Hydrogen is the most abundant element in the universe. It is also the lightest, consisting of only one proton and one electron. But don’t let its featherweight fool you: hydrogen has enormous potential for energy storage. When used in a fuel cell—a small device that converts chemical energy into electricity—hydrogen can power forklifts, passenger cars, or heavy-duty trucks, while yielding only heat and water as byproducts.
For decades, Los Alamos National Laboratory has led the development of fuel cell technologies. Today, in an era of increased investment in renewable energy, the Laboratory continues to use its extensive background in fuel cell research to improve technologies for emission-free hydrogen fuel cell electric vehicles.
Researchers at Los Alamos are also leveraging their fuel cell expertise to help develop a new generation of technologies to produce hydrogen from water molecules. When powered by wind, solar, or other renewable energy sources, the process of splitting water to make hydrogen, which is called electrolysis, can yield “clean” hydrogen produced with zero greenhouse gas emissions. (Currently, 95 percent of hydrogen in the United States is produced during a process called steam methane reforming, which involves heating natural gas and yields greenhouse gases that are mostly emitted into the atmosphere.)
New technologies that integrate hydrogen fuel cells and energy production may go even further, helping to stabilize the nation’s power grid as the Department of Energy (DOE) pursues the Biden administration’s goal of achieving a 100 percent clean energy power sector by 2035.
A lengthy history
The first hydrogen fuel cell was invented more than 180 years ago, when, in 1842, British scientist William Robert Grove developed what he described as a “gas voltaic battery” that combined hydrogen and oxygen to produce electricity.
However, Grove’s invention lay dormant for more than a century, until Francis Bacon, a chemical engineer at Cambridge University, rediscovered Grove’s research and worked to develop it further. In 1959, Bacon demonstrated a 5-kilowatt fuel cell that could power a welding machine, a circular saw, and a forklift. The fuel cell garnered the attention of engineers with the National Aeronautic and Space Administration (NASA), which was on the lookout for technology to power its space missions.
NASA chose Bacon’s fuel cell over batteries, which were bulky and suffered from a relatively short lifespan, and solar panels, which were not yet efficient enough to be practical. In addition to producing electricity, the fuel cells also produced potable water as a byproduct, which the Apollo 11 astronauts, who reached the moon in 1969, drank while in spaceflight. President Richard Nixon commended Bacon for his invention, saying, “Without you, we would not have gotten to the moon.”
Around the same time that NASA was designing its fuel cell-powered spacecraft, General Motors (GM) developed its Electrovan, the world’s first fuel cell electric automobile—that is, the first vehicle to use hydrogen to produce electricity and power a motor.
“The current state-of-the-art fuel cell design was developed here at Los Alamos a little more than 30 years ago.”
—Jacob Spendelow
The Electrovan, which GM introduced in 1966, had a top speed of 70 miles per hour and a range of some 150 miles. But the vehicle had shortcomings. Along with taking three hours to start—drivers had to follow a convoluted series of procedures in order to prevent mechanical mishaps—the Electrovan weighed more than 7,000 pounds. Its components so filled the chassis that in addition to a driver, only one passenger could fit inside.
Moreover, the van’s fuel cell required platinum as a catalyst. In a hydrogen fuel cell, a catalyst is necessary to split electrons from hydrogen molecules, producing an electric current. While today’s hydrogen fuel cell electric vehicles also rely on noble metal catalysts, the Electrovan required so much platinum that for the same cost, one might have purchased a whole fleet of gasoline-powered vans. In the end, GM scrapped the Electrovan after producing just one.
Fuel cells at Los Alamos
Interest in powering automobiles with hydrogen waned until the mid-1970s, when rising oil costs prompted a handful of scientists at Los Alamos to ask whether any of the research they’d conducted for Project Rover—which aimed to build a nuclear-powered rocket—could contribute to the nation’s energy security. That question led, in 1977, to $25,000 in Laboratory funding for hydrogen fuel cell research.
Nearly half a century later, the fuel cell program has become Los Alamos’ longest-running non-defense program. Work conducted in the fuel cell program has yielded hundreds of patents and produced many of the technologies that make fuel cells a viable technology today.
