Preparation and performance of solid oxide fuel cells with YSZ/SDC bilayer electrolyte

YSZ (Y2O3-stabilized ZrO2)/SDC (Sm-doped CeO2) bilayer electrolyte film was successfully fabricated on NiO/YSZ anode substrate using stepwise sintering processing by screen-printing technique. OCVs (open-circuit voltages) of 1.06 V, 1.05 V and 0.88 V were achieved at 750 degrees C for single cells with bilayer electrolyte of 12 mu m-SDC/8 mu m-YSZ, 12 mu m-SDC/5 mu m-YSZ, and 12 mu m-SDC/2 mu m-YSZ, respectively. Interdiffusion of ions at YSZ/SDC interface and formation of YSZ SDC solid solution after sintering at 1400 degrees C for 2 h was investigated. The EDX result suggested that the region for the interdiffusion in a YSZ/SDC bilayer structure was 2.0 mu m from the YSZ/SDC interface into the YSZ layer for Sm and Ce, and 0.5 mu m into the SDC layer for Zr and Y. The YSZ SDC solid solution exhibited a low electrical conductivity, which negatively affected the performance of single cell. After two thermal cycles, the maximum power density of the single cell exhibited a significant decrease. The destruction of YSZ/SDC bilayer electrolyte structure was not observed during the thermal cycles. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.