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.