To improve cathode-electrolyte interfaces of solid oxide fuel cells (SOFCs), dense YSZ electrolyte membranes with indented surfaces were fabricated on tubular NiO/YSZ anode supports by two comparable methods. Electrochemistry impedance spectroscopy (EIS) and current-voltage tests of the cells were carried out to characterize the cathode-electrolyte interfaces. Results showed that the electrode polarization resistances of the modified cells were reduced by 52% and 35% at 700 degrees C, and the maximum power densities of cells were remarkably increased, even by 146.6% and 117.8% at lower temperature (700 degrees C), respectively. The indented surfaces extended the active zone of cathode and enhanced interfacial adhesion, which led to the major improvement in the cell performance. (c) 2007 Elsevier B.V. All rights reserved.