Applicability of Gd_0.9Ca_0.1AlO_3-δ Ceramic Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells

Abstract:

In this paper, the applicability of Gd0.9Ca0.1AlO3-δ (GCAO) oxygen-ion conductor as ceramic electrolyte for intermediate temperature solid oxide fuel cells (SOFCs) was systematically investigated. XRD and TGA results demonstrate that GCAO material is in possession of sufficient structural stability from low to high temperature, desirable chemical stability against humidified reducing atmosphere and fine high-temperature thermal stability in air. Thermal shrinkage research during high temperature sintering shows that complete sintering of pressed green GCAO disk is around 1500 oC and the corresponding thermal expansion coefficient of sintered GCAO is 9.2×10-6 K-1 from room temperature to 1000 oC. In addition, total conductivity of GCAO ranges from 0.00073 to 0.0081 S•cm-1 in air as function of temperature increasing from 600 to 800 oC where the corresponding activation energy is determined as 96.19 KJ•mol-1. A 2-mm-thick electrolyte-supported single fuel cell was prepared with La0.8Sr0.2TiO3-δ/Ce0.8Gd0.2O2-δ and La0.8Sr0.2MnO3-δ/Ce0.8Gd0.2O2-δ as anode and cathode, and tested at 800 oC with humidified hydrogen and static air as fuel and oxidizer, respectively. The OCV reaches as high as 1.1 V which prove the pure oxygen-ion conduction of GCAO; and the corresponding maximum output and electrode polarization resistance reach 42 mW/cm2 and 0.15 Ώcm2, respectively. In summary, GCAO could be a possible electrolyte candidate for intermediate temperature SOFCs.

• Periodical: Advanced Materials Research (Volumes 476-478)
• Pages: 1785-1789
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.476-478.1785
• Online since: February 2012
• Authors: Gui Hua Liu, Fang Wang, Rui Qiang Yan
• Keywords: Conductivity, GdAlO₃, Sintering, Solid Oxide Fuel Cell (SOFC), Stability

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