Degradation and Stabilization of Ionomeric Membranes used in Fuel Cells: Focus on Early Fragmentation Events and Diffusion Processes

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TECHNICAL SUMMARYESR and Fourier transform infrared (FTIR) spectroscopies, ESR imaging (ESRI) and computational methods will be applied in order to provide details on and formulate the mechanism of degradation and stabilization of ionomer membranes used in fuel cells. The major objectives for the next four years are to: 1. Make the transition from ?ESR in an in situ fuel cell? to ?ESR Imaging of an in situ fuel cell? by combining in situ experiments with the ESR Imaging methods developed in the previous grant period. This approach will make possible measurements of the diffusion rate of nitroxide spin probes and spin adducts between the anode and cathode sides of the fuel cell and thus visualize crossover processes. 2. Focus on membrane stabilization by assessing and comparing the effect of various neutralizing cations on the stability of ionomeric membranes. 3. Increase the lifetimes of unstable intermediates by encapsulation in the hydrophobic environment of cyclodextrins and cucurbiturils as hosts. 4. Initiate density functional theory calculations in order to understand the effect of conformations of radical fragments and adducts on their magnetic parameters (hyperfine splittings and g values). The collaboration with scientists and engineers from 3M, Ford Laboratories, and the General Motors Electrochemical Energy Research Lab, as well as the contributions of international participants, will contribute to the success of the proposed project. NON-TECHNICAL SUMMARYFuel cells are a promising source of clean energy for automotive and stationary applications. Polymer membranes are crucial for fuel cell operation, but their durability is a major problem that must be solved before the fuel cells are in use. This proposal describes the application of spectroscopic, imaging and computational methods that are expected to provide important details on the degradation and stabilization of membranes in fuel cells. The collaboration of the Detroit group with scientists and engineers from 3M, Ford Laboratories, and the General Motors Electrochemical Energy Research Lab is an example of Translational Research: Fundamental studies on the mechanism of membrane degradation will lead to the synthesis of more robust membranes. International collaborations will add talent to the local group. This investigator will co-teach a course entitled ?Fundamentals of Fuel Cells?; the course will be tailored for engineers and scientists who lost their jobs due to the current economic problems and need to be retrained so as to participate in ?green? ways to generate clean energy.