Economic Hydrophobic Carbon Paper Sheet (T 0.2mm * L 100mm * W 100mm) for Electrolyzer and Fuel Cell, CEFCEHPOCPS

Hydrophobic carbon paper serves as the standard Gas Diffusion Layer (GDL) substrate in Proton Exchange Membrane Fuel Cells (PEMFCs) and specialized electrolyzer components. By treating raw carbon paper with a non-polar fluoropolymer—most commonly Polytetrafluoroethylene (PTFE / Teflon)—the porous matrix repels liquid water while maintaining open gas channels for reactant and product transport.

The primary application is PEM Fuel Cells (PEMFCs). In a fuel cell, water is continuously produced at the cathode during the Oxygen Reduction Reaction (ORR). If this water accumulates inside the GDL, it causes flooding, blocking oxygen from reaching active catalyst sites. (1) Capillary Exclusion: The hydrophobic PTFE coating alters the surface energy of the carbon fibers, forcing liquid water out of small pores under high capillary pressure. (2) Separated Flow Paths: Water is forced to pool and purge through specific larger pores or liquid pathways, leaving the majority of macropores open for rapid gaseous reactant diffusion (H2 and O2).

In water or CO2 electrolyzers, hydrophobic carbon paper is deployed when rapid gas removal is essential: Hydrophobic carbon paper prevents liquid electrolyte from penetrating the GDL, maintaining a stable gas-liquid-solid triple-phase boundary where gaseous CO2 can react. Moreover, controlled hydrophobicity prevents hydrogen gas bubbles (H2) from forming stagnant liquid blockages near the catalyst surface.