Exploring Methanol and Proton Diffusion in Blended Polymeric Ion Exchange Membranes for Fuel Cells: Computational Study vs. Experimental Evidences

Fuel cells are considered attractive energy sources due to their high energy density, environmental friendliness, and operation without the combustion of petroleum. Among the various types of fuel cells, direct methanol fuel cells are more convenient than hydrogen cells because they can be handled easily. New sulfonated hydrocarbon proton exchange membranes (PEMs) for direct methanol fuel cells have been prepared by blending sulfonated poly(arylene ether sulfone) with polyethersulfone (PES) to decrease methanol permeability while maintaining high proton conductivity. As computational power continues to increase, the idea of using theoretical modeling to find an ideal membrane becomes more feasible. Molecular dynamics simulations have been performed in order to assess the effects of the blending on the membrane properties and to suggest how to improve the understanding about the effect of charged functional groups on the polymeric ion exchange membrane structures. The incorporation of hydrophobic domains effect to transport behaviour of blend membrane. The blend membrane, showing higher hydronium ions and lower methanol diffusivity than pure SPEAS pure membrane, is very effective in hindering methanol permeability and providing an effective barrier to methanol crossover.