Influence of sintering temperature on the power density of samarium-doped-ceria carbonate electrolyte composites for low-temperature solid oxide fuel cells

The effects of sintering temperature on the current-voltage (I-V) performance of symmetrical cells with an SDCC electrolyte composite were evaluated in this study. The SDCC electrolyte composite was prepared by mixing 80 wt% SDC with 20 wt% Li and Na carbonate (Li/Na ratio of 2/1) via a solid state reaction method. The resultant SDCC electrolyte composite powder was uniaxially pressed into a circular pellet and sintered at 500 degrees C, 550 degrees C, 600 degrees C and 650 degrees C for 5 h. A symmetrical cell was finally fabricated by painting a conductive silver paste on both sides of the dense SDCC electrolyte composite pellet, and its I-V performance was measured using hydrogen and air as the fuel and oxidant, respectively. The phase structure and microstructure of the composite powders were investigated using an X-ray diffractometer, field emission scanning electron microscope, and transmission electron microscope. Ceramic pellets sintered at 550 degrees C exhibited a maximum power density of 63.3 mW/cm(2) and an open circuit voltage of 1.14 V at an operating temperature of 650 degrees C. This study contributes to the development of SDCC electrolyte composite substrates for electrolyte-supported low-temperature SOFCs. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.