Effect of water adsorption on conductivity in epitaxial Sm0.1Ce0.9O2-d thin film for micro solid oxide fuel cells applications

Water adsorption, splitting, and proton liberation were investigated on Sm0.1Ce0.9O2-d thin films by scanning probe microscopy. An irreversible volume expansion was observed by applying a positive bias with increased temperature. The volume expansion is also linearly dependent on the relative humidity. A reversible water adsorption process and its effect on the conductivity were also investigated by electrochemical strain microscopy and first order reversal curve under a number of experiment conditions. The presence of a Ce3+ along with OH groups, detected by hard x-ray photoemission spectroscopy established a clear correlation between the water incorporation and the valence state of Ce.