Abstract: Nanocomposites comprised of mixed Pr nickelates –cobaltites and Y/Gd-doped ceria are efficient and stable to carbonation cathodes of IT SOFC. In this work factors controlling their oxygen mobility and reactivity were studied. Nanocrystalline samples of doped ceria and Pr nickelates –cobaltites with perovskite and Ruddlesden-Popper structure were synthesized by Pechini method. Nanocomposites were prepared via ultrasonic dispersion of oxide mixtures in isopropanol. Thin layers of nocomposites were supported by slip casting on YDC/YSZ/NiO+YSZ anode substrates. Bulk samples and thin layers were sintered up to 1300 oC in air. Phase composition, morphology, microstructure and elemental composition of domains in nanocomposites were studied by XRD, HRTEM/SEM with EDX and SIMS. Oxygen mobility and reactivity were characterized by oxygen isotope exchange (including C18O2 SSITKA), weight loss and conductivity relaxation studies. Redistribution of Pr between perovskite-like and doped ceria domains and segregation of (Ni,Co)O domains as dependent upon sintering temperature and nanocomposite composition result in broad variation of these domains composition and disordering. Such microstructure provides fast oxygen self diffusion (DO up to 2*10-10 cm2/s at 600 K) via chains of Pr cations with disordered coordination sphere. Even faster oxygen diffusion (Dchem.~ 10-4 cm2/s at 600 K) occurs along domains interfaces amounting to ~1% of oxygen positions in nanocomposites.

Cite: Sadykov V.A. , Eremeev N.F. , Sadovskaya E.M. , Ishchenko A.V. , Pelipenko V.V. , Muzykantov V.S. , Krieger T.A. , Belyaev V.D. , Rogov V.A. , Ivanov V.P. , Vinokurov Z. , Shmakov A.N. , Uvarov N.F. , Okhlupin Y.S. , Ulikhin A.S.
Microstructure and oxygen mobility of doped ceria – Pr(Ni,Co)Ox nanocomposites
E-MRS 2014 Spring Meeting - Symposium C “Solid State Ionics: Thin Films for Energy and Information Applications” 26-30 May 2014