ZIM cooperation project H2Coat “Development of a novel special coating for the dispensed silicone seal on bipolar plates of fuel cells” Grant number: KK5190509MP4

(Duration: Jul. 2025 – Jun. 2027)

Hydrogen fuel cells are a key technology for climate-friendly mobility. For their safe operation, reliable handling of hydrogen is crucial, as the gas, due to its small molecular size, can diffuse through conventional seals. This so-called permeation effect leads to efficiency losses and can pose a safety risk.

To reduce this permeation, the Center for Fuel Cell Technology (ZBT) and Rhenotherm Miniparts Gesellschaft für Kleinteilbeschichtung mbH are developing a novel special coating for dispensed silicone seals on bipolar plates of fuel cells within the H2Coat project. The aim is to significantly reduce hydrogen permeation and thus increase both the safety and economic efficiency of fuel cell systems. The new coating is designed to maintain these mechanical advantages while simultaneously forming an effective barrier against hydrogen penetration.

Reducing hydrogen permeation in silicone seals is a demanding technological challenge. To evaluate the new coatings, coated and uncoated test specimens are examined on a specially developed permeation test rig, and the permeation rates are determined. Test protocols are also being developed to validate the coated seals later under real fuel cell conditions. Another focus is on the adhesion of the coating to the silicone surface, which is challenging due to its low surface energy. Furthermore, DVR measurement methods are being adapted to assess the mechanical stability and sealing performance of the coated materials under realistic conditions.

In the H2Coat project, the partners are pooling their expertise in materials technology and fuel cell development.

Rhenotherm Miniparts develops and investigates suitable coating systems, evaluates their adhesion and barrier effect, and later transfers the process to real fuel cell components.

ZBT provides test specimens and bipolar plates with seals, performs permeation and DVR measurements, and tests the coated seals in fuel cells under real operating conditions. The results are compared with reference stacks to evaluate the coating's effect on performance and aging.

With the development of the H2Coat special coating, the project partners are making an important contribution to the safe and economical use of hydrogen in fuel cell technology. By significantly reducing hydrogen losses, efficiency is increased and the foundation is laid for broader industrial application – a step towards greater safety, sustainability, and competitiveness in hydrogen mobility.

More information:
https://zbt.de/projects/h2coat-spezialbeschichtung-fuer-silikondichtungen-in-brennstoffzellen-soll-permeation-reduzieren/