ODNP of Fuel Cell Membranes

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Polyelectrolyte membrane fuel cells can be operated at low temperature suitable for their use in consumer electronics and vehicles. Fueled by hydrogen and oxygen fuel cells produce water, which critically affects the function of the membrane that separates the anode from the cathode and is permeable to cations. To design efficient fuel cells, the membrane function must be understood in great detail for different hydration levels. But the water and ion transport though the fuel cell membrane is heterogeneous and determined by the membrane morphology, which changes with its hydration state. Magnetic resonance methods like Laplace NMR of diffusion and relaxation as well as Overhauser Dynamic Nuclear Polarization (ODNP) are unique in their capabilities of unraveling the complex heterogeneity of transport regimes and assigning them to the different morphological sites inside the membrane. This project combines both magnetic resonance methods in a study of membrane function to resolve conflicting views on membrane water transport with the help of a magnetic resonance toolbox. A novel set-up for in operando investigations of membrane function will clarify and specify the moisture-dependent membrane structure and water transport.