In fact, DOE’s Hydrogen and Fuel Cell Technologies Office—which directs an annual research budget totaling more than $100 million and oversees a portfolio spanning diverse national laboratories, universities, and industries—has its roots in Los Alamos’ fuel cell program. The program’s work has also helped advance electrolyzers, which electrochemically split water molecules to produce hydrogen in a process that is essentially the inverse of what takes place inside a fuel cell.
“The Los Alamos program has changed a lot over the years,” says Rod Borup, who is the Laboratory’s fuel cell program manager. “Today, our concentration is really on materials. We work on essentially all the different internal components of fuel cells and electrolyzers.”
Not all fuel cells use hydrogen as a fuel, but those that do consist of three basic components: an electrolyte sandwiched between two electrodes. The electrodes on either side of the electrolyte, the anode and the cathode, are porous. When hydrogen molecules enter the anode side of the fuel cell, they interact with a catalyst—usually platinum—which splits them into protons and electrons.
The positively charged protons then pass through the electrolyte to the cathode. Meanwhile, the negatively charged electrons travel along a circuit, creating an electrical current. At the cathode, oxygen molecules join with the protons that have passed through the electrolyte to yield heat and H2O—water.
Los Alamos had early successes in hydrogen fuel cell research and development, producing, among other things, a hydrogen-powered golf cart by 1980. But a key breakthrough for the fuel cell program came in the early 1990s, when researchers developed a way to produce platinum-bearing electrodes that required 20 to 40 times less platinum than had hitherto been necessary. That advance alone lowered the cost of platinum needed for a passenger car’s fuel cell from tens of thousands to hundreds of dollars—an achievement that led automobile manufacturers to take an interest in hydrogen once more.
“Before, we were using way more platinum. The electrodes were based on what NASA was using,” Borup says. “The new electrode design was really the invention that got automotive companies like General Motors interested in fuel cells again.”
Today, nearly every major automobile manufacturer is researching or developing fuel cell electric vehicles. Fuel cell electric vehicles are already available from several manufacturers, including Honda, Hyundai, and Toyota. These vehicles all rely on proton exchange membrane fuel cells, or PEMFCs, which use a polymer membrane for their electrolyte. PEMFCs are the fuel cell with the greatest potential for use in automobiles and other forms of transportation. For this reason, PEMFCs are the subject of most of Los Alamos’ fuel cell program research.
PEMFCs have several advantages over other types of fuel cells. Unlike fuel cells that use liquid electrolytes, PEMFCs’ solid electrolytes are adept at ensuring that protons, but not electrons, pass directly through from the anode to the cathode. PEMFCs operate at lower temperatures than other fuel cells, which means that they can start quickly and easily. They are also small and relatively lightweight.
Despite these advantages, PEMFCs aren’t without their drawbacks. Historically, PEMFCs have been able to operate only within a relatively narrow temperature range—between 50 and 100 degrees Celsius. They also need moisture, meaning that they require expensive radiators and humidifiers to function in fuel cell electric vehicles.
New avenues for materials research
Los Alamos’ fuel cell program focuses on improving the materials inside fuel cells, the better to address shortcomings like temperature and moisture requirements. During the past decade, a team led by the Laboratory’s Yu Seung Kim developed a fuel cell with a redesigned electrolytic membrane that operates between 80 and 200 degrees Celsius—an optimal range for applications such as heavy-duty trucking—and that isn’t as sensitive to variations in humidity.
These advances will allow for fuel cell electric vehicles that can operate without the radiators and humidifiers that to date have helped drive up their cost. Kim won the Battelle Memorial Institute’s 2022 Inventor of the Year award for his research, and Massachusetts-based Advent Technologies recently opened a commercial fuel cell factory to manufacture membrane electrode assemblies based on his design.
Other research at the Laboratory has focused on redesigning fuel cells’ electrodes, updating a technology that had changed relatively little since the Laboratory’s platinum breakthrough in the early 1990s. The electrode that was developed then consists of a carbon-supported platinum catalyst and an ionomer that are mixed in an ink slurry and deposited onto a membrane or gas diffusion layer. This process produces an electrode whose structure is randomized—a fact that significantly reduces the flow of oxygen through the electrode, thereby inhibiting performance.
