Solid State Ionics 159 (2003) 167 – 179 www.elsevier.com/locate/ssi

Characterisation of the electrode–electrolyte BIMEVOX system for oxygen separation Part I. In situ synchrotron study
C. Pirovano a,*, R.N. Vannier a, E. Capoen a, G. Nowogrocki a, J.C. Boivin a, G. Mairesse a, M. Anne b, E. Dooryhee b, P. Strobel b a ´ Laboratoire de Cristallochimie et Physicochimie du Solide, UMR 8012, ENS Chimie Lille, Universite des Sciences et Technologies de Lille, B.P. 108, 59652 Villeneuve d’Ascq Cedex, France b Laboratoire de Cristallographie, UPR 5031, 25 Avenue des Martyrs, B.P. 166, 38042 Grenoble Cedex 09, France Received 3 November 2002; received in revised form 21 January 2003; accepted 24 January 2003

Abstract 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 jC 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. D 2003 Elsevier Science B.V. All rights reserved.
Keywords: BIMEVOX; Oxygen separation; Ionic conductivity; Electronic conductivity; Oxygen

1. Introduction Electrochemical oxygen separation from air is a promising application for oxide conductor solid electrolytes. Up to now, industrial production of oxygen is mainly achieved using two techniques. For large scale production, cryogenic distillation from air is the most suitable way while, for smaller quantities, a pressure

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