Tailoring the pore structure of cathode supports for improving the electrochemical performance of solid oxide fuel cells

Two types of lanthanum doped strontium manganite (LSM)-yttria-stabilized zirconia (YSZ) composite cathodes were prepared, one with the finger-like straight open pores by the phase inversion tape casting, and the other with the randomly distributed tortuous pores by the conventional tape casting. A gas permeation flux of 42.5 x 10(5) Lm(-2) h(-1) was measured under a trans-membrane pressure of 0.6 bar for the former while only 10.6 x 10(5) Lm(-2) h(-1) for the latter. Fuel cells supported on the as-prepared LSM-YSZ composite cathodes were fabricated, comprising a 15 mu m thick YSZ electrolyte layer and a 20 mu m thick NiO-YSZ anode. The electrochemical performance of the fuel cells was measured using H-2 as fuels and air as oxidants. The cell supported on the phase-inversion derived cathode showed a maximum power density of 362 mWcm(-2) at 850 A degrees C, while only 149 mWcm(-2) for the cell supported on the cathode formed by the conventional method. The difference in the electrochemical performance between the two cells can be attributed to the pore structure of the cathode supports. It is concluded that the phase inversion tape casting provides a simple and effective approach for tailoring the pore structure of the cathode support and thus enhancing the electrochemical performance.