Elucidating the role of La2NiO4±δ (LNO) nanoparticles in modulating chromium poisoning in LSM air electrodes of solid oxide cells: A study on oxygen reduction and evolution reactions

Abstract

As the solid oxide cells (SOCs) are becoming durable, their air electrode materials require investigation for their tolerance against chromium (Cr) poisoning. Herein, La2NiO4±δ (LNO), a highly electroactive and nucleation agent-free material, is infiltrated into the (La,Sr)MnO3-δ (LSM) backbone to diagnose its' influence on the Cr-poisoning of LSM. While the non-impregnated LSM's degrades by Cr contaminant, LNO-infiltrated LSM (LSM.LNO) shows less sensitivity to Cr presence specifically during the electrolysis mode. LNO's presence inhibits the formation of detrimental phases at the electrode/electrolyte interface during the anodic polarization in Cr-containing ambient. Moreover, surface promotion by LNO nanoparticles reduces, but not inhibits, the formation of undesirable phases during the cathodic polarization in the Cr presence. According to the electrodes' overpotential trends, the electrochemical impedance spectroscopy (EIS) responses in addition to the distribution of the relaxation times (DRT) analysis, the presence of Cr alters the LSM.LNO's electrochemical characteristics via reacting with the nanoparticles. As the XRD analysis proves, LaCrO3 formation on the LNO nanoparticles' surface gradually decays the LSM.LNO's cathodic performance. However, LNO's higher activity for oxygen evolution than oxygen reduction reaction accompanied by slower LNO/Cr reaction kinetics during anodic polarization improve and stabilize the LSM.LNO's anodic performance in Cr-containing environment.