**2.1 Powder synthesis**

Nanocrystalline complex oxides with ionic conductivity (fluorite-type electrolytes GDC, YSZ, δ-Bi2O3 stabilized by Er or Y+Sm) and mixed ionic-electronic conductivity (rare-earth manganites, nickelates, ferrites, cobaltites and their solid solutions including those doped by Sr and/or Bi) were synthesized by modified polymerized polyester citric acid-ethylene glycol precursors (Pechini) and mechanical activation routes. Synthesis procedures and structural features of these complex oxides are described in details elsewhere (Kharlamova et al., 2011; Sadykov et al., 2011). Nanocomposites were prepared by ultrasonic dispersion of the mixture of powders in isopropanol (solvent) using a T25 ULTRA-TURRAX (IKA, Germany) homogenizer with addition of polyvinyl butyral. Detailed compositions of complex oxide and their composites prepared for sintering are summarized in Table 1.


\* CH- conventional heating, MH- microwave heating, RTS-radiation-thermal sintering

Тable 1. Compositions and samples geometry.

#### **2.2 Samples preparation for sintering**

Pellets were uniaxially pressed from powders under 5.5 t/cm2. As a porous metal substrate for composite anode or cathode, a unique type of macroporous planar Ni-Al foam substrate with a high electric and thermal conductivity, thermal stability and corrosion resistance was used (Smorygo et al., 2008; Sadykov et al. 2010). Along with these metal substrates, traditional NiO/YSZ planar anode substrates covered by thin layers of YSZ electrolyte were used for supporting cathode layers (Sadykov et al, 2009, 2011). Functional layers were supported by slip casting or screen-printing on the support surface.
