REDUCED-TEMPERATURE SOLID OXIDE FUEL-CELL BASED ON YSZ THIN-FILM ELECTROLYTE

A planar thin-film solid oxide fuel cell has been fabricated with an i nexpensive, scalable, technique involving colloidal deposition of yttr ia-stabilized zirconia (YSZ) films on porous NiO-YSZ substrates, yield ing solid oxide fuel cells capable of exceptional power density at ope rating temperatures of 700 to 800 degrees C. The thickness of the YSZ film deposited onto the porous substrate is approximately 10 mu m afte r sintering, and is well bonded to the NiO/YSZ substrate. Ni-YSZ/YSZ/L SM cells built with this technique have exhibited theoretical open-cir cuit potentials (OCPs), high current densities, and exceptionally good power densities of over 1900 mW/cm(2) at 800 degrees C. Electrochemic al characterization of the cells indicates negligible losses across th e Ni-YSZ/YSZ interface and minor polarization of the fuel electrode. T hin-film cells have been tested for long periods of time (over 700 h) and have been thermally cycled from 650 to 800 degrees C while demonst rating excellent stability over time.