- Suppress corrosion by isolating the substrate from acidic media
- Stabilize electrical contact at critical interfaces
- Maintain low interfacial resistance over extended operating periods
Coating uniformity and cost-efficiency
Beyond durability, coating uniformity has a direct economic impact on PEM electrolyzer design. Noble metal coatings, such as platinum, are among the most expensive materials in the stack. Applying these coatings as thin, continuous layers allows manufacturers to achieve the required protective and conductive functions while minimizing precious metal loading. When coating thickness is precisely controlled and uniformly distributed, performance gains are achieved without proportional increases in material cost. In this way, well-engineered coatings support not only longer component lifetimes, but also lower capital costs and improved economic viability of hydrogen production at scale.
Quality over quantity
Crucially, these benefits depend less on coating thickness and more on the quality and stability of the coating itself. Coating continuity and defect control are essential, as even microscopic discontinuities can become initiation points for localized corrosion under acidic, high-potential conditions. Strong adhesion to the underlying substrate is equally important, ensuring that the coating remains intact during thermal cycling, dynamic loads from pressure variations and prolonged operation. Finally, the coating must maintain electrochemical stability at high anodic potentials and cyclic potentials from shut-down/turn-off operations, where surface reactions and oxidation processes are most aggressive.
Together, these factors determine whether a uniform thin coating functions as a durable lifetime enabler or degrades prematurely under real PEM operating conditions. In other words, a well-engineered thin coating can outperform a thicker, poorly bonded layer. However, the effectiveness of uniform thin coatings can be limited by:
- Mechanical stresses induced by thermal cycling
- Localized defects that become initiation points for corrosion
- Mismatch in thermal or electrochemical behavior between coating and substrate
For this reason, uniform thin coatings should be understood as lifetime enablers, not lifetime guarantees. They extend durability by slowing degradation mechanisms, but only when integrated into a stack design that considers operating conditions, load profiles, and component interfaces.
Summary
Uniform thin coatings can and do extend PEM electrolyzer lifetime in harsh acidic environments—but not by brute force. Their value lies in precise surface control, enabling corrosion resistance and interfacial stability. Without relying on bulk noble metal components. When treated as part of a system-level design strategy, uniform thin coatings become a powerful tool for improving durability in next-gen PEM electrolyzers. They also help reduce PGM use and optimize hydrogen production costs. Supporting more economically viable green hydrogen technologies.
