Stable, easily sintered Ca-Zn-doped YCrO3 as novel interconnect materials for co-fired yttrium-stabilized zirconia-based solid oxide fuel cells

Abstract

In order to develop co-fired yttrium-stabilized zirconia (YSZ)-based solid oxide fuel cells (SOFCs), stable and easily sintered Y0.7Ca0.3Cr1-xZnxO3- δ (x = 0-0.15) perovskite oxides were synthesized by the microwave-aided sol-gel process and then examined as novel ceramic interconnect materials. (The characterizations focused on phase structure, sintering behavior, relative density, electrical conductivity and thermal expansion.) The XRD analysis indicates that a pure orthorhombic perovskite phase was obtained for all the samples. Cell volume decreases as x increases from 0 to 0.10. The Y0.7Ca0.3Cr0.9Zn0.1O 3-δ (YCCZ10) powder exhibited the best sintering ability, and a relative density of 96.6% could be obtained for the sample sintered at 1400 °C for 4 h in air. The electrical conductivities of the specimens increase with the Zn2+ content at x ≤ 0.10, but then remarkably decrease at x = 0.15, which might relate to the over-range of the substitution amount of Zn (0.15) for Cr position. YCCZ10 shows a remarkable electrical conductivity of 20.9 S cm-1 at 850 °C in air, and a very suitable thermal expansion coefficient value of 10.8 × 10-6 K-1 (YSZ: ∼10.8 × 10-6 K-1). These investigations have indicated that YCCZ10 is a promising interconnect material for co-fired YSZ-based SOFCs. © 2008 Elsevier B.V. All rights reserved.