Researchers who are developing electrolyzers for hydrogen production are increasingly turning to a membrane platform originally used in fuel cells to scale up their technology. Their strategy: use anion exchange membranes, which could be more cost-effective and combine the best features of conventional proton exchange membranes and alkaline approaches.
Anion exchange membrane (AEM) technology enables the selective transport of negatively charged ions between cathode and anode. In a hydrogen fuel cell, the membrane helps facilitate the chemical reactions needed to generate electricity. In hydrogen electrolysis, the membrane helps split water by separating hydrogen from oxygen.
So far, AEM has only been deployed at a small scale. But several renewable hydrogen companies are poised to change that. On May 7, Ithaca, New York-based Ecolectro announced a partnership with Framingham, Massachusetts-based Re:Build Manufacturing to deploy advanced AEM electrolyzers in the United States. And in March the French tire company Michelin and several French research institutions launched a multi-year collaboration to develop more durable versions of these membranes as part of Michelin’s expansion into renewable markets.
These companies, and several others globally, are betting on AEM technology to fulfill the long-sought promise of “green” hydrogen produced with renewable energy. “This has long been considered the potential savior to a lot of issues with other types of electrolysis that we’ve been trying to scale,” says Lindsey Motlow, a physicist and research director at Darcy Partners, a market intelligence firm in Houston, Texas.
Scaling up green hydrogen comes with challenges that have rendered it less competitive than other hydrogen production methods. The field relies on electrolyzers, which use electricity to split water molecules to release hydrogen. Most employ either a proton exchange membrane (PEM), which uses precious metal catalysts and polymer membranes to split the molecules, or alkaline electrolysis, which works with an electrolyte solution.
PEM can quickly ramp up and down in response to variable energy sources like wind and solar power, but it requires iridium, which is in limited supply. Alkaline electrolysis is less capital intensive and more established at larger scales, but it lacks efficiency and its harsh, basic solution complicates system design.
That has led groups to turn to AEM, which substitutes nickel and steel for PEM’s costly metals. And while it does use a basic solution, AEM has better efficiencies than alkaline electrolysis, at least at the lab scale, Motlow says.
Saerbeck, Germany-based Enapter and Austin, Texas-based Agastya offer commercial megawatt-scale AEM electrolyzers used in industry for chemical reactions and heating. In China, Shandong-based Hygreen Energy in September 2024 launched a kilowatt-scale AEM electrolyzer for plug-and-play use in industrial parks, community buildings and transportation. However, these demonstrations remain limited in scale and maturity. AEM technology has not yet been proven at commercial scale for continuous industrial hydrogen supply.
Ecolectro’s AEM electrolyzer stack uses a PFAS-free, iridium-free membrane platform.Ecolectro
Why Choose AEM for Green Hydrogen?
The partnership between Ecolectro and Re:Build aims to reduce the high costs that have hindered the scale-up of green hydrogen for industrial use. In addition to sourcing cheaper materials for the electrolyzer components, Ecolectro is outsourcing the manufacturing to Re:Build’s plants in New York and Pennsylvania. For the membranes, Ecolectro will use a proprietary blend of chemicals with a nickel catalyst for better durability.
Ecolectro is taking it one step at a time, says cofounder and CEO Gabriel Rodríguez-Calero. The company’s first commercial-scale units, to be developed this year at Re:Build’s design plant in Rochester, New York, will be 250-500 kilowatts. Rodríguez-Calero says his team plans to reach megawatt scale in 2026.
To deploy beyond lab scale, powering AEM with renewables faces significant engineering hurdles. The high efficiencies at the lab scale assume a steady flow of electricity powered by fossil fuels, but the ability to quickly respond to fluctuations in renewable energy hasn’t been tested widely. Membrane durability is another challenge, because materials must withstand AEM’s harsh, basic conditions. Fluorinated polymer membranes are an efficient option, but they pollute water and introduce forever chemicals.
To solve the membrane issue, Michelin in Clermont-Ferrand, France and its research partners launched a collaboration they call Alcal’Hylab. Researchers will develop a new, more durable membrane using a mix of chemicals alongside a cost-effective metal catalyst—a similar model to Ecolectro. Alcal’Hylab’s goal is to deploy this membrane in a 25-kW AEM electrolyzer stack by 2027.
“It’s difficult to find a structure of a polymer that is really compatible with these operating conditions for a long time,” says Jacques Maddaluno, director of chemistry at the French National Centre for Scientific Research (CNRS), which will host the collaborative lab. “You get very good results at time zero, but it degrades very, very quickly.”
Can Green Hydrogen Compete With Renewable Electricity?
Despite the many research groups working on the problem, skepticism around green hydrogen remains. The scientific and economic hurdles to developing it at an industrial scale do not lend themselves to a worthwhile investment, even for a company like Michelin, says Joseph Romm, physicist at the University of Pennsylvania and author of The Hype About Hydrogen: False Promises and Real Solutions in the Race to Save the Climate. “The fact that they are making deals with research organizations tells you how far they have to go,” he says.
True, green hydrogen has yet to live up to its hype, says Rodríguez-Calero at Ecolectro. “I think the pace of adoption of some of this new hydrogen market has been slower than what a lot of people hoped,” he says. He sees Ecolectro as a meaningful step toward competing with fossil fuel-derived hydrogen for industrial users who need to produce it on site.
But to go beyond these kinds of point-to-point replacements, green hydrogen still struggles to compete with renewable electricity. The industry also lacks the infrastructure to transport hydrogen long distances. Says Romm: “The biggest problem for AEM is that hydrogen doesn’t just have one problem.”
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