean energy mix. And that in turn could “plummet the price of petroleum and depose dictators all over the world without one shot being fired,” he recently recalled.

    The liquid metal battery is the focus of Ambri, one of six companies based on Sadoway’s inventions. Bill Gates was the first funder of the company, which formed in 2010 and aims to install its first battery soon. That battery will store energy from a reported 500 megawatts of on-site renewable generation, the same output as a natural gas power plant.

    Then, in August of this year, Sadoway and colleagues published a paper in Nature about “one of the first new battery chemistries in 30 years,” Sadoway says. “I wanted to invent something that was better, much better,” than the expensive lithium-ion batteries used in, for example, today’s electric cars.

    That battery is the focus of Avanti, one of three Sadoway companies formed just last year. The other two are Pure Lithium, to commercialize his inventions related to that element, and Sadoway Labs. The latter, a nonprofit, is essentially “a space to try radical innovations. We’re gonna start working on wild ideas.”

    Another focus of Sadoway’s research: green steel. Steelmaking produces huge amounts of greenhouse gases. Enter Boston Metal, another Sadoway company. This one is developing a new approach to producing steel based on research begun some 25 years ago. Unlike the current technology for producing steel, the Boston Metal approach — molten oxide electrolysis — does not use the element at the root of steel’s problems: carbon. The principal byproduct of the new system? Oxygen.

    In 2012, Sadoway gave a TED talk to 2,000 people on the liquid metal battery. He believes that that talk, which has now been seen by almost 2.5 million people, led to the wider publicity of his work — and science overall — on “The Colbert Report” and elsewhere. “The moral here is that if you step out of your comfort zone, you might be surprised at what can happen,” he concludes.

    Colleagues’ reflections

    “I met Don in 2006 when I was working for the iron and steel industry in Europe on ways to reduce greenhouse gas emissions from the production of those materials,” says Antoine Allanore, professor of metallurgy, Department of Materials Science and Engineering. “He was the same Don Sadoway that you see in recordings of his lectures: very elegant, very charismatic, and passionate about the technical solutions and underlying science of the process we were all investigating; electrolysis. A few years later, when I decided to pursue an academic career, I contacted Don and became a postdoctoral associate in his lab. That ultimately led to my becoming an MIT professor. People don’t believe me, but before I came to MIT the only thing I knew about the Institute was that Noam Chomsky was there … and Don Sadoway. And I felt, that’s a great place to be. And I stayed because I saw the exceptional things that can be accomplished at MIT and Don is the perfect example of that.”

    “I had the joy of meeting Don when I first arrived on the MIT campus in 1994,” recalls Felice Frankel, research scientist in the MIT departments of Chemical Engineering and Mechanical Engineering. “I didn’t have to talk him into the idea that researchers needed to take their images and graphics more seriously.  He got it — that it wasn’t just about pretty pictures. He was an important part of our five-year National Science Foundation project — Picturing to Learn — to bring that concept into the classroom. How lucky that was for me!”

    “Don has been a friend and mentor since we met in 1995 when I was an MIT senior,” says Luis Ortiz, co-founder and chief executive officer, Avanti Battery Co. “One story that is emblematic of Don’s insistence on excellence is from when he and I met with Bill Gates about the challenges in addressing climate change and how batteries could be the linchpin in solving them. I suggested that we create our presentation in PowerPoint [Microsoft software]. Don balked. He insisted that we present using Keynote on his MacBook Air, because ‘it looks so much better.’ I was incredulous that he wanted to walk into that venue exclusively using Apple products. Of course, he won the argument, but not without my admonition that there had better not be even a blip of an issue. In the meeting room, Microsoft’s former chief technology officer asked Don if he needed anything to hook up to the screen, ‘we have all those dongles.’ Don declined, but gave me that knowing look and whispered, ‘You see, they know, too.’ I ate my crow and we had a great long conversation without any issues.”

    “I remember when I first started working with Don on the liquid metal battery project at MIT, after I had chosen it as the topic for my master’s of engineering thesis,” adds David Bradwell, co-founder and chief technology officer, Ambri. “I was a wide-eyed graduate student, sitting in his office, amongst his art deco decorations, unique furniture, and historical and stylistic infographics, and from our first meeting, I could see Don’s passion for coming up with new and creative, yet practical scientific ideas, and for working on hard problems, in service of society. Don’s approaches always appear to be unconventional — wanting to stand out in a crowd, take the path less trodden, both based on his ideas, and his sense of style. It’s been an amazing journey working with him over the past decade-and-a-half, and I remain excited to see what other new, unconventional ideas, he can bring to this world.” More