Available online at www.sciencedirect.com Journal of the European Ceramic Society 33 (2013) 2241–2250 Functional nanoceramics for intermediate temperature solid oxide fuel cells and oxygen separation membranes V. Sadykov a,∗ , V. Usoltsev a , N. Yeremeev a , N. Mezentseva a , V. Pelipenko a , T. Krieger a , V. Belyaev a , E. Sadovskaya a , V. Muzykantov a , Yu. Fedorova a , A. Lukashevich a , A. Ishchenko a , A. Salanov a , Yu. Okhlupin b , N. Uvarov b , O. Smorygo c , A. Arzhannikov d , M. Korobeynikov d , Ma.K.A. Thumm e,f a Boreskov Institute of Catalysis, Novosibirsk State University, Novosibirsk, Russia b Institute of Solid State Chemistry, Novosibirsk, Russia c Powder Metallurgy Institute, Minsk, Belarus d Budker Institute of Nuclear Physics, Novosibirsk State University, Novosibirsk, Russia e Karlsruhe Inst. Technol., Karlsruhe, Germany f Novosibirsk State University, Novosibirsk, Russia Available online 4 February 2013 Abstract This work reviews results of research aimed at design and characterization of mixed ionic–electronic conducting perovskite–fluorite nanocomposite oxide ceramics. Nanocrystalline oxides were prepared via Pechini route, nanocomposites – via ultrasonic dispersion of their mixture in organic solvents with addition of surfactants. Genesis of the real structure of nanocomposites at sintering by conventional as well as advanced (microwave or e-beam treatment) techniques was studied in details by structural methods. Applied preparation procedures ensured nano-sizes of perovskite/fluorite domains even in dense ceramics and a high spatial uniformity of their distribution. Redistribution of elements between perovskite and fluorite domains without formation of new phases was revealed. Characterization of nanocomposite transport properties by oxygen isotope heteroexchange and conductivity or weight relaxation demonstrated that perovskite–fluorite interfaces are paths for fast oxygen diffusion. Best perovskite–fluorite combinations tested as cathode layers or dense oxygen separation layers in asymmetric supported membranes demonstrated performance promising for the practical application. © 2013 Elsevier Ltd. All rights reserved. Keywords: Nanocomposites; Synthesis; Structure; Conductivity; Diffusion 1. Introduction Synthesis of inexpensive mixed ionic–electronic conducting (MIEC) materials, including composites comprised of one elec- tronic conductor (perovskite-like oxides) and one good ionic conductor (doped ceria, zirconia, etc.) is a very important task in design of advanced cathodes of solid oxide fuel cells (SOFC) and oxygen separation membranes. 1–11 Traditional method of ∗ Corresponding author at: Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Prospect Akademika Lavrentieva, 5, Novosi- birsk 630090, Russia. Tel.: +7 383 3308763; fax: +7 383 3308056. E-mail addresses: sadykov@catalysis.ru, sadykovy@academ.org (V. Sadykov), Uvarov@solid.nsc.ru (N. Uvarov), smorygo@rambler.ru (O. Smorygo), arzhannikov@phys.nsu.ru (A. Arzhannikov), manfred.thumm@kit.edu (Ma.K.A. Thumm). composites preparation by ball-milling a mixture of oxides 1–4 could not guarantee the uniform spatial distribution of parti- cles of constituting phases required for a good percolation, and, hence, high mixed ionic–electronic conductivity. Impreg- nation/infiltration of a porous electrolyte layer by perovskite suspension or precursor solution 7 is certainly more promising for manufacturing nanostructured cathode layers, but control of the spatial distribution of phases in composite could be difficult as well. Different versions of the sol–gel method are potentially more efficient in providing required uniform intermixing of phases in nanocomposites. 12,13 Polymerized cit- ric acid–ethylene glycol polyester precursor (Pechini) method used for synthesis of nanocrystalline complex oxides 14 could be applied for synthesis of nanocomposites as well. A pow- erful ultrasonic treatment of the mixture of nanocrystalline oxides in solvents with addition of surfactants 15 is promising 0955-2219/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jeurceramsoc.2013.01.007