Isotope exchange experiments were carried out on a dense 0.5μm-thick film of La0.6Sr0.4CoO3 which had been deposited onto a Ce0.9Ca0.1O1.9 substrate by means of laser ablation. The isotope exchange profile was measured from the surface and into the electrolyte by using secondary ion mass spectrometry. The diffusion of O through the La0.6Sr0.4CoO3 film was fast enough to prevent any observable gradient in O-isotope concentration across the film. The surface isotope-exchange rate was deduced from the diffusion profile into the electrolyte layer. The electrochemical impedance was compared with the surface isotope-exchange rate, and the O partial pressure dependences of the 2 parameters were found to be quite similar. The absolute value of the surface isotope-exchange rate was more than twice that expected on the basis of the electrochemical impedance.

Oxygen Isotope Exchange with a Dense (La,Sr)CoO3 Electrode on a (Ce,Ca)O1.9 Electrolyte. T.Kawada, K.Masuda, J.Suzuki, A.Kaimai, K.Kawamura, Y.Nigara, J.Mizusaki, H.Yugami, H.Arashi, N.Sakai, H.Yokokawa: Solid State Ionics, 1999, 121[1-4], 271-9