Many experts refer to hydrogen as “the fuel of the future.” It is expected to help decarbonize the global economy in two main ways: burning it or feeding it into a fuel cell produces storable energy with no carbon emissions, just water. And it can be used in place of fossil fuels or as a chemical feedstock in hard-to-decarbonize industrial processes such as steel and cement production.

But for hydrogen to realize its potential, two challenges must be overcome. Researchers worldwide are now working to address the first: finding a method of producing pure hydrogen that’s both cheap and low in carbon emissions.

Just as critical is finding a good means of transporting and storing hydrogen. A team led by researchers at the MIT Energy Initiative (MITEI) has been tackling that less-discussed but important challenge. The location where the pure hydrogen is produced is likely to be far away from where it will be used, so moving it will be critical — and difficult.

The problem stems from two characteristics of hydrogen: It’s the lightest gas there is, and it has low energy density per volume. Therefore, delivering a given amount of energy requires a large volume of hydrogen and a container that’s sealed so tightly that the hydrogen molecules can’t escape. Suffice it to say, moving a liquid fuel such as gasoline is easier. And without a good means of storing and transporting hydrogen, it can’t fulfill its promise as the world’s clean fuel of the future.

In 2024, with funding provided by ExxonMobil Technology and Engineering Co. through MITEI, a team of MITEI researchers and their Exxon colleagues began examining various approaches to transporting hydrogen. The researchers have now concluded that there’s no single answer; the cost and carbon emissions from a given transportation method will vary from one location to another. Therefore, instead of presenting a table showing the “best” outcome, the team created a tool that enables users to understand the various options and choose the best option for their particular use case. 

The researchers present their study and the tool they developed in a new paper published in the journal Fuel.    

The study was led by former MITEI postdocs Gasim Ibrahim, now an R&D engineer/scientist at Honeywell, and Guiyan Zang, former MITEI group lead who is now an associate professor at Washington State University. Additional MIT co-authors include former postdocs Bosong Lin, Jacqueline Garrido, Woojae Shin, and Haoxiang Lai.

The hydrogen challenge and hydrogen “carriers” that can help

The team’s starting assumption was that for hydrogen to become a viable fuel for the world, it would need to be transported over long distances — specifically, overseas, across continents, or across large water bodies. Given the properties of hydrogen gas, it would be best to convert it to some liquid form before shipping.

There are known ways to do that, but what would be best for shipping? How much would various methods cost, and how much would they add to the carbon intensity of the delivered hydrogen?

“There hasn’t been a lot of attention paid to addressing those questions,” Ibrahim says. While some studies have been done, their conclusions are inconsistent and many uncertainties remain, both because the cost and carbon emissions will differ from place to place and because there’s not a lot of data to inform how the large-scale transportation of hydrogen will work.

“So we decided the best thing to do was to develop an adaptive tool that would enable users to perform their own assessments — a tool that could be updated very easily,” Ibrahim explains. “And we would make it open source, so anyone can see and update the numbers that we used in formulating and testing it. As the industry develops, and as scale becomes more a factor, the assumptions made in [our initial] assessments of the economics and the carbon intensity [of different shipping methods] will need to be updated.”

To focus on the transportation and storage issues, their model — called the Hydrogen Carrier Analysis Tool, or HyCAT — doesn’t consider how the starting hydrogen is produced, or how the hydrogen is used after it’s delivered. HyCAT focuses on determining the costs and carbon emissions incurred as the hydrogen is transported and delivered. In addition, while a full life-cycle assessment would include all environmental impacts, HyCAT focuses on emissions of greenhouse gases (GHGs).

The tool is easy to use, says Ibrahim. Built into it is a user interface with drop-down menus for inputting assumptions, and results from an analysis are presented in simple bar charts that include links to tables presenting the details.

Ibrahim clarifies that, while HyCAT has a well-defined boundary — “incoming hydrogen to outgoing hydrogen” — in an analysis of a specific situation, the user will input various factors about the local situation, including the carbon intensity and cost associated with production of the incoming hydrogen. “So that will inform the final values that come out of a HyCAT analysis,” says Ibrahim, and in part explains why the results vary from place to place.

