3D phase mapping of solid oxide fuel cell YSZ/Ni cermet at the nanoscale by holographic X-ray nanotomography

Abstract

SOFC electrochemical performances are strongly dependent on the micro and nanostructure of the electrodes. 3D image analysis is an essential tool to characterise these microstructures. However, the studied volumes have to be sufficiently large to be representative of the heterogenous medium. In this study, quantitative phase contrast X-ray nano-holotomography is performed on large volumes of SOFC anode consisting by a Ni/YSZ cermet. Both the electrode functional layer and the current collector of anode supported cell are characterised in 3D. The setup and data processing adaptation needed for such an absorbing materials are described. The X-ray nano-holotomography was performed with an isotropic voxel size of 25 × 25 × 25 nm3 and a field of view of about 50 μm. This technique is non-destructive and was used in local tomography mode. After filtering and thresholding, the segmentation of the 3D reconstructions allows precisely separating the network of each phase of the electrode (metallic, ceramic and porosity), giving representative features of the microstructure.