Effect of Nanoscale Ce_0.8Gd_0.2O_2−δ Infiltrant and Steam Content on Ni–(Y₂O₃)_0.08(ZrO₂)_0.92 Fuel Electrode Degradation during High-Temperature Electrolysis

Abstract

Studies of Ni–yttria-stabilized zirconia (YSZ) fuel electrode degradation mechanisms in solid oxide electrolysis cells (SOECs) are complicated by the different possible Ni–YSZ microstructures and compositions, and the variations in the H2/H2O ratio encountered in an electrolysis stack. Here we describe a life testing scheme aimed at providing survey results on degradation as a function of the H2O–H2 composition, with life tests carried out at five different steam contents from 90% to 10%. A Ni–YSZ-supported symmetric cell geometry is employed both with and without infiltrated nanoscale gadolinia-doped ceria (GDC). Impedance spectroscopy is utilized to observe changes in electrochemical characteristics during the life test, and a transmission-line-based equivalent circuit is used to model the data. Post-test electrode microstructures were observed. The results suggest that the GDC infiltrant reduces the electrode polarization resistance and provides more stable electrode polarization over a range of conditions.

A Method for Time-Resolved Characterization of Polarization-Induced Solid Oxide Cell Microstructure Evolution

“…cells: P0 is an artifact of instrumentation inductance, P1 is the electrochemical reaction, P2 is gas diffusion through the porous support, and P3 is gas diffusion from a stagnant gas layer. 26 The cells all undergo an early-life impedance shape change by the 96hour mark wherein the impedance arcs become more depressed; this corresponds to a large decrease in P2 and the appearance of P3, which initially were indistinguishable due to frequency overlap. At longer times, the changes in the EIS spectra are minimal except for the 1.50 A cm −2 cell, for which both R Ohm and R Pol increase substantially with time, with DRT showing P1as the primary source of impedance increase.…”

Enhancing Sr-deficient Sr(Ti0.3Fe0.7)O3–δ Cathode Performance through Sm0.5Sr0.5CoO3–δ Infiltration

“…EIS data fitting and simulations for the individual circuit elements were performed using Python-based software supported by the scientific Python stack. 9,28,29 For full cell testing, silver grid (Heraeus) current collectors were screen-printed on the cathodes of full cells and contacted using silver wires. These cells were then mounted on alumina tubes and sealed with Ag paste (DAD-87, Shanghai Research Institute of Synthetic Resins).…”

Nanotechnologies in ceramic electrochemical cells

“…Park and colleagues’ research also supported that the infiltration of Gd 0.2 Ce 0.8 O 2− δ provided enhanced sustainability and stable electrode polarization at a high concentration of steam. 240 Li and co-workers developed a new technical process for synthesis of active NPs for CECs, i.e. hydrothermal treatment.…”