Based on the user’s assumptions, HyCAT calculates the cost and GHG emissions at five steps in the “supply chain”:

• converting the hydrogen into liquid form at the “export” terminal;
• storing the hydrogen-rich liquid;
• shipping it when an empty tanker becomes available;
• storing it at the “import” terminal; and
• releasing the hydrogen as a gas suitable for burning or being fed into a pipeline for distribution.  

Options for liquifying hydrogen gas

The main decision in analyzing the cost and emissions of a proposed hydrogen transport plan is how to convert the gaseous hydrogen to a liquid, and then how to recover the hydrogen gas at the end.

One approach is to simply change the gaseous hydrogen into an easily transportable liquid. But turning hydrogen gas into a liquid requires making it very, very cold. Indeed, notes Ibrahim, “you would need to consume about a third of the energy content of the hydrogen to make the gaseous hydrogen cold enough to liquify.” A further problem arises as the liquified hydrogen is being stored and moved. Unless the vessel containing the liquid hydrogen is properly insulated, the liquid hydrogen can re-gasify and escape. The upside of hydrogen liquefaction is that no chemical reactions are required.

Other options involve using a hydrogen “carrier.” Some liquid chemical compounds will absorb hydrogen atoms under certain conditions, and under other conditions will release them. Therefore, one approach to solving the hydrogen transportation problem is to make a carrier compound absorb the hydrogen where it’s made and then release it when it reaches its destination. This approach therefore involves two chemical reactions — one to bind the hydrogen to the carrier and the other to release it.  

In their demonstration runs, the researchers looked at the hydrogen carriers involving three potential compounds, each of which has known advantages and disadvantages.

One of those carriers is produced by adding hydrogen to toluene. That chemical reaction hasn’t been studied a lot, but there’s one known drawback: the source of toluene is typically the oil and gas industry, so the toluene itself has a relatively high carbon intensity when it picks up the hydrogen. Moreover, over time some of the toluene is lost, so more toluene must be added.
    
The researchers also looked at “synthetic methane,” which is made by reacting hydrogen with carbon dioxide. That reaction has been known for some time. Ibrahim notes that making synthetic methane actually consumes carbon dioxide, often captured from the atmosphere. On the negative side, however, one of the products of the reaction is water, so some of the hydrogen is lost each time the reaction occurs.

The final option they analyzed is ammonia, which forms when hydrogen reacts with nitrogen from the air. That reaction is very well-studied and is used commercially. “We’ve been producing ammonia for a long time,” says Ibrahim. And the infrastructure for transporting and storing it is well established. While Ibrahim refers to ammonia as the “most promising option,” the reaction needed to release the hydrogen has not received much attention.

Varying conclusions and future plans

Based on their sample runs, the researchers observed that the best path to follow will vary from place to place and from situation to situation. “As we developed the tool, we saw that the ‘best’ carrier was very specific to the supply chain at hand,” says Ibrahim. “It’s a function of how far you’re trying to ship your hydrogen, energy and shipping costs at your exporting and importing countries, the capital cost of building the needed facilities at both ends, and more.”

Ibrahim and his team are now planning a follow-up study in which they use HyCAT to analyze specific supply chains under certain conditions. They’ll then select assumptions that are highly uncertain and look at the range of possible values for those assumptions. “Then we’ll be able to say, ‘under these conditions, this carrier is better than that one,’ or ‘this carrier is better at cost, but worse at carbon intensity,’” says Ibrahim.

For now, the main conclusion of the study, says Ibrahim, is that “there’s no conclusion.” He warns decision-makers not to assume that anything they see in the literature can easily be generalized or extrapolated to their specific conditions. Instead, decision-makers should use HyCAT to explore the options available to them. Guided by their results and the objectives and values of their company, they will be able to optimize their supply chains and make clean-burning hydrogen a reality.

