Effects of Strong Cathodic Polarization of the Ni-YSZ Interface. Issue 10 (1st January 2016)

• Record Type: Journal Article
• Authors: Hansen, Karin Vels; Chen, Ming; Jacobsen, Torben; Thydén, Karl; Simonsen, Søren Bredmose; Koch, Søren; Mogensen, Mogens Bjerg
• Is Part Of: Journal of the Electrochemical Society. Volume 163:Issue 10(2016)
• Page Start: F1217
• Page End: F1227
• Publication Date: 2016-01-01
• Subjects: Dissolution of Zr -- Intermetallics -- Ni-YSZ cathode -- Reduction of zirconia -- SOEC -- Strong polarization -- Zirconia nanoparticles; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0871610jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Long-term strong cathodic polarization experiments of down to –2.4 V vs. E °(O2 ) of the Ni-YSZ interface were performed at 900°C in 97% H2 /3% H2 O on model electrodes. The Ni-YSZ interface underwent extensive changes and a large affected volume with a complex microstructure and phase distribution resulted. Impedance spectroscopy shows initial decrease but later increase in the series resistance and polarization resistance during the 140–160 h of polarization, and significant inductive behavior. An intermetallic Ni-Zr phase that formed during polarization was preserved when the polarization was kept during cooling, and was identified post-mortem by transmission electron microscopy as Ni7 Zr2 . ZrO2 nanoparticles were formed on the Ni-gas surface next to the Ni-YSZ-gas triple phase boundary. Explanations of the observed features are offered based on electron microscopy and impedance spectroscopy.