High-performance Gd0.5Sr0.5CoO3−δ and Ce0.8Gd0.2O1.9 nanocomposite cathode for achieving high power density in solid oxide fuel cells

Abstract

High power density operation is essential for cost reduction in solid oxide fuel cells (SOFCs), and thus the present work proposes a highly active Gd0.5Sr0.5CoO3−δ (GSC) and Ce0.8Gd0.2O1.9 (GDC) nanocomposite cathode for intermediate-temperature SOFCs. Its nanocomposite structure is formed by using GSC-GDC nanocomposite particles synthesized via spray pyrolysis, which produces uniform-sized secondary particles consisting of nano-sized GSC and GDC crystallites. The resulting cathode has an extensive electrochemically active triple-phase boundary and has electrically conductive networks formed with highly dispersed GSC and GDC crystallites. In addition, the GSC-GDC nanocomposite cathode exhibits a performance comparable to a high-performance Sm0.5Sr0.5CoO3−δ and Ce0.8Sm0.2O1.9 nanocomposite cathode. An anode-supported SOFC with the GSC-GDC nanocomposite cathode achieves remarkably high power densities at 0.75 V, i.e., 3.66, 2.60, 1.66, and 0.98 W cm−2 at 800, 750, 700, and 650 °C, respectively. These results suggest the proposed nanocomposite cathode yields a synergistic effect of a high catalytic activity of GSC-GDC and a fine nanocomposite structure, leading to high power density operation of an SOFC.