A three-dimensional heterogeneity analysis of electrochemical energy conversion in SOFC anodes using electron nanotomography and mathematical modeling Tomasz A. Prokop a , Katarzyna Berent b , Hiroshi Iwai c , Janusz S. Szmyd a , Grzegorz Brus a,* a AGH University of Science and Technology, Faculty of Energy and Fuels, 30 Mickiewicza Ave., 30-059 Krakow, Poland b AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, 30 Mickiewicza Ave., 30-059 Krakow, Poland c Kyoto University, Department of Aeronautics and Astronautics, Nishikyo-ku, 615-8540 Kyoto, Japan article info Article history: Received 13 February 2018 Received in revised form 3 April 2018 Accepted 4 April 2018 Available online 30 April 2018 Keywords: SOFC Model Micro-scale Pore-scale Three-dimensional Heterogeneity abstract In this paper a fully three dimensional, multiphase, micro-scale solid oxide fuel cell anode transport phenomena numerical model is proposed and verified. The Butler-Volmer model was combined with empirical relations for conductivity and diffusivity - notably the Fuller- Shetler-Giddings equation, and the Fickian model for transport of gas reagents. FIB-SEM tomography of a commercial SOFC stack anode was performed and the resulting images were processed to acquire input data. A novel method for estimating local values of Triple Phase Boundary length density for use in a three-phase, three-dimensional numerical mesh was proposed. The model equations are solved using an in-house code and the re- sults were verified by comparison to an analytical solution within the range of its appli- cability. A limited parametric study was performed to qualitatively assess simulation performance and impact of heterogeneity. Despite the high dependence of the SOFC anode performance on the geometry of its anisotropic, three-phase microstructure there are very few micro-scale numerical models simulating transport phenomena within these electrodes. © 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Introduction Fuel Cells are energy conversion devices capable of converting chemical energy directly into electrical energy. Solid Oxide Fuel Cells (hereafter SOFC) - excelling in terms of efficiency, magnitude of power output and relative affordability - are defined as fuel cells, where the electrolyte is composed of a solid-state ceramic material. Despite the progress of SOFC technology in recent years, devices of this type face several challenges [1]. Since commercial fuel cells include very thin ceramic and ceramic-metal composite elements, their * Corresponding author. E-mail address: brus@agh.edu.pl (G. Brus). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 43 (2018) 10016 e10030 https://doi.org/10.1016/j.ijhydene.2018.04.023 0360-3199/© 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.