Improved electrocatalytic properties of strontium-doped lanthanum nickelate cathodes by infiltrating samarium-doped ceria

Ce0.8Sm0.2O1.9 oxygen-ion conductor was infiltrated into the backbone of pre-prepared porous La1.8Sr0.2NiO4+delta electrode to enhance the electrocatalytic properties of the electrode for oxygen reduction reaction. The phase structure, microstructure, and electrocatalytic properties of the infiltrated electrodes were investigated in comparison with the pristine La1.8Sr0.2NiO4+delta electrode. The Ce0.8Sm0.2O1.9 infiltrated into the porous electrode backbone appeared as nano-sized particles deposited on La1.8Sr0.2NiO4+delta grains. The primary steps of the electrode reaction were facilitated to varying extents with the assistance of oxygen vacancies in the Ce0.8Sm0.2O1.9. As a result, the overall reaction kinetics of the infiltrated electrodes was accelerated. The oxygen vacancy-assisted acceleration effect was leveled off at a Ce0.8Sm0.2O1.9 loading of around 10 vol%. The leveling-off behavior was explained with respect to the microstructural evolution of the electrodes with increasing Ce0.8Sm0.2O1.9 loading. The 10 vol% Ce0.8Sm0.2O1.9 infiltrated electrode achieved appreciably improved electrocatalytic properties. Compared with the pristine La1.8Sr0.2NiO4+delta electrode, the polarization resistance (similar to 0.25 Omega cm(2)) and overpotential (similar to 53 mV at 200 mA cm(-2)) of the infiltrated electrode at 800 degrees C were reduced by similar to 40% and similar to 45%, respectively, while the exchange current density (similar to 190 mA cm(-2)) was enhanced by similar to 66%.

Automated summary

In this study, Ce0.8Sm0.2O1.9 oxygen-ion conductor was infiltrated into the porous electrode backbone of La1.8Sr0.2NiO4+delta to enhance the electrocatalytic properties for the oxygen reduction reaction. The infiltration of Ce0.8Sm0.2O1.9 nanoparticles onto La1.8Sr0.2NiO4+delta grains improved the overall reaction kinetics with the assistance of oxygen vacancies. The 10% Ce0.8Sm0.2O1.9 infiltrated electrode showed significantly improved electrocatalytic properties, with reduced polarization resistance and overpotential, and enhanced exchange current density.