Improved sintering behavior and electrical performance of Ce0.8Sm0.2O2-δ - BaZr0.1Ce0.7Y0.2O3-δ (SDC -BZCY) composite electrolytes with the addition of iron (III) oxide for IT-SOFCs

Abstract

Ce0.8Sm0.2O2-δ-BaZr0.1Ce0.7Y0.2O3-δ (SDC-BZCY), one of the promising electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFCs), often suffers from its high sintering temperature. In this study, SDC-BZCY (weight ratio 50:50) electrolytes with addition of x wt.% Fe2O3 (x = 0, 0.5, 1.0, 1.5 and 2.0), named as SDC-BZCY-xFe, were fabricated. The effect of Fe2O3 addition on sintering and electrical properties were investigated. The results show that Fe2O3 makes the sintering temperature of SDC-BZCY effectively decrease from 1500 °C to 1400 °C. The SDC-BZCY-1.5Fe electrolyte achieves the highest conductivity of 8.06 × 10−3 S cm−1 at 700 °C, 3 times higher than that of pure SDC-BZCY (1.78 × 10−3 S cm−1). With humidified hydrogen (20 ml min−1) as the fuel and static air (40 ml min−1) as the oxidant, the SDC-BZCY-1.5Fe electrolyte-supported single cell shows much higher OCV values (0.87 V at 600 °C, 0.85 V at 700 °C, 0.80 V at 800 °C) than pure SDC, and obtain the peak power density of 133 mW cm−2 at 800 °C.