Jul 30, 2026
Freiburg – ionysis has achieved its first successful full cell size stack validation with gas diffusion electrodes for anion exchange membrane (AEM) electrolysis. The result was obtained with H2i GreenHydrogen as an early customer and validation partner, demonstrating the readiness of ionysis components.
Anion exchange membrane (AEM) electrolysis is attracting increasing industrial attention as a promising route towards efficient and scalable green hydrogen production. Gas diffusion electrodes are a central component in typical stack architectures, enabling efficient gas management, stable electrochemical operation and compatibility with today’s stack concepts designed for scale-up. ionysis is developing and producing AEM electrolysis electrodes and MEA components from prototypes to pilot series, including roll-to-roll processed electrodes with coating widths suitable for industrial pilot projects > 40 cm.
The result was generated together with H2i GreenHydrogen, an Austrian company developing and operating AEM stacks and modular electrolyzer systems for green hydrogen production.
The recent full-cell-size stack result demonstrates that ionysis gas diffusion electrodes can be integrated into electrolyzer hardware beyond small laboratory cells. H2i carried out the first validation of these electrodes in a full-size H2i-AEM-Stack under real operating conditions, including differential pressure. The transition from single-cell and short-stack testing to full-stack evaluation at H2i's development site in Graz, Austria, is a major step forward for the qualification of ionysis MEA components in pilot projects and future commercial AEM electrolysis systems.
Ralf Vogt, CEO of H2i GreenHydrogen, commented:
"H2i consistently qualifies promising components up to stack level, as reliability from manufacturing to plant operation is what customers ultimately buy. Therefore, the successful integration of ionysis gas diffusion electrodes into our industrialized AEM stack technology is very encouraging. Following extensive testing at single-cell and short-stack level, full-stack evaluation was the next logical step. The advanced electrode components from ionysis fitted seamlessly into our stack design and assembly concept."
By testing ionysis electrodes in stack-relevant conditions, the partners created a stronger basis for the next phase of technical validation, including performance mapping, operational window definition and durability testing under realistic conditions. ionysis will continue to support electrolyzer developers with component supply, customization and stack-level qualification. Lisa Langer, CFO and Co-Founder of ionysis, stated: “The successful full cell size stack validation with H2i GreenHydrogen is an important business milestone for ionysis and a strong confirmation of our AEM electrolysis component portfolio. We greatly value the opportunity to work with H2i as the first customer to demonstrate this step at stack level. This result marks now the starting point for broader industrial deployment, and we look forward to engaging with electrolyzer companies globally.”
As next steps, ionysis will continue extended stack testing, reproducibility work across electrode batches and the transfer of validated electrode designs into further pilot-scale supply formats with H2i GreenHydrogen and other industrial partners. The objective is to support the accelerated development of efficient, scalable and commercially relevant AEM electrolysis systems across a broad customer base.
H2i will continue operating under dynamic load profiles, including start-stop cycling, to generate robust long-term data — the basis for qualifying the electrodes for deployment in customer pilots.
About ionysis
ionysis GmbH develops and produces next-generation membrane electrode assemblies, catalyst-coated membranes and gas diffusion electrodes for advanced electrochemical systems. The company serves hydrogen applications such as fuel cells and electrolysis, Power-to-X processes including CO₂ electrolysis and green ammonia, and electrochemical separation applications such as water treatment and lithium recovery. Based in Freiburg, Germany, ionysis translates electrochemical materials innovation into scalable component solutions for industrial partners.
About H2i GreenHydrogen
H2i GreenHydrogen GmbH is an Austrian company focused on innovative anion exchange membrane (AEM) electrolysis technology. Founded in 2019, H2i develops the H2i-AEM-Stack and the modular H2iVE-SKID platform for hydrogen production at industrial megawatt scale. Its own test infrastructure spans everything from single-cell test benches to a containerized demonstration plant, where complete AEM stacks and systems are validated under real operating conditions. Headquartered in Wallern an der Trattnach, Austria, H2i also operates a development site in Graz.
Contact:
Lisa Langer (CFO, ionysis): lisa.langer@ionysis.com
H2i GreenHydrogen GmbH Website: h2i.tech
Foto Credits: H2i Green Hydrogen GmbH