Fabrication and characterization of functionally-graded LSCF cathodes by tape casting

Functionally graded cathodes for solid oxide fuel cells are prepared using a tape casting process. The microstructures of the cathodes are gradually changed from a finer LSCF layer with smaller grains (to increase the number of active sites for oxygen reduction) to a coarser LSCF layer with larger grains and higher porosity (for efficient current collection and fast gas transportation). The microstructure and electrochemical properties of the porous electrodes are characterized using scanning electron microscopy and electrochemical impedance spectroscopy, respectively. The cathodic polarization resistance of test cells with functionally-graded LSCF cathodes fired at 1050 °C is reduced to 0.075 Ω cm2 at 700 °C and 0.036 Ω cm2 at 750 °C, demonstrating peak power densities of 371.5, 744.6, and 1075.3 mW/cm2 at 700, 750, and 800 °C, respectively.