Development of Novel Fe-Doped Barium Calcium Niobates as Promising Mixed Conductors for Solid Oxide Fuel Cells (SOFCs)

Synthesis, structural analysis, chemical stabilities and electrochemical measurements of a new Fe-doped barium calcium niobates (Fe-BCNs) family as promising mixed conductors for SOFCs were reported. The Fe-BCNs, prepared by conventional solid state method, exhibited as single phases which can be indexed as Fm-3m (space group no. 225) structure with cell parameter a ~ 8.4 Aå by PXRD and SAED. The Fe-BCNs showed superior chemical stability in pure CO2 gas at 800oC for 24 h, boiling H2O for 72 h, 30 ppm H2S at 600oC for 24 h and pure CH4 gas at 600oC for 12 h, confirmed by PXRD. The highest total conductivity of 1.3 × 10-2 Scm-1 (Ea~0.5eV) was found for Ba2Ca0.787Fe0.566Nb0.646O6-δ at 400oC in air.