Self-Supporting Microporous Layer for Polymer Electrolyte Fuel Cells Using Thin Carbon Mesh Gas Diffusion Layer

The gas diffusion layers (GDLs) used in polymer electrolyte fuel cells (PEFCs) are relatively thick compared with the electrocatalyst layer and electrolyte membrane. Reducing GDL thickness is expected to reduce gas transport resistance. Such thin GDLs with high electrical conductivity enable higher power density per volume of cell stacks. Here, thin MPL/GDLs are fabricated by printing a highly conductive microporous layer (MPL) on carbon meshes or carbon nanotube sheets as a substrate to create tailored self-supporting MPLs. The electrical conductivity was improved by optimizing the carbon black material used in the MPL, and carbon nanotubes were added to tailor a pore structure within the MPL. The thickness of the resulting MPL/GDLs is approaching 50 µm, which is not only thinner than the current MPL/GDL, but also results in lower gas transport resistance. The thinner MPL/GDLs are a promising solution to increase the power density of PEFC cell stacks.