Sintering Aid Strategy for Promoting Oxygen Reduction Reaction on High-Performance Double-Layer LaNi(0.6)Fe(0.4)O(3–δ) Composite Electrode for Devices Based on Solid-State Membranes

Strontium and cobalt-free LaNi(0.6)Fe(0.4)O(3–δ) is considered one of the most promising electrodes for solid-state electrochemical devices. LaNi(0.6)Fe(0.4)O(3–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 LaNi(0.6)Fe(0.4)O(3–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 LaNi(0.6)Fe(0.4)O(3–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 (Bi(0.75)Y(0.25)O(2–δ) and CuO) in the collector layer on the performance of LaNi(0.6)Fe(0.4)O(3–δ)-based highly active electrodes in contact with the most common solid-state membranes (Zr(0.84)Sc(0.16)O(2–δ), Ce(0.8)Sm(0.2)O(2–δ), La(0.85)Sr(0.15)Ga(0.85)Mg(0.15)O(3–δ), La(10)(SiO(4))(6)O(3–δ), and BaCe(0.89)Gd(0.1)Cu(0.01)O(3–δ)) was investigated. It was shown that LaNi(0.6)Fe(0.4)O(3–δ) has good chemical compatibility with the abovementioned membranes. The best electrochemical activity (polarization resistance about 0.02 Ohm cm(2) at 800 °C) was obtained for the electrode with 5 wt.% Bi(0.75)Y(0.25)O(1.5) and 2 wt.% CuO in the collector layer.