Less Iridium, Greater Efficiency: A New Generation of CCMs for PEM Electrolyzers

Reducing the Capital and Operating Costs of Electrolysis

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