Investigation on Nd1-xCaxBaCo2O5+? double perovskite as new oxygen electrode materials for reversible solid oxide cells

Novel perovskite-type A-site calcium-doped Nd1-xCaxBaCo2O5+delta oxides were studied in terms of oxygen electrode materials for reversible solid oxide cells (RSOCs). The electrode of x <= 0.2 was composed of a tetragonal perovskite structure with a P4/mmm space group. A Ca2+ dopant was used to improve the thermal expansion coefficient (TEC), conductivity, and electrochemical properties of the NdBaCo2O5+delta oxides, with TEC and conductivity values of Nd1-xCaxBaCo2O5+delta (x = 0-0.2) of 17.5-16.2 x 10-6 K-1 and 960.4-1068 S cm-1, respectively. The X-ray photoelectron spectroscopy results indicated that Ca2+ doping has a beneficial influence on the surface oxygen adsorption properties and the increase in the concentration of Co4+. On the basis of the first-principles density functional theory, doping with Ca2+ leads to easier oxygen release and uptake. The area specific resistance of the x = 0.2 electrode was 0.058 omega cm2 at 700 degrees C, whereas at 800 degrees C, the cell using the x = 0.2 oxygen electrode exhibited a maximum power density of 740 mW cm-2 when H2 was used as the fuel, and the current density of the electrolytic pure CO2 at 1.5 V was 1.68 A cm-2. These attractive electrochemical properties suggest that Ca-based doping is an effective method for developing (reversible solid oxide cell) RSOC oxygen electrodes. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Novel perovskite-type A-site calcium-doped Nd1-xCaxBaCo2O5+delta oxides were studied as oxygen electrode materials for reversible solid oxide cells (RSOCs). Ca2+ doping improved the thermal expansion coefficient, conductivity, and electrochemical properties of the NdBaCo2O5+delta oxides, resulting in attractive electrochemical properties for oxygen electrodes in RSOCs.