| Abstract Scope |
Chromium (Cr) poisoning from metallic interconnects is a major cause of degradation in solid oxide electrolysis cells (SOECs), yet its influence on internal oxygen partial pressure (pO₂) remains unclear. In this study, a specially designed probe cell with probe and reference electrodes was employed to monitor local pO₂ within the electrolyte under operating conditions. Lanthanum strontium cobaltite (LSC) was used as the air electrode. Crofer 22 APU mesh served as the chromium source, while Pt mesh was used as a chromium-free reference. Electrochemical impedance spectroscopy (EIS) was conducted to evaluate resistance changes, and low-voltage scanning electron microscopy (LV-SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) were used to analyze microstructural and phase evolution. Under chromium-free conditions, the internal pO₂ remained stable. In contrast, the presence of chromium led to a gradual increase in pO₂, accompanied by increased polarization resistance due to the formation of insulating chromium-containing secondary phases. |
