FU Mengyu, JIN Yingmin, LI Dong, ZONG Xin, ZHANG Xuebai, XIONG Yueping

(School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150000, Heilongjiang, China)

Abstract: The presence of chromium in the interconnector of solid oxide fuel cells poisons the cathode material and seriously damages electrochemical performance of the cathode. La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ(LSCF)-Gd_0.2Ce_0.8O_1.9(GDC) composite cathode was prepared by using an impregnation method. The effect of GDC on chromium poisoning behavior of the LSCF cathode was studied by using scanning electron microscopy (SEM), inductively coupled plasma spectroscopy (ICP-MS) and X-ray photoelectron spectroscopy (XPS). The impregnations with GDC can not only improve electrochemical performance of the LSCF cathode, but also inhibit the chromium poisoning of the cathode to a certain extent. Compared with the pristine LSCF cathode, the LSCF-GDC composite cathode exhibited lower degradation in electrochemical performance after polarization for 120 h in a chromium-containing atmosphere. The GDC formed a coating layer on the cathode to reduce the contact between Cr and Sr, thus preventing the formation of SrCrO₄ and the Cr poisoning of the LSCF cathode.

Key words: solid oxide fuel cells; LSCF cathode; composite cathode; chromium poisoning; toxicity