Proton and Oxygen Ionic Conductivity of Doped Ceria-Carbonate Composite by Modified Wagner Polarization

• The impressive ionic conductivity and tunable conduction behaviors have made the ceria-carbonate composite an attractive electrolyte for low temperature ceramic fuel cells. However, the conduction mechanism is not yet well studied. In the present study, both proton and oxygen ion conductivity as well as the transport properties of samaria-doped ceria/ sodium-lithium-carbonate (denoted as SDCLN) composite are investigated by the fuel cell study and the modified Hebb-Wagner polarization measurements. The multi-ionic polarization behaviors and the transfer processes in composite electrolyte under external electrical field are analyzed. A maximum power density of 780 mW cm(-2) and a calculated total ion (proton and oxygen ion) conductivity of 0.153 S cm(-1) are obtained under H-2/air condition at 550 degrees C. The Wagner DC polarization measurements show that the proton conduction dominates the total ionic conductivity. A synergistic effect exists between the charge carriers in the doped ceria-carbonate composite system. An ideal interfacial conduction model is also proposed based on the obtained results.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Keyword

Solid oxide or ceramic fuel cell

Ceria-carbonate composite electrolyte

Proton and oxygen ion conductivity

Wager polarization

Synergistic effect

Publication and Content Type

ref (subject category)

art (subject category)