Evaluation of Stress Conditions in Operated Anode Supported Type Cells Based on In-Situ Raman Scattering Spectroscopy

We develop the evaluation method of stress conditions in operated SOFC based on in-situ raman scattering spectroscopy. This method uses F2g vibration mode of CeO2 in interlayer of anode supported type SOFC as a probe, and we can calculate stress in an interlayer, i.e. stress in an electrolyte from the shift of a raman peak. We apply this method to typical anode supported type cells and evaluate stress conditions during operation. Using this method, stress conditions in the electrolyte before operation is evaluated to be compressive, consistent with XRD and literature. During operation, stress conditions were changed by the reduction of NiO to Ni. The compressive stress was decreased. In addition, the standard deviation of stress becomes larger than before reduction, and nonreversible. Those results indicate that compressive residual stress introduced into the electrolyte during fabrication process is relaxed, and suggest that an electrolyte become mechanically unstable during operation.