Structural features of the magnetron sputtered CuO/GDC anodes for solid oxide fuel cells

Abstract

Abstract The paper presents the results of the research of structure of a thin film CuO/Ce0.9Gd0.1O2-δ (CuO/GDC) anode for solid oxide fuel cells (SOFCs) prepared by magnetron sputtering. Cu-based anode materials of SOFCs are of great interest because they exhibit greater tolerance to sulfur-containing fuels than the widely used Ni-based composite anodes. After deposition, annealing in air and reducing atmospheres, the composition, microstructure and crystallinity of the films were characterized using energy dispersive X-Ray spectroscopy, scanning electron microscopy and X-ray diffractometry, respectively. The as-deposited film consists of cubic fluorite structures of GDC and Cu2O and has a dense, homogeneous structure, in which Cu is evenly distributed over the volume of the film. However, it was shown that, strong Cu segregation is observed in CuO/GDC films, after reduction in hydrogen at a temperature of 750 °C, with the formation of massive agglomerates on the surface. The influence of pre-calcination of the as-deposited films at 1000 °C and 1200 °C on their structure was studied. It is shown that annealing at a temperature of 1000 °C does not prevent the agglomeration of Cu in a reducing atmosphere, while Cu evaporation is observed if annealing temperature is 1200 °C.