Cr Poisoned the Lini 0.8 Co 0.15 Al 0.05 O 2- Δ Cathode and the Alkaline Li Impregnation To Recover The Performance of Cr Poisoned Solid Oxide Fuel Cell

Abstract

The mixed electron-ion conducting LiNi0.8Co0.15Al0.05O2 (NCAL), utilized as a cathode for solid oxide fuel cells (SOFCs), has garnered significant attention. Nonetheless, NCAL's prevalent application as a cathode encounters the substantial challenge of chromium poisoning within the SOFC stack configuration. Therefore, advancing NCAL-based SOFC technology necessitates elucidating the underlying mechanisms of chromium poisoning and devising solutions to address this issue. In our study, we employed the impregnation of chromium nitrate into the NCAL cathode to mimic the effects of chromium poisoning within the SOFC stack. Our findings, derived from electrical conductivity relaxation and electrochemical impedance spectroscopy, indicate that chromium poisoning in NCAL cathodes is associated with a decline in oxygen surface exchange kinetics. Furthermore, the impregnation of alkaline Li at a concentration of 0.33 mol/L effectively compensates for the initial degradation prompted by chromium poisoning, thereby restoring the electrochemical performance of the fuel cell. We discovered that LiOH infiltration enhances the conductivity of the NCAL cathode and reduces its oxygen exchange coefficient, facilitating recovery from chromium poisoning. This study offers a viable strategy for addressing chromium poisoning and enhancing the catalytic efficiency of NCAL cathodes.

Keywords: Solid oxide fuel cells, Chromium poisoning, Conductivity relaxation, Oxygen exchange coefficient