In Situ TEM Analysis

In situ observations of nano- or sub-nano scale structures at the interface between the electrode and electrolyte of an oxide-ion conductor by transmission and scanning transmission electron microscopes are described. After the introduction of several characteristic techniques, the development of instruments for in situ observations is described. Electron holography can visualize the electrostatic potential inside a material. Shifts of such potentials resulting from the shifts of oxygen distribution are observed at high temperatures in a vacuum and an oxygen atmosphere. Electron energy loss spectroscopy identifies the cations responsible for the redox reactions in ion conductors. Comparing half-cell models (tungsten/oxide-ion conductor/platinum) and complete cell models (platinum/oxide-ion conductor/platinum), we recognize clearly the activeness of platinum electrodes by electron holography and electron energy loss spectroscopy.