The surface segregation and inter-diffusion of cations and impurities in La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF) electrode structures micro-patterned on a Zr0.84Y0.16O1.92 (YSZ) single crystal was investigated by high-resolution Time-of-Flight Secondary Ion Mass Spectrometry and Low-Energy Ion Scattering. The outermost and near surface of the microelectrodes showed significant changes after patterning and electrochemical testing of the cell. As occurring in bulk LSCF ceramics, Sr segregation towards the surface is observed after annealing at 500°C. Furthermore, the electrode showed that impurities (i.e. Na, Si and Ca) originating from the YSZ electrolyte bulk migrate actively to the LSCF electrode during electrochemical testing. The impurity migration has implications for oxygen surface exchange at the cathodeelectrolyte and air interface for solid oxide fuel cells: the electrolyte YSZ surface becomes cleaner whereas the segregation of Sr to the LSCF outer surface seems to be suppressed with respect to the operation time of the device.