AEMelektrolys

AEMelektrolys, or AEM electrolysis, refers to water electrolysis systems that use an anion-exchange membrane to transport hydroxide ions from the anode to the cathode, enabling hydrogen production at the cathode and oxygen evolution at the anode under alkaline conditions.

A typical AEM electrolyzer consists of a membrane-electrode assembly with an anion-exchange membrane, catalysts on the anode and cathode, gas diffusion layers, and flow-field plates. The membrane acts as a selective conductor for OH- ions while preventing excessive mixing of hydrogen and oxygen.

During operation, water is oxidized at the anode to produce oxygen and hydroxide ions; the hydroxide migrates through the membrane to the cathode, where it participates in hydrogen evolution. The overall reaction is the decomposition of water into hydrogen and oxygen.

Materials underlying AEMs are polymeric matrices with fixed cationic groups (for example, quaternary ammonium) that provide OH- conductivity in alkaline media. Cathode and anode catalysts are often nickel- or cobalt-based to reduce reliance on expensive noble metals. System design emphasizes membrane stability and ionic conductivity.

Advantages of AEM electrolysis include compatibility with non-precious metal catalysts and the ability to operate in alkaline environments, which can lower material costs and enable integration with renewable-energy sources. The approach also allows in-situ handling of electrolytes and potential resilience to impurities.

Current challenges involve chemical and mechanical stability of the membrane at high pH and temperature, management of carbonate formation from CO2, gas crossover, and durability for long-term operation. Research aims to improve membrane conductivity, reduce costs, and demonstrate scalable, durable devices in pilot settings.

See also: water electrolysis, PEM electrolysis, solid oxide electrolysis.