Author(s)

S. Chupin, N. Vivet, D. Rochais & E. Bruneton

Abstract

SOFC (Solid Oxide Fuel Cells) appear to be a great alternative way to produce electricity from hydrogen with high efficiency and no greenhouse gas emissions. SOFC are efficient at high temperatures (around 800°C) and are meant to be used for stationary applications as heat and electric co-generation devices. To understand how gases, electricity and heat flow through these media and to improve their efficiency, it is critical to know the actual microstructure of these electrodes. The studied electrodes are Ni-YSZ cermets in which characteristic element sizes are around 1m. The 3D microstructure has been reconstructed using FIB (Focused Ion Beam) tomography. This technique has been used on several samples (different Ni-YSZ proportions) and gives representative 3D volumes of around 10×10×10μm with a 10nm resolution. Theses 3D volumes are then analysed to extract some important structural parameters such as volumetric proportions, active surfaces, connectivity of each components and \“three phase boundaries” (TPB). Then, the 3D reconstructed volumes have been used to determine homogeneous media equivalent properties such as thermal, ionic and electric conductivities. These homogeneous equivalent properties are estimated using a hot guarded plate simulation that takes into account each component properties and the 3D structure. Keywords: SOFC, FIB, tomography, thermal conductivity. 1 Introduction Solid oxide fuel cell (SOFC) based-technology is one of the most promising energy conversion systems due to its high efficiency and fuel flexibility [1]. The materials involved in their constitution have become increasingly sophisticated, both in composition and microstructure. One of the most common anode

Keywords

SOFC, FIB, tomography, thermal conductivity