Professor Jesse Thaler has been named director of the MIT Laboratory for Nuclear Science (LNS), effective Aug. 1. He succeeds Professor Bolek Wyslouch, who directed LNS for the past decade. Thaler is a theoretical particle physicist who combines techniques from quantum field theory and machine learning to address outstanding questions in fundamental physics. 

“In his research, Jesse has done pioneering work on particle jets at the Large Hadron Collider and is a leader in combining AI and machine learning with fundamental particle physics,” says Nergis Mavalvala, dean of the MIT School of Science and the Curtis and Kathleen Marble Professor of Astrophysics. “The collaborative nature of his research programs will serve the Laboratory for Nuclear Science as science enters a new era of AI-driven discovery.”

Thaler is the William and Emma Rogers Professor of Physics in the MIT Center for Theoretical Physics — a Leinweber Institute (CTP-LI). Since 2020, he has served as inaugural director of the National Science Foundation (NSF) AI Institute for Artificial Intelligence and Fundamental Interactions, or IAIFI, which was recently renewed for another five years. Mike Williams, professor of physics, will succeed Thaler as IAIFI director. LNS is also poised to pursue new research projects through the Department of Energy’s Genesis Mission, which has a focus on AI-enabled scientific discovery.

“In my own field of particle physics, researchers are developing cutting-edge AI algorithms to handle the data deluge from collider experiments and to perform heroic theoretical calculations. This work has direct implications for discovering new physics, but the algorithms themselves turn out to be valuable well beyond our field,” says Thaler. “I’m excited to bring LNS into the next wave of discoveries supported by AI-driven capabilities.”

At IAIFI, Thaler has championed education and research activities at the intersection of physics and AI. With the MIT Institute for Data, Systems, and Society, IAIFI leadership created a doctoral program in physics, statistics, and data science. IAIFI also created dedicated postdoctoral fellowships to give early-career researchers the freedom to pursue interdisciplinary work. 

“Giving young scientists space to build connections across domains, universities, and career stages has been transformative within IAIFI,” says Thaler, who hopes to bring this type of framework to LNS. Established in 1946 to support nuclear and particle physics, LNS now encompasses research spanning cosmology, gravity, field theory, and quantum information science.

As head of LNS, Thaler will also oversee his home center of CTP-LI, which last year received a donation from the Leinweber Foundation to establish a network of theoretical physics research institutes. According to the Science Philanthropy Alliance, a nonprofit organization that promotes philanthropy for science, this constitutes the largest philanthropic commitment ever for this field.

Thaler received his PhD in physics from Harvard University in 2006, and his BS in math/physics from Brown University in 2002. From 2006 to 2009, he was a fellow at the Miller Institute for Basic Research in Science at the University of California at Berkeley. He joined the MIT faculty in 2010.

As advanced medical technology gets closer to hitting consumer markets, the need for guardrails on protected usage should increase. What might begin as a neural implant to aid in communication could become a device used to police one’s innermost thoughts.

Intrigued by the far-reaching benefits and risks of neural implants, Rachel Sava, a PhD candidate in the Harvard-MIT Program in Health Sciences and Technology, explores how a life-changing medical device can become a tool for surveillance by corporations and government entities in her winning submission, “Superintelligence, Superintimate,” for the fourth annual Envisioning the Future of Computing Prize. 

Sava’s concept was inspired by an internship at IBM, where she worked on a project with the PACE Center in London. “A mentor on the project was Kevin Brown, who had himself designed one of the earliest brain decoders — an EEG-based system he built for a colleague who had suffered a stroke that left him with locked-in syndrome,” she says. “It was this patient population for whom the body has become an unreliable vehicle for the mind that motivated my writing about neuroprostheses some six years later.”

Sava explains that research and applications right now are at a “watershed moment in neurotechnology.” Using examples like companies taking advantage of neural implants to monitor mental productivity, or authorities policing a population for “thought crimes,” Sava said that as this tech hits consumer markets, there is a genuine fear that what starts as a revolutionary medical device could transition into more dystopian usages.

