The central component of the electrolyzer, which has a major influence on efficiency and reliability, is an ion-conducting membrane. Evonik has now developed a novel anion exchange membrane (AEM), which should contribute to the breakthrough of electrolytic production of hydrogen.

Anion exchange membrane (AEM) electrolysis can potentially combine the beneficial features of the PEM and alkaline electrolyzer technologies—i.e. a low cost, raw materials that do not raise concerns in terms of supply bottlenecks (electrodes that do not include PGMs, stainless steel current collectors), a compact design, the adoption of feeds based on non-corrosive liquids (low concentration alkali or DI water), and differential pressure operation.

However, as of today AEM electrolysis is limited by AEMs exhibiting an insufficient ionic conductivity as well as a poor chemical and thermal stability. Moreover, most non-PGM electrocatalysts, in addition to poor electrical conductivity mentioned, are only stable above pH 12, and really active at pH 14. Therefore, new material breakthroughs and design concepts are needed before AEM technology can challenge PEM electrolyzers. These include:

• Increase in membrane and ionomer conductivity and stability;

• Decrease in membrane thickness while retaining good gas separation;

• Improve mechanical stability;

• Optimize chemical composition and activity of non-PGM electrocatalysts;

• Optimize electrocatalyst conductivity, dispersion and utilization in the electrode;

• Improved cell design.

Our membrane could allow commercial realization of highly efficient and economically viable electrolysis technology.

—Oliver Conradi, who is responsible for membrane research at Creavis, Evonik’s strategic innovation unit

The membrane developed by researchers at Creavis and experts from the High Performance Polymers unit in the Membranes innovation growth field is a resistant polymer with excellent conductivity.

The innovative AEM concept reduces investment costs because the cells used for electrolysis in alkaline conditions do not require precious metals. Therefore, far less expensive materials can be used. Other attributes of this AEM electrolysis platform are high current density, very good efficiency, and high flexibility.

In the CHANNEL project, a consortium of highly qualified partners from industry and research organizations will plan, construct, and test an AEM electrolysis system based on the new membranes from Evonik. CHANNEL stands for Cost-efficient Hydrogen production unit based on ANionN exchange membrane Electrolysis.

The project will run for three years and will receive funding of around €2 million from the European Union’s Horizon 2020 research program.

In addition to Evonik, which is providing the AEM membrane, the other project partners are Shell (Netherlands; hydrogen user), Enapter (Italy; plant engineer for the electrolyzer), Forschungszentrum Jülich (Germany; R&D on membrane-electrode assemblies), the Norwegian University of Science and Technology (NTNU; catalysts), and SINTEF, an independent research organization in Norway, which is responsible for project coordination.

The consortium therefore covers the entire value chain for the production of green hydrogen.