A 2D and 3D X-ray m-diffraction and m-ﬂuorescence study of a mixed ionic electronic conductor Dario Ferreira Sanchez a,* , Daniel Grolimund a , Maxime Hubert b,c , Pierre Bleuet b,d ,J  er ^ ome Laurencin b,c a Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland b Univ. Grenoble Alpes, F-38000 Grenoble, France c CEA/Liten, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France d CEA/LETI, MINATEC Campus, F-38054 Grenoble, France article info Article history: Received 14 July 2016 Received in revised form 31 October 2016 Accepted 13 November 2016 Available online xxx Keywords: Solid oxide fuel cell X-ray diffraction tomography X-ray ﬂuorescence tomography X-ray micro beam abstract Due to the mixed ionic electronic conductive properties of the Lanthanum Strontium Co- balt Ferrite (LSCF) La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3d compound, it is of great scientiﬁc and techno- logical interest. Especially in the Solid Oxide Fuel Cell (SOFC) technology, this compound has receiving great attention as a cathode material. However, its chemical reactivity with the Yttria-stabilized Zirconia (YSZ) electrolyte still remains one of the main challenges, which demands a comprehension in the mm and sub-mm range. In order to address the reactivity issues locally in the micrometre scale range, 2D and 3D X-ray m-diffraction and m- ﬂuorescence analysis have been performed on a pristine LSCF cathode layer. The cathode was deposited on a dense YSZ electrolyte substrate spaced by a thin Gadolinium doped Ceria Oxide (CGO) barrier layer in between LSCF and YSZ to limit the reactivity. The present approach offers a larger ﬁeld of view in comparison to electron microscopy techniques. The method can provide a more representative information and may offer some insights on the reactivity distribution along the interfaces. The formation of micro SrZrO 3 inclusions in LSCF layer is then indubitably identiﬁed, as well as in the CGO/YSZ interface. © 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Solid Oxide Fuel Cells (SOFCs) are of great technological in- terest owing to their efﬁciency in converting a wide variety of hydrocarbon fuels and hydrogen to electricity, this route being of higher efﬁciency and more environmentally benign than a combustion process. There are several challenges involved in the development of this technology. The combination of high operating temperatures and mismatch between the thermal expansion coefﬁcients of the cell components can induce re- sidual stresses. Besides, species interdiffusion between the cell materials can lead to detrimental chemical reactions. The understanding of these phenomena is essential to design innovative solutions such as new alternative materials, and overcome the SOFC technology challenges by extending de- vices lifetime and reliability. In this context, the development of standard methodologies to investigate the SOFCs local structure and chemical/elemental composition in the micro- metre range is critical. To address these SOFCs issues, X-ray imaging techniques have been demonstrated by several authors to be among the most suitable ones. Among their advantages, it can be mentioned (i) the potential to perform in situ experiments [40]; * Corresponding author. E-mail addresses: dario.f.sanchez@gmail.com, dario.ferreira@psi.ch (D.F. Sanchez). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (2016) 1 e9 http://dx.doi.org/10.1016/j.ijhydene.2016.11.094 0360-3199/© 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Sanchez DF, et al., A 2D and 3D X-ray m-diffraction and m-ﬂuorescence study of a mixed ionic elec- tronic conductor, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.11.094