Electrochemical and microstructural characterization of the solid oxide fuel cell anode prepared by co-precipitation
Elektrochemische und mikrostrukturelle Charakterisierung von durch Co-Abscheidung hergestellten Anoden für Festoxidbrennstoffzellen
Nickel oxide and yttria-stabilized zirconia (NiO/YSZ) cermets have been prepared using a chemical co-precipitation of hydroxides. The influence of different factors on the microstructure, mechanical and electrochemical properties of the anode were investigated. The electrochemical tests were carried out on dense 8YSZ and 10Sc1CeSZ tapes (50x50x0.150 mm(exp 3) Kerafol GmbH) with symmetrically screen-printed cathodes and anodes with a lateral dimension of 40x40 mm. The cells were sintered in co-firing. The anodes were characterized by impedance spectroscopy at open circuit potential and under current load at temperatures of 850-950 deg C in hydrogen/steam atmosphere (H2:H2O = 1:1). The electrode polarization resistance (R(ind p)) of the spectra was identified and the influences of operating temperature (850, 900 and 950 deg C), current load and pH2O on the impedance spectra of the anode were discussed. The long-term stability of the cell with an anode prepared by co-precipitation was carried out over 1000 hours under current density of 430-450 mA/cm2 at 0.7V at a temperature of 850 deg C.