Three-dimensional reconstruction and optimization of porous fuel electrode in reversible solid oxide cells based on the Lattice Boltzmann method

Abstract

A reversible solid oxide cell can work as a fuel cell (FC) or an electrolyzer cell (EC) with superior efficiency in a single device, which has the potential to become the core of energy conversion and storage. Since the redox reaction occurs at the three phase boundary in the porous electrode, the microstructure of which has a significant effect on the dynamic performance of the cell. Current research on porous electrodes mainly focuses on parametric and steady-state analysis but lacks studies on dynamic performance. In this study, we investigate the mass transfer process and dynamic performance of rSOC fuel electrodes by 3D reconstruction and artificial generation combined with a two-dimensional lattice Boltzmann method. The results show that the effective diffusion coefficients and cell performance of the XCT cross-sectional and random sphere method are much higher than those of the Gaussian filter and fiber rod structure. The change in H2 concentration is larger for switching from FC to EC compared to switching from EC to FC, but the transient steady-state difference and relaxation time of the voltage is smaller. These results can be used as a reference for the design and optimization of the porous electrodes in reversible solid oxide cells.