Influence of Humidity and Carbon Dioxide on the (La_(0.6)Sr_(0.4))_(0.99)Co_(1-x)M_xO_(3-δ) (M = Nb, Ti) Oxygen Electrode Characteristics

摘要

Cathode material, (La_(0.6)Sr_(0.4))_(0.99)CoO_(3-δ), is highly active for oxygen reduction process in SOFC applications. Humidity and CO_2 content in the cathode compartment increase the degradation rate of the cathode. Substituting Nb and Ti into (La_(0.6)Sr_(0.4))_(0.99)CoO_(3-δ) B-site has an effect on the chemical stability of this material. Synthesized (La_(0.6)Sr_0._4)_(0.99)CoO_(3-δ), (La_(0.6)Sr_(0.4))_(0.99)Co_(1-x)Nb_xO_(3-δ) and (La_(0.6)Sr_(0.4))_(0.99)Co_(1-x)Ti_xO_(3-δ) powders with different stoichiometry were analyzed with thermogravimetric analysis (TGA) and with X-ray diffraction method (XRD). The results obtained indicate that doping of (La_(0.6)Sr_(0.4))_(0.99)CoO_(3-δ) B-site with Nb and Ti make these materials more resilient to form unwanted compounds on the cathode surface.