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<p>Electrochemical activity of composite (100-x) wt% Ba<sub>0.5</sub>Sr<sub>0.5</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3-δ</sub>–x wt% Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> (x = 10, 20, 30, 40) electrodes in contact with the BaCe<sub>0.7</sub>Zr<sub>0.1</sub>Y<sub>0.1</sub>Yb<sub>0.1</sub>O<sub>3-δ</sub> proton-conducting electrolyte has been studied by impedance spectroscopy depending on temperature, oxygen partial pressure, and the presence of H<sub>2</sub>O/D<sub>2</sub>O in the atmosphere. An H/D isotope effect in the electrode response has been observed for all the investigated conditions, resulting in an increase in polarization resistance in a D<sub>2</sub>O-containing atmosphere. The distribution of relaxation times reveals that the electrode reaction mechanism is similar for all the investigated electrode compositions, with two main rate-determining processes being highlighted. The main contribution to electrode polarization gives the low-frequency stage. Based on the dependencies of the partial resistances on the oxygen partial pressure and the substitution of H<sub>2</sub>O by D<sub>2</sub>O, the processes were assigned to oxygen reduction and water formation at the triple-phase boundary. The increase in proton conduction in the electrode is a possible way to improve the electrode performance.</p>

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Revealing the Oxygen Reduction Kinetics on Ba0.5Sr0.5Co0.8Fe0.2O3-δ–Ce0.8Sm0.2O1.9 Composites as Cathodes for H+ Solid Oxide Fuel Cells

  • 期刊论文

  • 发表日期：

    2025年9月30日

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  • K. A. Fedorova,
  • E. V. Gordeev,
  • O. E. Seliverstova,
  • E. P. Antonova

摘要

Electrochemical activity of composite (100-x) wt% Ba0.5Sr0.5Co0.8Fe0.2O3-δ–x wt% Ce0.8Sm0.2O1.9 (x = 10, 20, 30, 40) electrodes in contact with the BaCe0.7Zr0.1Y0.1Yb0.1O3-δ proton-conducting electrolyte has been studied by impedance spectroscopy depending on temperature, oxygen partial pressure, and the presence of H2O/D2O in the atmosphere. An H/D isotope effect in the electrode response has been observed for all the investigated conditions, resulting in an increase in polarization resistance in a D2O-containing atmosphere. The distribution of relaxation times reveals that the electrode reaction mechanism is similar for all the investigated electrode compositions, with two main rate-determining processes being highlighted. The main contribution to electrode polarization gives the low-frequency stage. Based on the dependencies of the partial resistances on the oxygen partial pressure and the substitution of H2O by D2O, the processes were assigned to oxygen reduction and water formation at the triple-phase boundary. The increase in proton conduction in the electrode is a possible way to improve the electrode performance.