The effects of electrode and electrolyte materials used in single-chamber micro solid oxide fuel cells (SC-mu SOFCs) with coplanar electrodes on the cell performance have been little investigated so far. In this study, different combinations of conventional SOFC materials such as NiO-YSZ (ZrO2 doped with 8 mol% Y2O3) and NiO-GDC (Ce0.9Gd0.1O1.95) anodes as well as (La0.8Sr0.2)(0.98)MnO3 (LSM)-YSZ and (La0.6Sr0.4)(0.995)(Fe0.8Co0.2)O-3 (LSCF) cathodes in the form of coplanar interdigitated electrode patterns on YSZ electrolytes were compared at 700 degrees C in methane-air mixtures with a methane-to-oxygen ratio of R-mix = 2. The best cell performance was obtained for coplanar NiO-YSZ anodes combined with LSM-YSZ cathodes, whereas the NiO-GDC//YSZ//LSCF cell delivered the lowest power output Chemical interaction between LSM-YSZ cathodes and adjacent anodes during sintering was identified to cause blackening of the anode parts in close vicinity to the cathode, and manganese was detected in the anode, probably through diffusion from the LSM cathode into the anode. In addition to cell performance, the proper choice of electrode materials for coplanar electrodes appears to be important because of the possible chemical interactions between the closely-spaced electrodes. (C) 2010 Elsevier B.V. All rights reserved.