Impact of segregation-induced effects on the transfer of charge and matter across the gas/electrolyte interface: the Oxygen/Zirconia system

This paper considers a model which describes the effect of segregation on defect chemistry of the boundary layer of ionic conductors and the impact of this layer on performance of electrochemical devices, such as solid oxide fuel cells. It is shown that segregation may have a dual effect on functionality of solid electrolytes involving: (i) generation of an electrical potential barrier which acts as a diffusive resistance for the transport of charged defects across the interface and (ii) the formation of a mixed-type conductivity within the boundary layer. Specifically, this paper considers the effect of segregation on defect chemistry of the boundary layer of yttria-stabilised zirconia and its effect on the formation of concentration gradient in the interface layer.