Over the past decade, many efforts have been made to develop new materials exhibiting high oxide ion mobility at low temperature. In addition to the improvements of existing materials, new classes of conductors in which the structure have been shown to play an important role has been proposed. These materials are reviewed according to their structure type. Their performances and limitations are presented and discussed.

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Mit Hilfe von DTA‐ und HT‐Röntgenanalysen werden im SrO‐reichen Teil des Systems die Verbindungen Srßi, O4, Sr3Bi2O6 und Sr2Bi2O5 (Pcmm, Z=4) charakterisiert.

Oxygen permeation measurements were performed on two layered bismuth based oxide ceramics: a rhombohedral phase belonging to the Bi 2 O 3 -CaO system, (Bi 2 O 3 ) 0.73 -(CaO) 0.27 (BICAO) and a BICOVOX phase. Oxygen permeability for these systems was compared to permeability of the cubic fluorite type structure with composition (Bi 2 O 3 ) 0.75 (Er 2 O 3 ) 0.25 (BE25). Low oxygen permeability was observed for the pure ceramic.As for BE25, permeability was considerably increased if 40 vol% of silver was added to BICAO. In contrast, permeability was not improved by addition of gold to BICOVOX. For this latter phase, the oxygen molecular exchange at the surface is clearly the limiting step in the oxygen transfer.

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