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 °C, 550 °C, 600 °C and 650 °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 °C exhibited a maximum power density of 63.3 mW/cm2 and an open circuit voltage of 1.14 V at an operating temperature of 650 °C. This study contributes to the development of SDCC electrolyte composite substrates for electrolyte-supported low-temperature SOFCs.