Sintering Aid Strategy for Promoting Oxygen Reduction Reaction on High-Performance Double-Layer LaNi0.6Fe0.4O3–δ Composite Electrode for Devices Based on Solid-State Membranes

Abstract

Strontium and cobalt-free LaNi0.6Fe0.4O3–δ is considered one of the most promising electrodes for solid-state electrochemical devices. LaNi0.6Fe0.4O3–δ has high electrical conductivity, a suitable thermal expansion coefficient, satisfactory tolerance to chromium poisoning, and chemical compatibility with zirconia-based electrolytes. The disadvantage of LaNi0.6Fe0.4O3–δ is its low oxygen-ion conductivity. In order to increase the oxygen-ion conductivity, a complex oxide based on a doped ceria is added to the LaNi0.6Fe0.4O3–δ. However, this leads to a decrease in the conductivity of the electrode. In this case, a two-layer electrode with a functional composite layer and a collector layer with the addition of sintering additives should be used. In this study, the effect of sintering additives (Bi0.75Y0.25O2–δ and CuO) in the collector layer on the performance of LaNi0.6Fe0.4O3–δ-based highly active electrodes in contact with the most common solid-state membranes (Zr0.84Sc0.16O2–δ, Ce0.8Sm0.2O2–δ, La0.85Sr0.15Ga0.85Mg0.15O3–δ, La10(SiO4)6O3–δ, and BaCe0.89Gd0.1Cu0.01O3–δ) was investigated. It was shown that LaNi0.6Fe0.4O3–δ has good chemical compatibility with the abovementioned membranes. The best electrochemical activity (polarization resistance about 0.02 Ohm cm2 at 800 °C) was obtained for the electrode with 5 wt.% Bi0.75Y0.25O1.5 and 2 wt.% CuO in the collector layer.

Design of Mixed Ionic-Electronic Materials for Permselective Membranes and Solid Oxide Fuel Cells Based on Their Oxygen and Hydrogen Mobility

“…Nevertheless, LaNi 0.6 Fe 0.4 O 3 , as the most stable in the series, found widespread application in SOCs due to its superior conductivity, low thermal expansion coefficient value, and tolerance to chromium poisoning [256]. It is also successfully used in different composite electrodes for intermediate-temperature SOFCs [257][258][259][260], and as cathode contact materials [261,262]. Materials with mixed oxygen ion and electron conductivity (MIECs), such as Sr-doped lanthanum ferrites-nickelates/cobaltites (LSFN, LSFC) possess much higher oxygen mobility (Figure 18) enabling the O reduction reaction (ORR) along both triple-and double-phase boundaries, thus improving cathode performance, as well as oxygen permeation fluxes across oxygen-separation membranes [69,128,129,247,248,263].…”

Design of Mixed Ionic-Electronic Materials for Permselective Membranes and Solid Oxide Fuel Cells Based on Their Oxygen and Hydrogen Mobility

“…Nevertheless, LaNi0.6Fe0.4O3, as the most stable in the series, found wide application in SOCs due to its superior conductivity, low thermal expansion coefficient value, and tolerance to chromium poisoning [145]. It is also successfully used in different composite electrodes for intermediate temperature SOFCs [146][147][148][149], and as a cathode contact materials [150,151]. Materials with mixed oxygen ion and electron conductivity (MIECs), such as Sr doped lanthanum ferrites-nickelates/cobaltites (LSFN, LSFC) possess much higher oxygen mobility (Figure 9) enabling the O reduction reaction (ORR) along both triple and double phase boundaries, thus improving cathode performance, as well as oxygen permeation fluxes across oxygen separation membranes [75,86,87,136,137,152].…”

Determination of Kinetic Parameters and Identification of the Rate-Determining Steps in the Oxygen Exchange Process for LaNi0.6Fe0.4O3−δ

“…One of the most important issues in solid oxide fuel cell (SOFC) development [ 11 ] is improving electrode performance, particularly on the cathode side. Recently, researchers have focused considerably on exploring the use of doped perovskites as materials for solid oxide fuel cells (SOFCs) [ 12 , 13 , 14 ]. LaNi 1− x Fe x O 3− δ has attracted interest due to its resistance to certain degradation effects, so these materials may find application as oxygen electrodes for future generations of SOFCs with lower degradation rates and longer lifetimes [ 15 ].…”