Physicochemical properties of proton-conducting SmNiO3 epitaxial films

• Main Authors: Xing Xu, Chen Liu, Jing Ma, Allan J. Jacobson, Cewen Nan, Chonglin Chen
• Format: Article
• Language: English
• Published: Elsevier 2019-06-01
• Series: Journal of Materiomics
• Online Access: http://www.sciencedirect.com/science/article/pii/S235284781830114X

Proton conducting SmNiO3 (SNO) thin films were grown on (001) LaAlO3 substrates for systematically investigating the proton transport properties. X-ray Diffraction and Atomic Force Microscopy studies reveal that the as-grown SNO thin films have good single crystallinity and smooth surface morphology. The electrical conductivity measurements in air indicate a peak at 473 K in the temperature dependence of the resistance of the SNO films, probably due to oxygen loss on heating. A Metal-Insulator-Transition occurs at 373 K for the films after annealing at 873 K in air. In a hydrogen atmosphere (3% H2/97% N2), an anomalous peak in the resistance is found at 685 K on the first heating cycle. Electrochemical Impedance Spectroscopy studies as a function of temperature indicate that the SNO films have a high ionic conductivity (0.030 S/cm at 773 K) in a hydrogen atmosphere. The activation energy for proton conductivity was determined to be 0.23 eV at 473–773 K and 0.37 eV at 773–973 K respectively. These findings demonstrate that SNO thin films have good proton conductivity and are good candidate electrolytes for low temperature proton-conducting Solid Oxide Fuel Cells. Keywords: SmNiO3, Thin film, Transport properties, Ionic conductivity, Impedance measurements