Computer Modeling of Diffusion Behavior of H2/02 Gases in Aromatic Membranes

The oxidant (air 02) and fuel (hydrogen H2) transports between electrodes through a sulfonated hydrocarbon type membrane matrix were modeled under varied solvent uptake situations applying atomistic modeling tools. It was observed that the transport dynamics of both H2 and 02 gases improved against an increase in amount of absorbed solvent, implying the pronounced oxidant and fuel crossover inside the acidic membranes with significant solvent uptake values, which could considerably diminish the membrane performance when applied in polymer electrolyte membrane fuel cells. These observations are rationalized with the higher fractional free volume of hydrophobic phase as well as larger hydrophilic clusters appeared within the membrane.