Presented by the Social and Ethical Responsibilities of Computing (SERC), a cross-campus initiative of the MIT Schwarzman College of Computing, in collaboration with the School of Humanities, Arts, and Social Sciences and with support from MAC3 Philanthropies, the competition invited MIT students to identify, in 3,000 words or fewer, which sector stands to gain the highest net positive impact from artificial intelligence. Students were encouraged to explore realistic technological deployments while considering potential risks and ethical concerns. All submissions were eligible for cash awards with the grand prize set at $10,000.

During a live awards ceremony hosted by Caspar Hare, former associate dean of SERC and professor of philosophy, who founded the prize in 2023, three finalists each gave a 20-minute presentation on their concepts and took questions from a panel of judges and audience members.

“SERC and the donors who make this prize possible year after year are asking us, the next generation of scientists: ‘what world do you want to see?’ I think it’s worth taking the time to ask yourself the same,” Sava said. “And if, as it did for me, the sentiment grows bright enough to motivate further action — then it’s worth giving yourself permission to explore it as deeply as you do your other academic work.”

Each year, the Envisioning the Future of Computing Prize asks students to look beyond technological advancement and consider the societal benefits and costs of their work from the outset. From its inception, the competition has consistently attracted undergraduate and graduate students from across a wide range of disciplines.

“This year’s submissions were amazing and included essays on brain-computer interfaces, AI and religion, AI for scientific discovery, finding efficiencies in the power grid, and many more,” says Brian Hedden, co-associate dean of SERC and a professor of philosophy, who holds an MIT Schwarzman College of Computing shared position with the Department of Electrical Engineering and Computer Science. “They showed the breadth and depth of thinking going on at MIT on the social and ethics impacts of technologies.”

Nikos Trichakis, co-associate dean of SERC and the J.C. Penney Professor of Management, adds “what is most striking about these essays is the breadth of imagination they display: the students move fluidly across medicine, neurotechnology, law, ethics, and public institutions, while keeping human agency at the center. Their work is creative, rigorous, and deeply thoughtful, showing a remarkable ability to envision not only what AI can do, but what it should do.”

In addition to awarding Sava the $10,000 grand prize, the judges recognized two runners-up with $5,000 each: Cordiana Cozier, a PhD candidate in the Department of Chemistry, for her paper on the use of AI as a cognitive buffer for public defenders; and Strahinja Janjusevic, a graduate student in the Technology and Policy Program in the Institute for Data, Systems, and Society, for his submission on agency and ownership in the field of neural-controlled prosthetics. The judges also named four honorable mentions, each of whom received a $500 cash prize.

Next generation batteries that use new electrolyte materials could achieve far higher energy density than today’s lithium-ion batteries, without many of the safety concerns. But advanced batteries, such as those that use solid or almost-solid electrolytes, have been plagued by the formation of tiny spikes of lithium metal called dendrites that cause the batteries to lose efficiency and fail.

Exactly how those dendrites form is still up for debate. While the interface between the battery’s electrolyte and electrodes has been the focus of most research, another culprit is the boundary where two grains of electrolyte in a solid material meet. Researchers know these boundaries can seed dendrites within electrolytes, although the effects have been difficult to study.

Now researchers at MIT and the Technical University of Munich have uncovered why such boundaries can lead to dendrites: Hidden electrical imbalances across the boundaries affect how the electrolyte conducts electrical charges, which influences how the ions and electrons move through the material during battery operation. In a paper published today in Nature Nanotechnology, the researchers characterized the electrical and chemical behavior of the boundaries and showed that adjusting how the electrolyte is processed enhances the movement of ions while reducing electron leakage. This adjustment can increase critical current density by more than 300 percent, which could enable solid-state batteries that charge faster and last longer.

