Effects of pore formers on microstructure and performance of cathode membranes for solid oxide fuel cells

La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) is the most widely used cathode material for intermediate temperature solid oxide fuel cells. In the present communication, porous LSCF cathodes are fabricated by tape casting, a low-cost and reproducible fabrication process. The effects of four different pore formers, namely, graphite, carbon black, rice starch, and corn starch, on the microstructure and electrochemical performance of the LSCF cathode are investigated. Examination of the microstructures reveals that the shape of the pores, the pore size, and the pore distribution in the final ceramic are related to the type of pore formers. Impedance analysis and cell testing show that the best performance is obtained from the cathode using graphite as the pore former. The microstructure indicates that graphite results in a porous LSCF cathode with a large surface area and high porosity, which can offer a considerably long triple phase boundary for catalytic reactions as well as channels for gas phase transport.

► LSCF cathodes are fabricated by tape casting method. ► The type of pore formers has significant effect on the LSCF cathode microstructures. ► Graphite gave a porous cathode with large surface area and high porosity. ► The best electrochemical performance is obtained from the LSCF cathode using graphite as pore formers.