Impedance analysis of a disk-type SOFC using doped lanthanum gallate under power generation

Tohru Kato, Ken Nozaki, Akira Negishi, Ken Kato, Akihiko Monma, Yasuo Kaga, Susumu Nagata, Kiyonami Takano, Toru Inagaki, Hiroyuki Yoshida, Kei Hosoi, Koji Hoshino, Taner Akbay, Jun Akikusa

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Impedance measurements were carried out under practical power generation conditions in a disk-type SOFC, which may be utilized as a small-scale power generator. The tested cell was composed of doped lanthanum gallate (La 0.8Sr0.2Ga0.8Mg0.15Co 0.05O3-δ) as the electrolyte, Sm 0.5Sr0.5CoO3 as the cathode electrode and Ni/Ce0.8Sm0.2O2 cermet as the anode electrode. The cell impedance was measured between 10mHz and 10kHz by varying the fuel utilization and gas flow rate and plotted in complex impedance diagrams. The observed impedance shows a large semi-circular pattern on the low frequency side. The semi-circular impedance, having a noticeably low characteristic frequency between 0.13 and 0.4Hz, comes from the change in gas composition, originally caused by the cell reaction. The change in impedance with the fuel utilization (load current) and the gas flow rate agreed qualitatively well with the theoretical predictions from a simulation. This impedance was dominant under high fuel-utilization power-generation conditions. The impedance, which described the activation polarizations in the electrode reactions, was comparatively small and scarcely changed with the change in fuel utilization (load current) and gas flow rate.

Original languageEnglish
Pages (from-to)169-174
Number of pages6
JournalJournal of Power Sources
Issue number2
Publication statusPublished - Jun 4 2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering


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