Submicrometer 3D Structural Evidence of Fuel Cell Membrane Heterogeneous Degradation.

Polymer membranes used in the proton exchange membrane fuel cell (PEMFC) technology are subject to severe chemical and physical degradations during operation. A microscopic diagnosis of the effects of aging on the microstructure of benchmark perfluorinated sulfonic acid (PFSA) membranes is crucial to developing long-lasting devices. We report here the first μSAXS study of membranes aged for 2500 h in a stack.

Characterization of porous structure through the dynamical properties of ions confined in sulfonated polyimide ionomers films.

The structure of sulfonated PolyImide (sPI) ionomer membrane has been investigated via the transport properties of ions confined inside. Transport coefficients of N(CH(3))(4)(+) and Na(+) ions have been determined by several techniques in order to get a range of time/space scale as wide as possible: a method using radiotracers, conductivity, pulsed field gradient NMR and NMR quadrupolar relaxation rates determination. For N(CH(3))(4)(+), the self-diffusion has been measured in the direction of membrane plan (parallel) and in the perpendicular direction (transverse), whereas for Na(+) only transverse self-diffusion has been measured.