Effects of Sintering Temperature on the Electrical Performance of Ce0.8Sm0.2O1.9–Pr2NiO4 Composite Electrolyte for SOFCs

Abstract

Novel composite electrolyte Sm0.2Ce0.8O1.9–Pr2NiO4 (SDC–PNO) for solid oxide fuel cells (SOFCs) was prepared. The effects of sintering temperature on the performance of SDC–PNO composite electrolyte were studied. X-ray diffraction (XRD) analysis confirms that the composite samples sintering at different temperatures contain two pure phases corresponding to SDC and PNO, respectively. It indicates that there is no interfacial reaction between Sm0.2Ce0.8O1.9 and Pr2NiO4, and the composite electrolyte keeps regular grain boundaries after long-term operation. The results of scanning electron microscopy (SEM) show that a dense structure can be formed after sintering at 1250 °C. The electrical properties were tested in air by electrochemical impedance spectroscopy technique in the temperature range of 400–800 °C. Results show that an appropriate increase of the sintering temperature can effectively increase the conductivity of SDC–PNO composite electrolyte, and the maximum conductivity of 0.102 S/cm can be obtained in the sample sintered at 1250 °C and tested at 800 °C. In summary, the electrical conductivity of Sm0.2Ce0.8O1.9 can be significantly increased by adding Pr2NiO4, and SDC–PNO composite electrolyte is a promising electrolyte for solid oxide fuel cells.