Advanced electrochemical properties of Pr0.9Y0.1BaCo1.8Ni0.2O6–δ – Ce0.8Sm0.2O1.9 composite as cathode material for IT–SOFCs

The co-doped double perovskite-type cobaltite Pr0.9Y0.1BaCo1.8Ni0.2O6–δ (PYBCN) is synthesized via organo-metallic precursors. The concentrations of electronic and ionic defects in PYBCN at variations of gaseous environment are obtained from the analysis of the experimental isothermal plots for equi...

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Bibliographic Details
Published in:Journal of alloys and compounds 2019-03, Vol.779, p.712-719
Main Authors: Marshenya, S.N., Politov, B.V., Osinkin, D.A., Suntsov, A.Yu, Leonidov, I.A., Kozhevnikov, V.L.
Format: Article
Language:English
Subjects:
Activation energy
Cathodes
Cerium oxides
Chemical activity
Cobaltites
Double perovskites
Electrochemical analysis
Electrode materials
Electronic states
Ion transport
IT-SOFC cathodes
Organic chemistry
Oxygen content
Oxygen ions
Partial pressure
Perovskites
Point defects
Samarium
SDC composite
Solid oxide fuel cells
Thermal expansion
Vacancies
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Summary:The co-doped double perovskite-type cobaltite Pr0.9Y0.1BaCo1.8Ni0.2O6–δ (PYBCN) is synthesized via organo-metallic precursors. The concentrations of electronic and ionic defects in PYBCN at variations of gaseous environment are obtained from the analysis of the experimental isothermal plots for equilibrium oxygen content (6 – δ) vs. oxygen partial pressure pO2 in the ambient gaseous phase. It is argued that nickel doping is beneficial for enhanced formation of vacancies in O2– positions controlling oxygen ion transport in the cobaltite. The cobaltite based dual-phase composite with 30 wt% addition of samarium doped ceria Ce0.8Sm0.2O1.9 (SDC) is found to have considerably reduced thermal expansion compared to the parent cobaltite. The impedance measurements show that the area specific resistance (ASR) of the composite decreases to 0.11 Ω cm2 at 973 K with the activation energy 1.2 eV. Further increase of the temperature is accompanied by the decline of the activation energy to 0.9 eV, and ASR attains 0.045 Ω cm2 at 1073 K. The observed small ASRs are attributed to a large concentration of O2–vacancies in the cobaltite component of the composite. The cathodic overvoltage for oxygen reduction that does not exceed 40 mV at 1073 K and current density 1000 mA cm−2, moderate thermal expansion, good conductivity and high electro-chemical activity distinguish the developed composite as one of the promising cathode materials for intermediate temperature solid oxide fuel cell applications. •Sol-gel process was used to obtain Pr0.9Y0.1BaCo1.8Ni0.2O6-δ (PYBCN).•Composite cathode was manufactured by adding 30 wt% of Ce0.8Sm0.2O1.9 to PYBCN.•Cathode performance was shown to correlate with oxygen vacancy content in PYBCN.•The composite cathode exhibited extremely low ASR and overvoltage values.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2018.11.255