Yttria stabilized zirconia (YSZ) based microtubular solid oxide fuel cells (mT-SOFCs) using La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) and Ce 0.9 Gd 0.1 O 2-δ (GDC) as the oxygen electrode, along with a porous GDC electrolyte-electrode barrier layer, were fabricated and characterized in both fuel cell (SOFC) and electrolysis (SOEC) operation modes. The cells were anode-supported, the NiO-YSZ microtubular supports being made by Powder Extrusion Moulding (PEM). The cells showed power densities of 695 mW•cm-2 at 800 °C and 0.7 V in SOFC mode, and of 845 mA•cm-2 at 800 °C and 1.3 V in SOEC mode. AC impedance experiments performed under different potential loads demonstrated the reversibility of the cells. These results showed that these cells, prepared with a method suitable for using on an industrial scale, are highly reproducible and reliable, as well as very competitive as reversible SOFC-SOEC devices operating at intermediate temperatures.

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The high-temperature mechanical properties of the mixed ionic-electronic conductor perovskite BaCe 0.95 Y 0.05 O 3−δ with average grain size of 0.40 m have been studied in compression between 1100 and 1300 • C in air at different initial strain rates. The true stress-true strain curves display an initial stress drop, followed by an extended steady-state stage. As the temperature decreases and/or the strain rate increases, there is a transition to a damage-tolerant strain-softening stage and eventually to catastrophic failure. Analysis of mechanical and microstructural data revealed that grain boundary sliding is the primary deformation mechanism. The strength drop has been correlated with the growth of ultrafine grains during deformation, already present at grain boundaries and triple grain junctions in the as-fabricated material.