Influence of polarization on the electrochemical activity of La2exCaxNiO4 thorn d electrodes in contact with Ce0.8Sm0.2O1.9 electrolyte

The effect of electrode polarization on the electrochemical activity of La2NiO4+d and La1.9Ca0.1NiO4+d electrodes in contact with the Ce0.8Sm0.2O1.9 electrolyte is studied by impedance spectroscopy. It is found that anodic polarization facilitates electrode reaction for both electrodes leading to significant decrease in the polarization resistance. The effect of cathodic polarization differs between the electrodes: the polarization resistance of La2-NiO4+d electrode slightly increases, while the polarization resistance of La1.9Ca0.1NiO4+d electrode strongly decreases with the increase in the applied potential. It is established that in all cases the polarization mostly affects the low-frequency stage of the electrode reaction, connected with oxygen surface exchange and diffusion. The surface state of the samples after exposure under polarization is studied by X-ray photoelectron spectroscopy. Correlations between electrochemical activity of the electrodes and the changes in their surface composition under polarization are discussed.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The effect of electrode polarization on the electrochemical activity of La2NiO4+d and La1.9Ca0.1NiO4+d electrodes in contact with the Ce0.8Sm0.2O1.9 electrolyte is studied by impedance spectroscopy. Anodic polarization facilitates electrode reaction and decreases the polarization resistance. The effect of cathodic polarization differs between the electrodes: the polarization resistance of La2-NiO4+d electrode slightly increases, while the polarization resistance of La1.9Ca0.1NiO4+d electrode strongly decreases. The polarization mostly affects the low-frequency stage of the electrode reaction.