Self-assembled cubic-hexagonal perovskite nanocomposite as intermediate-temperature solid oxide fuel cell cathode

Self-assembly is an emerging strategy for preparing composite cathodes with good oxygen electrochemical reduction activity and congenital chemical compatibility for intermediate-temperature solid oxide fuel cell (IT-SOFC). Here we report that a self-assembled BaCo0.6Zr0.4O3-delta (BZC-BC) nanocomposite is prepared through one-pot glycine-nitrate process and exhibits high cathode performance. The BZC-BC nanocomposite is composed of 62 mol% cubic perovskite BaZY(0.82)Co(0.18)O(3-delta) (BZC) as an ionic conductor and 38 mol% hexagonal perovskite BaCo0.96Zr0.04O2.6+delta (12H-BC) as a mixed ionic and electronic conductor. The BZC-BC nanocomposite has the pomegranate-like particles aggregated with a larger number of nanoparticles (50-100 nm) which greatly enlarge the three-phase boundary sites. The BZC-BC nanocomposite exhibits a thermal expansion coefficient of 12.89 x 10(-6) K-1 well-matched with that of Ce0.8Gd0.2O3-delta (12.84 x 10(-6) K-1) electrolyte. The high electrocatalytic activity of BZC-BC nanocomposite cathode for oxygen reduction is reflected by the low polarization resistances of oxygen ions incorporation at cathode/electrolyte interface (0.02823 Omega cm(2)), oxygen species diffusion (0.03702 Omega cm(2)) and oxygen adsorptive dissociation (0.07609 Omega cm(2)) at 700 degrees C. The single cell with BZC-BC nanocomposite cathode achieves the maximum power density of 1094 mW cm(-2) at 650 degrees C and shows good stability under 25 h run.