Synthesis and characterisation of Ni-SrCe0.9Yb0.1O3-δ cermet anodes for protonic ceramic fuel cells

Cermet anode material with a proton-conducting ceramic phase, Ni-SrCe0.9Yb0.1O3 (-) (delta), was syrithesised by-combustion from mixtures of molten nitrates and urea followed by sintering and reduction. Co-pressing the anode combustion powder on "green" SrCe0.9Yb0.1O3-delta electrolyte and co-firing produced symmetrical anode/electrolyte/anode assemblies with planar electrodes of thickness ca. 100 mum. The addition of Co(NO3)(2) . 6H(2)O to the electrolyte as sintering aid lowered the sintering temperature to 1250 degreesC, thereby allowing high anode porosity while retaining good. anode/electrolyte adherence. The anode microstructure is composed of a uniform distribution of submicron Ni and perovskite particles. Analysis of the symmetrical assemblies by a.c. impedance spectroscopy indicates that the electrode polarisation resistances are composed of at least two contributions. Stability issues concerning the Ni-SrCe0.9Yb0.1O3 - delta anodes in reducing atmospheres are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.