Highly functional nano-scale stabilized bismuth oxides via reverse strike co-precipitation for solid oxide fuel cells

Abstract

Nano-scale erbia stabilized bismuth oxides (ESBs) were successfully synthesized by a wet chemical reverse strike co-precipitation. Due to homogenous, molecular level mixing, the desired cubic fluorite structure was formed at a dramatically reduced temperature of 500 degrees C, which was confirmed by X-ray diffraction and Raman spectroscopy. Moreover, this low calcine temperature led to nano-scale ESB powders with a crystallite size of similar to 20 nm and a specific surface area of similar to 13.2 m(2) g(-1). Due to the high surface area, the nano-sized ESB powders show high functionality for solid oxide fuel cell (SOFC) applications. As an SOFC electrolyte, the high sinterability of the co-precipitated ESB was demonstrated, achieving over 98% density after sintering at only 750 degrees C for 30 min. Moreover, the total conductivity of the sample was identical to that obtained by conventional methods after sintering at 890 degrees C (for 16 h), regardless of the different grain boundary densities. In addition, the co-precipitated ESB was used in a composite cathode with lanthanum strontium manganite (LSM), achieving significantly reduced cathodic ASRs, 0.55 and 0.03 Omega cm(2), at 550 and 700 degrees C by extending triple phase boundary (TPB) lengths in the cathode bulk and at the cathode-electrolyte interface.