Fabrication and performance of Ni/3 mol% Y2O3-ZrO2 cermet anodes for solidoxide fuel cells

A fabrication method for the preparation of Ni/3 mol% Y2O3-ZrO2 (Ni/TZ3Y) c ermet electrodes from various commercial powders has been described. The fa brication parameters investigated include: particle size and particle size distribution of NiO and TZ3Y powders, Ni content in the cermet, firing temp erature, electrode thickness and the effect of adding pore-formers. Ni/TZ3Y cermet anodes were prepared by screen printing and the electrode performan ce was characterised by galvanostatic current interruption and electrochemi cal impedance spectroscopy techniques. The results showed that the electroc hemical activity of Ni/TZ3Y cermet anodes for hydrogen oxidation is strongl y dependent on the selection of fabrication parameters, and the effect of t hese processing parameters on the electrode microstructure is closely inter linked. The most critical parameters appear to be the particle size and par ticle size distribution of NiO and TZ3Y powders, which can be controlled by screening various commercial powders and by optimising the heat treatment conditions of these powders. For the best anode, the overpotential losses a t 800 degrees C were less than 90 mV at a current density of 350 mA cm(-2). The anode degradation, performed on 50 mm x 50 mm x 100 mu m TZ3Y electrol yte cells, was less than 1.7% over the similar to 4300 h test period under a current load of 250 mA cm(-)2 at 900 degrees C. (C) 2000 Elsevier Science B.V. All rights reserved.