Weinheim, October 16, 2026. From October 20 to 22, 2026, Freudenberg Sealing Technologies will present a new generation of catalyst-coated membranes (CCMs) for PEM electrolysis at the Hydrogen Technology Expo in Hamburg. The membranes require just 0.5 milligrams of iridium per square centimeter and achieve a cell voltage of 1.74 volts at a current density of 3 amperes per square centimeter. An integrated protection technology also limits hydrogen migration to the oxygen side, thereby enhancing operational safety.
Iridium is one of the rarest metals on Earth. Yet no PEM electrolyzer can operate without this precious metal, which serves as a catalyst on the oxygen side of the membrane, where water is split. According to Fraunhofer ISE, one gigawatt of electrolysis capacity requires 25,000 to 35,000 square meters of CCM. At a loading of 0.5 mg/cm², this corresponds to approximately 125 to 175 kilograms of iridium; many commercially available membranes require even more. The loading therefore affects not only capital expenditure (CAPEX); the catalyst structures also have a significant impact on operating expenditure (OPEX), which accounts for approximately 67 percent of the total cost of ownership of hydrogen production.
Low Cell Voltage Reduces Operating Costs
However, using less precious metal is beneficial only if efficiency is maintained. Freudenberg Sealing Technologies has therefore structured the catalyst layers so that the new CCM achieves excellent cell voltages – and thus high efficiency – despite its low iridium content. As a result, the electrolyzer requires less electricity per kilogram of hydrogen, reducing operating expenditure. In accelerated aging tests – which simulate long-term operation in fast-forward – the CCM showed no significant degradation. The membrane therefore already delivers the efficiency customers are seeking for future generations of electrolyzers.
Protection Against Explosive Gas Mixtures
The oxyhydrogen gas reaction that ends with a loud bang in a chemistry class must be prevented at all costs in an electrolyzer. Pressure on the hydrogen side is often up to 30 bar higher than on the oxygen side. As a result, hydrogen can migrate through the membrane, creating an explosive mixture at concentrations of approximately four percent by volume or higher. HTO-Protection, a proprietary safety technology incorporated into all CCMs from Freudenberg Sealing Technologies, limits this migration: at 0.5 A/cm², the hydrogen content in the oxygen is less than 0.25 percent by volume – about one-sixteenth of the lower explosive limit – providing a very high safety margin.
“The cost of precious metals at the purchasing stage and electricity consumption during operation are two key factors in the economic viability of electrolysis. Our new generation of CCMs addresses both, reducing total costs over the electrolyzer’s life cycle without compromising safety,” says Michael Milch, Global Head of New Markets Sales, CCM, at Freudenberg Sealing Technologies.
Variants for Different Stack Configurations
The new generation is available with membrane thicknesses of 50 and 80 micrometers, roughly equivalent to the thickness of a human hair. Thinner membranes enable higher efficiency, while thicker membranes offer a longer service life. The choice depends on the customer’s design philosophy.
Upon request, Freudenberg Sealing Technologies supplies the membranes not only in rolls or sheets, but also as ready-to-install assemblies: laminated or bonded to a frame using a hot-melt process and, if required, equipped with integrated seals made from the company’s own elastomer materials. Combining the assembly with a gas diffusion layer from its sister company, Freudenberg Performance Materials, creates, for example, a membrane electrode assembly (MEA). The frame design must protect the active surface from contamination while simplifying assembly in the stack. The company also offers CCMs and MEAs for PEM fuel cells in trucks, buses, and ships.
Freudenberg Sealing Technologies will showcase the new generation of CCMs at the Freudenberg Group’s joint booth (Hall B6, Booth H10). Company experts will be available to present the test results and advise visitors on customized frame and sealing solutions.