Solid oxide fuel cells with bi-layered electrolyte structure

In this work, we have developed solid oxide fuel cells with a bi-layered electrolyte of 2 μm SSZ and 4 μm SDC using tape casting, screen printing, and co-firing processes. The cell reached power densities of 0.54 W cm−2 at 650 °C and 0.85 W cm−2 at 700 °C, with open circuit voltage (OCV) values larger than 1.02 V. The electrical leaking between anode and cathode through an SDC electrolyte has been blocked in the bi-layered electrolyte structure. However, both the electrolyte resistance (Rel) and electrode polarization resistance (Rp,a+c) increased in comparison to cells with single-layered SDC electrolytes. The formation of a solid solution of (Ce, Zr)O2−x during sintering process and the flaws in the bi-layered electrolyte structure seem to be the main causes for the increase in the Rel value (0.32 Ω cm2) at 650 °C, which is almost one order of magnitude higher than the calculated value.