Bipolar Plate Materials and Corrosion Behavior in Fuel Cells

Bipolar plates are fundamental components in proton exchange membrane fuel cells, serving as current collectors, gas distribution channels and structural supports. Traditionally fabricated from graphite composites, the quest for lightweight, cost-effective and mechanically robust alternatives has spurred research into metallic and composite materials. Stainless steels, titanium alloys and coated aluminium variants offer high conductivity and manufacturability, yet suffer from corrosion under acidic and high-potential conditions, leading to fuel contamination and performance degradation. Corrosion mechanisms—uniform, pitting and crevice—reflect interactions between the electrolyte, passive films and operational potentials. Protective strategies encompass surface modifications such as nitriding, carbiding and deposition of conductive polymers or ceramic coatings to balance corrosion resistance with low interfacial contact resistance. Recent efforts focus on multilayer architectures, hybrid organic–inorganic composites and advanced deposition techniques to meet stringent targets for durability, efficiency and cost. These advances support the deployment of fuel cells in transport, stationary power and portable devices, aligning with global decarbonisation goals and enhancing the commercial viability of hydrogen technologies.

Research from Nature Portfolio

Polyaniline–Zn-porphyrin composite coatings on 303 stainless steel reinforce the passive film under simulated fuel cell conditions. These organic–metal hybrids achieved markedly lower corrosion current densities and improved power output by combining the barrier properties of conductive polymers with the catalytic stability of porphyrin complexes. The coating maintained performance in acidic medium at elevated temperatures, demonstrating stable interfacial contact resistance and enhanced electrochemical impedance characteristics. This approach exemplifies the integration of functionalised polymers and metallorganic compounds to address intertwined corrosion and conductivity challenges.

Bipolar Plate Materials and Corrosion Behavior in Fuel Cells publication trend

The graph below shows the total number of articles in bipolar plate materials and corrosion behavior in fuel cells across all publications each year (not limited to Nature Index journals).

Technical terms

Interfacial contact resistance (ICR): The electrical resistance at the interface between the bipolar plate and gas diffusion layer, critical for efficient current collection.

Passive film: A thin oxide or nitride layer that forms spontaneously on metal surfaces, providing corrosion protection but often increasing contact resistance.

Pitting corrosion: Localised breakdown of the passive film leading to small cavities that can propagate under acidic conditions.

Electrochemical impedance spectroscopy (EIS): A technique to characterise the resistive and capacitive behaviour of coatings and passive films under applied AC potentials.

Magnetron sputtering: A physical vapour deposition method to deposit thin films with controlled composition and microstructure.

References

1. Stainless steel bipolar plate coated with polyaniline/Zn-Porphyrin composites coatings for proton exchange membrane fuel cell. Scientific Reports (2020).
2. Thin Niobium and Niobium Nitride PVD Coatings on AISI 304 Stainless Steel as Bipolar Plates for PEMFCs. Coatings (2020).
3. Properties of a Plasma-Nitrided Coating and a CrNx Coating on the Stainless Steel Bipolar Plate of PEMFC. Coatings (2020).
4. Concepts for preventing metal dissolution from stainless-steel bipolar plates in PEM fuel cells. Energy Conversion and Management (2022).