Nanostructure of HT-PEFC Electrodes Investigated with Scattering Methods

Abstract

The nanostructure of the electrode layer of a HT-PEFC is studied with neutron and X-ray small-angle scattering techniques. The different contrasts of the two probes provide a view on different aspects of the electrode layer. In combination with contrast variation by H-D isotope exchange further insight into the distribution of the different components on length scales in the range of 1-100 nm is obtained. An outlook shows the perspectives of scattering techniques for studying proton diffusion in such heterogeneous materials.

Dynamics studied by Quasielastic Neutron Scattering (QENS)

“…Schematic picture of a HT-PEFC with proton conducting polymer membrane surrounded by the electrode layers. The zoom on the right shows a sketch of the electrode layer consisting of Pt catalyst particles on a carbon-PTFE support with phosphoric acid in the remaining space[55]…”

Fuel Cell Electrode Characterization Using Neutron Scattering

“…The structure of HT-PEFC catalyst layers has been analyzed with SAXS, SANS and transmission electron microscopy (TEM) with samples of the same kind (20% and 60% Pt) [19,25,26]. In these publications we have shown that the combination of different scattering methods highlights different parts of the sample.…”

“…In the SANS regime, such experiments have been presented in Ref. [25]. This is especially useful for such heterogeneous systems as electrode layers.…”

Fuel Cell Electrode Characterization Using Neutron Scattering

“…The structure of HT-PEFC catalyst layers has been analyzed with SAXS, SANS and transmission electron microscopy (TEM) with samples of the same kind (20 and 60 % Pt) [13,19,20]. In these 2 instances of the Beaucage model, with R g,0 of about 10 Å from the Pt particles, and a larger length scale R g,1 500 Å of the supporting structure, with a fractal power law decay with an exponent P close to 4 indicating a compact structure.…”