Microstructure control of cathode and cathode/electrolyte systems for intermediate-temperature SOFC

초록

In order to apply La0.6Sr0.4Co0.2Fe0.8O3-d (LSCF) as a cathode and scandia (Sc2O3)-stabilized zirconia (ScSZ) as an electrolyte for intermediate-temperature SOFCs, a gadolinium-doped ceria (GDC) buffer layer was inserted between the cathode and electrolyte. It was confirmed that the GDC buffer layer could prevent unfavorable solid-state reactions at the LSCF/ScSZ interfaces. The GDC buffer layer was deposited on the ScSZ electrolyte by two different methods; a screen-printing and a pulsed-laser deposition (PLD) process. The screen-printed GDC buffer layer showed a porous microstructure, while a dense GDC layer could be obtained by the PLD process. A porous LSCF cathode prepared on a thin and dense GDC buffer layer exhibited excellent electrocatalytic performance even at 600°C. The performance was enhanced further by dispersing GDC or Pt small particles into the LSCF cathode.