Mechanism of chromium poisoning of LSM cathode in solid oxide fuel cell

Although metallic interconnects have many advantages, the formation of Cr₂O₃ scale and the evaporation of Cr(VI) species from alloys will greatly degrade the solid oxide fuel cell(SOFC) performance. In this paper, the electrochemical impedance spectroscopy (EIS) and the cathode polarization method of galvanostatic current interruption were employed to investigate the deposition mechanism of chromium with the electrochemical behavior of LSM cathode in the presence of chromia-forming alloys. The results show that the dissociative adsorption and the diffusion of oxygen on the LSM surface were inhibited by the gaseous chromium species and the migration processes of oxygen ions into YSZ electrolyte were inhibited by the solid chromium species deposited on the YSZ surface.