Effects of compression on mechanical integrity, gas permeability and thermal stability of gas diffusion layers with/without sealing gaskets

The compressibility, the gas permeability and the thermal stability of 4 commercially available uncoated GDLs (or carbon substrates) and MPL-coated GDLs are, with/without Teflon and silicone sealing gaskets, investigated before and after performing ex-situ compression tests mimicking the compressive stresses within the fuel cell. The results show that the gas permeability of the tested GDLs are impacted more with Teflon gaskets than with the silicone gaskets and this is due to the lower stiffness of the former gaskets. Likewise, the GDLs are more deformed with the Teflon gaskets than with silicone gaskets and this is due to the same reason mentioned above. The thermogravimetric analysis (TGA) data suggests that the bare carbon substrates, unlike the MPL-coated GDLs, lose up to 40% of the PTFE material after the compression test either with or without sealing gaskets.