Evaluation of layered perovskites YBa1−xSrxCo2O5+δ as cathodes for intermediate-temperature solid oxide fuel cells
Langue
en
Article de revue
Ce document a été publié dans
International Journal of Hydrogen Energy. 2014, vol. 39, n° 9, p. 4531-4543
Elsevier
Résumé en anglais
This study is focused on the structural characteristics, oxygen nonstoichiometry, electrical conductivity, electrochemical performance and oxygen reduction mechanism of YBa1−xSrxCo2O5+δ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5). ...Lire la suite >
This study is focused on the structural characteristics, oxygen nonstoichiometry, electrical conductivity, electrochemical performance and oxygen reduction mechanism of YBa1−xSrxCo2O5+δ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5). The high oxygen nonstoichiometry, δ = 0.18-0.43 at 700 °C, indicates the large oxygen vacancy concentrations in oxides. The electrical conductivity is improved due to the greater amount of electronic holes originated from the increased interstitial oxygen, and the conductivities of all samples are above 100 S cm−1 at 400-700 °C in air. The results demonstrate the promising performance of YBa1−xSrxCo2O5+δ cathodes at intermediate temperatures, as evidenced by low area-specific resistances (ASRs) e.g. 0.21-0.59 Ω cm2 at 700 °C. The lowest ASR, 0.44 Ω cm2, and the cathodic overpotential, −40 mV at a current density of −136 mA cm−2, are obtained in YBaCo2O5+δ cathode at 650 °C. The dependence of polarization resistance on oxygen partial pressure suggests that the charge transfer process is the rate-limiting step for oxygen reduction reaction in YBaCo2O5+δ cathode.< Réduire
Mots clés en espagnol
Solid oxide fuel cell (SOFC)
Cathode material
Layered perovskite
Electrochemical performance
Origine
Importé de halUnités de recherche