The potential of in situ-scanning electron microscopy - Morphology changes of electrically polarized thin film Pt(O_2)/YSZ model electrodes

摘要

Scanning electron microscopy (SEM) is a powerful standard tool for investigating surface topographies with high resolution. By equipping a SEM with a heating stage and a sample holder with electrical contacts for the study of electrochemical cells, morphology changes of solid state electrochemical cells can be monitored at high temperature and under electrical polarization in situ. In this study we demonstrate the potential of in situ-SEM using the example of the ex situ well-characterized electrode model system Pt(O_2)/YSZ. Gas tight, nearly single crystalline, and (111)-orientated thin Pt films on YSZ(111) show bubble formation, cracking, and delamination during anodic polarization caused by the pressure build-up of oxygen pumped to the Pt/YSZ interface. These plastic deformations occur irreversibly; cathodic polarization cannot reverse the blistering. Close to the electrode edges, the electron beam of the SEM influences the electrode process and promotes bubble formation; therefore possible side effects of in situ-SEM as examination method on experimental results are discussed.