Synthesis of dispersed PrBaCo0.9Cu0.1O5+δ cathode nanopowders with layered perovskite structure for intermediate temperature solid oxide fuel cells

Abstract

PrBaCo1.9Cu0.1O5+δ (PBCCO) nanopowders were synthesized by an EDTA-citrate complexing process using water and ethanol as solvents, and their structures and electrochemical properties were characterized. PBCCO precursor gels were highly oxidized at 450°C, using either water (PBCCO-W) or ethanol (PBCCO-E) as the solvent. PBCCO powders calcined at 450°C had a second phase, while those calcined at 850°C for 4h were obtained as single phase PBCCO with a layered perovskite structure in the P4mm space group. PBCCO-E primary particles were approximately 5–10nm in size and were well-dispersed compared with those of the PBCCO-W powder. We hypothesized that the enhanced dispersibility of the PBCCO-E powder was caused by a decrease in bridging hydrogen bonds on the chelate surface, which prevents chelate agglomeration in sol state. It causes the larger specific surface area of PBCCO-E powders and thus a lower polarization resistance (Rp) than that of PBCCO-W powders at the measured temperature. The Rp value of PBCCO-E powder was 0.041Ωcm2 at 750°C, which is about 1.5times lower than that of PBCCO-W at the same temperature.