Nondestructive reconstruction and analysis of SOFC anodes using x-ray computed tomography at sub-50 nm resolution

A high-resolution, nondestructive X-ray computed tomography (XCT) technique is applied to image the three-dimensional (3D) microstructure of a solid oxide fuel cell (SOFC) composed of a solid yttria-stabilized zirconia (YSZ) electrolyte and a porous nickel YSZ (Ni-YSZ) anode. The X-ray microscope uses the 8 keV Cu K alpha line from a laboratory X-ray source, with a reflective condenser optic lens providing a spatial resolution of 42.7 nm. The reconstructed volume data is visualized as 3D images and further postprocessed in binary-image format to obtain structural parameters. The porosity is calculated using a voxel counting method, and tortuosity is evaluated by solving the Laplace equation. A 3D representation of the microstructure is used to calculate true structural parameters and carry out a detailed study of the gas transport within an SOFC electrode at the pore scale. Simulation of multicomponent mass transport and electrochemical reactions in the anode microstructure using the XCT data as geometric input illustrate the impact of this technique on SOFC modeling. (c) 2008 The Electrochemical Society.