Development of LaNiO_3-Ce_(0.9)Gd_(0.1)O_(1.95) Composite Cathode for Lowering the Operating Temperature of SOFCs

摘要

The electrochemical performance of LaNiO_3-Ce_(0.9)Gd_(0.1)O_(1.95) (GDC) composite cathode was evaluated by electrochemical impedance spectroscopy with the symmetric cells fabricated. The performance was improved by mixing GDC into LaNiO_3 due to increasing triple-phase boundary length per specific volume. Intriguingly, interfacial conductivity of LaNiO_3-GDC composite cathode heat treated for 1 hour at 1173 K was higher than that of the (La_(0.6)Sr_(0.4))_(0.99)CoO_3 cathode at around 773 K. heat treatment temperature was sensitive to both ohmic resistance and activation resistance. In the case of LaNiO_3-GDC composite cathode heat treated for 4 hours at 1273 K, a fluorite structure impurity is detected in the XRD pattern. We showed LaNiO_3-GDC composite cathode is a potential candidate for cathode material for IT-SOFCs operating at around 773 K.