Untersuchungen zu den Eigenschaften der Anode der Festoxid-Brennstoffzelle (SOFC)

This thesis investigates the electrical and electrochemical properties and the long-term stability of anodes of the solid oxide fuel cell (SOFC). A model is suggested, which describes the impedance spectra of symmetrical anode cells. According to this, the series resistance in the spectra is caused by the resistance of the electrolyte (YSZ), ohmic parts of the anodes, which are described as porous electrodes, and by the partial contacting of the anodes. A major contribution to it is provided by the nickel matrix in the anodes. The high frequency relaxation in the spectra is assigned to the transfer reaction, the low frequency to a gas diffusion inhibition along the gas supply channels. The degradation of the symmetrical anode cells, which has been observed in long-term experiments, is ascribed to a degradation of the electrolyte material, of the transfer reaction, of the nickel matrix in the anodes and of the contact resistance between the anodes and the current collecting nickel grids. The degradation rate of the last two depends on the gas composition. A model for the observed behaviour in time is presented.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Technische Universität Dresden

Year

2002

Author dc:creator

• Stübner, Ralph

Contributors dc:contributor

• Plieth, Waldfried
• Mund, K.
• Langbein, Hubert

• Anode
• Bahnwiderstand
• Degradation
• Diffusionsimpedanz
• Festoxid-Brennstoffzelle
• Impedanzspektroskopie
• Kontaktwiderstand
• Langzeitstabilität
• Modell
• Nickel
• SOFC
• Zirkonoxid
• contact resistance
• diffusion impedance
• impedance spectroscopy
• long term stability
• model
• sheetresistance
• solid oxide fuel cell
• zirconia