“The current state-of-the-art fuel cell design was developed here at Los Alamos a little more than 30 years ago,” says Jacob Spendelow, a researcher in the fuel cell program. “That electrode was a big breakthrough at the time. But since then, progress has kind of stagnated. We asked, if we could redesign the electrode from the ground up, what would it look like?”
“Today, our concentration is really on materials. We work on essentially all the different internal components of fuel cells and electrolyzers.”
—Rod Borup
Spendelow and his colleagues wound up developing what they describe as a “grooved electrode.” (A draft of a paper that the team eventually published in Nature Energy initially referred to the electrode as a “groovy electrode,” but the journal’s editors insisted on the more staid “grooved electrode.”)
The Spendelow team’s electrode is designed with microscale grooves and ridges that resemble those of a Ruffles potato chip. Unlike a potato chip, however, these grooves are precisely engineered, having been optimized with machine learning and multiphysics modeling. The design significantly improves oxygen transport, yielding an electrode that performs 50 percent better than the older model.
“Most of the work on improving fuel cell performance and durability has focused on improved materials,” Spendelow says. “What we did with the grooved electrode was different. We didn’t change the materials, but just the way that the materials are put together.”
Interlaboratory collaboration
In addition to operating more efficiently than its predecessor, Spendelow’s grooved electrode is more durable, capable of exhibiting 170 percent higher current density after 500 activity cycles. Durability is an increasingly important goal for Los Alamos’ researchers, in part because the fuel cell program has shifted its focus to designing fuel cells for heavy-duty applications.
Indeed, Los Alamos’ fuel cell program now plays a leading role in the Million Mile Fuel Cell Truck consortium, which Borup co-directs. The consortium unites five national laboratories’ efforts to develop PEMFCs for heavy-duty applications, with long-haul trucking as its focus.
Medium- and heavy-duty vehicles generate more than 20 percent of the transportation sector’s total carbon dioxide emissions, making the development of alternative trucking technologies important. Hydrogen makes sense for trucking because as a fuel, the element is relatively lightweight. Battery-powered semitrucks, for example, require batteries so heavy that a third of cargo capacity can be lost.
“What we did with the grooved electrode was different. We didn’t change the materials, but just the way that the materials are put together.”
—Jacob Spendelow
Developing the infrastructure to support hydrogen trucks might also set the stage for adoption of other kinds of hydrogen vehicles. At present, 60 hydrogen refueling stations exist in the United States. Fifty-nine of those are in California (the other one is in Hawaii). Because semitrucks tend to travel along regular routes, building a series of refueling stations to accommodate the trucks on those established routes—creating a so-called “hydrogen highway”—would be easier than building enough stations to service fuel cell-powered passenger cars.
“DOE is looking at heavy-duty hauling as a way to get the hydrogen infrastructure to fill out,” Borup says. “And then, at a later date, that infrastructure could be expanded to medium-duty and light-duty vehicles.”
Durability has become a key objective for the fuel cell program’s research because long-haul trucks, which often log 40,000 miles per year or more, put significant wear on their components. In particular, the heat produced by a PEMFC tends to degrade the fuel cell’s electrolyte membrane. The Million Mile Fuel Cell Truck consortium’s name refers to its ultimate ambition: to develop a fuel cell that can withstand one million miles of use—well beyond the 500,000 miles that many internal combustion engine-powered semitrucks log in their lifetimes.
Thee consortium also reflects a shift in programmatic emphasis away from smaller projects and toward increased collaboration with other laboratories and institutions. For example, Los Alamos, in collaboration with Argonne National Laboratory, is leading ElectroCat 2.0, a four-laboratory consortium that seeks to develop platinum group metal-free catalysts that will help make fuel cell and electrolyzer electrodes more durable and affordable.
“We’re employing a systematic approach in which potential catalysts are synthesized and analyzed comprehensively using a variety of techniques, including high-throughput combinatorial methods,” says Los Alamos’ Piotr Zelenay, who co-directs ElectroCat 2.0. “One approach recently introduced at Los Alamos to accelerate electrocatalyst discovery involves using machine learning to guide catalyst synthesis based on the performance of earlier-developed materials.”
Producing clean hydrogen
The Laboratory is also involved in the H2NEW (H2 from the Next Generation of Water Electrolyzers) consortium, which is co-led by the National Renewable Energy Laboratory and Idaho National Laboratory. Los Alamos participates alongside five other laboratories to develop technologies related to the large-scale production of hydrogen with electrolysis—that is, by applying an electric current to water molecules, splitting them into oxygen and hydrogen.
