Analysing Tortuosity for Solid Oxide Fuel Cell Anode Material: Experiments and Modeling

Xiaoqiang Zhang, Danan Yang, Min Xu, Aaron Naden, Mayken Espinoza-Andaluz, Tingshuai Li, John T.S. Irvine, Martin Andersson

Research output: Contribution to journalArticlepeer-review

Abstract

Solid oxide fuel cells (SOFCs) directly convert chemical energy to electricity with high electrical efficiency. It involves gas transport through the porous electrode to the three-phase boundaries (TPB). The tortuosity of gas transport relates the bulk diffusion of gas in free space to the effective diffusion coefficient of gas migrating through a porous material. Therefore, determining the tortuosity is of great importance. This paper tests button SOFCs with NiO-YSZ as anode material followed by dual beam-focused ion beam scanning electron microscopy (FIB-SEM) to obtain 2D serial slice images. Based on processed 2D images and reconstructed 3D microstructure, the tortuosity is calculated using three approaches i.e., porosity-tortuosity correlations, voxel-based, and path-length-based approaches. The test results show that a decrease in Ni content in the anode greatly decreases the cell performance due to a decreased percolated electronic phase. The sample with low performance has high tortuosity. Different approaches vary regarding the tortuosity value and computational time. The path-length-based approach can achieve reasonable accuracy in a relatively short time but is only valid for using the longest path length.

Original languageEnglish
Article number094502
JournalJournal of the Electrochemical Society
Volume170
DOIs
Publication statusPublished - 2023 Sept

Subject classification (UKÄ)

  • Other Chemical Engineering

Free keywords

  • Anode
  • CFD simulation
  • DRT analysis
  • Reconstruction
  • SOFC
  • Tortuosity

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