PTFE Nanopowder (50-500 nm, Dupont) as Electrode Additive for Hydrophobic Gas Diffusion Layer (GDL), CHGDLEANPTFE

In the fabrication of Gas Diffusion Layers (GDL) for fuel cells and electrolyzers, Polytetrafluoroethylene (PTFE) nanopowder serves as the primary hydrophobic agent. Its role is to balance the "competing" transport of gases (reactants) and liquid water (products) within the porous structure of the carbon paper or cloth.

Hydrophobicity and Water Management: The GDL must remain "dry" enough to allow gases (H2, O2, or CO2) to reach the catalyst layer. PTFE nanopowder coats the carbon fibers, increasing the contact angle of water. This creates hydrophobic channels that prevent the GDL from "flooding" (saturating with liquid water), which would otherwise block gas transport and "choke" the cell. By tuning the PTFE content, manufacturers control the capillary pressure within the pores, actively pushing produced water out toward the flow channels.

Binding and Structural Integrity: PTFE acts as the "glue" for the Microporous Layer (MPL)—the thin coating of carbon black applied to the GDL base. During the high-shear mixing or "calendering" process, PTFE nanopowder undergoes fibrillation, where the particles stretch into microscopic "cobwebs" or fibrils. These fibrils lock the carbon black particles together, creating a robust, flexible, and crack-resistant film.

Notes: Please try to store the PTFE nanopowder in the dry place. 

References: 

1. Y. Wu, et al. Mitigating Electrolyte Flooding for Electrochemical CO2 Reduction via Infiltration of Hydrophobic Particles in a Gas Diffusion Layer, ACS Energy Lett. 2022, 7, 9, 2884–2892.
2. E, M. Can, et al. Superhydrophobic fluorinated carbon powders for improved water management in hydrogen fuel cells, J. Power Sources, 2022, 548, 232098. 
3. J. Lee. Hoang, et al., Directly integrated membrane-electrode assembly with a macroporous-carbon functional layer for the flexible operation of fuel cells under varying humidity, J. Power Sources, 2025. 636, 236493.