Enhanced sinterability and electrical performance of Sm2O3 doped CeO2/BaCeO3 electrolytes for intermediate-temperature solid oxide fuel cells through Bi2O3 co-doping

Abstract CeO2/BaCeO3 based electrolytes, one kind of the most promising electrolytes for intermediate-temperature solid oxide fuel cells, usually suffer from poor sinterability and poor electrical performance caused by high sintering temperatures. In this work, Sm2O3 doped CeO2/BaCeO3 electrolytes with Bi2O3 co-doping (90 wt% Ce0.8Sm0.1Bi0.1O2-δ-10 wt% BaCe0.8Sm0.1Bi0.1O3-δ, Bi-SDC-BCS) are developed, while Sm2O3 doped CeO2/BaCeO3 electrolytes without Bi2O3 co-doping (90 wt% Ce0.8Sm0.2O2-δ-10 wt% BaCe0.8Sm0.2O3-δ, BCS-SDC) are taken as a comparison. The electrolyte-supported cells with 75 wt% Ag-25 wt% Ce0.8Gd0.2O1.9 as electrodes are assembled and characterized. The results show that the Bi2O3 co-doping allows the sintering temperature to decrease from 1300 °C to 1100 °C, showing a significantly enhanced sinterability. The Bi-SDC-BCS electrolyte sintered at 1100 °C shows a high electrical conductivity (6.08 × 10−2 S cm−1 at 700 °C in wet air) and a long-term stability, superior to that for most existing electrolytes with the similar chemical constitution. The Bi-SDC-BCS electrolyte-supported single cell shows a peak power density of 352 mW cm−2 at 700 °C using humidified hydrogen as fuel and ambient air as oxidant, almost double of that for the BCS-SDC supported cells. Therefore, the Bi2O3 co-doping into CeO2/BaCeO3 based electrolytes provides a promising way for the development of high performance intermediate-temperature solid oxide fuel cells.