Long Term SOFCs Button Cell Testing

Abstract

This paper reports a new study where relatively longterm tests of about a 1000 h are performed on several planar anodesupported solid oxide fuel cells. The cell electrochemical behaviors are studied by using voltagecurrent density measurement, electrochemical impedance spectroscopy, scanning electron microscopy, and energydispersive Xray spectroscopy. The cell total polarization obtained from electrochemical impedance spectroscopy results is shown to be consistent with the areaspecific resistance calculated from the voltagecurrent density curve over the course of the test. In addition, a fourconstant phase element model is used to analyze the cell components resistances at different intervals over the lifetime of the test. Scanning electron microscopy and energydispersive Xray spectroscopy are used postmortem to determine if any damages occurred to the cells and to determine if any change in composition occurred to the lanthanum strontium cobalt ferrite cathode. This study shows that the tested cells remain stable with a relatively small increase in the cell total polarization but with no increase in ohmic resistance.