In this study, novel SrCe1 - xYbxO3 (-) (alpha)(x = 0, 0.05, 0.10, 0.15)-(Na/K)Cl composite electrolytes were synthesized at low temperature (750 degrees C). The structural and microstructural properties of the composite electrolytes are observed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the upper doping limit of Yb3+ in SrCeO3 is 15 mol%. The XRD results shown that no chemical reactions take place between SrCe1 - xYbxO3 (-) (alpha) (x = 0, 0.05, 0.10, 0.15) and NaCl/KCl. The SEM images revealed that NaCl/KCl is coated on the surface of SrCe1 - xYbxO3 (-) (alpha) (x = 0, 0.05, 0.10, 0.15) act as a binder. The electrical conductivity is determined by impedance spectroscopy. The log sigma similar to log (pO(2)) plots results indicate that the composites are almost pure ionic conductors. Finally, the excellent performance of SCYb15-NK is obtained with a maximum power density of 615 mW.cm(-2) at 700 degrees C.