Alkaline electrolysis (AEL) is the oldest electrolysis technology which uses a porous diaphragm as separator, but it has limitations: With AEL, hydrogen can only be produced at low production rates and pressures.
It cannot be easily started up or shut down, and the hydrogen produced needs to be compressed cost intensively. In contrast, proton exchange membrane electrolysis (PEM electrolysis) is much more advanced. It is operated at three times the current density than AEL, hydrogen is produced under pressure, and operation is dynamic. However, the aggressive acidic environment requires the use of noble metal catalysts like iridium at the anode. Also, titanium or even platinated titanium is needed for the design of the electrolysis cells. These materials are on one hand classified by the European Union as critical raw materials and on the other hand are very expensive. This results to high investment costs for PEM electrolyzers.
By integrating the DURAION® membrane into an AEM electrolyzer, the investment and operation costs can be reduced compared to today's benchmark technologies. Since the operation of AEM electrolysis takes place under slightly alkaline conditions, noble metal free catalysts for the electrodes and inexpensive materials for the cell design can be used. In contrast to the AEL, AEM electrolysis can be operated at higher current densities and can be dynamically started up providing a high degree of flexibility. Therefore, the AEM electrolysis combines the benefits of both PEM and AEL technology.