Characterisation of the electrode–electrolyte BIMEVOX system for oxygen separation: Part I. In situ synchrotron study

BIMEVOX membranes for electrochemical oxygen separation were characterised under operating conditions using X-ray synchrotron radiation. Three compositions were studied: a slightly Bi-enriched non-doped phase, BIBIVOX.02, a BICOVOX and a BICUVOX phase. Both anodic and cathodic behaviours were investigated at 620 °C for current densities up to 1 A/cm2. These experiments demonstrated the self-ability of these electrolytes to dynamically transform into electrode materials under polarisation. This transformation is due to a slight reduction of the material under bias. The transformation is reversible. The initial phase was recovered when the current was turned off. Even low current densities were sufficient to induce this electrolyte–electrode adaptation.