“Grain boundaries are like the weather: Everyone talks about it, but nobody does anything about it,” says senior author Harry Tuller, a professor in MIT’s Department of Materials Science and Engineering. “In this paper, we’ve decided to do something about grain boundaries, and by doing something we’ve shown improved performance and demonstrated the importance of grain boundaries more broadly.”

Joining Tuller on the paper are first author Hyunwon Chu PhD ’25; former MIT professor Jennifer Rupp, the Electrochemical Material Professor at the Technical University of Munich (TUM), who led the study; TUM researchers Waldemar Kaiser, Lukas Wolz, Fran Kurnia, Kun Joong Kim, David Egger, and Johanna Eichhorn; Thomas Defferriere PhD ’22; Willis O’Leary PhD ’24; and University of Antwerp researchers Proloy Nandi, Johan Verbeeck, Sara Bals, and Thomas Altantzis.

Investigating grain boundaries

Rupp’s research group, which moved from MIT to TUM during this research, has spent years studying the behavior of next-generation electrolyte materials. Electrolytes in solid-state batteries are made of many tiny crystals of material packed together.

“What we call a grain, like a grain of salt, is actually a single crystal, but it might only be on the order of 1 micron in size,” explains Tuller. “Under high temperature processes, the best materials essentially consolidate to be void or pore-free and can be nearly 100 percent dense, but each of those crystallites is separated from its neighbor by a grain boundary.”

Solid-state battery researchers have increasingly focused on grain boundaries as the source of the lithium metal dendrites that cause them to short circuit. It’s been suspected that grain boundaries have different chemical and electrical properties from the grains, which interact with the ions and electrons shuttling between electrodes during battery charging and discharging. However, the exact mechanisms by which the boundaries slowed the ions down, leaked electrons, and led to dendrites was unknown.

“Grain boundaries are like defects,” Tuller says. “The boundaries have a higher level of defects than in the grains themselves, and generally that means as carriers of charge approach the boundary, whether electrons or ions, there’s some kind of blockage to overcome.”

To better understand that interference, the researchers developed a model to explain how local electrical imbalances at grain boundaries change the movement of lithium ions and electronic charge carriers. They tested the model in a common solid electrolyte material called lithium lanthanum zirconate, or LLZO, using techniques including electron microscopy, machine learning modeling, and electrochemical impedance spectroscopy, which measures how easily a charge moves through a material.

They found the cores of the boundaries carry a local electrical charge, building up local electric fields that lead to enhanced ionic resistance while causing a build-up of electrons in the boundary region, where they can reduce lithium ions, leading to lithium metal dendrite formation.

“For the last 30 years, the world has been dominated by lithium-ion batteries, but there is a growing recognition that other battery types are needed for batteries used in a variety of uses,” Rupp explains. “This work gives us the fundamental understanding of the space charge interface at the grain boundary. If understood properly, we can come up with engineering concepts to increase cycle life, transference of ions over electrons at these interfaces, and ultimately a better battery.”

Better battery materials

The researchers used their observations to adjust the material processing conditions of the LLZO electrolyte material and minimize the negative charges at the boundaries, finding they could ease the movement of lithium ions and reduce the leakage of electrons.

The modifications allowed them to create an electrolyte that had a critical current density more than 300 percent higher than a baseline sample. Higher current density allows for faster charging and discharging. It should also delay short circuiting to extend the life of batteries.

“Fires are currently a huge issue in the battery industry,” Rupp says. “By showing how to engineer these space charges in a controlled way, which is new in the field, we can have a strong impact on safety. It’s a new way to turn up the notch and get these batteries to charge faster and last longer before they break.”

The findings, along with the researchers’ engineering work, present a roadmap for battery researchers to accelerate the development of high-performance, longer lasting solid-state batteries.

“We showed we can control the initiation of these dendrites to maximize solid state batteries’ high performance,” Chu says. “In this paper, we started with a theory for how these dendrites form, then we did the material characterization to support that theory, then we did the engineering to apply the findings and actually improve battery performance.”

The work was supported, in part, by the National Science Foundation and the U.S. Department of Homeland Security.