Enhanced anti-chromium poisoning ability of high entropy La0.2Nd0.2Sm0.2Sr0.2Ba0.2Co0.2Fe0.8O3-δ cathodes for solid oxide fuel cells

The instability of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF6428) for Cr-containing atmospheres limits its utilization in the cathode of solid oxide fuel cells (SOFCs). High entropy La0.2Nd0.2Sm0.2Sr0.2Ba0.2Co0.2Fe0.8O3-delta (HE-LSCF) is presented as a potential Cr-resistant cathode in this paper. At a test temperature of 750 degrees C, the polarization resistance (R-p) of the cathode of HE-LSCF is 0.53 Omega cm(2) after 40 h of Cr-treatment, which is comparable with the original value without Cr-treatment (0.50 Omega cm(2) at 750 degrees C), and significantly lower than LSCF6428 cathodes with the same Cr-treatment condition (3.11 Omega cm(2) at 750 degrees C), suggesting an excellent ability of anti-chromium poisoning. Raman and DFT simulation results verify that the high-entropy structure effectively suppresses the segregation of SrO and prevents Cr vapor from reacting with the segregated SrO to form SrCrO4 due to the higher segregation energy (1.38 eV) and lower desorption energy (-2.55 eV) of HE-LSCF. The anode-supported single cell of NiO-SDC/SDC/HE-LSCF shows a peak power density of 556 mW cm(-2) at 700 degrees C with wet H-2 (with similar to 3 vol% H2O) fuels and ambient air oxidants, and maintains a stable cell performance after the Cr-treatment (537 mW cm(-2)).