Gas Diffusion Layer with a Regular Hydrophilic Structure Boosts the Power Density of Proton Exchange Membrane Fuel Cells via the Construction of Water Highways

The gas diffusion layer (GDL) is an essential carrier for the mass transmission of proton exchange membrane fuel cells (PEMFCs), which decides the peak power density of PEMFCs. Herein, a gas diffusion layer with a regularly arranged hydrophilic and hydrophobic pattern structure was prepared by a template method combined with the ultrasonic spray process. The peak power density was enhanced by 30% (from 520 to 678 mW/cm2) compared to an unpatterned structure, and the breakthrough pressure of the GDL was reduced from 13.61 to 2.96 kPa. In addition, the finite element analysis (FEA) results indicate that the polarization curve of calculation was highly consistent with the experimental results. Importantly, the capillary pressure of the hydrophilic area was about 0.3 kPa, much lower than that of the hydrophobic area (2 kPa), demonstrating that the hydrophilic and hydrophobic synergistic structure reduced the water transmission resistance in separating water and oxygen and builds a high-speed channel for water transmission.