Enhancing chromium poisoning tolerance of La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ cathode by Ce_0.8Gd_0.2O_1.9−δ coating

Cr poisoning has been regarded as a significant reason for the degradation of La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ (LSCF) cathode in practical application. In recent years, protective coating on cathode surface has been recognized as an effective approach to improve the Cr poisoning resistance of cathode. In this work, Ce_0.8Gd_0.2O_1.9−δ (GDC) layer is successfully coated on LSCF nanoparticles by sol-gel method, endowing the GDC coated LSCF (LSCF@GDC) composite material with excellent electrochemical properties and Cr poisoning tolerance. The LSCF@GDC0.32 composite cathode exhibits a lower total impedance increase of 0.20 Ω cm² per 200 h and 0.31 Ω cm² per 200 h for open circuit and constant current test with SUS430 as Cr source, respectively, compared with the bare LSCF cathode (0.90 Ω cm² per 200 h and 1.53 Ω cm² per 200 h, respectively). In addition, according to energy dispersion spectrum (EDS) and tip enhanced Raman characterization, the enhanced Cr poisoning tolerance of composite cathode can also be verified through the alleviated SrCrO₄ formation and Cr deposition on LSCF cathode.