Anion exchange membrane electrolyser
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Technology Description
Electrolysis uses electricity to split water into its basic components (H2 and O2). Anion exchange membrane electrolysers are a type of electrolyser that uses an anion-exchange membrane in combination with nickel-based electrodes. In contrast to alkaline electrolysis the use of the anion-exchange membrane enables the use of a dilute alkaline electrolyte or even pure water. In contrast to PEM, AEM enables the use of non-noble metal electrodes. This makes AEM a potentially highly competitive technology.
The potential benefit of AEM electrolysers is low cost. Capital cost is reduced because of alkaline conditions which are milder than the acid conditions of PEM. This means platinum group metal free catalysts like Ni alloys and Ni, Fe, Co oxides may be used. In addition, and more importantly when it comes to cost, low-cost stainless steel current collectors and Ni based porous transport layers may be used instead of the expensive Pt coated Ti required for PEM. Operational cost is reduced by the membrane which reduces resistance in the cell making AEM electrolysis more electrically efficient than traditional alkaline electrolysis. It is important to note that AEM systems may still use an alkaline feed solution of up to 1 M KOH. The low ionic conductivity of current membranes and ionomers means operation with a pure water feed results in low performance.
At the same time, AEM still requires significant development in terms of performance (efficient operation at high current densities) and scaling up cell area.
Relevance for Net Zero
Although anion exchange membrane electrolysers present high cost reduction potential, high flexibility and can achieve high efficiencies, but they are least developed electrolyser design and will likely deploy more slowly and to lower extent in the near-term. However, they offer excellent medium- to long-term potential since they require less critical minerals and do not work in a corrosive environment, unlike other electrolysis designs, which should allow them to last longer with less degradation, thereby maintaining high efficiencies for a longer period of time.
Key Countries
Germany, Italy
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