Improved electrodes/electrolyte interfaces for solid oxide fuel cell by using dual-sized powders in electrolyte slurry

The dense electrolyte film with the rough surfaces for solid oxide fuel cell (SOFC) was fabricated on NiO/yttria-stabilized zirconia (YSZ) anode substrate by using dual-sized YSZ powders without additional effort to roughen electrolyte film. The dual-sized YSZ powders consisted of the fine YSZ powder and the coarse YSZ powder at different weight ratios. Incorporation of the coarse YSZ powder into the fine YSZ powder is in order to increase the surface roughness of electrolyte film, and the surface roughness obviously increased with the increase of coarse YSZ powder. The rough surfaces resulted in an enlargement of the electrochemical active area. It was found that electrode polarization was reduced evidently and cell electrochemical performance was enhanced, as the surface roughness increased. However, the excessive coarse YSZ powder was not beneficial for densification of electrolyte film and thus the open-circuit voltage (OCV) was declined. The cell with 17 wt.% coarse YSZ powder in the electrolyte exhibited the best performance and the maximum power density was 1,930 mW cm^-2 at 800 °C.