In this study, the enhanced electrochemical performance of single layer fuel cells (SLFCs) based upon mixed ion and electron conductors is analyzed as a function of composition. We synthesize a series of Ce0.8Sm0.2O2-delta-Li0.3Ni0.6Cu0.07Sr0.03O2-delta (SDC-LNCS) with different weight ratios. The microstructure and morphology of the composite materials are characterized through X-ray diffraction (XRD), transmission electron microscope (TEM), and energy-dispersive X-ray spectrometer (EDS). Stability of the synthesized samples is evaluated by thermal gravity analysis (TGA). The SLFC with 6SDC-4LNCS exhibits a uniform distribution of the two compositions as well as demonstrates the highest power density of 312 mW cm-2 at 550 mu C. The performance is correlated to the balance of the conduction properties (ionic and electronic) of the functional SLFC layer. The results are a critical contribution to further development of this new energy transfer device. (C) 2014 Elsevier B.V. All rights reserved.