Hydrogen can be produced in several ways, but at present, in the United States, approximately 95 percent of hydrogen is produced from natural gas by a method called steam methane reforming. In addition to the carbon monoxide and carbon dioxide produced in this process, steam methane reforming is—like most of the United States’ energy grid—powered primarily by fossil fuels.
Hydrogen produced from steam methane reforming and used in a fuel cell electric vehicle amounts to a 50 percent reduction in greenhouse gas emissions over those of a standard internal combustion engine. By using technology to capture and sequester the carbon dioxide emitted in steam methane reforming—and by detecting and addressing the methane leaks that often occur as a part of the production process—even cleaner hydrogen production is possible.
However, carbon capture and sequestration technologies have yet to see widespread adoption, meaning that most of the greenhouse gases produced in steam methane reforming are emitted directly into the atmosphere. DOE is encouraging the production of “clean” hydrogen, which includes hydrogen produced from natural gas with carbon capture technology. The cleanest hydrogen is produced by electrolysis, powered by renewable energy. An electrolyzer can convert solar or wind energy into hydrogen gas that can be used in fuel cell electric vehicles, with no greenhouse gases generated in the process.
Secretary of Energy Jennifer Granholm has said that “Clean hydrogen is the future.” At present, though, clean hydrogen is also expensive: a kilogram of hydrogen produced with electrolysis costs more than $5, versus $1–2 per kilogram of hydrogen produced from natural gas.
DOE’s Hydrogen Energy Earthshot plan aims to address that disparity by reducing the cost of producing a kilogram of clean hydrogen to $1 by mid-2031. “If we can lower the cost of clean hydrogen,” said Granholm at the DOE’s 2021 Hydrogen Earthshot Summit, “we will have the means to decarbonize industrial manufacturing, to refuel hydrogen fuel cell trucks, make alternative low-carbon fuel for planes, produce clean ammonia and other chemicals, create longer-duration storage, and so much more.”
At present, of the 10 million metric tons of hydrogen that the United States produces each year, less than 1 percent is clean hydrogen. DOE hopes to see clean hydrogen production reach 10 million tons of hydrogen per year by 2030, 20 million tons by 2040, and 50 million tons by 2050, with approximately half of this hydrogen produced from electrolysis.
To achieve these numbers, more and better electrolyzers will have to be developed. The Bipartisan Infrastructure Law, which was signed by President Joe Biden in 2021, provides $1 billion in funding for electrolysis research and development—an outlay that is spurring innovation in the field.
At first glance, electrolyzers—which produce hydrogen by splitting water molecules—are less well researched than, say, fuel cells, which consume hydrogen. “There has been a rapid acceleration in the number of publications about electrolyzers, but there’s not the historical aspect that there is with fuel cells,” says Siddharth Komini Babu, a researcher in Los Alamos’ fuel cell program who represents the Laboratory in the H2NEW consortium, and who was a co-author on Spendelow’s grooved electrode paper.
While the research on electrolyzers is relatively scant, fuel cells and electrolyzers have a lot in common for a simple reason: the technologies are in a sense the inverse of each other. “The overall reaction is similar between them,” Komini Babu says. “In essence, you’re running a fuel cell backwards as an electrolyzer. The things that differ are the catalyst and the materials being used.”
Like fuel cells, electrolyzers rely on an electrolyte sandwiched between two noble-metal catalysts. In fuel cells, it is possible to use carbon-based materials. However, in an electrolyzer, the carbon-based electrodes that are commonly used in fuel cells tend to corrode, meaning that they must be metal-based instead.
The similarities are such that technology developed at Los Alamos, like the grooved electrode, might be adapted for electrolyzers. “All of our work on electrode design was done initially for fuel cells, but we’re looking at adapting the technology for electrolyzer applications as well,” Spendelow says.
Like the research that is being conducted for the Million Mile Fuel Cell Truck consortium, durability is a focus for H2NEW research. This emphasis is due in part to the strain placed on electrolyzers by renewable energy sources. Previously, electrolyzers were designed to operate continuously. But because renewable energy peaks at certain hours and declines at others—as the sun sets or the wind stops blowing, for example—the next generation of electrolyzers must be able to tolerate frequent cycling between on- and off-states.
