Impact of ‘redox’ cycles on performances of solid oxide fuel cells: Case of the electrolyte supported cells

Nickel with yttria stabilised zirconia (Ni-YSZ) is usually used as anode material for the solid oxide fuel cells (SOFCs) technology. Upon cyclic reduction and oxidation of Ni-YSZ ceramic–metal (cermet), the induced cell degradation constitutes one of the main limitations to the SOFCs lifetime. In this study, the effect of anode reduction and oxidation cycling on typical electrolyte supported cell (ESC) has been investigated. The electrochemical degradation has been followed by impedance spectroscopy. The cell damage has been characterised after testing with scanning electron microscopy (SEM). It has been shown that cells can withstand several ‘redox’ cycles without major decrease in electrochemical performances. The ‘redox’ cycling induces only a slight degradation rate estimated to ∼70 mΩ cm2 per cycle. The microstructural observations are found to be consistent with the impedance diagram analysis. Both reveal that the damage is restricted to bulk cermet microstructure change, whereas no cracking is initiated at the anode/electrolyte interface.