Comparing the 3D morphology of solid-oxide fuel cell anodes for different manufacturing processes, annealing times, and operating temperatures

TL;DR

This study compares the 3D morphology of SOFC anodes produced by different manufacturing processes, annealing times, and operating temperatures, revealing how these factors influence electrode structure and performance.

Contribution

It provides a detailed quantitative analysis of how manufacturing methods, annealing, and temperature affect SOFC anode morphology using advanced 3D imaging and geometrical descriptors.

Findings

Manufacturing process significantly impacts anode microstructure.

Annealing time alters the triple phase boundary length.

Operating temperature influences pore connectivity and tortuosity.

Abstract

Solid oxide fuel cells (SOFCs) are becoming increasingly important due to their high electrical efficiency, the flexible choice of fuels and relatively low emissions of pollutants. However, the increasingly growing demands for electrochemical devices require further performance improvements. Since it is well known that the 3D morphology of the electrodes, which is significantly influenced by the underlying manufacturing process, has a profound impact on the resulting performance, a deeper understanding for the structural changes caused by modifications of the manufacturing process or degradation phenomena is desirable. In the present paper, we investigate the influence of the annealing time and the operating temperature on the 3D morphology of SOFC anodes using 3D image data obtained by focused-ion beam scanning electron microscopy, which is segmented into gadolinium-doped ceria, nickel and pore space. In addition, structural differences caused by manufacturing the anode via infiltration or powder technology, respectively, are analyzed quantitatively by means of various geometrical descriptors such as specific surface area, length of triple phase boundary per unit volume, mean geodesic tortuosity, and constrictivity. The computation of these descriptors from 3D image data is carried out both globally as well as locally to quantify the heterogeneity of the anode structure.