“Clean hydrogen is the future.”
—Jennifer Granholm
“New systems will have to operate in more of a dynamic environment, which leads to a lot more degradation,” Komini Babu says. “That’s why there is a lot more interest in developing new materials that can work under these dynamic conditions.”
Other research involves reducing the quantity of precious metals used in electrolyzers. While electrolyzers often use platinum, like fuel cells, they also rely on iridium, a byproduct of platinum mining that is one of the scarcest elements on Earth. This fact has historically driven up electrolyzers’ cost, preventing widespread adoption.
The H2NEW consortium is two years into its five-year program. Komini Babu says that already the consortium has succeeded in establishing many of the degradation methods that were absent from the extant electrolyzer research. Now researchers are working to develop materials to construct electrolyzers that are better able to withstand the stresses of an irregular power supply.
Putting it all together
One recently-funded project will see the Laboratory’s fuel cell program attempt to combine electrolyzer and fuel cell technology into a single package with the potential to help stabilize the nation’s electric grid.
For decades, scientists have grappled with the challenge of providing “baseload”—that is, round-the-clock energy generation—to the power grid with renewable energy sources like wind and solar. (Fossil fuel power sources can operate continuously, meaning that they don’t struggle to provide baseload in the same way.)
Pumped storage is an emerging solution, but requires both water and favorable geology. This method uses energy produced during periods of peak production to pump water to a higher elevation. During off hours, that water is released, generating hydroelectric energy. Another method involves using lithium-ion batteries to store extra energy for later use. In California, a network of lithium-ion batteries can store up to 5,600 megawatts of electricity, enough to power 4.6 million homes for four hours. But such batteries are expensive and provide power for only a short time.
At Los Alamos, Spendelow is leading a recently funded project to produce a unitized reversible fuel cell (URFC) that could become a key energy storage technology. The idea is to combine the functions of a fuel cell and an electrolyzer into a single unit. At times of peak renewable energy production, such a system could use electrolysis to produce hydrogen. When energy production slows, the system could operate as a fuel cell, turning hydrogen into electricity.
“This is a project where our knowledge of both fuel cells and electrolyzers will come into play,” says Komini Babu, who will be a part of the project team. “We’re designing new materials and combining them with our knowledge of fuel cells and electrolyzers into one single unit.”
“We’re designing new materials and combining them with our knowledge of fuel cells and electrolyzers into one single unit.”
—Siddharth Komini Babu
A unit that combines the functions of a fuel cell and an electrolyzer could be less expensive, and require a smaller footprint, than two side-by-side units that perform these functions independently. And a URFC could have military and space applications as well.
While URFCs have been designed before, they suffered significant shortcomings in durability and efficiency that kept them from ever evolving beyond prototypes. The URFC that Spendelow and his team intend to pursue will draw on Los Alamos’ expertise in fuel cells, deploying a polymer electrolyte membrane of the sort used in PEMFCs, along with the grooved electrode that Spendelow and his colleagues recently developed.
Among other challenges, the team will need to develop a porous transport layer—which is a key component of electrolyzers—that can be hydrophobic (water repellant) or hydrophilic (water attractant), depending on which mode the URFC is operating in. But with the fuel cell program’s track record of producing innovative technologies, and with growing interest in developing novel hydrogen technologies, success seems within reach.
“There is a lot more focus on fuel cells and electrolyzers now,” Komini Babu says. “The growing deployment of solar and wind power, and the whole hydrogen economy that’s being developed, have the potential to be super beneficial.”
For her part, Secretary of Energy Granholm is optimistic about the Laboratory’s ability to help advance electrolyzer technology. In August 2023, the secretary visited Los Alamos, where she took part in a panel discussion that ranged from the legacy of the Manhattan Project and changes in the geopolitical landscape to the nation’s clean energy transition.
Granholm noted that national laboratories like Los Alamos are poised to play a major role in helping to combat climate change and develop technologies like clean hydrogen. She added that much of the research that made electrolysis possible in the first place came from the United States’ national laboratories.
“The ability to go through the labs to bring down the cost of electrolyzers for clean hydrogen is really, really important,” Granholm said. “The mission—it’s so great!” ★