Visualizing Interface Degradation of Solid Oxide Cell

Solid oxide electrolysis and fuel cells (SOEC/SOFC) can help achieve global net-zero carbon emissions. Understanding the degradation mechanisms of the cells and their components is crucial for enhancing longevity to ensure the cost-effectiveness of large-scale applications. Traditional degradation research relies on post mortem analysis, limiting our ability to elucidate dynamic changes and their separate contributions. The work introduces an operando environmental transmission electron microscope (ETEM) approach to investigate degradation processes in SOEC/SOFC. As a proof-of-concept, degradation experiments were conducted on cells composed of lanthanum-strontium-cobalt oxide (LSC) electrodes and an yttrium-stabilized zirconia (YSZ) electrolyte, where the symmetric LSC-YSZ-LSC cells are subjected to strong polarization, in 2.7 mbar O₂, at an operation temperature of 700 °C inside an ETEM. The results highlight the capability of real-time monitoring of structural and compositional changes of active solid oxide cells through scanning transmission electron microscope imaging and electron energy loss spectroscopy analysis. Additional post mortem TEM and energy-dispersive spectroscopy confirmed previously reported decomposition of the negatively polarized LSC electrode and crack formation on the anodic side. Thereby, this work demonstrates the feasibility of using operando ETEM for in-depth, nanoscale observation of SOEC/SOFC degradation during cell operation.