Abstract: The composite electrolytes Ce0.8Sm0.2O1.9-BaCe0.8Sm0.2O2.9(SDC-BCS, molar ratio 9∶1, 7∶3, 5∶5 and 3∶7) were synthesized by one-step citric acid-nitrate gel combustion method.In this work, the effect of SDC-BCS composition on the conductivity and electrochemical performance were studied.The results indicate that grain size and electrical conductivity of SDC-BCS increase with increasing of SDC content in SDC-BCS.Compared to electrolyte SDC, the grain-boundary conductivity of composite electrolytes is much higher.The power density of the single cell NiO-SDC-BCS|SDC-BCS|LSCF-SDC-BCS which was prepared by composite electrolytes with different phase compositions increases with increasing SDC content.When the molar ratio of SDC∶ BCS gets 9∶1,the peak power density of the single cell is 550 mW/cm2 at temperature 700 ℃, which is 3 times higher than that of NiO-SDC|SDC|LSCF-SDC single cell.

Key words: The composite electrolytes Ce0.8Sm0.2O1.9-BaCe0.8Sm0.2O2.9(SDC-BCS, molar ratio 9∶1, 7∶3, 5∶5 and 3∶7) were synthesized by one-step citric acid-nitrate gel combustion method.In this work, the effect of SDC-BCS composition on the conductivity and electrochemical performance were studied.The results indicate that grain size and electrical conductivity of SDC-BCS increase with increasing of SDC content in SDC-BCS.Compared to electrolyte SDC, the grain-boundary conductivity of composite electrolytes is much higher.The power density of the single cell NiO-SDC-BCS, SDC-BCS, LSCF-SDC-BCS which was prepared by composite electrolytes with different phase compositions increases with increasing SDC content.When the molar ratio of SDC∶ BCS gets 9∶1,the peak power density of the single cell is 550 mW/cm2 at temperature 700 ℃, which is 3 times higher than that of NiO-SDC, SDC, LSCF-SDC single cell.