Enhanced Electrochemical Activity and Chromium Tolerance of the Nucleation-Agent-Free La2Ni0.9Fe0.1O4+δ Cathode by Gd0.1Ce0.9O1.95 Incorporation

For the sake of improving the electrochemical activity and chromium tolerance of the K 2 NiF 4 -type oxide, La 2 NiO 4+δ (LNO), with nonnucleation agents like Mn and Sr elements, the electrochemical performance and degradation were comparatively studied at two cathodes La 2 Ni 0.9 Fe 0.1 O 4+δ (LNF) and LNF-40wt%Gd 0.1 Ce 0.9 O 1.95 (LNF-GDC) on the GDC electrolyte, where 5wt%Cr 2 O 3 incorporation provides Cr-containing atmosphere. Compared with non-doped LNO, LNF shows a higher interstitial oxygen concentration (δ = 0.298) and a lower electrical conductivity, where bivalent Ni ion, Ni Ni × , and trivalent Ni ion, Ni Ni · , and trivalent Fe ion on Ni-site, Fe Ni · , were observed from the XPS measurements. LNF-GDC shows greatly reduced interfacial polarization resistances (Rp), which are only half of those of LNF, indicating a better electrochemical performance. More importantly, no significant degradation of LNF-GDC in performance has been observed under exposure of Cr-containing atmosphere at 700 °C for 350 h, while Rp of LNF increased by nearly 20%, suggesting LNF by GDC incorporation can enhance the electrochemical performance as well as chromium tolerance for intermediate temperature solid oxide fuel cells (IT-SOFCs).