Numerical microstructural optimization for the hydrogen electrode of solid oxide cells

A multiscale model has been used to optimize the microstructure of a classical hydrogen electrode made of nickel and yttria-stabilized zirconia (Ni-8YSZ). For this purpose, a 3D reconstruction of a reference electrode has been obtained by X-ray nano-holotomography. Then, a large dataset of synthetic microstructures has been generated around this reference with the truncated Gaussian random field method, varying the ratio Ni/8YSZ and the Ni particle size. All the synthetic microstructures have been introduced in a multiscale modeling approach to analyze the impact of the microstructure on the electrode and cell responses. The local electrode polarization resistance in the hydrogen electrode, as well as the complete cell impedance spectra, have been computed for the different microstructures. A significant performance improvement was found when decreasing the Ni particle size distribution. Moreover, an optimum has been identified in terms of electrode composition allowing the minimization of the cell polarization resistance. The same methodology has been also applied to assess the relevance of graded electrodes. All these results allow a better understanding of the precise role of microstructure on cell performances and provide useful guidance for cell manufacturing.

Automated summary

A multiscale model was used to optimize the microstructure of a classical hydrogen electrode made of nickel and yttria-stabilized zirconia (Ni-8YSZ). Synthetic microstructures with different Ni/8YSZ ratios and Ni particle sizes were generated and analyzed to understand their impact on the electrode and cell responses. Results showed that decreasing the Ni particle size distribution significantly improved performance, and an optimum electrode composition was identified to minimize cell polarization resistance. These findings provide valuable insights for understanding the role of microstructure in cell performances and guiding cell manufacturing.