A new atomically engineered platinum-nickel catalyst could address one of the biggest barriers facing AEM electrolyzers, durability, while helping advance lower-cost green hydrogen production.
Atomic engineering targets a key weakness in AEM electrolyzers
An alloy engineered at the atomic level could help accelerate the commercial adoption of AEM electrolyzers, which use an anion exchange membrane to produce hydrogen. The breakthrough comes from researchers at the Korea Institute of Materials Science (KIMS) in South Korea, who developed highly active and durable electrocatalysts designed for the alkaline environment typical of this technology.
To understand why the research matters, however, it is worth taking a closer look at the challenges AEM technology still faces.
AEM electrolysis: advantages and limitations
Making green hydrogen production economically viable while allowing electrolyzers to respond to the variable output of solar and wind power remains a major challenge. AEM electrolysis is designed to help bridge that gap.
On paper, the technology offers an attractive combination of features. It brings together some of the advantages of other electrolyzer technologies, including the ability to operate under highly dynamic conditions while using non-precious materials. Commercial deployment, however, remains limited.
Germany’s Enapter has already begun bringing the first thousands of AEM stacks to market. But compared with conventional alkaline electrolyzers or PEM electrolyzers, which use proton exchange membranes, AEM technology still accounts for only a small share of the market.
One of the main obstacles is technical: hydrogen production reactions proceed more slowly than in technologies operating in acidic environments. In alkaline solutions, there are no readily available free protons, such as H+ or H3O+, meaning catalysts must perform an additional step to split water molecules.
That is why highly active catalysts such as nickel-platinum alloys are often used. These materials can deliver excellent initial performance in green hydrogen production.
During prolonged operation, however, nickel gradually dissolves from the catalyst in the form of ions or hydroxides, according to the National Research Council of Science & Technology of South Korea. This alters both the catalyst’s composition and its electronic structure, causing performance to deteriorate rapidly.
In chemistry, the phenomenon is known as leaching. In this case, it can result in the loss of more than half of the nickel atoms.
That durability gap makes it difficult for today’s AEM electrolyzers to compete with alkaline and PEM electrolyzers, which have established operating lifetimes of roughly 60,000 to 80,000 hours.
This is where the Korean researchers’ approach comes in.
A highly ordered platinum-nickel catalyst
The scientists sought to address the problem at the atomic level. Specifically, the team developed a platinum-nickel electrocatalyst in which nickel atoms occupy well-defined positions within the crystal lattice, rather than being randomly distributed as they typically are.
The ordered structure makes nickel less likely to leach out of the catalyst, improving the material’s structural stability.
The work began with modeling. Quantum calculations showed that the ordered intermetallic structure requires significantly more energy for nickel atoms to dissolve or migrate away from the surface.
To create this crystalline arrangement, researchers reduced the alloy at low temperature using sodium borohydride before subjecting it to heat treatment in a nitrogen atmosphere.
The new catalyst was then applied to the cathode of an AEM half-cell. Researchers progressively scaled up their tests, eventually moving to a three-cell stack with an active area of 64 cm² per cell.
The result was significant. The system operated continuously for 3,000 hours, or about four months, while recording less than 2% performance degradation.
That is still far from the durability already achieved by mature PEM and alkaline electrolyzers, but it represents a meaningful step toward closing the gap.
The researchers said the work could pave the way for highly active, durable and cost-effective electrocatalysts with low platinum-group-metal content. They also argue that the results demonstrate the practical potential of nanostructured intermetallic electrocatalysts for use in industrial systems.
The cost of green hydrogen from AEM electrolyzers
What could these advances mean economically?
Estimating the levelized cost of hydrogen (LCOH) produced with an AEM electrolyzer remains complex, since the final figure depends on electricity prices, stack lifetime, system size, operating conditions and other factors.
A 2023 study estimated a baseline LCOH of $5.79/kg for a 1 MW AEM electrolysis system operating at an optimal current density of 1.38 A/cm², assuming renewable electricity costs of $0.06/kWh and a 20-year economic system lifetime without stack replacement. The analysis assumed a stack lifetime of 35,000 hours.
As the technology matures and manufacturing scales up, hydrogen produced by AEM electrolyzers could become significantly cheaper.
Even a fivefold increase in stack size, combined with improvements to balance-of-plant components and longer operating lifetimes, could reduce the final cost by 30%.
| Technology scenario | LCOH ($/kg) | Current density (A/cm²) | Operating conditions |
|---|---|---|---|
| Current AEM baseline | 5.79 | 1.38 | Electricity at $0.06/kWh; 1 MW stack; balance-of-plant (BOP) cost equal to 2.5 times the stack cost; water consumption of 18 kg/kg H₂; 35,000-hour stack lifetime. |
| PEM baseline | 4.16 | Higher | Mature commercial technology, but with high CAPEX due to the use of precious metals such as iridium and platinum. |
| Alkaline baseline | 4.15 | Low | Durable systems, but limited by high internal resistance, requiring larger stacks and increasing their physical footprint and associated costs. |
| AEM DOE target, medium term | 2.00 | — | Achievable primarily through lower-cost electricity and the deployment of larger stacks. |
| Optimized AEM, medium to long term | 1.29 | Variable | Electricity at $0.03/kWh; a fivefold increase in stack size; 50% reduction in overpotentials; degradation rate reduced by 50%. |
