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