Electrochemical characterization of Pr2CuO4-Ce0.9Gd0.1O1.95 composite cathodes for solid oxide fuel cells

Pr2CuO4-Ce0.9Gd0.1O1.95 (PCO-GDC) composites screen printed on Ce0.9Gd0.1O1.95 (GDC) electrolyte were considered as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). Phase composition, microstructure and electrochemical properties were investigated by X-ray powder diffraction (XRD), scanning electron microscopy and AC impedance spectroscopy, respectively. The oxygen reduction on porous PCO-GDC electrode applied on CGO electrolyte was studied in a symmetrical cell configuration by AC impedance spectroscopy at OCV conditions at 670-730 °C and pO2=10-2-0.21atm. The charge transfer process and the dissociation of adsorbed molecular oxygen were found to be rate-determining steps of the oxygen reduction reaction. Results reveal that both GDC addition and electrode morphology have strong influence on area specific resistance (ASR) of the electrode/electrolyte interface. The lowest ASR value of 0.41 Ω cm2 was achieved for the composition containing 33 wt.% GDC at 700 °С in air. The data obtained allow to consider the PCO-GDC33 composite as a promising cathode material for IT-SOFCs.