Electrochemical performances of single component fuel cells (SCFCs) based on mixed ion and electron conductors have been studied as a function of composition and pellet thickness by polarization curves and electrochemical impedance spectroscopy. The electronic conductor of LNCZO shows conductivities of 21.7 and 5.3 S cm(-1) in H-2 and in air, respectively. SCFC using 40 wt. % of LNCZO and 60 wt. % of ion conductive SDC-Na2CO3 with a thickness of 1.10 mm shows the highest power density of 0.35 W cm(-2) at 550 degrees C. The performance is correlated to the mixed conduction properties (ionic and electronic, p and n-type) and the microstructure of the functional SCFC layer. (C) 2012 Elsevier B.V. All rights reserved.