Chemical Analysis of Activation Process of LSM Thin Film Electrode

In this study, the activation process of strontium-doped lanthanum manganite (LSM) was investigated. LSM thin films on yttria-stabilized zirconia (YSZ) half cells were fabricated with an LSCF counterelectrode and the effects of cathodic current density and overpotential on the polarization behavior of the LSM thin film electrode were investigated. The surface morphology as well as surface chemistry and bonding environment of LSM before and after polarization were investigated using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The formation of SrO was found on the LSM surface after polarization. The cross-section microstructures of LSM were examined using transmission electron microscope (TEM) and TEM-based energy dispersive X-ray spectroscopy (EDS). The presence of Mn-rich phases were observed before and after polarization. The pre- and post-activation electrode performances were investigated, which help reveal the nature of the activation mechanism in combination with the microstructural and chemical analysis.