Sintering Aid Strategy for Promoting Oxygen Reduction Reaction on High-Performance Double-Layer LaNiFeO Composite Electrode for Devices Based on Solid-State Membranes.

Strontium and cobalt-free LaNiFeO is considered one of the most promising electrodes for solid-state electrochemical devices. LaNiFeO has high electrical conductivity, a suitable thermal expansion coefficient, satisfactory tolerance to chromium poisoning, and chemical compatibility with zirconia-based electrolytes. The disadvantage of LaNiFeO 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 LaNiFeO. 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 (BiYO and CuO) in the collector layer on the performance of LaNiFeO-based highly active electrodes in contact with the most common solid-state membranes (ZrScO, CeSmO, LaSrGaMgO, La(SiO)O, and BaCeGdCuO) was investigated. It was shown that LaNiFeO has good chemical compatibility with the abovementioned membranes. The best electrochemical activity (polarization resistance about 0.02 Ohm cm at 800 °C) was obtained for the electrode with 5 wt.% BiYO and 2 wt.% CuO in the collector layer.